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Learjet 20 Series Pilot Training Manual

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FlightSafety
international
LEARJET 20 SERIES
PILOT TRAINING
MANUAL
VOLUME 2
AIRCRAFT SYSTEMS
SECOND EDITION
FlightSafety International, Inc.
Marine Air Terminal, LaGuardia Airport
Flushing, New York 11371
(718) 565-4100
www.flightsafety.com

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  • Page 1 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL VOLUME 2 AIRCRAFT SYSTEMS SECOND EDITION FlightSafety International, Inc. Marine Air Terminal, LaGuardia Airport Flushing, New York 11371 (718) 565-4100 www.flightsafety.com...
  • Page 2 Courses for the Learjet 20 and other Learjet aircraft are taught at the following FlightSafety learning centers: Wichita Learning Center Two Learjet Way Wichita, KS 67209 (800) 491-9807 Fax: (316) 943-0314 Tucson Learning Center 1071 E. Aero Park Blvd. Tucson, AZ 85706...
  • Page 3 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL INSERT LATEST REVISED PAGES, DESTROY SUPERSEDED PAGES LIST OF EFFECTIVE PAGES Dates of issue for original and changed pages are: Second Edition ..0 ..April 2005 Revision....01... July 2005 NOTE:...
  • Page 4 F O R T R A I N I N G P U R P O S E S O N LY NOTICE The material contained in this training manual is based on information obtained from the aircraft manufacturer’s pilot manuals and maintenance manuals. It is to be used for famil- iarization and training purposes only.
  • Page 5 CONTENTS Chapter 1 AIRCRAFT GENERAL Chapter 2 ELECTRICAL POWER SYSTEMS Chapter 2A ELECTRICAL POWER SYSTEMS Chapter 3 LIGHTING Chapter 4 MASTER WARNING SYSTEM Chapter 5 FUEL SYSTEM Chapter 5A FUEL SYSTEM Chapter 6 AUXILIARY POWER UNIT Chapter 7 POWERPLANT Chapter 8 FIRE PROTECTION Chapter 9 PNEUMATICS...

  • Page 6: Table Of Contents

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 1 AIRCRAFT GENERAL CONTENTS Page INTRODUCTION ........................1-1 GENERAL..........................1-1 STRUCTURES ........................1-2 General ..........................1-2 Fuselage ........................... 1-7 Wing..........................1-15 Empennage........................1-15 AIRPLANE SYSTEMS ......................1-16 Electrical Power systems ....................1-16 Lighting..........................
  • Page 7 Passenger Windows (Typical) ................1-13 1-14 Tailcone Entry Door ....................1-13 1-15 Wing ........................1-14 1-16 Empennage......................1-15 1-17 Static Wicks (Typical) .................... 1-18 TABLE Table Title Page Learjet 20 Series Models and Serialization.............. 1-2 FOR TRAINING PURPOSES ONLY 1-iii...

  • Page 8: Introduction

    This training manual provides a description of the major airframe and engine systems installed in the Learjet 20 series airplanes. The information contained herein is intended only as an instructional aid. This material does not supersede, nor is it meant to substi- tute for, any of the manufacturer’s maintenance or operating manuals.

  • Page 9: Structures

    The discussion for reference. on the fuselage includes the doors and windows. General dimensions are shown in Figure 1-2. Figure 1-1. Learjet 25 Table 1-1. LEARJET 20 SERIES MODELS AND SERIALIZATION EARLY LATE MODEL SERIAL BLOCK...

  • Page 10: Airplane Dimensions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL MODELS 23 AND 24 12 FT 3 IN. 41 FT 43 FT 3 IN. 14 FT 8 IN. ALL MODELS 8 FT 3 IN. 34 FT 1 IN. 35 FT 7 IN.

  • Page 11: Airplane Turning Radii

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL MODELS MODEL 23 AND 24 27 FT 10 IN. 31 FT 3 IN. 34 FT 4 IN. 37 FT 6 IN. 31 FT 11 IN. 35 FT 1 IN. NOTE: THE VALUES SHOWN REFLECT NORMAL NOSEWHEEL STEERING.

  • Page 12: Danger Areas

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figures 1-3 and 1-4 show the airplane turning radii and the danger areas from the weather radar and engine intakes and exhausts. 40 FT 150°F WEATHER 30 FT RADAR OPERATING 12 FT 45°...
  • Page 13 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY...

  • Page 14: Fuselage

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUSELAGE General The fuselage is constructed of stressed all- m e t a l s k i n w i t h t r a n s v e r s e f r a m e s a n d stringers.

  • Page 15: Cockpit Layout (Typical)

    To check the function of the reel, tug sharply on A typical seating arrangement in a Learjet is the strap. The reel should lock under this test two crew seats, four reclinable adjustable pas- and prevent the strap from extending.

  • Page 16: Cabin Interior (Typical)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 1-8. Cabin Interior (Typical) Passenger-Crew Door door is 36 inches wide, but an optional 24-inch The primary entrance and exit for passengers and crewmembers is through the clamshell door is available. The upper door serves as an...

  • Page 17: Door Locking Pin Hole

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The upper portion of the door has both outside NOTE and inside locking handles connected to a One hook is used on 24-inch doors, common shaft through the door. Rotating ei- while two hooks are used on 36- ther of these handles to the closed position inch doors.
  • Page 18 Emergency Exit NOTE A hatch near the right rear of the cabin serves as an emergency exit on all Learjet 20 models Anytime the airplane is occupied (Figure 1-11). with the entry doors locked, the hooks must be released.
  • Page 19 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The method of opening the hatch from the ex- Windshield—All 24 and 25 Models terior varies with airplane model: The windshield is divided into two sections— the pilot’s and copilot’s halves—and consists •...

  • Page 20: Passenger Windows (Typical)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Fuel Section The fuselage fuel section is located immedi- ately aft of the rear pressure bulkhead. (See Figure 1-5.) The fuel section is located as follows: • Frames 22 to 24: Models 23, 24, 24B, D, F, and 24E, when installed •...
  • Page 21 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 1-15. Wing FOR TRAINING PURPOSES ONLY 1-14...

  • Page 22: Wing

    The Learjet 20 wing is fitted with either vor- tanks containing 40 gallons of fuel per side. tex generators or boundary layer energizers.

  • Page 23: Airplane Systems

    FUEL SYSTEM The following is a brief introduction to the Fuel is contained in integral wing tanks, tip major airplane systems on the Learjet 20 se- tanks, and in a bladder fuselage tank just aft ries airplanes. Detailed descriptions of these...
  • Page 24 Each main gear has dual wheels, each equipped cohol to both the pilot and copilot windshields with multiple-disc brakes. Hydraulic braking and not to the radome. The Learjet 23 does not is controlled from either the pilot’s or copilot’s have an alcohol system.

  • Page 25: Static Wicks (Typical)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PITOT-STATIC SYSTEM OXYGEN SYSTEM There are two heated tubes installed—one on The oxygen system consists of the crew and each side of the nose compartment. passenger distribution systems connected to a high-pressure oxygen storage cylinder lo- There are five static ports—two on the pilot’s...
  • Page 26 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 2 ELECTRICAL POWER SYSTEMS CONTENTS Page INTRODUCTION ........................2-1 GENERAL..........................2-1 DC POWER..........................2-2 Batteries ........................... 2-2 Optional Emergency Battery System................2-4 Generators and Regulators....................2-6 Ground Power ........................2-7 Circuit Components ......................2-8 Distribution ........................

  • Page 27: Figure Title Page

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page Battery Installation ....................2-2 Battery Switch and DC Voltmeter................2-3 Battery Switches....................... 2-3 Emergency Battery No. 1 Switch and Schematic ............ 2-5 Generator Cooling Scoop..................2-6 Generator Switches ....................2-7 DC Ammeters......................

  • Page 28: Introduction

    This chapter covers the electrical power systems for SNs 24-230 through 24-357, 25-061, and 25-070 through 25-373. DC electrical power on the Lear 20 series airplanes is provided by two engine-driven starter generators. Backup DC electrical power is supplied by two batteries. A ground power receptacle allows connection of the ground power unit.

  • Page 29: Dc Power

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DC POWER through SN 25-235. Lead-acid batteries may be installed on these airplanes with ECR 1663. Lead-acid batteries are standard equipment BATTERIES on SNs 24-356 and subsequent, and 25-236 and subsequent. Nickel-cadmium batteries are Two batteries (Figure 2-1), located in the tail- optional.
  • Page 30 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Battery Overheat Warning— Nicad Batteries Only There are two red battery overheat lights (Appendix B), one labeled “BAT 140” and the other “BAT 160.” The BAT 140 light indicates that either or both batteries have reached 140°F.

  • Page 31: Nose Section

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL battery is connected to the battery bus and Operation—Airplanes Equipped battery charging bus. Individual battery volt- with a Single Emergency age may be read by turning on the respective Battery battery switch if no other power source is con- nected to the battery charging bus.
  • Page 32 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY...

  • Page 33: Generators And Regulators

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL GENERATORS AND due to temperature. Each regulator is set to 28.5 ±0.3 VDC. REGULATORS Should generator output exceed 32 VDC, a Generators circuit within the voltage regulator completes a ground circuit and reduces generator output Two independent, engine-driven DC genera- to zero.
  • Page 34 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 2-6. Generator Switches Figure 2-7. DC Ammeters GROUND POWER A ground power unit (GPU) can be connected to the airplane through a power receptacle (Figure 2-8) located on the left side of the air- plane adjacent to the tailcone door.
  • Page 35 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CIRCUIT COMPONENTS Overload Sensors The DC overload sensors are located in the tail- Current Limiters cone. An overload control sensor consists of a 70-ampere thermal circuit breaker mechan- A current limiter panel is installed on the gen- ically connected to a set of switch contacts.
  • Page 36 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL L IGN L ESS ST-GEN L AIR L STALL AUD 1 L MAIN L FIRE DOOR ACTR COMM 1 L FIRE L AC NAV 1 L FW ADF 1 L JET DME 1...
  • Page 37 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AC BUS R ESS R AIR R STALL WARN AUD 2 BUS TIE R FIRE MAIN COMM 2 BUS TIE EMER R FIRE BAT 2 EMER NAV 2 BAT 1 R FW...
  • Page 38 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DISTRIBUTION Battery Charging Bus The battery charging bus is located in the cur- A multiple bus, multiple conductor system is rent-limiter panel in the tailcone. It distributes used (Figures 2-11 and 2-12). Buses and major...
  • Page 39 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PRIMARY SECONDARY INVERTER INVERTER INVERTER START-GEN START-GEN MAIN BUS MAIN BUS 50 A 60 A L ESS R ESS 20 A 60 A 70 A 70 A 60 A FREON SYS STAB HEAT...
  • Page 40 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PRIMARY SECONDARY INVERTER INVERTER INVERTER START-GEN START-GEN MAIN BUS MAIN BUS 50 A 60 A L ESS R ESS 20 A 60 A 70 A 70 A 60 A FREON SYS STAB HEAT...
  • Page 41 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AC POWER INVERTERS Alternating current for the AC electrical instru- ments and electronic equipment is provided by two or three 1,000-VA solid-state static invert- ers located in the tailcone. Figure 2-13 illustrates the typical inverter system.
  • Page 42 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DISTRIBUTION reducing the voltage to 26 VAC. The 26 VAC is then distributed to the installed equipment Alternating current from the inverters is dis- requiring 26 VAC. tributed through the left and right AC buses.
  • Page 43 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS 1. The systems powered directly from the 5. The maximum voltage (red line) value battery bus with the airplane battery on the DC voltmeter is: switches in OFF are: A. 24 VDC A.
  • Page 44 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 10. The number, rating, and type inverters 13. The inverters for your particular airplane for your airplane are: are located: A. Two, 750 VA, rotary A. In the nose compartment B. Three, 400 VA, solid-state B.
  • Page 45 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 2A ELECTRICAL POWER SYSTEMS CONTENTS Page INTRODUCTION ........................ 2A-1 GENERAL..........................2A-1 DC POWER .......................... 2A-2 Batteries......................... 2A-2 Generators ........................2A-4 Circuit Components ...................... 2A-5 Distribution ......................... 2A-14 Ground Power ......................2A-17 AC POWER........................
  • Page 46 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 2A-1 Battery Installation ....................2A-2 2A-2 Battery Switch ....................... 2A-3 2A-3 Electrical Indicators....................2A-3 2A-4 Generator Switches....................2A-4 2A-5 Circuit-Breaker Panels—Model 23 ............... 2A-6 2A-6 Tail Compartment Circuit-Breaker Panel—Model 23 .......... 2A-6 2A-7 Circuit-Breaker Panels—SNs 24-100 through 24-129 .........

  • Page 47: Introduction

    This chapter covers the electrical power systems for SNs 23-003 through 24-229 and 25- 003 through 25-064, excluding 25-061. DC electrical power on the Learjet 20 series airplanes is provided by two engine-driven starter-generators. Backup DC electrical power is supplied by two batteries. A ground receptacle allows connection of the ground power unit.

  • Page 48: Dc Power

    28 ±0.5 volts/1,000 amperes maximum. nickel-cadmium (nicad) batteries are certi- • Voltage and battery temperature must fied for use in 20 series Learjets. They are be continuously monitored. rated at 24 VDC and vary in amperage de- pending on size.
  • Page 49 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Charging lead-acid batteries in the airplane is single DC voltmeter indicates the voltage on not recommended because of poor GPU out- the battery charging bus from the highest volt- put regulation, but if absolutely necessary, age input (batteries, generator, or GPU).

