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ENSTROM F-28F Series Maintenance Manual

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ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Revision 11, dated Oct 25/19, applies to the Enstrom F-28F/280F Series Maintenance Manual,
nd
1985 Edition/1990 2
removing and inserting the pages listed below.
Remove Pages
iii through x
xiii through xiv
MM-1-3 through MM-1-4
MM-2-11 through MM-2-20
MM-4-3 through MM-4-4
MM-4-9 through MM-4-12
MM-4-21 through MM-4-22
MM-4-31 through MM-4-32
MM-4-47 through MM-4-48
MM-4-51 through MM-4-56
MM-4-65 through MM-4-66
MM-4-77 through MM-4-78
MM-6-1 through MM-6-8
MM-8-35 through MM-8-36
MM-9-1 through MM-9-48
MM-10-1 through MM-10-50
MM-12-1 through MM-12-71
None
MM-13-31 through MM-13-32
MM-13-35 through MM-13-38
MM-13-49 through MM-13-50
MM-13-67 through MM-13-72
MM-13-93 through MM-13-100
MM-21-15 through MM- 21-16
None
MM-24-7 through MM-24-8
........................................................................... End of List ...........................................................................
Edition. Place this cover sheet behind the "Record of Revisions" card after
Insert Pages
iii through x
xiii through xiv
MM-1-3 through MM-1-4
MM-2-11 through MM-2-20
MM-4-3 through MM-4-4
MM-4-9 through MM-4-12
MM-4-21 through MM-4-22
MM-4-31 through MM-4-32
MM-4-47 through MM-4-48
MM-4-51 through MM-4-56
MM-4-65 through MM-4-66
MM-4-77 through MM-4-78
MM-6-0.1 through MM-6-8
MM-8-35 through MM-8-36
MM-9-1 through MM-9-48
MM-10-1 through MM-10-68
MM-12-1 through MM-12-80
MM-13-0.1 through MM-13-0.2
MM-13-31 through MM-13-32
MM-13-35 through MM-13-38
MM-13-49 through MM-13-50
MM-13-67 through MM-13-72
MM-13-93 through MM-13-100
MM-21-15 through MM-21-16
MM-24-0.1 through MM-24-0.2
MM-24-7 through MM-24-10

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  • Page 1 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Revision 11, dated Oct 25/19, applies to the Enstrom F-28F/280F Series Maintenance Manual, 1985 Edition/1990 2 Edition. Place this cover sheet behind the “Record of Revisions” card after removing and inserting the pages listed below.
  • Page 2 INTENTIONALLY LEFT BLANK...
  • Page 3 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL TABLE OF CONTENTS Section 1 – Introduction Table of Contents ..................MM-1-1 1-1. Manual Arrangement ................. MM-1-3 1-2. Aircraft Effectivity ..................MM-1-3 1-3. Maintenance Manual Supplements ............MM-1-3 1-4. Maintenance Manual Changes and Revisions .......... MM-1-3 1-5.
  • Page 4 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 4-9. Overrunning Clutch ................. MM-4-27 4-10. Servicing ..................MM-4-27 4-11. Main Rotor Transmission ................ MM-4-28 4-12. Servicing ..................MM-4-28 4-13. Draining ..................MM-4-29 4-13.1 Flushing ..................MM-4-29 4-14. Tail Rotor Transmission ................MM-4-30 4-15. Servicing ..................MM-4-30 4-16.
  • Page 5 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 4-59. Tail Rotor Blade Strike/Sudden Stoppage ........MM-4-62 4-60. Hard Landing ................. MM-4-62 4-61. Main Rotor Overspeed..............MM-4-63 4-62. Main or Tail Rotor Transmission Chip Indication ......MM-4-64 4-63. Engine Overboost ................MM-4-65 4-64. Engine Overspeed ................. MM-4-66 4-65.
  • Page 6 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Section 7 – Instruments 7-1. Instrument Panel ..................MM-7-1 7-2. Altimeter ....................MM-7-1 7-3. Airspeed Indicator ..................MM-7-4 7-4. Engine and Rotor Tachometer ..............MM-7-5 7-5. Fuel Quantity Indicator ................MM-7-5 7-6. Engine Oil Pressure Gauge ..............MM-7-6 7-7.