  • Page 50: Generators

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL GENERATORS to the voltage regulator, a circuit for power to the Freon system compressor motor, and a cir- Two engine-driven starter-generators, one on cuit for the voltage regulator equalizer bus. each engine, provide the primary source of airplane DC power.
  • Page 51 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Reverse Current Diodes— current limiter is like a slow-blow fuse; once a current limiter has blown, it must be re- SNs 24-190 through 24-229, and placed. Current limiters are used to provide...

  • Page 52: Tail Compartment Circuit-Breaker Panel-Model 23

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL BLANK CABIN RADAR AFCS DAMPER PRIMARY PUMP DUMP COMM AUDIO LH STANDBY OUTER VOLTAGE RH STANDBY FUEL PUMP LOCKOUT FUEL PUMP SECONDARY CARD POINTER COMM AUDIO EMERGENCY DOOR FREON CABIN LEFT RIGHT...

  • Page 53: Circuit-Breaker Panels-Sns 24-100 Through 24-129

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL STEER COPILOT GYROS PRIMARY BUS TIE COMM AUDIO 115 VAC PRI RADAR VERT AFCS GYRO O SECONDARY CARD POINTER COMM AUDIO 115 VAC SEC NOSE CABIN VERT STEER PRESS VOLTMETER EMERG MKR BCN AIR IGN TURN &...

  • Page 54: Circuit-Breaker Panels-Sns 24-130 Through 24-169

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LEFT & PRIMARY RIGHT & SECONDARY AUDIO COMM COMM AUDIO 115 VAC 26 VAC PILOT’S PILOT’S RADAR AFCS NOSE CABIN VOLT VERT DIRECT GYRO O STEER PRESS METER PRESS MKR BCN TURN...
  • Page 55 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LEFT & PRIMARY RIGHT & SECONDARY AUDIO COMM COMM AUDIO MKR BCN TURN AFCS WARN WARN TAB & FLAP TURN & BANK DAMPER LIGHTS LIGHTS POSITION & BANK FIRE FIREWALL ENG FIRE...

  • Page 56: Circuit-Breaker Panels-Sns 25-003 Through 25-010

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL BAT BUS EMER TRIM TAB CABIN PITCH DUMP AIRPLANE SN 25-003 ONLY TRIM PITCH ROLL STALL WARN SPOILER GEAR FLAPS AIRPLANES SNs 25-004 AIRPLANE SN 25-010 ONLY THROUGH 25-009 LEFT & PRIMARY RIGHT &...

  • Page 57: Circuit-Breaker Panels-Sns 25-011 Through 25-024

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AIRPLANES SNs 25-011 THROUGH 25-024 LEFT & PRIMARY RIGHT & SECONDARY 115 VAC 26 VAC PILOT’S PILOT’S RADAR AFCS NOSE CABIN VOLT VERT DIRECT GYRO O STEER PRESS AUDIO COMM COMM AUDIO...

  • Page 58: Circuit-Breaker Panels-Sns 24-181 Through

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LEFT & PRIMARY RIGHT & SECONDARY LEFT & PRIMARY RIGHT & SECONDARY AUDIO COMM COMM AUDIO AUDIO COMM COMM AUDIO MKR BCN MKR BCN TURN AFCS WARN WARN TAB & FLAP TURN...

  • Page 59: Circuit-Breaker Panels-Sns 24-200 And Subsequent, And 25-035 And Subsequent

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AUDIO COMM COMM AUDIO 115 VAC 26 VAC PILOT’S PILOT’S RADAR AFCS NOSE CABIN VOLT VERT DIRECT GYRO O STEER PRESS METER PRESS STAB HEAT COPILOT COPILOT RADAR AFCS TONE VOLT VERT...

  • Page 60: Dc Power Distribution-Sns 23-003 Through

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DISTRIBUTION • Left stall warning (all models) • Right stall warning (all models) The power distribution system functions as a single system, but it is really separate systems in- • Cabin door motor (all models) terconnected by a series of current limiters and •...

  • Page 61: Dc Power Distribution-Sns 24-190 Through 24-229

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL • Right standby fuel pump (23 models Battery Bus without jet pumps) SNs 23-003 through 24-189, and • Freon and cabin fan systems (SNs 23- 25-003 through 25-029 002 through 23-069) The battery bus is connected directly to the •...
  • Page 62 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL SNs 24-190 through 24-229, Generator Buses 25-030 through 25-064 except 25-061 The left and right generator buses are in the The battery bus may be powered by external current limiter panel in the tailcone. The gen- power if the voltage from the GPU is 33 ±2...

  • Page 63: External Power Receptacle

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL GROUND POWER The overvoltage circuit prevents the GPU from powering the airplane electrical system if GPU The external power receptacle (Figure 2A-16) voltage exceeds 33 ±2 volts. GPU capability is located immediately forward of the tail com-...
  • Page 64 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL SNs 24-130 through 24-229, and CONTROLS 25-003 through 25-064 SNs 23-003 through 24-129 Three JET solid-state static inverters located One three-position MAIN–OFF–STANDBY in the tail compartment provide 115-VAC and inverter switch is located on the switch panel.

  • Page 65: Ac Power Distribution-Sns 24-130 Through

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PRI VOLTMETER AC SWITCHING TO INDICATOR PILOT VERT LIGHT PILOT DIRECT 115 VAC RADAR GYRO DC PWR 115 VAC AFCS L GEN BUS NOSE STEER INVERTER CABIN PRESS 26 VAC INVERTER POWER...

  • Page 66: And 25-003 Through 25-024

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL INDICATORS Stepdown Transformers The stepdown transformers, located on the On SNs 24-130 through 24-229, and 25-003 forward side of frame 28, reduce a portion of through 25-064, three amber inverter warning the 115 VAC to 26 VAC. The 26 VAC is used...

  • Page 67: Auxiliary Battery System-Sns 24-100 Through 24-129

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL EMERGENCY MODES EMERGENCY BATTERY SYSTEM In emergency operation, three different modes of inverter operation are possible: (1) With a An emergency battery is probably installed primary inverter failure, the standby inverter, in most model 23 airplanes. SNs 24-100...
  • Page 68 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The battery may be used to power the following: VDC from the emergency battery is applied to the pilot’s audio panel, ADF, extra transceiver, • Emergency attitude gyro and post light nosewheel steering relay, wheel master switch, and trim systems (including the self-contained •...
  • Page 69 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL GEAR FEEDER BUS FLAPS INPUT SPOILERS AUX COMM 25 VDC 28 VDC ATTITUDE GYRO BATTERY EMERGENCY 25-VDC INPUT BATTERY C/B INPUT POWER 115-VAC OUTPUT INTERNAL LIGHTS 4.6-VAC OUTPUT INSTRUMENT LIGHTS Figure 2A-21.
  • Page 70 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS The voltage and amperage rating of the Generator current flow in amperes is engine-driven generator is: measured from the: A. 24 VDC and 400 amperes A. Battery charging bus B. 28.5 VDC and 300 amperes B.
  • Page 71 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 3 LIGHTING CONTENTS Page INTRODUCTION ........................3-1 GENERAL..........................3-1 INTERIOR LIGHTING ......................3-2 Cockpit Lighting ......................3-2 Cabin Lighting ......................... 3-3 Emergency Lighting......................3-4 EXTERIOR LIGHTING ......................3-4 General ..........................3-4 Landing–Taxi Lights ......................
  • Page 72 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page Cockpit Lighting Controls..................3-2 Map Lights (Typical)....................3-2 Overhead Lights Control (Typical) ................3-3 Advisory Lights and Control..................3-3 Emergency Lights Switch ..................3-4 Exterior Lighting Locations ..................3-5 Exterior Lighting Switches ..................

  • Page 73: Introduction

    EXIT INTRODUCTION Airplane lighting for the Lear 20 series airplanes is divided into interior, exterior, and emergency (if installed) lighting packages. Interior lighting provides illumination of both the cockpit and cabin areas under normal conditions. The cockpit area is provided with general illumination and specific lighting for instruments and map reading.

  • Page 74: Interior Lighting

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL INTERIOR LIGHTING The pilot’s controls on the left side, and the copilot’s, on the right side of the cockpit, control separate sections of the floodlights. COCKPIT LIGHTING The lights are powered through the INSTR LT circuit breakers.

  • Page 75: Cabin Lighting

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CABIN LIGHTING by a switch on the pedestal. In addition to en- ergizing the lights, the control switch applies 28 VDC to the tone generator, which produces General an audible tone through the aft cabin speaker.

  • Page 76: Emergency Exit

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL EMERGENCY LIGHTING the cabin overhead lights. Setting the switch to ARM will arm the system to illuminate the emergency lights in the event of a failure of General normal DC electrical power. With power on the...
  • Page 77 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ANTICOLLISION LIGHT WING INSPECTION LIGHT NAVIGATION LIGHT STROBE LIGHT STROBE LIGHT LANDING-TAXI LIGHTS NAVIGATION LIGHT RECOGNITION LIGHT ANTICOLLISION LIGHT STROBE LIGHT NAVIGATION LIGHT Figure 3-6. Exterior Lighting Locations FOR TRAINING PURPOSES ONLY...

  • Page 78: Landing-Taxi Lights

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LANDING–TAXI LIGHTS The landing light system consists of one 450- watt lamp mounted on each main landing gear strut (Figure 3-8), one 20-amp current limiter for each side, relays, dimming resistors, and the L and R LDG LT switches.

  • Page 79: Recognition Lights (Not Installed On All Airplanes)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL power circuits between the respective gener- STROBE LIGHTS ator bus and lamp filament. The strobe light system consists of one strobe On SNs 23-003 through 23-084, 24-140 and light mounted inside each wingtip navigation...

  • Page 80: Anticollision Lights

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ANTICOLLISION LIGHTS of the emergency exit window. This light is de- signed to illuminate the leading edge of the Anticollision lights are installed on top of the right wing. The light may be installed as part vertical stabilizer and on the bottom of the of the emergency lighting system.

  • Page 81: Questions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS The instrument panel floodlight control The lights that are illuminated by the is located: emergency lighting system are the: A. Just forward of the warning panel A. Instrument panel floodlights B. On the pilot’s side panel B.
  • Page 82 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 4 MASTER WARNING SYSTEM CONTENTS Page INTRODUCTION ........................4-1 GENERAL..........................4-1 GLARESHIELD WARNING LIGHTS................... 4-2 TEST FUNCTION........................4-2 INTENSITY CONTROL......................4-2 BULB CHANGE ........................4-2 ILLUMINATION CAUSES ....................4-2 QUESTIONS ........................... 4-5...
  • Page 83 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATION Figure Title Page Test Switch ....................... 4-2 TABLE Table Title Page Annunciator Illumination Causes................4-3 FOR TRAINING PURPOSES ONLY 4-iii...
  • Page 84 TEST INTRODUCTION The glareshield warning lights for the Lear 20 series provide a warning for airplane equip- ment malfunctions, an indication of an unsafe operation condition requiring immediate attention, or an indication that a system is in operation. Airplanes prior to 24-156 and 25-010 did not originally have glareshield warning lights, but they may have been retrofitted.
  • Page 85 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL GLARESHIELD • Air ignition lights • All fuel panel lights WARNING LIGHTS • Pitot heat indicator lights (if installed) The red and amber lights illuminate when a • T/O TRIM and OVSPD lights (if in-...
  • Page 86 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table 4-1. ANNUNCIATOR ILLUMINATION CAUSES Annunciator Cause for Illumination Annunciator Cause for Illumination There is less than .25 psi of fuel Either nacelle inlet temperature is L. FUEL PRESS INLET HTR pressure to the indicated engine.
  • Page 87 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table 4-1. ANNUNCIATOR ILLUMINATION CAUSES (Cont) Annunciator Cause for Illumination Annunciator Cause for Illumination LOW HYD—Hydraulic system The pitot heat switch is off. PITOT HEAT FUEL pressure is less than 1,200 psi.
  • Page 88 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS All glareshield lights can be tested by: The glareshield annunciator light intensity is adjusted: A. Individual system testing A. Automatically by a photoelectric cell B. Depressing each individual capsule B. By depressing the test switch C.
  • Page 89 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 5 FUEL SYSTEM CONTENTS Page INTRODUCTION ........................5-1 GENERAL..........................5-1 FUEL TANKS AND TANK VENTING SYSTEM ..............5-3 General ..........................5-3 Tip Tanks.......................... 5-3 Wing Tanks ........................5-3 Fuselage Tank ........................5-3 Ram-Air Vent System ......................
  • Page 90 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL TRANSFER SYSTEM....................5-11 Crossflow Valve ......................5-11 Transfer Valve/Xfer–Fill Switch (Normal Transfer Line) ..........5-11 Fuselage Valve/Fus Valve Switch (Gravity-Flow Line) ..........5-12 Float and Pressure Switches ..................5-12 Fuselage Fuel Fill-Transfer Operations ................. 5-13 TIP TANK FUEL JETTISON SYSTEM (OPTIONAL) ............
  • Page 91 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page Fuel System ......................5-2 Ram-Air Vent and Vent Sump Drain (Typical) ............5-4 Fuel Vent System...................... 5-5 Fuel Control Panels ....................5-6 Fuel Flow Indicators....................5-7 Jet Pump Schematic ....................5-8 Fuel Drain Locations....................

  • Page 92: Introduction

    FUEL LBS X 100 INTRODUCTION The Learjet fuel system consists of the fuel tanks, tank venting, indicating, distribution, transfer, and jettison systems. This chapter covers the operation of the fuel system up to the engine-driven fuel pumps. At that point, fuel system operation becomes a function of the engine. Refer to Chapter 7, “Powerplant,”...

  • Page 93: Wing

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CROSSFLOW VALVE SUMP MODELS 24D, E, F, AND 25B, D WING PRESS SW EMPTY LIGHT PRESSURE TRANSFER SWITCH VALVE TRANSFER FUEL JETTISON LINE SHUTOFF VALVE FUSELAGE LOW FUEL PRESSURE SWITCH TANK (NOT INSTALLED...