  • Page 7: Table Of Contents

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 9-6. Main Rotor Blades................... MM-9-49 9-7. Description ..................MM-9-49 9-8. Removal..................MM-9-49 9-9. Inspection ..................MM-9-52 9-10. Repair .................... MM-9-62 9-11. Refinishing ..................MM-9-74 9-12. Corrosion Prevention ..............MM-9-75 9-13. Installation..................MM-9-76 Section 10 – Tail Rotor 10-1.
  • Page 8 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 13-5. Turbocharger ..................MM-13-47 13-6. Turbocharger Static Air Fuel Nozzle Pressure System ......MM-13-49 13-7. Primary Airflow System ................. MM-13-52 13-8. Cooling System ..................MM-13-57 13-9. Ignition System..................MM-13-64 13-10. Fuel System ..................MM-13-72 13-11.
  • Page 9 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 21-9. Illuminated Panels ................. MM-21-33 Illuminated Collective Switch Panel ..........MM-21-33 Illuminated Switch and Circuit Breaker Panel ......MM-21-35 Section 22 – [Reserved] Section 23 – [Reserved] Section 24 – Instruments 24-1. Engine Monitor ..................MM-24-1 24-2.
  • Page 10 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 5 Nov 5/13...
  • Page 11 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL REV. NO REV DATE DESCRIPTION DATE FAA APPROVED Cover ix, xiii, xiv MM-4-40, MM-4-42 MM-8-0 through MM-8-0.2 MM-8-12 through MM-8-16.2 Feb 7/19 MM-12-18 through MM-12-22 MM-21-1 through MM-21-4 MM-21-6 through MM-21-8, MM-21-14 MM-21-33 through MM-21-58...
  • Page 12 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 10 Feb 7/19...
  • Page 13 Supplement 1: Avionic Systems, Revision 8, Dated: Jan 15/19. 1-4. Maintenance Manual Changes and Revisions Subsequent to the publication of the initial issue of the Enstrom F-28F/280F Series Maintenance Manual, changes in aircraft equipment, support concepts and procedures, as well as information developed by experience, may affect the contents of the manual. To...
  • Page 14 Directive Bulletins are also located under the Tech Publications section of the website. Enstrom distributes maintenance manual reissues and revisions in hardcopy form via mail to owners and operators who are registered with Enstrom. Notice of recently released Service Information Letters and Service Directive Bulletins is provided via a postcard mailing.
  • Page 15 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 2-14. Vendor Information The following components listed in Table 2-2 are to be maintained I/A/W the manufacturer's instructions to ensure the continued airworthiness of the aircraft. The owner/operator is responsible for ensuring that current maintenance publications are available to ensure continued airworthiness of the aircraft.
  • Page 16 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-2. Vendor Contact Information Component Part Number* Manufacturer* Airwolf Aerospace LLC (440) 632-1687 Tension-Torson P/N AA-ECD-084-280 15369 Madison Rd. (440) 632-1685 Fax (TT) Straps (STC SR03465CH) Middlefield, OH 44062-8404 www.airwolfaerospace.com info@airwolfaerospace.com * The manufacturer of the component may differ depending on the time the aircraft was manufactured or overhauled.
  • Page 17 The special tools listed in Table 2-2 are used for removal, installation, and overhaul of components used on the F-28F/280F series aircraft: NOTE The special tools listed in Table 2-2 are available through Enstrom’s Tool Rental Program. Contact Enstrom Helicopter Product Support for details. Table 2-3. Special Tools...
  • Page 18 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-3. Special Tools Part Number Nomenclature T-0080 Tail Rotor Rigging Tool T-0086 Upper Guidetube Nut Tool T-0087-15 Tail Rotor Assembly Static Balance Mandrel T-0088 Tail Rotor Driveshaft Alignment Tool T-0092-5 Taper Pin Removal Tool...
  • Page 19 T-2896-1 Damper Bleeding/Servicing Tool (2 Required) Main Rotor Transmission Stand Main Rotor Hub Stand Sprag Clutch Purge Tool ATP761 Digital Mast Torque Multiplier Contact the Enstrom Helicopter Product Support for assistance in obtaining these tools. Rev. 11 MM-2-15 Oct 25/19...
  • Page 20 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 2-16. Torque Data Unless specified in Table 2-4 and/or in this manual’s maintenance procedures or as called out in the component manufacturer’s specifications, all hardware should be torqued to standard torque values listed in Tables 2-5 through 2-12.
  • Page 21 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-5. Torque Values for Nuts and Bolts CAUTION THE FOLLOWING TORQUE VALUES ARE DERIVED FROM OIL FREE CADMIUM PLATED THREADS. TORQUE LIMITS RECOMMENDED FOR INSTAL- MAXIMUM ALLOWABLE TIGHTENING LATION (BOLTS LOADED PRIMARILY IN SHEAR)
  • Page 22 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-7. Fittings, Hose Assemblies Flexible Hose or Tube Fittings (excluding nylon pitot static lines)  Measurements based on Hose Inside Diameter or Fitting Size Fitting Size Tube Size Thread Flex Hose and 6061-T6 Aluminum Steel (Torque Limits (inches) Alloy Torque Limits (in-lb) (in-lb) 3/16 3/8-24 7/16-20 5/16 1/2-20 3/4-16 3/4-16 7/8-14 1-1/6-12 1,100 Table 2-7.1.
  • Page 23 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-8. Steel Fittings Using Jam Nuts or Straight Thread O-Ring Boss Torque Limits (inch-pounds) Thread Size Tube Size (inches) 5/16-24 3/8-24 7/16-20 1/2-20 9/16-18 3/4-16 7/8-14 Table 2-9. Pitot Static System Nylon Fittings Torque Limits (inch-pounds)
  • Page 24 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 2-11. Crush Type Gaskets NOTE Turn the part until the sealing surfaces are in contact and then tighten to the angle of turn listed for the appropriate thread size. Thread Pitch On Angle of Turn...
  • Page 25 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-2-19.2 Oct 25/19...
  • Page 26 NOTE Enstrom does not stock engine parts for customer service use. Obtain engine parts through Lycoming Engines Distribution Partners. For assistance, refer to the Genuine Parts tab on the Lycoming Products web page to find distributors near you (www.lycoming.com).
  • Page 27 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 4 SERVICING, RECOMMENDED OVERHAULS, INSPECTIONS, AND GENERAL MAINTENANCE TABLE OF CONTENTS Paragraph Description Page 4-80. Storage from 45 Days to 6 Months ..........MM-4-75 4-81. Storage for Longer than 6 Months ..........MM-4-75 4-82.
  • Page 28 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 4 MM-4-4 Jun 21/12...
  • Page 29 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Note 1: Refer to the Figure 4-1 illustrations on pages MM-4-13 through MM-4-24 for the lubrication/servicing locations. Note 2: Refer to paragraph 4-28 for lubrication procedure. Note 3: Hand pack the bearing if the bearing housing is not equipped with a grease fitting.
  • Page 30 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 4-3. Qualified Domestic Commercial Oils for MIL-PRF-7808 MANUFACTURER MANUFACTURER'S DESIGNATION Air BP Lubricants, Inc. BP Turbo Oil 2389 American Oil American PQ Lubricant 689 Castrol, Inc. Brayco 880 Exxon Mobil Corp. EXXON ETO 2389 Exxon Mobil Corp.
  • Page 31 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 4-5. Qualified Domestic Commercial Oils for SAE-J2360/API GL-5/MIL-PRF-2105 MANUFACTURER MANUFACTURER'S DESIGNATION Exxon Mobil Corp. Mobil 1 Synthetic Gear Lubricant LS 75W-90 Mobil Delvac 1 Synthetic Gear Oil 75W-90 Mobilube HD LS 80W-90 Mobilube HD Plus 80W-90...
  • Page 32 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 4-8. Qualified Domestic Commercial Greases for MIL-PRF-23827 MANUFACTURER MANUFACTURER'S DESIGNATION NYCO America Nyco Grease GN10 Anderol Specialty Lubricants Royco 27 Exxon Mobil Corp. Beacon 325 Exxon Mobil Corp. Mobilgrease 27 Petronomics Plus M-P Aircraft Grease...
  • Page 33 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL View O Collective Guidetube Bearing Grease Fitting Cyclic Swashplate Bearing Grease Fitting Cyclic Swashplate Control Rod Pivots Sheet 9 of 12 Figure 4-1. Servicing Locations Rev. 4 MM-4-21 Jun 21/12...
  • Page 34 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL View P Pitch Change Bellcrank Pivot Bearings (3 places) Pitch Change Bellcrank Inboard Pivot Points (3 places) Main Rotor Lead/Lag Bearings (3 places) Main Rotor Feathering Bearings (6 places) Main Rotor Damper Service Plugs View Q...
  • Page 35 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 4-16. Draining – Tail Rotor Transmission A. If equipped with a chip detector, remove the chip detector from the quick disconnect receptacle. B. Place a suitable container under the receptacle/magnetic plug. C. Remove the quick disconnect receptacle/magnetic plug and drain the transmission.
  • Page 36 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 4-17. Main Rotor Dampers (Figure 4-5, View P) 4-18. Servicing (Bleeding) – Main Rotor Dampers NOTES Refer to Table 4-1 for system capacity and approved oil. The dampers may be serviced while installed on or removed from the aircraft.