  • Page 94: Fuel Tanks And Tank Venting System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL TANKS AND TANK WING TANKS VENTING SYSTEM Each wing tank extends from the airplane cen- terline to the tip tank and holds 1,160 pounds of usable fuel. Areas which are not part of the...

  • Page 95: Ram-Air Vent System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL RAM-AIR VENT SYSTEM tank when the vent float valves are closed.The pressure-relief valves are set at 1.0 and 1.5 psi, A NASA ram-air scoop located on the under- the second valve providing a backup in case side of each wing (Figure 5-2) supplies posi- the first valve fails.
  • Page 96 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL VACUUM RELIEF FLOAT VALVE 1.5-PSI RELIEF VALVE 1.0-PSI RELIEF FUEL VACUUM- VALVE VENT RELIEF DRAIN VALVE OVERBOARD DRAIN TO AMBIENT FLAME ARRESTER RAM-AIR SCOOP VACUUM RELIEF PRESSURE RELIEF WING VENT FLOAT VALVE (TYPICAL) Figure 5-3.
  • Page 97 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 24D/F MODELS MODEL 24E FUEL FUEL QUANTITY QUANTITY 0 0 0 0 0 0 0 0 LBS 1000 LBS 1000 JET PUMPS JET PUMPS R WING R WING R WING STANDBY PUMPS...

  • Page 98: Fuel Flow Indicating System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NOTE If the left inboard compensator probe becomes dry, it will cause erroneous fuel quantity indications at all switch positions. Each probe uses an electrical capacitance meas- uring system to sense the fuel level. It then trans- mits an electrical signal to the cockpit indicator where it is read as pounds x 1,000 on the dial.

  • Page 99: Fuel Distribution

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL four-digit readout (in pounds of fuel consumed pump in each wing adjacent to the jet pump and by both engines) and uses DC power. It should one transfer pump in the fuselage tank.

  • Page 100: Filters

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL which causes the jet pumps to function. The NOTE fuel is routed through the motive-flow control If a jet pump indicator light remains valves (one on each side) to the jet pumps,...

  • Page 101: Pressure-Relief Valves

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL engine. The probable cause is failure of the af- when the engines are shut down by venting fuel fected wing jet pump. overboard. Two one-way pressure-relief valves are lo- NOTE cated at wing rib 0.0, which separates the left The engine-driven pump is capable and right wing fuel tanks.

  • Page 102: Fuel Transfer System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NOTE divert pressure being delivered to the affected engine-driven pump by the operating standby Models 24D, E, and F have one fuse- pump on that side. Asymmetric power set- lage drain valve; models 25B and D tings may be used to balance fuel, if necessary.

  • Page 103: Fuselage Valve/Fus Valve Switch (Gravity-Flow Line)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUSELAGE VALVE/FUS VALVE be avoided because it will cause both fuselage transfer lines and the cross- SWITCH (GRAVITY-FLOW LINE) flow line to be open and the fuselage pump to be energized. The result of...

  • Page 104: Fuselage Fuel Fill-Transfer Operations

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Wing Fuel Pressure Switch • The fuselage transfer pump is energized. • T h e w h i t e E M P T Y l i g h t ( p r e s s u r e A wing fuel pressure switch is installed to switch) is enabled.

  • Page 105: Tip Tank Fuel Jettison System (Optional)

    JETTISON SYSTEM solution and subsequently freeze. The anti- icing additive specified for use in the Learjet (OPTIONAL) 20 series must conform to MIL-I-27686. It also prevents the growth of microbiological or- A DC motor-driven valve in the tailcone of ganisms in the fuel.
  • Page 106 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 5-8. Airplane Grounding Points BLENDER HOSE FUEL ADDITIVE TRIGGER RING HANDLE FUEL NOZZLE Figure 5-9. Anti-icing Blending Apparatus FOR TRAINING PURPOSES ONLY 5-15...
  • Page 107 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL APPROVED FUELS • Do not take off with fuel temperature lower than –54ºC (–65ºF). The “Limitations” section of the approved • Restrict airplane flights to below 15,000 AFM lists specific manufacturer’s fuels ap- feet.
  • Page 108 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ANTI-ICING ADDITIVE CAUTION Any approved fuels not containing the addi- On models 25C and D with the FUS tive must have it blended during refueling. VALVE switch, do not set the FUS Prior to refueling, check with the fuel supplier VALVE switch to OPEN.
  • Page 109 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL If either wing tank is below 600 pounds, limit If the crossflow valve fails to open, fuselage prolonged pitch attitude to 10° nose up. fuel gravity-flow into the right wing tank (left tank on 25C airplanes).
  • Page 110 LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Approximately 23 gallons of fuel in the The crossflow valve opens: 20 series is trapped. This fuel weight: A. Only when the CROSS FLOW A. Must be added to the weight of fuel switch is set to OPEN taken on board when servicing the B.
  • Page 111 D. All the above should be turned on B. That both fuel filters are bypassing 13. The Learjet 20 series requires anti-icing fuel; the light does not illuminate if additive: only one filter is bypassing A.
  • Page 112 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 5A FUEL SYSTEM CONTENTS Page INTRODUCTION ........................ 5A-1 GENERAL..........................5A-1 FUEL TANKS AND TANK VENTING SYSTEM.............. 5A-5 Tip Tanks........................5A-5 Wing Tanks........................5A-5 Fuselage Tank........................ 5A-5 Ram-Air Vent System ....................5A-5 FUEL INDICATING SYSTEMS ..................
  • Page 113 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Fuselage Fuel Transfer....................5A-12 Float, Pressure, and Temperature Switches ..............5A-12 Fuselage Fuel Fill Operation..................5A-13 Tip Tank Fuel Jettison System (Optional) ..............5A-13 FUEL SERVICING ......................5A-14 General........................5A-14 Safety Precautions....................... 5A-14 Approved Fuels and Fuel Density Adjustments ............
  • Page 114 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 5A-1 Fuel System—SNs 23-003 through 23-069 ............5A-2 5A-2 Fuel System —SNs 23-070 through 23-099 ............5A-3 5A-3 Fuel System—24, 24B, and 25 Models..............5A-4 5A-4 Fuel Vent System....................5A-6 5A-5 Fuel Control Panels ....................

  • Page 115: Introduction

    FUEL LBS X 100 INTRODUCTION The Learjet 20 series fuel system consists of the fuel tanks, tank venting, indicating, distribution, and transfer systems. This chapter covers Learjet 23-003 through 24-229, and 25-003 through 25-063. Major differences, where applicable, will be described by serial number.
  • Page 116 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL QUANTITY GAGE FUEL TIP TANK EMPTY LIGHT-LH EMPTY TANK CROSSFLOW VALVE CROSS FLOW LH WING TANK FIREWALL SHUTOFF MAIN FUEL REFUEL SHUTOFF VALVE-LH LINE EMPTY FUEL FUEL BYPASS FILTER TRANSFER REFUEL VALVE...
  • Page 117 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL failure has occurred. Four or five motorized e n g i n e m a i n fi r ew a l l s h u t o ff va l ve a n d...
  • Page 118 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL STANDBY PUMP START START LOW FUEL CROSSFLOW VALVE FUEL FILLER OPEN CLOSE CROSSFLOW TANK LH WING TANK XFER EMPTY FILL TRANSFER FUEL VALVE (OPTIONAL) FILTER FUEL FILTER FUEL SHUTOFF VALVE-LH FIRE L FUEL PRESS...

  • Page 119: Fuel Tanks And Tank Venting System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL TANKS AND TANK NOTE The 23 models without jet pumps VENTING SYSTEM have two electric fuel pumps in each wing tank. All other Learjets have TIP TANKS one electric standby pump and one jet pump in each wing tank.

  • Page 120: Fuel Indicating Systems

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL VACUUM-RELIEF VALVE FORWARD SUMP ASSEMBLY PRESSURE-RELIEF VALVES CHECK VALVE CHECK VALVE AFT SUMP ASSEMBLY RAM-AIR MAST OVERBOARD VENT LINE Figure 5A-4. Fuel Vent System Two vent drain valves are located at the fuel on the fuel control panel (Figure 5A-5).
  • Page 121 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL MAIN CROSS MAIN STDBY STDBY FLOW LH ENG RH ENG FUEL FUEL EMPTY EMPTY FULL EMPTY 23 MODEL (EARLY) L WING R WING 1092 1092 FUEL L TIP R TIP QUANTITY 1196...

  • Page 122: Fuel Flow Indicating System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL There are seven resistance (SNs 23-003 through Learjets SNs 23-015 through 23-089 use 115 024) or capacitance fuel quantity probes in- VAC for the fuel quantity indicating system. stalled. One fuel probe is located in each tip All other Learjets use 28 VDC.

  • Page 123: Fuel Distribution

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL DISTRIBUTION pump in the fuselage tank directs fuel for- ward to the wing tanks. GENERAL NOTE O n a i r p l a n e s w i t h e l e c t r i c f u e l...

  • Page 124: Filters And Pressure Switches

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Motive-flow pressure varies with engine rpm. FILTERS AND Consequently, jet pump discharge pressure PRESSURE SWITCHES also varies with engine rpm. At idle, discharge pressure is approximately 10 psi, while at full- A fuel filter is installed in each engine feed power settings, discharge pressure is approx- line.

  • Page 125: Pressure-Relief Valves

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL when fuel pressure drops below 0.25 psi. The The valves relieve pressure buildup caused by light extinguishes when pressure increases thermal expansion of trapped fuel when the en- above 1.0 psi. Illumination of a FUEL PRES gines are shut down by venting fuel overboard.

  • Page 126: Fuel Transfer System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL TRANSFER To prevent overpressurization of the wing tanks and the tip tanks, the fuel quantity in the tip SYSTEM tanks must be decreased before fuel transfer. On model 23 airplanes not incorporating jet...

  • Page 127: Fuselage Fuel Fill Operation

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL On airplanes SNs 23-070 through 23-099, 24, tank and the fuselage tank. The fuselage 24B, and 25 models, when the float switch de- refuel valve is controlled by the FUS FILL tects a full fuselage tank, the transfer and cross- switch (see Figure 5A-1).

  • Page 128: Fuel Servicing

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL SERVICING APPROVED FUELS AND FUEL DENSITY ADJUSTMENTS GENERAL Approved Fuels Fuel servicing includes those procedures neces- Refer to Section I of the AFM for a listing of sary for refueling and adding anti-icing additive.

  • Page 129: Aviation Gasoline

    ANTI-ICING ADDITIVE Anti-icing additive conforming to MIL-I- Either of two types of fuel control units may 27686 must be added to all fuels for Learjet be installed on the engines. The fuel control operations. The additive concentration shall density adjustment knobs are different on each be a minimum of .06% to a maximum of .15%...

  • Page 130: Refueling

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL REFUELING fill both tip tanks simultaneously or alternately add 125 gallons (472.3 liters) of fuel to each tip tank until the Gravity Refueling d e s i r e d a m o u n t i s o b t a i n e d . O n...

  • Page 131: Jet Fuel

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL With the LOW FUEL warning light illumi- nated, limit pitch attitude to the minimum required for go-around. Maximum fuel in tip to begin transfer is 760 pounds for model 25, and 800 pounds for mod- els 23, 24, and 24B.

  • Page 132: Questions

    LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Approximately 23 gallons of fuel in the The wing standby pumps are used for 20 series models is trapped. This fuel all of the following functions except: weight: A. Engine start A. Must be added to the weight of the B.
  • Page 133 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL When the XFER–FILL switch is placed 12. The Learjet 20 series airplanes require to the FILL position, the: anti-icing additive: A. Float switch is disabled. A. At all times B. Wing standby pumps are disabled.
  • Page 134 This information normally contained in this chapter is not applicable to this particular airplane.
  • Page 135 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 7 POWERPLANT CONTENTS Page INTRODUCTION ........................7-1 GENERAL..........................7-1 Engine Parameters......................7-2 ENGINE ..........................7-2 General ..........................7-2 Major Sections ......................... 7-2 Engine Nacelles ....................... 7-7 Operating Principles......................7-8 ENGINE SYSTEMS ....................... 7-8 General ..........................
  • Page 136 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Engine RPM........................7-17 Fuel Flow ........................7-17 Oil Pressure........................7-17 Oil Temperature ......................7-17 ENGINE STARTING ......................7-17 ENGINE SYNCHRONIZING ....................7-17 Woodward Electronic Synchronizer (Optional) ............7-17 Synchroscope (Optional) ....................7-18 THRUST REVERSERS (OPTIONAL) ................
  • Page 137 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page CJ610 Engine (Typical) Major Sections and Gas Flow........... 7-3 Front Frame Section....................7-2 Compressor Section....................7-4 Mainframe Section ....................7-5 Combustion Section ....................7-6 Turbine Section ......................7-7 Oil Servicing Access ....................

  • Page 138: Introduction

    CHAPTER 7 POWERPLANT INTRODUCTION This chapter describes the powerplant installed on Learjet 20 series airplanes. In addi- tion to the powerplant, the chapter describes such engine-related systems as oil, fuel, ignition, engine controls and instrumentation, engine synchronization, and the Dee Howard thrust reversers.