  • Page 37 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE Ground Handling Wheels: Inspect the ground handling wheels and brackets for condition and security _________ of installation. Inspect the tires for condition and proper inflation. _________ Inspect the quick disconnect locking pins for condition.
  • Page 38 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE C. Jackstrut and Lower Pulley Assembly: Inspect the jackstrut for bond separations, condition, and security of _________ installation. Inspect the lower pulley for wear, excessive grease leakage, condition, and _________ security of installation.
  • Page 39 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE Main Rotor Retention Assemblies: Inspect the flapping stops and pitch horn for condition and security of _________ installation. Inspect the blade grips and drag links for condition and security of _________ installation.
  • Page 40 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE 12. SWASHPLATE CONTROL SYSTEM Swashplate Assembly: Inspect the lower swashplate assembly for condition and security of _________ installation. Inspect the lower swashplate assembly universal joint for looseness (Refer _________ to para. 12-10, C).
  • Page 41 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE Inspect the safety belts and shoulder harnesses for condition, proper _________ operation, and security of attachment. Inspect the fire extinguisher for date of the last inspection and security of _________ installation.
  • Page 42 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE Inspect the collective sticks, torque tube assembly, control rods and bellcranks for excessively worn rod end bearings/bushings, and security of _________ installation. Inspect the collective spring capsule assembly for proper operation, _________ condition and security of installation.
  • Page 43 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 100 HOUR/ANNUAL INSPECTION GUIDE 16. ELECTRICAL SYSTEMS Inspect the wiring harness and terminal strips for condition and security of _________ installation. Inspect the external power system for proper operation, condition and security _________ of installation.
  • Page 44 Check engine/post flight requirements in the Textron-Lycoming O, HO, AIO, HIO, TIO-360 Series Operator’s Manual. Run the aircraft I/A/W the Enstrom F-28F, 280F, or 280FX Rotorcraft Flight Manual. Check the engine instruments, fuel quantity and flow systems for proper operation.
  • Page 45 If indications of a rough bearing are felt, the transmission must be replaced. NOTE If the gearbox is to be returned to Enstrom Service, do not clean the metal from the chip detector. If none of the above conditions are found, flush and service the transmission (main rotor, para.
  • Page 46 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 4-64. Engine Overspeed – Special Instruction A. Inspect the engine in accordance with the latest revision of Textron-Lycoming Service Bulletin 369. NOTE Perform the appropriate main rotor overspeed inspection if required. 4-65. Maintenance Ground Run A.
  • Page 47 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Wash the aircraft with mild soap and fresh water weekly. NOTE Use a good quality paste wax. Wax the aircraft every second week. B. Aircraft that are operated in tropical or semi-tropical high humidity regions. Use the following procedures: Wash the aircraft with mild soap and fresh water weekly.
  • Page 48 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Tip the transmission to horizontal or vertical, as appropriate, approximately 90° from its storage position. Tip the transmission back to storage position. Turn the pinion approximately three times completely lubricate all moving parts. G. Prior to returning the main rotor transmission to service: Remove the breather tube plug or cap, if installed.
  • Page 49 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 6 ELECTRICAL TABLE OF CONTENTS Paragraph Description Page Electrical System ..................MM-6-1 A. General Information ................MM-6-1 B. General Troubleshooting ..............MM-6-1 Battery ...................... MM-6-2 A. General Information ................MM-6-2 B. Troubleshooting – Battery ..............MM-6-2 C.
  • Page 50 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-6-0.2 Oct 25/19...

  • Page 51: Electrical System

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 6 ELECTRICAL 6-1. ELECTRICAL SYSTEM A. General Information The F28F/280F Series electrical system is either a 12 volt or a 28 volt D.C. solid state regulated type. The system consists of one main buss, one generating source and one power storage source.

  • Page 52: Battery

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Continuous wire runs (ref. schematic diagram) are typically identified by an assigned wire number, i.e. 24-2, from the aircraft battery positive terminal to the starter relay contacts. In cases where wire runs are interrupted by splices, disconnects, fuses etc., the wire number is also assigned a letter, i.e., wire 49-...
  • Page 53 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Fig. 6-1A. Alternator (left) and Starter Installation (right) (shroud removed for clarity) Fig. 6-1B. Alternator and Starter Installation (Inactive) Top - Fan shroud side showing alternator mount pivot slide tension bar and drive belt Bottom - Underside of engine showing alternator mount position and pivot mount bolts Rev.

  • Page 54: General Information

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL D. Buss Faults Breaker System General Description – Early F-28F/280F Series The battery protection system is designed to remotely sense electrical overloads in the aircraft which cause excessive battery current drain. This system consists of fuse (FIB), overcurrent breaker (CB17) and the “overcurrent trip”...
  • Page 55 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (6) Housing cleanliness – End housing should be kept clean by wiping with a cloth dampened in solvent NOTE: It is recommended that the service manual applicable to your alternator type be consulted for detailed repair procedures.
  • Page 56 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install the alternator adjusting arm and tighten the bolts finger tight to allow the alternator to pivot. Install the starter ring gear support (flywheel) on the crankshaft and secure with two, temporary, ½ x 20 x 1 inch bolts installed in the two positions where there are no crankshaft bushings.
  • Page 57 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-6-7 Oct 25/19...

  • Page 58: Voltage Regulator

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: Updates to lighting, caution/warning annunciators, and electrical schematics are provided in Section 21. 6-4. VOLTAGE REGULATOR A. General Information Alternator voltage is controlled by a solid state transistor regulator. The regulator is factory set for proper voltage control and should not normally require field adjustment.
  • Page 59 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: The piston must be inserted into the cylinder assembly slowly to allow the hydraulic fluid to work through the staggered notches of the rebound rings and the flow passage in the piston assembly. (k) Install the piston and guide shaft assembly into the cylinder assembly. Slowly push the piston to the base of cylinder assembly (collapsed position).
  • Page 60 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Oleo Strut – Installation (see Figure 8-11) NOTE: Helicopter must be jacked or hoisted with a sling for oleo strut installation. (a) Lubricate the attachment hardware with LPS 2, ACF 50, or MIL-PRF-81322 grease and install while wet.
  • Page 61 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 9 MAIN ROTOR TABLE OF CONTENTS Paragraph Description Page Main Rotor System .................. MM-9-3 A. General ....................MM-9-3 Main Rotor Hub ..................MM-9-3 A. Removal ..................... MM-9-3 B. Disassembly ..................MM-9-4 C. Inspection ................... MM-9-5 D.
  • Page 62 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-9-2 Oct 25/19...

  • Page 63: Main Rotor System

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 9-1. MAIN ROTOR SYSTEM General – Main Rotor System The main rotor system is a three bladed, high inertia, fully articulated rotor system. The main rotor hub assembly is comprised of two opposing forged aluminum hub plates separated by an aluminum cylindrical spacer.
  • Page 64 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL electric impact wrench. If a 3/4” drive electric impact wrench is not available, install one main rotor blade and pull the breaker bar against the blade while using a large (2 kg) hammer to shock the tool (T-0048).
  • Page 65 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Using tool T-0003, remove the nuts, shims (8), and DU washers (7). (10) Turn the hub assembly over and remove the hardware (11) from the center hub adapter. (11) Remove upper and lower spline adapters (12) and (18) by tapping them from the hub plates with a nylon drift.
  • Page 66 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Pitch Arm Bolt Pitch Change Link Washer Bolt Bolt Cotter Pin Pitch Change Bellcrank Bolt Push-Pull Rod Assembly Washer (Harper/ECD) Spacer Spacer Spacer Figure 9-1. Pitch Change Bellcrank and Pitch Link Installation Rev. 11 MM-9-6...
  • Page 67 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Bolt Lock Key Grease Fitting Bolt Bolt Grease Fitting Bracket Upper Spline Adapter Stop Pad Dust Cover Dowel Pin Bearing Retaining Nut Upper Hub Plate DU Washer Lock Washer Universal Block Spacer DU Washer Center Spacer...
  • Page 68 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL If required, reinstall the bearings in the U-block assembly and assemble (para. 9-5). Install U-block assemblies (15) into the bearing bore of the hub plate with the threaded notched end of the U-blocks down (3 places).
  • Page 69 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install DU washer (7) into recess of hub plate with chamfer in board toward hub plate. Install approximately 0.025 shims (8) and lower U-block nut (9). Using tool T- 0003, torque nut to 50 ft-lb/67.8 Nm.
  • Page 70 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Installation – Main Rotor Hub (Figure 9-1, Figure 9-2) Locate the spline with phasing mark at top of main rotor shaft and mark it with a black felt marker for alignment ease. Apply a lubricant (MIL-PRF-81322) to the rest of the rotor shaft splines.
  • Page 71 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-1. Inspection Requirements – Main Rotor Hub Assembly Part No. Figure 9-2 Part Name Inspection* Serviceable Limits* Repair Limits Repair or Action Item # 28-14202 Bellcrank Deformed or cracked None Allowed Not Repairable Replace Bracket...
  • Page 72 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-1. Inspection Requirements – Main Rotor Hub Assembly Part No. Figure 9-2 Part Name Inspection* Serviceable Limits* Repair Limits Repair or Action Item # ≤ .010 Deep 28-14224 12 (& 18) Spline Nicks, scratches, or .010 Deep...
  • Page 73 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-1. Inspection Requirements – Main Rotor Hub Assembly Part No. Figure 9-2 Part Name Inspection* Serviceable Limits* Repair Limits Repair or Action Item # 28-14117 U-Block Bore Dia. 2.4988 to +.0002 Not Repairable Replace U-Block 2.4996...
  • Page 74 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-1. Inspection Requirements – Main Rotor Hub Assembly Part No. Figure 9-2 Part Name Inspection* Serviceable Limits* Repair Limits Repair or Action Item # 28-14281 Lower Hub Recesses for the DU +.0005 Not Repairable...
  • Page 75 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-1. Inspection Requirements – Main Rotor Hub Assembly Part No. Figure 9-2 Part Name Inspection* Serviceable Limits* Repair Limits Repair or Action Item # ECD092-1 Bearing O.D. 2.4994 to 2.5000 No Tolerance Allowed Not Repairable...