  • Page 139: Engine Parameters

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ENGINE PARAMETERS 1. Front frame 2. Compressor 1. Model......General Electric CJ610-1—2,850 pounds thrust 3. Mainframe General Electric CJ610-4—2,850 pounds thrust 4. Combustion General Electric CJ610-6—2,950 pounds thrust 5. Turbine General Electric CJ610-8A—2,950 6.
  • Page 140 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL TURBINE EXHAUST SECTION SECTION FRONT FRAME COMPRESSOR MAIN COMBUSTION SECTION SECTION FRAME SECTION SECTION LEGEND AMBIENT AIR COMPRESSOR AIR COMBUSTION AIR EXHAUST ACCESSORIES SECTION Figure 7-1. CJ610 Engine (Typical) Major Sections and Gas Flow are positioned by the variable geometry actu- The No.
  • Page 141 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL STATOR VANE STATOR CASING SPACER CARBON SEAL RUNNER ROTOR BLADE NO. 2 BEARING INNER RACE BALANCE FORWARD HALF WASHER OIL SLINGER CARBON SEAL RUNNER COMPRESSOR DRIVE SHAFT AIR DUCT 8TH-STAGE AIR SEAL...
  • Page 142 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The mainframe has inner and outer casing seal air leakage pressure level. A two-piece bands joined by six hollow struts. Each strut fuel manifold is mounted around the main- ends in a pad on the outer casing band. These...
  • Page 143 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Combustion The inner combustion casing is one piece. At the front, it is bolted to the inner casing of the main- The combustion section (Figure 7-5) is that frame, at the rear, to the No. 3 bearing support.

  • Page 144: Engine Nacelles

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The first-stage turbine nozzle has an outer The major components of the turbine rotor and an inner band joined by hollow partitions. assembly are two turbine wheel assemblies, a The vanes of the nozzle direct the gases from...

  • Page 145: Operating Principles

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OPERATING PRINCIPLES Oil Tank The oil is contained in an engine-mounted tank Figure 7-1 illustrates that the air entering the that includes a dwell chamber for deaerating the front frame through the nacelle air inlet is di-...
  • Page 146 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Oil Cooler A fully automatic oil cooler transfers the oil heat to cold fuel passing through the cooler. PRESS PRESS The oil cooler is a liquid-to-liquid heat ex- changer mounted on the oil tank mounting flange and against the right side of the oil tank.
  • Page 147 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FRONT FRAME SUMP VENT VENT RELIEF VALVE EIGHTH-STAGE LEAKAGE FILLER PORT FRONT TURBINE ROTOR AIR BLEED HOLE AND DIPSTICK FRAME OIL INLET BEARING TANK BEARING BEARING OIL TEMP INDICATOR OIL TEMP BULB NO.

  • Page 148: Fuel System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FUEL SYSTEM The function of the variable geometry system is to prevent compressor stalls and surging when operating in a low power range and dur- General ing acceleration and deceleration. A hydromechanical engine fuel system provides...
  • Page 149 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Fuel Pressurizing and two outlet ports which supply fuel to the noz- zle section through two tubes—the primary and Drain Valve secondary fuel nozzles tubes. The air-cooled The pressurizing valve includes a sliding nozzles section contains a primary and second- spring-loaded piston and a Teflon seat.

  • Page 150: Ignition System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL retain the drainage from three engine shut- downs. Following this, the canister itself must be drained; otherwise, it will begin to dump the collected fuel overboard. Operation Figure 7-11 illustrates operation of the fuel system and the associated variable geometry and engine overspeed systems.
  • Page 151 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY 7-14...

  • Page 152: Engine Power Control

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL holes in the aft flange of the inner combustion 25-135, -181 and subsequent, for hydraulic casing and mating flanges. The air then flows reservoir pressurization. On 24-350, -352 and through the turbine wheel inner labyrinth seal subsequent and 25-227 and subsequent, it is to pressurize the No.

  • Page 153: Engine Instrumentation

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 7-13. Center Console ENGINE The EPR system includes two probes in the ex- haust system, four transducers (two for each INSTRUMENTATION engine) on 23 models and 24 models through 24-180, and 25-003 through -024, and a probe in the ram-air duct.

  • Page 154: Engine Rpm

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ENGINE RPM ENGINE STARTING Engine rpm is supplied from an engine-driven Moving the starter-generator switch to the START tach generator mounted on the rear of each en- position applies power to close the respective...

  • Page 155: Synchroscope (Optional)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The system should be off below 70% rpm. THRUST REVERSERS The indicator light will light if the system is (OPTIONAL) inadvertently left on with the landing gear down. The control box senses pulse differ-...

  • Page 156: Control And Indication

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CONTROL AND INDICATION AUTOMATIC STOW The thrust reverser control switches and an- An automatic stow system is also incorpo- nunciator lights are located in a subpanel rated into the system. In flight, a stow com-...

  • Page 157: Differences

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DIFFERENCES The two CJ610 engine configurations vary generally in the gearbox and accessory area. On the CJ610-1, power to drive the engine- mounted accessories is extracted from the en- gine through the power takeoff assembly. A...

  • Page 158: Questions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS The engines powering the 20 series The primary thrust indicator for the Learjets are defined as: CJ610 engine is: A. Single-spool, reverse flow turbojets A. EGT B. Twin-spool, straight flow turbojets B.
  • Page 159 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 8 FIRE PROTECTION CONTENTS Page INTRODUCTION ........................8-1 GENERAL..........................8-1 ENGINE FIRE DETECTION AND INDICATORS ............... 8-1 Sensing Elements and Control Units ................8-1 Fire Lights ........................8-2 Fire Detection System Test ....................8-2 Exterior Extinguisher Discharge Indicators ..............
  • Page 160 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page FIRE Warning Lights ....................8-2 FIRE DET Test Switch..................... 8-3 Fire Extinguisher Discharge Indicators ..............8-3 Engine Fire-Extinguishing System (Airplanes with Glareshield Warning Lights) ..................8-4 Engine Fire-Extinguishing System (Airplanes without Glareshield Warning Lights) ..................

  • Page 161: Introduction

    FIRE PULL INTRODUCTION The Learjet 20 series airplanes are equipped with engine fire detection and fire-extinguishing systems as standard equipment (except model 23 airplanes, which have fire detection only). The systems include detection circuits which give visual warning in the cockpit and controls to activate one or both fire extinguisher bottles.

  • Page 162: Fire Lights

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL a control unit which monitors the electrical re- DC electrical power for the system is supplied sistance of the sensing elements. The sensing through circuit breakers on the appropriate elements are made of Inconel metal tubing pilot’s and/or copilot’s circuit-breaker panels.

  • Page 163: Exterior Extinguisher Discharge Indicators

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL steady. Returning the switch to NORM extin- integrity of the two discs is checked during the guishes the lights. external preflight inspection. ENGINE FIRE EXTINGUISHING EXTINGUISHER CONTAINERS Two spherical extinguishing agent contain- ers are located in the tailcone area.
  • Page 164 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL *SNS 24-350 AND SUBSEQUENT AND SHUTOFF VALVE (PINHEAD) LIGHT 25-227 AND SUBSEQUENT ARMED ARMED ARMED ARMED FIRE FIRE FUEL SHUTOFF VALVE *BLEED- *BLEED- AIR VALVE AIR VALVE PRESSURE GAGE PRESSURE GAGE TWO-WAY...
  • Page 165 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DISCHARGE SWITCHES NO. 1 NO. 2 PRESSURE GAGE PRESSURE GAGE TWO-WAY CHECK CONTAINER CONTAINER FUEL SHUTOFF FUEL SHUTOFF VALVES VALVE VALVE RELIEF VALVE RELIEF VALVE HYDRAULIC HYDRAULIC LH NACELLE RH NACELLE SHUTOFF VALVE...
  • Page 166 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Engine fire detection and/or overheat is Airplanes with glareshield warning sensed by: lights—When the left FIRE light is depressed: A. Thermocouples A. It discharges one extinguisher into B. Thermostats the left nacelle.
  • Page 167 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 9 PNEUMATICS CONTENTS Page INTRODUCTION ........................9-1 GENERAL..........................9-1 DESCRIPTION AND OPERATION ..................9-2 SNs 23-003 through 24-349 and 25-003 through 25-226 ..........9-2 SNs 24-350 and Subsequent and 25-227 and Subsequent ..........9-2 QUESTIONS ...........................
  • Page 168 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page Pneumatic System—SNs 23-003 through 24-349 and 25-003 through 25-226 ..................9-3 Pneumatic System—SNs 24-350 and Subsequent and 25-227 and Subsequent ..................9-4 AIR BLEED Switches....................9-5 FOR TRAINING PURPOSES ONLY...

  • Page 169: Introduction

    BLEED AIR INTRODUCTION The Lear 20 series pneumatic system uses bleed air extracted from the engine compressor section. Bleed air is used for cabin pressurization and heating and anti-icing systems on all airplanes, and servo air is used for hydraulic reservoir pressurization, pressurization control, temperature control, and radome/windshield alcohol anti-icing on later models.

  • Page 170: Description And Operation

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DESCRIPTION AND control valve is controlled by an ON–OFF AIR BLEED switch and a NORM–MAX CABIN OPERATION AIRFLOW switch. The AIR BLEED switch opens or closes the valve while the CABIN AIRFLOW switch selects either the normal or SNs 23-003 THROUGH 24-349 maximum airflow rate.
  • Page 171 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LH ENGINE ENGINE BLEED AIR FRONT FRAME HEAT BLEED ✽ LH ENGINE BLEED-AIR SHUTOFF VALVE WING ANTI-ICE FLOW WINDSHIELD HEAT CONTROL VALVE ANTI-ICE TO CABIN (IF INSTALLED) PRESSURIZATION JET PUMP ✽ HYDRAULIC BLEED ✽...
  • Page 172 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ENGINE FRONT FRAME HEAT LH AIR BLEED PRESSURIZATION EMER ANEROID SWITCH 9,500 FT (± 250 FT) BLEED-AIR SHUTOFF VALVE LH ECS VALVE EMERG TO CABIN PRESS VALVE L CAB AIR OVERTEMPERATURE SWITCH...
  • Page 173 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL normal position. The loss of either electrical Flow Control Valve power or servo air automatically positions the The flow control valve regulates the flow of valve to the emergency position. Below are...

  • Page 174: Questions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Bleed air is used for: In the event of single-engine operation, the check valves in the bleed-air line A. Pressurization/heating from each engine: B. Windshield defog A. Must be electrically closed C.
  • Page 175 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 10 ICE AND RAIN PROTECTION CONTENTS Page INTRODUCTION ......................... 10-1 GENERAL ..........................10-1 ICE DETECTION ......................... 10-3 Windshield Ice Detection....................10-3 Wing Ice Detection ......................10-3 ANTI-ICE SYSTEMS......................10-3 Engine Anti-ice System (Nacelle Heat)................. 10-3 Windshield Anti-ice/Defog and Rain Removal System..........
  • Page 176 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 10-1 Ice and Rain Protected Areas ................10-2 10-2 Ice Detection Lights ..................... 10-3 10-3 Recognition Light....................10-3 10-4 Engine Anti-ice System..................10-4 10-5 L and R NAC HEAT Switches ................10-5 10-6 Windshield Anti-ice/Defog Rain Removal System..........

  • Page 177: Ice And Rain Protection

    CHAPTER 10 ICE AND RAIN PROTECTION INTRODUCTION Anti-icing equipment on the Learjet 20 series is designed to prevent buildup of ice on: • The engine nacelle lip, inlet guide vanes, and nose cone • The windshield and radome • The leading edge of the wings and horizontal stabilizer •...
  • Page 178 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Engine bleed air is used to heat the windshields, Icing conditions exist when visible moisture wing leading edges, and the engine front frame. is present and the indicated ram-air tempera- ture (RAT) is +10º C or below. Takeoff into...

  • Page 179: Ice Detection

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ICE DETECTION The ice detection light on the pilot’s side is in- side the anti-ice airstream; the light on the copilot’s side is located outside the anti-ice During daylight operation, ice accumulation airstream.
  • Page 180 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY 10-4...

  • Page 181: Windshield Anti-Ice/Defog And Rain Removal System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Each engine anti-ice system is independently Inlet Heater Light controlled by the L and R NAC HEAT switches A temperature-sensing switch is located in the (Figure 10-5) located on the anti-ice control panel.
  • Page 182 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LOW-LIMIT THERMOSTAT WSHLD OV'HT WSHLD OV'HT HIGH-LIMIT THERMOSTAT FRAME 5 (FWD PRESSURE BULKHEAD) WINDSHIELD NORMAL DE-FOG OVERBOARD DRAIN CHECK VALVE CHECK VALVE WINDSHIELD HEAT AUTO (AFT PRESSURE FOOTWARMERS BULKHEAD) DEFOG PRESSURE REGULATOR VALVE...
  • Page 183 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL When the knob is pushed in to NORMAL, held in the ON position while the valve drives bleed air is diverted to the pilot’s and copilot’s toward the fully open position. The switch...

  • Page 184: Windshield/Radome Alcohol Anti-Ice System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CONDITIONED AIR BLEED-AIR DUCT MANUAL DEFOG CONTROL VALVE INTERNAL DEFOG NOZZLE DEFOG CONTROL KNOB EXTERNAL DEFOG OUTLET HIGH-LIMIT THERMOSWITCH LOW-LIMIT THERMOSWITCH EXTERNAL DRAIN FOOTWARMER Figure 10-9. Windshield Heat Diagram Manual Operation In flight, the low-limit switches are disabled.
  • Page 185 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL on the radome. If necessary, this system may be used as a backup for the windshield anti- ice defog system for the pilot’s windshield. There are two different systems in use. The sys- tems are operated by DC power routed through the ALC PUMP circuit breaker.
  • Page 186 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PILOT’S EXTERNAL DEFOG OUTLET ALC AI ORIFICE ASSEMBLY RADOME ANTI-ICE LOW-PRESSURE VALVE (N.C.) SWITCH WINDSHIELD/RADOME PRESSURE RELIEF RADOME MOTOR-DRIVEN LEGEND PUMP FILTER SUPPLY PRESSURE OVERBOARD VENT Figure 10-12. Alcohol System—SNs 24-181 through 24-349 and 25-025 through 25-226 and...
  • Page 187 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PILOT’S WINDSHIELD OUTLET THREE-WAY SHUTOFF BLEED AIR VALVE FROM RH ENGINE FILTER CHECK VALVE RADOME SHUTOFF OUTLET VALVE AND PRESSURE REGULATOR ALC AI CHECK VALVE FLOAT PRESSURE- SWITCH RELIEF VALVE SUPPLY TANK...
  • Page 188 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL WING 25-260 AND TEMP SUBSEQUENT STAB AND WING HEAT WING OV'HT WING TEMP SCUPPER SCUPPER TO DEFOG SYSTEM CONTROL VALVE LH ENGINE RH ENGINE TO AIR-CONDITIONING (PRESSURIZATION) SYSTEM STAB HEAT SEQUENCE TIMER...