  • Page 76: Removal

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 9-3. RETENTION ASSEMBLY NOTE: F-28F S/N 832 and subsequent and 280FX S/N 2147 and subsequent are equipped from the factory with tension-torsion straps (STC SR03465CH). Refer to Table 2-2 for publications. Removal – Retention Assembly (Figure 9-3) Remove the main rotor blade (para.
  • Page 77 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: One shim P/N 28-14019-5 (Item 2) is installed, either the left or right side of the universal block. DU Washer Shim Retention Assembly Flapping Hinge Pin Lock Washer Figure 9-3. Retention Assembly Installation Rev. 11...
  • Page 78 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Droop Stop O-Ring Dust Cap Blade Grip Spindle Lamiflex Bearing Flapping Stop Shim Nylatron Strap Retaining Nut Seal Cotter Pin Bearing Dust Cover Spacer Blade Retention Pin Bearing Drag Link Retaining Ring Pitch Arm DU Washer Figure 9-4.
  • Page 79 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 9-5. Lamiflex Bearing Installation Rev. 11 MM-9-19 Oct 25/19...
  • Page 80 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Remove shims (15), lamiflex bearing (14), and nylatron strap (5). Tap blade grip (13) with a plastic mallet to remove. CAUTION: If lamiflex bearing wears through the nylatron strap, a careful inspection of the spindle is required. The maximum depth allowed for a groove worn in the spindle is .020 inch.
  • Page 81 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Apply zinc chromate to the bore of the spindle (3) and install plug (2) in the end of bore. Clamp spindle (3) in vise in a vertical position. Apply lubrication to seal surface of the spindle (3) and install seal (6).
  • Page 82 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (18) Shim (15) the nut until the cotter pin hole in the nut aligns with the hole in the spindle when the nut is tightened (5-15 in-lb/0.6-1.7 Nm). NOTE: Add or subtract shims until the cotter pin hole in the nut aligns with the hole in the spindle when the nut is tightened finger tight.
  • Page 83 Carefully slide the retention assembly into position over the DU washer and U-block. NOTE: Enstrom recommends replacing Flapping Hinge Pin, P/N 28-14233-1, with Flapping Hinge Pin, P/N 28-14233-3, when reinstalling the main rotor retention assemblies after the flapping bearings have been shimmed. The Flapping Hinge Pin, P/N 28-14233-3, is manufactured to closer tolerances for bearing fit and will improve service life.
  • Page 84 9-4, C. NOTE: Enstrom recommends internal shimming (Method 1) to increase the service life. NOTE: Match each retention assembly to the location marked in the upper hub adapter (reference para.
  • Page 85 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Check the flapping bearing drag resistance at the flapping pin. Initially, the grip should not stay up. If the retention assembly stays up, remove shims in 0.005-inch increments until the retention assembly will drop with no resistance when the nut is torqued.
  • Page 86 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-9-26 Oct 25/19...
  • Page 87 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-2. Inspection Requirements – Retention Assembly Part Number Figure 9-4 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-14240-1 Droop Stop General Condition .003 wear Not Repairable Replace Stop 28-14282-13...
  • Page 88 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-2. Inspection Requirements – Retention Assembly Figure 9-4 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 40NBC20- Bearing O.D. 3.2492 to 3.2500 No Tolerance Not Repairable Replace Bearing 52YZP Allowed I.D.
  • Page 89 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-2. Inspection Requirements – Retention Assembly Figure 9-4 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-14279 Blade Grip (Cont'd) Threads (crossed or None Allowed Not Repairable Replace Blade Grip missing) ≤...
  • Page 90 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-2. Inspection Requirements – Retention Assembly Figure 9-4 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-14007 Blade Retention Bolt Threads None Allowed Not Repairable Replace Bolt (continued) (continued) (crossed or missing) ≤...

  • Page 91: Universal Block Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 9-4. UNIVERSAL BLOCK ASSEMBLY Disassembly – Universal Block (Figure 9-2) Remove upper and lower bearings (22) and DU washers (23) from U-block (15). Press flapping bearings (22), spacer (24), and shims (25) from bore of U-block.
  • Page 92 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 9-6. Flapping Bearing and Spindle Dimension Check Figure 9-7. “Forward” Flapping Bearing Installation Rev. 11 MM-9-32 Oct 25/19...
  • Page 93 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 9-8. “Aft” Flapping Bearing and Spacer Installation Figure 9-9. Flapping Bearing Installation Alignment Tool Rev. 11 MM-9-33 Oct 25/19...

  • Page 94: Dampers

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 9-5. DAMPERS General Information – Dampers The damper assembly consists of a damper housing, a piston and restrictor assembly, and a reservoir with two relief valves. The damper is used to damp lead-lag movement of the main rotor blades.
  • Page 95 9/16” deep-well socket. Refer to paragraph 9-5, F for replacement instructions. CAUTION: The relief valve pressure has been preset at the factory and cannot be adjusted in the field. Return a faulty valve to Enstrom Helicopter Service for inspection and valve adjustment/exchange.
  • Page 96 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Inboard Pivot Bolt Washer Chamfered Washer Washer Cotter Pin Spacer Bolt Figure 9-10. Damper Installation Rev. 11 MM-9-36 Oct 25/19...
  • Page 97 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Damper Housing O-Ring Reservoir Bushing Sleeve Valve Assembly Bushing Wiper Cap Plug O-Ring Seal O-Ring Sleeve O-Ring O-Ring Piston Washer Plug Restrictor Sleeve Bolt Sleeve Set Screw Lock Key Bolt O-Ring or Seal Pack Jam Nut...

  • Page 98: Relief Valve Replacement

    Relief Valve Replacement (Figure 9-11) NOTE: The relief valve pressure has been preset at the factory and cannot be adjusted in the field. Return faulty valves to Enstrom Helicopter Service for inspection and valve adjustment/exchange. Remove damper from the aircraft (para. 9-5, C).
  • Page 99 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Place the damper housing in a vise with the bore up. CAUTION: Ensure components are free of dirt or other contaminants prior to assembly. CAUTION: Do not damage the O-rings or seals during the assembly process.
  • Page 100 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: The rod end bearing assembly may have been previously treated with ACF- 50 or MIL-PRF-23377 Type I Class 2C or Class N epoxy primer corrosion inhibitor per SDB 0127. If continuing use of ACF-50, removal of prior ACF-50 application is unnecessary.
  • Page 101 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 9-12. Damper Rod End Installation Rev. 11 MM-9-41 Oct 25/19...

  • Page 102: Installation

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (19) Hold the rod end with a wrench or tool T-0005 and tighten the jam nut (19) when the correct position is set. (-1 and -5 dampers) Bend the locking washer tabs (29). (ii) (-3, -7, -101, and -105 dampers) Position the locking key toward the top of the damper.

  • Page 103: Inspection

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-3. Inspection Requirements – Damper Assembly Part Number Figure 9-11 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-14357-5 Housing Sleeve fore Dia. 1.1250 +.0002 Not Repairable Replace Housing 28-14357-3 to 1.255...
  • Page 104 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-3. Inspection Requirements – Damper Assembly Part Number Figure 9-11 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-14356-5 5 and 12 Sleeve O.D. 1.1260 to 1.1265 -.0002 Not Repairable Replace sleeve Piston shaft bore Dia.
  • Page 105 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 9-3. Inspection Requirements – Damper Assembly Part Number Figure 9-11 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # ECD091-1 Damper Bearing Radial Play .007 Not Repairable Replace Bearing Axial Play .005...
  • Page 106 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-9-46 Oct 25/19...
  • Page 107 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: Figure 9-13 through Figure 9-15 are reserved for future use. Rev. 11 MM-9-47 Oct 25/19...
  • Page 108 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-9-48 Oct 25/19...
  • Page 109 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 10 TAIL ROTOR TABLE OF CONTENTS Paragraph Description Page 10-1 Tail Rotor Assembly ................MM-10-3 A. General Description ................MM-10-3 B. Troubleshooting ................MM-10-3 C. Removal ................... MM-10-4 D. Disassembly ..................MM-10-4 E. Cleaning ................... MM-10-7 F.
  • Page 110 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 10 TAIL ROTOR TABLE OF CONTENTS Paragraph Description Page Inspection – Pillow Block ..............MM-10-54 J. Assembly – Pillow Block ..............MM-10-56 K. Installation – Driveshaft ..............MM-10-56 L. Alignment – Driveshaft ..............MM-10-57 M.