  • Page 189: Wing And Horizontal Stabilizer Anti-Ice System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL WING AND HORIZONTAL STABILIZER ANTI-ICE SYSTEM Wing Heat Bleed air is used to prevent ice formation on the wing leading edges. The bleed air is di- rected from the bleed-air manifold through a...

  • Page 190: Pitot, Static, And Angle-Of-Attack Vane Anti-Ice System

    A con- densate drain valve is installed adjacent to the left nosewheel gear door. On aircraft with the Learjet Century III wing, the shoulder ports are heated whenever a bat- tery or generator is turned on and the PITOT HEAT circuit breakers are set.

  • Page 191: Questions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Bleed air is used for anti-icing on: Anti-icing equipment should be turned on: A. Windshields A. When in icing conditions B. Engine front frame B. Before entering icing conditions C. Wing leading edges C.
  • Page 192 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 10A ICE AND RAIN PROTECTION CONTENTS Page INTRODUCTION ......................10A-1 GENERAL.......................... 10A-1 ICE DETECTION ......................10A-2 ANTI-ICE SYSTEMS......................10A-3 Engine Anti-ice System (Nacelle Heat)..............10A-3 Windshield Anti-ice/Defog and Rain Removal System..........10A-5 Windshield Alcohol System..................
  • Page 193 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 10A-1 Ice and Rain Protected Areas ................10A-2 10A-2 Ice Detection System................... 10A-2 10A-3 Ice Detection Lights .................... 10A-3 10A-4 Engine Anti-ice System..................10A-4 10A-5 Defog Push-Pull Knobs..................10A-5 10A-6 Defog System—Model 23...................

  • Page 194: Introduction

    ICE AND RAIN PROTECTION INTRODUCTION Anti-icing equipment on Learjet SNs 23-003 through 24-180, and 25-002 through -024 not certified for flight in known icing conditions is provided and approved for engine protection only. The wing anti-ice system should be operated in concurrence with nacelle heat.

  • Page 195: Ice Detection

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FRONT FRAME ANTI-ICING (BLEED AIR) WING LEADING-EDGE ANTI-ICE (BLEED AIR) NACELLE CAP ANTI-ICE (ELECTRIC BLANKET) WINDSHIELD ANTI-ICE (BLEED AIR AND ALCOHOL) Figure 10A-1. Ice and Rain Protected Areas ICE DETECTION The ice detection system (Figure 10A-2) in- cludes an ice detector and interpreter mounted in the left engine intake at the two o’clock...

  • Page 196: Anti-Ice Systems

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL created which distends the detector diaphragm, approximately 1 inches in diameter, to appear actuating the diaphragm switch. This action on the windshield if particles of ice or moisture moves the system to the sensing phase by en- form.
  • Page 197 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL HEAT R ENG ICE 80 70 ABOVE 70% INLET HTR ICE DETECT Figure 10A-4. Engine Anti-ice System Engine Anti-ice Control Valve on the warning panel. Therefore, the ENG ICE light only indicates insufficient bleed-air The engine anti-ice control valve is located on pressure to the front frame.

  • Page 198: Windshield Anti-Ice/Defog And Rain Removal System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL WINDSHIELD ANTI-ICE/DEFOG On SNs 23-003 through -008, a thermal switch in the defog duct automatically closes the AND RAIN REMOVAL SYSTEM defog shutoff valve (via the defog relay) when the temperature reaches 205ºF (Figure 10A- Defog System—Model 23...
  • Page 199 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LH EXTERNAL RH EXTERNAL DEFOG OUTLET DEFOG OUTLET (OPTIONAL) INTERNAL OUTLETS PLENUM CHAMBER PLENUM CHAMBER CHECK VALVE COPILOT’S EXTERNAL DEFOG INTERNAL DEFOG PULL PULL WATER WATER ACCUMULATOR ACCUMULATOR 220°–180°F PULL W/S O’HEAT PILOT’S...
  • Page 200 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PILOT AND COPILOT W/S O’HEAT COPILOT’S EXTERNAL OUTLET PILOT PILOT’S EXTERNAL OUTLET WINDSHIELD INTERNAL OUTLET NORMAL DEFOG CONDITIONED AIR FROM CABIN DISTRIBUTION SYSTEM CHECK CHECK DEFOG VALVE FOOTWARMERS VALVE EMER CAB PRESS EXT DEFOG–ON...
  • Page 201 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL External Defog The light extinguishes when the temperature drops to 180ºF. When the W/S O’HEAT light There are two push-pull defog knobs located illuminates, the defog system should be turned on the left side of the pedestal. The top knob off or the airflow decreased to prevent possi- (Figure 10A-8) is labeled “IN–NORMAL—...

  • Page 202: Windshield Alcohol System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL WINDSHIELD ALCOHOL a two-position switch may be used to control the pump motor speed. The maximum flow SYSTEM rate is 5 to 10 gph through the two external defog nozzles. SNs 24-100 through -180, and...
  • Page 203 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL the leading edge (Figure 10A-10). The air is valves installed. The earlier kind is a Janitrol then exhausted overboard through a scupper valve which is electrically closed and fails to drain on the bottom of the leading edge near the open position.

  • Page 204: Pitot, Static, And Angle-Of-Attack Vane Anti-Ice System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PITOT, STATIC, AND ANGLE- Static Port Heating OF-ATTACK VANE ANTI-ICE The five static ports on SNs 23-003 through SYSTEM 24-137 are unheated unless SK 23/24-226 has been completed. If SK 23/24-226 has been...

  • Page 205: Questions

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Bleed air is used for anti-icing on: Anti-icing equipment should be turned on: A. Pitot tubes and static ports A. During descent B. Nacelle lips B. Before entering icing conditions C. Wing leading edges and engine C.
  • Page 206 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 11 AIR CONDITIONING CONTENTS Page INTRODUCTION ......................... 11-1 GENERAL ..........................11-1 ENGINE BLEED-AIR CONDITIONING AND DISTRIBUTION ........11-2 General........................... 11-2 Air-Conditioning System (SNs 24-350 and 25-227 and Subsequent ......................11-2 Air-Conditioning System (SNs 24-230 through -349 and SNs 25-003 through -226....................
  • Page 207 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 11-1 Conditioned Bleed-Air Distribution ..............11-2 11-2 Air-Conditioning System—SNs 24-350 and 25-227 and Subsequent....11-3 11-3 CAB AIR Switch ....................11-4 11-4 H VALVE Indicator (Current Models)..............11-4 11-5 Cabin Climate Switch Panel ..................

  • Page 208: Introduction

    AIR CONDITIONING INTRODUCTION Air conditioning on the Lear 20 series is provided by regulated bleed air that is temperature controlled and distributed throughout the cabin cockpit. Supplemental cooling and heat- ing are provided by a refrigeration system and an optional auxiliary heating system. These supplemental systems have a separate distribution network through which the air is cir- culated by a cabin blower and cockpit fan.

  • Page 209: Engine Bleed-Air Conditioning And Distribution

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DIFFUSER (TYPICAL) WINDSHIELD HEAT DUCT COPILOT’S AIR OUTLET CHECK VALVE LOWER CABIN DOOR AIR OUTLET PILOT’S AIR OUTLETS FOOTWARMER WINDSHIELD HEAT SYSTEM Figure 11-1. Conditioned Bleed-Air Distribution ENGINE BLEED-AIR AIR-CONDITIONING SYSTEM (SNs 24-350 AND 25-227 AND...
  • Page 210 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LEGEND BLEED AIR INTERNAL DEFOG OUTLETS RAM AIR CONDITIONED BLEED AIR CREW FOOTWARMER SERVO AIR OUTLETS OUTLET TO SENSOR BLOWER MOTOR CABIN TEMP SENSOR CABIN AIR VALVE VALVE DIFFUSERS (TYPICAL) MAIN MAIN...
  • Page 211 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL From the bleed-air manifold, bleed air is function is to split the flow of bleed air, distributed to the flow control valve for pres- directing some to the heat exchanger for cool- surization and cabin heating.
  • Page 212 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The cooled bleed air flowing out the heat Cabin Air Distribution exchanger core is ducted back to the bypass Cabin air distribution is furnished by diffusers side of the H-valve where it mixes with hot installed at intervals along the two ducts, and bypassed bleed air.
  • Page 213 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Temperature Control COLD–HOT knob) to the H-valve butterfly. Changing the COLD–HOT knob position Temperature control of the engine bleed air simply changes the servo air pressure on the entering the cabin area is accomplished by H-valve butterfly.

  • Page 214: 25-090, 25-095 And Subsequent

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AUTO CABIN AIR FLOW PRESS REGULATOR MAN COOL COOL NORM NORM COLD AUTO COLD AUTO DUMP DEFOG AUTO RATE SAFETY VALVE AUTO EMER CAB PRESS EXT DEFOG ON CABIN CLIMATE CABIN CLIMATE CONTROL...
  • Page 215 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL manifold, bleed air is distributed to the flow entire range (full heat to full cold) and is con- control valve for pressurization and cabin trolled by the cabin heat system in both the heating, to the pressurization jet pump, to the automatic and manual modes.
  • Page 216 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Cabin and Cockpit temperature is controlled by using the spring- loaded HOT–COLD switch to operate the Air Distribution bypass valve. Conditioned airflow distribution to the cabin and cockpit areas is essentially the same for all airplanes (see Figure 11-1).

  • Page 217: Air-Conditioning System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL fuselage skin beside the copilot seat, and a duct Duct Temperature Limiter temperature sensor located in the tailcone. A duct temperature limiter, adjacent to the These sensors determine what the H-valve po-...
  • Page 218 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORM AUTO COLD OPEN OPEN BLEED BLEED CLOSED CLOSED FOOTWARMER AND EXTERNAL DEFOG (BLEED AIR) CABIN OUTLETS (CONDITIONED AIR) CABIN OUTLETS (CONDITIONED AIR) CABIN TEMP INTERNAL DEFOG SENSOR (CONDITIONED AIR) TEMPERATURE CONTROL...
  • Page 219 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Flow Control Valve Heat Exchanger The flow control valve admits air from the The heat exchanger is a high-effectiveness, bleed-air manifold and routes it to the heat ex- two-pass crosscounterflow plate fin unit. High- changer for temperature control.

  • Page 220: Auxiliary Air-Conditioning Systems

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL and automatically. In both modes, the desired and 25-040 and subsequent, a dual duct and temperature is maintained by varying the blower are installed with a cockpit cooling fan amount of external ram air that is allowed to mounted between the ducts (Figure 11-14).
  • Page 221 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Cabin Blower Distribution on the climate control panel (Figure 11-17). The cockpit cooling fan is controlled by a rheostat The cabin bower assembly consists of a squirrel- on the copilot’s side panel.

  • Page 222: Auxiliary Cooling System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL COCKPIT NOTE: CABIN OUTLETS SNs 25-343 AND SUBSEQUENT ARE EQUIPPED WITH A COCKPIT ROTARY COMPRESSOR COOL BLOWER HIGH-PRESSURE VAPOR PRESSURE SWITCH COCKPIT LOW-PRESSURE CABIN VAPOR COMPRESSOR BLOWER ASSEMBLY AIRFLOW EVAPORATOR CONDENSER CONDENSER...

  • Page 223: Auxiliary Heating System (Optional) (Not Available On Sns 23-003 Through 24-129)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Operation Manually operated diverter doors installed in the air ducts from the evaporator may be positioned The Freon system may be operated on the to direct some of the cool air into the baggage ground or in flight below 18,000 feet (15,000 compartment.
  • Page 224 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL l i m i t s a s s e n s e d b y t h e r e s p e c t ive t h e r - moswitches, maintaining a constant airflow temperature.
  • Page 225 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL EVAPORATOR AND THERMAL THERMOSWITCH FUSE (HIGH LIMIT — 150°F) BLOWER ASSEMBLY (LOW LIMIT — 125°F) HEATER COILS HEATER ELEMENTS EVAPORATOR AND EVAPORATOR AND BLOWER ASSEMBLY BLOWER ASSEMBLY THERMAL HEATING FUSE ELEMENTS THERMOSWITCH...
  • Page 226 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS The diverter doors must be fully The Freon system should not be closed to: used above: A. Operate the cockpit fan A. 5,000 feet B. Operate the Freon system B. 8,000 feet C.
  • Page 227 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 12 PRESSURIZATION CONTENTS Page INTRODUCTION ......................... 12-1 GENERAL ..........................12-1 SYSTEM DESCRIPTION ....................12-3 Components ........................12-3 Indicators ........................12-8 Normal Operation ......................12-9 Flight Operation......................12-9 EMERGENCY PRESSURIZATION.................. 12-10 QUESTIONS........................12-13...
  • Page 228 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 12-1 Pressurization Control System Diagram—SNs 24-350 and Subsequent, and 25-227 and Subsequent ............12-2 12-2 Pressurization Control Panel .................. 12-3 12-3 Pressurization Control System Diagram—SNs 24-230 through -349 and 25-070 through -226..................
  • Page 229 PRESSURIZATION INTRODUCTION The Learjet 20 series airplanes are equipped with a pressurization system that maintains a spec- ified level of cabin pressure consistent with built-in limits. Cabin pressure is regulated by con- trolling the outflow of conditioned bleed air supplied from the engines. During normal operation, the system functions automatically to provide crew and passenger comfort within the operational envelope of the airplane.
  • Page 230 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY 12-2...

  • Page 231: Pressurization Control Panel

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL During climbs and descents, the controller regulates the outflow discharge rate. This rate control is necessary to maintain a cabin change rate that is comfortable regardless of the air- craft rate of climb or descent.
  • Page 232 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY 12-4...

  • Page 233: Up-Dn Lever

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CABIN CONTROLLER The lever is spring-loaded to the center posi- tion and is guarded on later airplanes to pre- In the automatic mode of operation, the CABIN vent inadvertent activation. CONTROLLER regulates cabin pressure in...

  • Page 234: Horn Silence Switch

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Controller Solenoid Valves CAB ALT annunciator (see “Annunciator Panel” section) to illuminate. When the aneroid Three solenoid-operated valves are installed in resets, the annunciator extinguishes. the controller and are used to control the rout-...

  • Page 235: And Subsequent, And 25-227 And Subsequent

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Cabin Safety Valve Cabin Altitude Limiter (Secondary) A cabin safety valve is installed in the aft pressure bulkhead. Its purpose is to relieve a The cabin altitude limiter for the cabin safety...

  • Page 236: Air Bleed Switches

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL INSTRUMENT PANEL LOCATOR AIR BLEED EMER NORM BLEED 24-230 THROUGH 24-349 24-350 AND SUBSEQUENT 25-070 THROUGH 25-226 25-227 AND SUBSEQUENT Figure 12-6. AIR BLEED Switches INDICATORS Cabin Altitude and Differential Pressure Indicator...
  • Page 237 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL OPERATION Monitor cabin altitude and differential pres- sure throughout the flight. Before Takeoff Manual During ground operation, the CAB AIR or AIR BLEED switch is normally not turned to If the CABIN CONTROLLER is not function-...

  • Page 238: In Normal/Out De-Fog Knob

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL valve closes, and on SNs 24-350 and subse- pilot’s footwarmer and bypass possible leaks quent, and 25-227 and subsequent, the safety in the conditioned bleed-air distribution system. valve simultaneously opens. To isolate bleed-air leaks downstream of the flow control valve, it is necessary to place the AIR BLEED switch to OFF.

  • Page 239: Through -349, And 25-067 Through -226

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL With an ECS VAL circuit breaker open, the If the emergency valves are positioned to emer- emergency pressurization valve will position gency for any reason, they may be reset by cy- to emergency and the bleed-air shutoff valve cling the AIR BLEED switches to OFF, then will fail open.

  • Page 240: Automatic Protection And Warning Features-Sns 24-350 And Subsequent, And 25-227 And Subsequent

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table 12-2. AUTOMATIC PROTECTION AND WARNING FEATURES — SNs 24-350 AND SUBSEQUENT, AND 25-227 AND SUBSEQUENT CABIN ALTITUDE PROTECTION AND WARNING 8,750 ±250 feet • Pressurization aneroid automatically switches to manual control.
  • Page 241 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS To regulate cabin pressure, the CABIN To dump residual cabin pressure on CONTROLLER modulates the: touchdown: A. Cabin safety valve A. The outflow valve opens automati- cally. B. Flow control valve B.
  • Page 242 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 12A PRESSURIZATION CONTENTS Page INTRODUCTION ......................12A-1 GENERAL.......................... 12A-1 SYSTEM DESCRIPTION ....................12A-1 Components ........................ 12A-1 Indicators ........................12A-10 Operation ........................12A-11 EMERGENCY PRESSURIZATION ................12A-12 QUESTIONS........................12A-13 FOR TRAINING PURPOSES ONLY...
  • Page 243 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 12A-1 Pressurization System—SNs 23-003 through 24-139......... 12A-2 12A-2 Pressurization System—SNs 24-140 through -169 and 25-003 through -010.................... 12A-3 12A-3 Pressurization System—SNs 24-170 through 24B-184, -186, -187, and -189, and 25-011 through -026 and 25-028..........12A-4 12A-4 Pressurization System—SNs 24B-185, -188 and -190...
  • Page 244 PRESSURIZATION INTRODUCTION The Learjet models 23, 24, 24B, and 25 are equipped with a pressurization system that maintains cabin pressure within comfortable limits. At maximum cabin pressure dif- ferential, the system maintains sea level pressure between 21,000 and 26,000 feet and an 8,000-foot cabin altitude at 45,000 feet.
  • Page 245 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL STATIC SOURCE ALTERNATE NORMAL OUTFLOW INTO STATIC SOURCE CABIN PRESSURE NOSE COMPARTMENT RELIEF VALVE CABIN AIR EXHAUST CONTROL VALVE FILTER CABIN ALTITUDE * CABIN EMERGENCY UNDER CONTROL PRESS VALVE SWITCH LEGEND...

  • Page 246: Pressurization System-Sns 24-140 Through -169 And 25-003 Through -010

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL STATIC SOURCE ALTERNATE STATIC SOURCE NORMAL OUTFLOW INTO CABIN PRESSURE NOSE COMPARTMENT RELIEF VALVE CABIN AIR EXHAUST CONTROL VALVE *FILTER CABIN ALTITUDE EMERGENCY CABIN CONTROL UNDER *ON SNs 24-150 VALVE PRESS...
  • Page 247 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL STATIC SOURCE ALTERNATE STATIC SOURCE NORMAL OUTFLOW INTO CABIN PRESSURE- NOSE COMPARTMENT RELIEF VALVE CABIN AIR EXHAUST CONTROL VALVE TO CABIN AIR DISTRIBUTION DUCT (CONDITIONED) CABIN ALTITUDE EMERGENCY SWITCH CABIN UNDER...

  • Page 248: Pressurization System-Sns 24B-185, -188 And -190 Through -209, And 25-027 And -029 Through -045

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL STATIC SOURCE NORMAL OUTFLOW INTO NOSE COMPARTMENT CABIN PRESSURE- ALTERNATE RELIEF VALVE* SOURCE CABIN AIR EXHAUST CONTROL VALVE SECONDARY SECONDARY SOLENOID VALVE SOLENOID VALVE FILTER TIME DELAY RELAY TIME GEAR CONTROL...

  • Page 249: Pressurization System-Sns 24B-210 Through -229

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL NORMAL STATIC SOURCE NORMAL OUTFLOW INTO NOSE COMPARTMENT FRAME 5 CABIN AIR REGULATED PRESSURE EXHAUST CONTROL TIME VALVE DELAY RELAY CABIN GEAR CONTROL ALTITUDE SWITCH EMERGENCY REGULATED VACUUM SWITCH CABIN UNDER UNDER...

  • Page 250: Pressurization Control Module

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Cabin Outflow Valve The outflow valve is located on the forward pressure bulkhead and maintains the desired cabin pressure by regulating cabin air exhaust flow. The outflow valve position is controlled by two solenoid-operated valves which re- ceive signals from the cabin altitude controller.

  • Page 251: Outflow Valve (Typical)

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL the outflow valve when the differential be- or INCREASE will open the outflow valve tween atmospheric pressure and cabin pressure and the cabin will climb. Holding the switch to reaches a preset value. The preset value for DOWN or DECREASE will close the outflow model 23 airplanes is 8.3 psid and for model...

  • Page 252: Cabin Safety Dump Switch

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Differential Pressure Relief (Outflow Valve) A pilot valve in the outflow valve (Figure 12A-7) prevents overpressurization by ad- mitting ambient air into the reference cham- ber to open the outflow valve. This valve is set to maintain 8.3 psid on SNs 23-003 through...
  • Page 253 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Cabin Safety Valve A cabin safety valve (Figure 12A-9) is in- stalled in the aft pressure bulkhead to relieve a cabin overpressure differential. In flight, the valve normally remains fully closed unless opened by the pilot valve or activated by the cabin safety (dump) switch.
  • Page 254 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The cabin altitude is indicated by a single pointer Manual and a circular scale on the outer edge with In case of a malfunction of the cabin altitude CABIN ALT markings from 0 to 50,000 feet.
  • Page 255 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Landing EMERGENCY As the airplane descends and reaches the pre- PRESSURIZATION selected cabin altitude, the outflow valve mod- ulates toward the open position. The cabin Starting with SN 23-030, on those airplanes should be unpressurized at landing.
  • Page 256 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS To regulate cabin pressure, the cabin On all airplanes except SNs 23-003 controller modulates the: through 23-030, if DC power fails: A. Cabin safety valve A. Pressurization control reverts to manual control.
  • Page 257 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 13 HYDRAULIC POWER SYSTEMS CONTENTS Page INTRODUCTION ......................... 13-1 GENERAL ..........................13-1 HYDRAULIC SYSTEM OPERATION................13-2 HYDRAULIC SUBSYSTEMS ..................... 13-6 QUESTIONS ......................... 13-7 FOR TRAINING PURPOSES ONLY 13-i...
  • Page 258 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 13-1 Hydraulic System Schematic (SNs 24-296 and Prior, and 25-180 and Prior, Except 25-135) ..................13-3 13-2 Hydraulic System Schematic (SNs 24-297 and Subsequent, and 25-135, -181, and Subsequent)................13-4 13-3 System Controls and Indicators (Typical)..............

  • Page 259: Hydraulic Power Systems

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 13 HYDRAULIC POWER SYSTEMS INTRODUCTION Two engine-driven pumps normally provide hydraulic pressure for operation of the landing gear, wheel brakes, flaps, spoilers, and thrust reversers. An electrically driven auxiliary pump, incorporated for use in the event of system failure, is normally used only on the ground for operation of the brakes, spoilers, and flaps when both engines are shut down.
  • Page 260 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Hydraulic shutoff valves installed at the reser- After starting the first engine, the HYDRAULIC voir in each engine-driven pump supply line PRESSURE indicator should be checked to can be closed from the cockpit in the event of verify engine-driven pump operation.
  • Page 261 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL RELIEF VALVE * AIRPLANES WITHOUT GLARESHIELD LIGHTS (10 PSI) ** NOT INSTALLED ON SNs 23-003 THROUGH -079 OVERBOARD VACUUM RELIEF AIR FROM PRESSURIZED CABIN 28 VDC FIRE JET PUMP (VENTURI) LEGEND PRESSURE...
  • Page 262 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL RELIEF VALVE FILTER (20 PSI) OVERBOARD VACUUM REGULATOR RELIEF BLEED AIR 28 VDC FIRE FIRE 28 VDC LEGEND PRESSURE SUPPLY RETURN AIR (NITROGEN) BLEED AIR REGULATED BLEED AIR VARIABLE-VOLUME ELECTRICAL ENGINE-DRIVEN PUMP (2)
  • Page 263 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL SHUTOFF VALVE AIRPLANES EQUIPPED WITH INDICATOR GLARESHIELD WARNING LIGHTS PINHEAD LIGHT ARMED ARMED FIRE LO HYD PRES S AIRPLANES NOT EQUIPPED WITH GLARESHIELD WARNING LIGHTS Figure 13-3. System Controls and Indicators (Typical)
  • Page 264 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL HYDRAULIC SUBSYSTEMS Operation of the hydraulic subsystems is pre- sented in Chapter 7, “Powerplant,” (Thrust Reversers), Chapter 14 “Landing Gear and Brakes,” and Chapter 15, “Flight Controls,” (Flaps and Spoilers). FOR TRAINING PURPOSES ONLY...
  • Page 265 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS In the event of hydraulic system fail- On airplanes with glareshield warning ure, the optional LO HYD PRESS light lights, the hydraulic shutoff valves are will illuminate at approximately: closed: A. 1,200 psi A.
  • Page 266 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 14 LANDING GEAR AND BRAKES CONTENTS Page INTRODUCTION ......................... 14-1 GENERAL ..........................14-1 LANDING GEAR ......................... 14-2 Indicating System ......................14-2 Components ........................14-3 Operation ........................14-6 BRAKES ..........................14-10 General......................... 14-10 Normal Operation ......................
  • Page 267 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 14-1 Gear Selector Switch and Position Lights (Typical) ..........14-2 14-2 Gear Position Indications ..................14-3 14-3 Main Gear....................... 14-4 14-4 Nose Gear....................... 14-4 14-5 Nose Gear Centering Cams..................14-5 14-6 Landing Gear Retracted ..................

  • Page 268: Landing Gear And Brakes

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 14 LANDING GEAR AND BRAKES INTRODUCTION The landing gear is electrically controlled and hydraulically operated. The main gear incorporates dual wheels equipped with individual hydraulic brakes, and it retracts inboard. The single-wheel, self-centering nose gear incorporates an electrical steering system and retracts forward.

  • Page 269: Landing Gear

    The computer- amplifier determines the amount and direction that a DC electric motor deflects the nosewheel. Lear 20 series airplanes may have either variable or nonvariable authority nosewheel steering. The following Landing Gear, Brakes, and Nosewheel Steering sections describe the operation of those systems.

  • Page 270: Components

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL UNSAFE GEAR LEFT NOSE RIGHT UP AND LOCKED LOCKED DOWN TEST GEAR DOWN MUTE UNSAFE GEAR LEFT NOSE RIGHT IN TRANSIT LOCKED DOWN TEST GEAR DOWN MUTE UNSAFE GEAR LEFT NOSE RIGHT...
  • Page 271 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL surface should be visible on the lower portion of the main gear strut. Main Gear Wheel and Tires Each main gear wheel incorporates a fusible plug that prevents tire blowout caused by exces- sive heat resulting from hard braking.
  • Page 272 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The nose gear actuator incorporates an integral Since nosewheel centering depends on air pres- downlock mechanism to maintain a positive sure in the strut, proper inflation of the strut is downlocked condition; therefore, a downlock especially important.

  • Page 273: Operation

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL • Antiskid (25 model) Stall test inhibit—Stall warning testing flight on aircraft with Century III wing disabled. • Nose steering • Stall warning test inhibit (Century III Antiskid—On model 25 aircraft, antiskid system wing) prevents brake application in flight.
  • Page 274 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL or GEAR DOWN position. It is energized to the When the inboard doors are fully open, the door- door-close position by main gear-operated open switches are actuated. This energizes the switches when the gear is fully retracted gear control valve to the retract position, and or extended.
  • Page 275 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL pressure to release the main gear inboard door uplatches and to open the doors. The two main gear red UNSAFE lights illuminate simultane- ously with uplatch release. When the inboard doors are fully open, the door open switches are actuated to energize the gear control valve.
  • Page 276 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Emergency Extension General The emergency gear extension system is pneu- matically operated by a bottle charged to 1,800–3,000 psi with dry air or nitrogen located in the nose compartment. Bottle pressure is shown on the direct-reading EMERGENCY AIR indicator on the copilot’s instrument panel...

  • Page 277: Brakes

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Operation permits stopping in the shortest possible distance for any given runway condition. Parking brakes Pushing the emergency gear extension lever can be set by pulling a handle located on the left down opens a valve to release air bottle pressure side of the throttle quadrant.
  • Page 278 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL TO RESERVOIR FROM NOSE GEAR DOWN LINE PILOT PILOT COPILOT COPILOT BRAKE VALVE BRAKE VALVE BRAKE VALVE BRAKE VALVE GEAR EMERGENCY EXTENSION CONTROL VALVE PARKING BRAKE VALVES OVERBOARD ANTI ANTISKID SKID DISCONNECT...
  • Page 279 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL TO RESERVOIR FROM NOSE GEAR DOWN LINE PILOT PILOT COPILOT COPILOT BRAKE VALVE BRAKE VALVE BRAKE VALVE BRAKE VALVE PARKING BRAKE GEAR VALVE EMERGENCY EXTENSION CONTROL VALVE PARKING BRAKE VALVES OVERBOARD ANTI...

  • Page 280: Antiskid Systems

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL If a takeoff is made in slush or snow, the wheels Operation should be allowed to spin down for approximate- Antiskid operation requires: ly one minute prior to gear retraction. This mini- mizes the possibility of brake freezing by sling- •...

  • Page 281: Emergency Brakes

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Operation 600 psi may be applied. Releasing the handle stops flow from the bottle and allows applied air Antiskid operation requires: pressure to be vented overboard, releasing the brakes. • The ANTISKID switch must be on.

  • Page 282: Operation-Without Variable Authority

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL WHEEL MASTER SWITCH Figure 14-13. Nosewheel Steering System (Airplanes without Variable Authority Steering) The steering actuator, mounted on top of the Primary mode is engaged by depressing nose strut, steers the nosewheel through a gear- and holding either PRI STEER switch box and an electrical clutch.
  • Page 283 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL If the steering system is inoperative, differential Variable-authority steering commands to the power and braking can be used to taxi the air- computer-amplifier are controlled by wheel plane. Pulling the 28 VDC NOSE STEER circuit speed transducers.

  • Page 284: Landing Gear

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Engage steer lock mode by momentary actuation If the UNSAFE light remains on at the comple- of the STEER LOCK switch. Depressing either tion of the retract cycle, one or both main gear wheel master switch disengages steer lock mode.
  • Page 285 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Directional Control Valves (SNs gear actuator; however, the return fluid from the gear actuator is restricted by an orifice. The uplock 23-003 through 23-079) opens, the inboard doors open, and the gear slowly A rotary three-position, four-way directional extends.
  • Page 286 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL BRAKES Parking Brakes On SNs 23-003 through 23-049, the parking brake can be set only by the pilot. Fluid reserve chambers in the parking brake valves cause diffi- culty in parking brake release. Depress the ped- als slowly while holding the PARK BRAKE handle in the off position.
  • Page 287 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS If a green LOCKED DOWN light is On airplanes without variable authority burned out, main gear down-and-locked nosewheel steering, the amount of condition can be confirmed by: steering available in either direction with the steer lock mode engaged is: A.
  • Page 288 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 11. Model 23—The red UNSAFE light will 14. Illumination of a main gear red be on when: UNSAFE light may indicate: A. The nose gear is unsafe or in transit. A. The corresponding main gear is not down and locked.
  • Page 289 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 15 FLIGHT CONTROLS CONTENTS Page INTRODUCTION ......................... 15-1 GENERAL ..........................15-1 PRIMARY FLIGHT CONTROLS ..................15-3 Elevators......................... 15-3 Ailerons.......................... 15-6 Rudder..........................15-9 TRIM SYSTEMS ........................15-9 General........................... 15-9 Rudder Trim........................15-9 Aileron Trim ........................
  • Page 290 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Operation—Airplanes with Standard Wing..............15-19 Operation—Airplanes with Century III Wing ............. 15-20 Operation—Airplanes with MKII Wing..............15-21 MACH OVERSPEED WARNING/STICK PULLER—ALL AIRPLANES EXCEPT MODEL 23......................15-22 General......................... 15-22 Operation ........................15-22 Test..........................15-22 DIFFERENCES ........................
  • Page 291 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 15-1 Flight Control Surfaces ..................15-2 15-2 Flight Controls Gust Lock..................15-3 15-3 Elevator Control System ..................15-4 15-4 Aileron Tabs ......................15-6 15-5 Aileron Control System....................15-7 15-6 Rudder Control System ..................

  • Page 292: Flight Controls

    FLIGHT CONTROLS INTRODUCTION The manually operated primary flight controls on Learjet 20 series airplanes incorporate elec- trical trim in all three axes. Secondary flight controls consist of hydraulically actuated spoilers and flaps. Other systems related to flight controls are the yaw damper, stall warning, and Mach overspeed warning systems.
  • Page 293 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL On models 23 and 24, a single yaw damper sys- A Mach overspeed warning system warns of tem provides yaw stability. Model 25 airplanes overspeed and on all airplanes induces an aft have a dual yaw damper system.
  • Page 294 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PILOT’S CONTROL WHEEL PILOT’S RIGHT RUDDER PEDAL Figure 15-2. Flight Controls Gust Lock PRIMARY FLIGHT Pitch Servo CONTROLS The pitch servo (torquer) is DC operated. It is mechanically connected to the elevator control...
  • Page 295 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL DOWNSPRING ASSEMBLY AUTOPILOT PITCH SERVO AFT ELEVATOR SECTOR FORWARD ELEVATOR SECTOR FORCE SENSOR BOB WEIGHT SNs 140 AND SUBSEQUENT, ALL MODEL 25 AIRPLANES, AND AIRPLANES MODIFIED FOR 45,000-FOOT OPERATION Figure 15-3. Elevator Control System (Sheet 1 of 2)
  • Page 296 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL SNs PRIOR TO 24-140 EXCLUDING AIRCRAFT MODIFIED FOR 45,000-FOOT OPERATION Figure 15-3. Elevator Control System (Sheet 2 of 2) FOR TRAINING PURPOSES ONLY 15-5...
  • Page 297 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The electric clutch must be engaged to couple Balance Tab the servo to the elevator linkage for elevator The balance tab on each aileron (Figure 15-4) positioning. The clutch engages when any one...
  • Page 298 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AUTOPILOT ROLL SERVOACTUATOR Figure 15-5. Aileron Control System FOR TRAINING PURPOSES ONLY 15-7...
  • Page 299 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL PRIMARY YAW DAMPER SERVOACTUATOR SERVO SECTOR RUDDER BELLCRANK SECONDARY YAW DAMPER RUDDER SECTOR AILERON/RUDDER INTERCONNECT AIRPLANES CERTIFIED FOR 45,000-FOOT OR HIGHER OPERATION SERIAL NUMBERS PRIOR TO 24-140 EXCLUDING AIRCRAFT MODIFIED FOR 45,000-FOOT OPERATION Figure 15-6.
  • Page 300 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL RUDDER have a single toggle or a rocker switch for rudder trim. The rudder trim system is DC powered The rudder is manually positioned with either set through the YAW circuit breaker.
  • Page 301 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL TRIM SWITCH ARMING SWITCH WHEEL MASTER SWITCH PILOT’S CONTROL WHEEL (COPILOT’S SIMILAR) Figure 15-7. Trim Systems Controls and Indicators FOR TRAINING PURPOSES ONLY 15-10...
  • Page 302 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The pilot-operated normal pitch trim and emer- P TRIM Selector Switch gency pitch trim systems are electrically inde- The P TRIM (pitch trim) selector switch pro- pendent systems. Mode selection (normal or...
  • Page 303 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL SECONDARY FLIGHT the control valve and the actuators to hold the flaps in the selected position. Full flap extension CONTROLS is 40º. When extended, the flaps are protected from FLAPS excessive airloads by a 1,650-psi relief valve in the downline.
  • Page 304 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FLAP ACTUATOR INTERCONNECT CABLE FLAP LIMIT SWITCH (PRESELECT) POSITION TRANSMITTER FLAP CONTROL VALVE RELIEF VALVE EXTEND RETRACT LEGEND NORMAL HYDRAULIC SYSTEM PRESSURE RETURN STATIC MECHANICAL ELECTRICAL AIRPLANES WITH MKII WING SNs 24-297, 25-181, AND SUBSEQUENT OPTIONAL ON ALL AIRPLANES WITH MKII WING Figure 15-8.
  • Page 305 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL UP results in further flap retraction. Operation Simultaneous extension of the flaps and spoilers When the SPOILER switch (Figure 15-9) is in flight is prohibited because of possible dam- positioned to EXT, the spoilers begin to extend age to the flaps.
  • Page 306 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LEGEND PRESSURE SPOILER CONTROL VALVE RETRACT EXTEND RETURN (SHOWN IN EXTEND POSITION) RESTRICTOR RESTRICTOR ACTUATOR ACTUATOR SPOILER LH SPOILER RH SPOILER Figure 15-10. Spoiler System Schematic FOR TRAINING PURPOSES ONLY 15-15...
  • Page 307 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL YAW DAMPERS DUAL YAW DAMPER SYSTEM All 25 series airplanes are equipped with dual GENERAL (primary and secondary) yaw damper systems. Each system is completely independent with its A single yaw damper is installed on model 23...
  • Page 308 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AUTOPILOT FLIGHT CONTROLLER AUTOPILOT EFFORT INDICATORS PRIMARY YAW DAMPER SERVO SELECTOR SWITCH SECONDARY YAW ALL MODELS DAMPER SERVO 25 SERIES AIRPLANES Figure 15-11. Yaw Damper System FOR TRAINING PURPOSES ONLY 15-17...
  • Page 309 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL STALL WARNING SYSTEMS GENERAL One of three stall warning systems is installed, depending on the type of wing used. Each system provides visual and tactile warning of an impend- ing stall, and includes the following major com-...
  • Page 310 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL one or both red STALL lights begin to flash motor operation (but prior to pusher operation), a push command is applied to the pitch servo with (Figure 15-13). When both vanes simultaneously approximately 1/4 the force of the pusher.
  • Page 311 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OPERATION—AIRPLANES lights flash, the indicator pointer enters the yel- low segment, and the stick shakers actuate. If WITH CENTURY III WING angle of attack continues to increase until air- speed is approximately 3 knots above airplane...
  • Page 312 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL two-speed trim system), the stick pusher actu- When both vane-operated transducers simultane- ates, then releases as the pointer recedes into the ously detect an angle of attack beyond stall con- yellow segment. Repeat the test, positioning the ditions, the computer/amplifier disengages the switch to the L TEST position.
  • Page 313 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL MACH OVERSPEED TEST WARNING/STICK With the BATTERY switch(es) on, test the stick puller by placing the L STALL WARNING PULLER—ALL switch on and actuating the MACH TEST switch AIRPLANES EXCEPT on the test switch panel.
  • Page 314 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CONTROL WHEEL TRIM SWITCH On model 23 airplanes it is possible to trim the ailerons with the autopilot engaged. On airplanes with two-speed trim, any trimming action disen- gages the autopilot completely.
  • Page 315 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS The airplane systems that use the pitch In the event of airplane electrical fail- servo to position the elevator are: ure, the flap position indicator will: A. Autopilot and Mach trim A.
  • Page 316 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 16 AVIONICS CONTENTS Page INTRODUCTION ......................... 16-1 GENERAL ..........................16-1 AIR DATA SYSTEM ......................16-3 Pitot-Static System......................16-3 Air Data Sensor......................16-4 Ram-Air Temp Gage...................... 16-4 AUTOMATIC FLIGHT CONTROL SYSTEM (AFCS) ............16-5 General...........................
  • Page 317 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 16-1 Pitot-Static System (Typical) ................. 16-2 16-2 Pitot Head (Typical) ....................16-3 16-3 Pitot-Static Drains (Typical)................... 16-3 16-4 Static Ports (Typical)....................16-3 16-5 ALTERNATE STATIC SOURCE Valve ..............16-4 16-6 RAM AIR TEMP Gage ..................
  • Page 318 AVIONICS INTRODUCTION The Learjet 20 series avionics consists of, but is not limited to, the air data system, the automatic flight control system, the navigation system, and the communication system. This chapter includes information on the air data, automatic flight control, and flight director systems used in the Learjet 20.
  • Page 319 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL LH SHOULDER RH SHOULDER STATIC PORT STATIC PORT AUTOPILOT ALTITUDE DRAIN CONTROLLER VALVE ALTITUDE PRESSURE AIR DATA SENSOR SWITCH RH PITOT HEAD LH PITOT HEAD DRAIN VALVE DRAIN VALVE RH FWD LH FWD...

  • Page 320: Pitot-Static System

    FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL AIR DATA SYSTEM instruments. Each static system has one static port on each side of the airplane nose (Figure 16-4). PITOT-STATIC SYSTEM The dual pickups are provided for redundancy The pitot-static system supplies pitot and static...
  • Page 321 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL to the copilot’s instruments. The right rear static port is connected with an alternate static port inside the nose compartment to provide the pressurization module or outflow valve with a static source. The static source goes to the pres-...
  • Page 322 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL COMPONENT DESCRIPTION Computer Amplifier—The computer amplifier for the AFCS is located on the floor of the cockpit beneath the pilot’s seat. Servos—The 28-VDC servos are mounted in the following locations: • Roll—under the floor in the forward part of the cabin •...
  • Page 323 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Control Switches—Control of the autopilot If a new attitude is established and the maneu- and the yaw damper is by means of the AUTOPI- ver switch is then released, the roll and pitch LOT MASTER switch on the pilot’s subpanel...
  • Page 324 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Pitch Trim Monitor Switch—This switch is in- the autopilot effort indicators (Figure 16-9) stalled on the pedestal switch panel and is labeled “EL” (pitch), “AIL” (roll), and “RUD” used to test the autopilot disengage function (yaw).
  • Page 325 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL • Emergency pitch trim switch (up or pressed, the HDG mode will disengage. Turning down) the turn knob out of detent will disengage NAV and/or REV CRS modes. • Pilot’s VG erect button •...
  • Page 326 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Speed (SPD) Hold Mode—The speed (SPD) FLIGHT DIRECTOR hold mode, when pressed, will maintain the air- SYSTEM plane at the speed existing when the SPD mode was engaged. Above 29,000 feet, the autopi- lot will maintain Mach number indicated;...
  • Page 327 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ATTITUDE BANK DISPLAY POINTER HORIZON BANK INDEX LINE RADAR GLIDE-SLOPE ALTITUDE POINTER COMMAND AIRPLANE BARS SYMBOL INCLINOMETER RUNWAY SYMBOL DISTANCE COURSE DISPLAY DISPLAY 01 1 COURSE HEADING MILES ARROW MARKER (BUG) COURSE AZIMUTH TO–FROM...
  • Page 328 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figures 16-10 and 16-11 show the flight direc- If selected mode(s) is subsequently disen- tor mode selector and annunciators and the gaged, the command bars will stow. Pitch hold flight director symbology.
  • Page 329 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY 16-12...
  • Page 330 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL RVSM SYSTEM References to static ports in the basic Airplane Flight Manual (AFM) are to be disregarded. References to pitot heads shall mean pitot- RVSM system aircraft are equipped with static probes. The pressurization static port has STC STO 1195WI manufactured by Avcon not changed in this configuration.
  • Page 331 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Figure 16-14. Air Data Panel Indications AIU FAIL—The AIU FAIL is an amber cap- tion that illuminates to advise that the analog interface unit (AIU) is no longer outputting Figure 16-15. Air Data Display Unit (ADDU) valid data.
  • Page 332 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Changing the barometric scale from in. Hg to only applies when the STBY annunciator is il- Hpa: luminated on the ADDU display. Under nor- mal conditions, the corrections are negligible. • Depress and hold the barometric knob...
  • Page 333 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The slave unit will display the same selected Selecting the L or R static port switch could altitude as the master (“A” illuminated) and ad- also affect altitude position corrections as pre- justing its ALT SEL knob will change the se- sented in the “Performance”...
  • Page 334 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Performance The following charts in the basic AFM are su- perceded by charts contained in the RVSM supplement: • All airspeed and Mach calibration charts except ground airspeed calibrations • All altitude position correction charts •...
  • Page 335 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS Pitot and static drain valves are D. Operated as outlined in A, B, or C located: A. In the nose wheel well The basic attitude reference mode is B. On the skin below the entrance door energized when: C.
  • Page 336 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL CHAPTER 17 MISCELLANEOUS SYSTEMS CONTENTS Page INTRODUCTION ......................... 17-1 GENERAL ..........................17-1 OXYGEN SYSTEM......................17-2 General........................... 17-2 Oxygen Cylinder......................17-5 Overboard Discharge Indicator..................17-5 OXYGEN PRESSURE Gage ..................17-6 Crew Distribution System....................17-6 Passenger Distribution System ..................
  • Page 337 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ILLUSTRATIONS Figure Title Page 17-1 Oxygen Schematic No. 1..................17-2 17-2 Oxygen Schematic No. 2..................17-3 17-3 Oxygen Schematic No. 3..................17-4 17-4 Oxygen Cylinder and Overboard Discharge Indicator........... 17-5 17-5 OXYGEN PRESSURE Gage................. 17-6 17-6 Crew Oxygen Mask....................
  • Page 338 NO 1 BATT INTRODUCTION Miscellaneous systems used on the Lear 20 series include the oxygen system and the drag chute. The airplane uses high-pressure oxygen stored in a cylinder located in the right nose section or the dorsal fin. The drag chute is offered as optional equipment.

  • Page 339: Oxygen System

    Figures 17-1 through 17-3 depict GENERAL the crew and passenger oxygen distribution The oxygen system components include an systems installed in the Lear 20 series oxygen storage cylinder, a cylinder shutoff airplanes. OXYGEN CYLINDER MANUAL SHUTOFF VALVE...
  • Page 340 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OXYGEN CYLINDER MANUAL SHUTOFF VALVE AND REGULATOR (NORMALLY OPEN) DISCHARGE INDICATOR FLOW DETECTOR FILLER VALVE PRESSURE GAGE (ON INSTRUMENT PANEL) CREW OXYGEN MASK PASS OXY VALVE AUTO—OFF SOLENOID VALVE NORMALLY OPEN (AUTO) PASS MASK VALVE MAN—AUTO...
  • Page 341 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OXYGEN CYLINDER MANUAL SHUTOFF VALVE AND REGULATOR DISCHARGE INDICATOR (NORMALLY OPEN) FLOW DETECTOR PRESSURE GAGE (ON INSTRUMENT PANEL) FILLER VALVE CREW OXYGEN MASK CREW OXYGEN MASK PASS OXY VALVE AUTO—OFF NORMALLY OPEN (AUTO)
  • Page 342 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OXYGEN CYLINDER The pilot should be aware that if the oxygen cylinder shutoff valve is closed, oxygen pressure The system is supplied with oxygen from a will still be read on the OXY PRESS gage in the storage cylinder located in the right nose section cockpit.
  • Page 343 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL OXYGEN PRESSURE GAGE The crew masks (Figure 17-6) are stowed on the pilot’s and copilot’s sidewalls. The mask oxygen The OXYGEN PRESSURE gage (Figure 17-5) lines are connected to quick-disconnect provides a direct reading of oxygen cylinder receptacles located on the cockpit sidewalls.
  • Page 344 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL cabin altitude. Above 20,000 feet, 100% oxygen must be selected. With the selector in the 100% position, 100% oxygen is delivered at any cabin altitude. The 100% position should be used when smoke or fumes are present in the pressurized compartment.
  • Page 345 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL pilot’s sidewall (Figure 17-8), and the third is With the PASS OXY valve in the NORM (open) solenoid-operated by an aneroid switch. The position, rotating the PASS MASK valve from manually controlled PASS OXY (forward) valve...
  • Page 346 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The passenger oxygen masks (Figure 17-9) are Should the doors be inadvertently opened from stowed in compartments in the convenience the cockpit, oxygen pressure must be bled from panels above the passenger seats. The...
  • Page 347 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL For cabin altitudes of 10,000 feet and above, the pilot chute then pulls the main chute canopy out oxygen duration times listed in the AFM include of the canister. cabin altitude ascent time from 8,000 feet to the...
  • Page 348 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL The drag chute can be used: • Ensure that the riser attaching loop is inserted in the riser attachment hook and that the hook is unlocked; ensure that the riser passes • When landing on wet or icy runway through the loop on the riser keeper.
  • Page 349 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL QUESTIONS During preflight, the pilot can determine The OXY PRESS gage reads: if the oxygen bottle is turned on by: A. Direct pressure of the cylinder A. Reading the pressure indicated on the B.
  • Page 352 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ③ 8. NOSEWHEEL AND TIRE—CONDITION AND NOSE GEAR UPLOCK FORWARD ② 12. RIGHT PITOT HEAD—COVERS REMOVED, CLEAR OF OBSTRUCTIONS 13. RIGHT STALL WARNING VANE—FREEDOM OF 9. RADOME ALCOHOL DISCHARGE PORT—CLEAR OF MOVEMENT, LEAVE IN DOWN POSITION OBSTRUCTIONS 10.
  • Page 353 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 15. RIGHT PITOT-STATIC DRAIN VALVES (2)—DRAIN 16. RIGHT SHOULDER STATIC PORT—CLEAR OF OBSTRUCTIONS 17. COPILOT’S WINDSHIELD DEFOG OUTLET—CLEAR OF OBSTRUCTIONS 19. EMERGENCY EXIT—SECURE 20. UPPER FUSELAGE ANTENNAE—CONDITION ④ 18. LOWER FUSELAGE ANTENNAE, ROTATING 21.
  • Page 354 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 22. RIGHT ENGINE INLET—CLEAR OF OBSTRUCTIONS 25. RIGHT MAIN GEAR LANDING LIGHT—CONDITION AND CONDITION 26. RIGHT MAIN GEAR WHEELS, BRAKES, AND TIRES— CONDITION 23. F U E L C R O S S OV E R , L E F T W I N G S U M P, L E F T ENGINE FUEL, RIGHT WING SUMP, AND RIGHT 27.
  • Page 355 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ⑤ 29. R I G H T F U E L V E N T ( U N D E R S I D E O F W I N G ) —...
  • Page 356 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 35. R I G H T T I P TA N K F U E L C A P — C O N D I T I O N A N D SECURE 39.
  • Page 357 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ⑥ 45. FUEL VENT DRAIN VALVE, TRANSFER LINE DRAIN VALVE, FUSELAGE TANK SUMP DRAIN VALVE— DRAIN 42. RIGHT ENGINE OIL TANK FILLER CAP AND ACCESS DOOR—SECURE 46. LEFT AND RIGHT FUEL FILTER DRAIN VALVES—...
  • Page 358 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 51. TAILCONE INTERIOR—CHECK FOR FLUID LEAKS, 48. FUEL VENT RAM-AIR MAST (WITHOUT DRAG S E C U R I T Y, A N D C O N D I T I O N O F I N S TA L L E D CHUTE INSTALLED)—CHECKED...
  • Page 359 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 57. OXYGEN SERVICING DOOR—SECURE 58. OXYGEN DISCHARGE DISC—CONDITION 54. DRAG CHUTE—CHECK FOR PROPER INSTALLATION 59. RIGHT VOR/LOC ANTENNA—CONDITION 60. VERTICAL STABILIZER, RUDDER, HORIZONTAL S TA B I L I Z E R , A N D E L E VATO R — C O N D I T I O N , DRAIN HOLES CLEAR 61.
  • Page 360 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 69. L E F T A I L E RO N — C H E C K F R E E M OT I O N , B A L - ANCE, AND TRIM TABS LINKAGE, AND BRUSH 66.
  • Page 361 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 76. LEFT TIP TANK—CONDITION 72. LEFT TIP TANK NAVIGATION LIGHT, STROBE LIGHT AND LENS—CONDITION 73. L E F T T I P TA N K F U E L C A P — C O N D I T I O N A N D SECURE 77.
  • Page 362 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 83. STALL FENCE (IF INSTALLED)—CONDITION 80. L E F T W I N G AC C E S S PA N E L S ( U N D E R S I D E O F WING)—CHECK FOR FUEL LEAKAGE...
  • Page 363 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL 87. LEFT ENGINE INLET—CLEAR OF OBSTRUCTIONS AND CONDITION FOR TRAINING PURPOSES ONLY WA-14...
  • Page 366 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL APPENDIX 15 HB This appendix contains the following conversion tables: Table Page APP-1 Conversion Factors ..................... APP-1 APP-2 Fahrenheit and Celsius Temperature Conversion ..........APP-2 APP-3 Inches to Millimeters (0.001 Inch to 10 Inches) ..........APP-3 APP-4 Weight (Mass): Ounces or Pounds to Kilograms ..........
  • Page 367 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table APP-1. CONVERSION FACTORS FOR TRAINING PURPOSES ONLY APP-1...
  • Page 368 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL FOR TRAINING PURPOSES ONLY APP-2...
  • Page 369 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table APP-3. INCHES TO MILLIMETERS (0.0001 INCH TO 10 INCHES) FOR TRAINING PURPOSES ONLY APP-3...
  • Page 370 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table APP-4. WEIGHT (MASS): OUNCES OR POUNDS TO KILOGRAMS FOR TRAINING PURPOSES ONLY APP-4...
  • Page 371 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL Table APP-5. WEIGHT (MASS): THOUSAND POUNDS TO KILOGRAMS FOR TRAINING PURPOSES ONLY APP-5...
  • Page 372 FlightSafety international LEARJET 20 SERIES PILOT TRAINING MANUAL ANNUNCIATOR PANEL The Annunciator Panel section presents a color representation of all the annunciator lights in the airplane. Please unfold page ANN-1 to the right and l e ave i t o p e n f o r r e a d y r e f e r e n c e a s t h e annunciators are cited in the text.

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