  • Page 111: Tail Rotor Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-1 TAIL ROTOR ASSEMBLY General Description – Tail Rotor Assembly The tail rotor assembly consists of two blade and grip units mounted on a common spindle by the use of a pair of matched DT ball bearings and one needle bearing per grip.

  • Page 112: Removal

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Problem Cause Required Action Excessive end play in Remove tail rotor assembly and teeter bearings, retighten retainer caps until hub creating out of rotates firmly by hand with no end balance condition play. Grease and static balance.
  • Page 113 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Tail Rotor Spindle Lock Washer Tail Rotor Hub Bumper Washer Blade and Grip Assembly Bearing Journal Dowel Pin Teeter Bearing Lubrication Fitting Seal Strike Indicator Thrust Bumper Washer Shims Screw End Cap Bolt Retaining Ring...
  • Page 114 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Remove the safety wire and bolts (25) from the pitch change plates. NOTE: Remove the lubrication fitting (21) from the blade grip to ease removal and installation of the blade and grip assembly. CAUTION: DO NOT tap on the root of the blade during the removal process or remove the blade from the blade grip.
  • Page 115 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (17) Move the hub to the opposite side of the spindle as the bearing to be removed and insert the split pressing tools from the tool kit onto the journal (4). Press the needle bearing (5) from the spindle. Insert the T-2893 split pressing tools onto the opposite side of the hub and press out the remaining needle bearing.
  • Page 116 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Repair small areas of the paint finish (para. 9-11). Reject tail rotor blades with the following bond line separations or voids: Trailing edge separations deeper than .050 inch/1.3 mm or more than 2.0 inch/5.1 cm in length.
  • Page 117 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Reject tail rotor blades with the following root doubler damage: Nick, scratches, or sharp dents deeper than .010 in/.25. Smooth dents deeper than .020 in/5.1 mm. Cracks. Repair damage to the root doublers not exceeding the limits in step (8) above, as follows: Blend nicks, scratches, or sharp dents out smooth to approximately .50...
  • Page 118 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-2. Tail Rotor Blade Trailing Edge Repair Limits Rev. 11 MM-10-10 Oct 25/19...
  • Page 119 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Assembly – Tail Rotor Assembly (Figure 10-1) Install hub (2) into the spindle (1) using the following procedure: Install one of the washers (3) onto the hub with the chamfer toward the center of the hub.
  • Page 120 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: The installation procedures are the same for both blade and grip assemblies. CAUTION: Use brass protector plated in the vise jaws to prevent from damaging the tail rotor spindle. Place the spindle into a vise so that the blade and grip assemblies can be rotated when installed or use tool T-0168-1.
  • Page 121 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: Alternately tighten the bolts 1 to 2 turns to pull the pitch change plate and grip straight together. (14) Start three bolts (25) into the grip, each closest to a dowel pin (20), and tighten to pull the grip and the pitch change plate together.
  • Page 122 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install lock nuts on rod ends. Apply VC-3 Loctite to threads of rod ends. Turn right hand rod end into barrel until threads just cover the witness hole in the barrel. Turn left hand rod end into barrel until overall length of pitch link measures 4.260 in ±...
  • Page 123 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-3. Tail Rotor Pitch Change Link Installation Bolt Washer Washer Spacer Spacer Spacer Pitch Change Link Rod End O-ring Washer Pitch Change Link (28-16391-3 or -5 shown) Washer Cotter Pin Figure 10-4. Pitch Change Link Installation Rev.
  • Page 124 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-5. Tail Rotor Pitch Change Link Rev. 11 MM-10-16 Oct 25/19...
  • Page 125 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Installation – Tail Rotor Assembly Start a .041 wrap of safety wire around the hub. NOTE: The tail rotor assembly may be rotated 180° or the center hub may be pivoted 180° to obtain the proper installation position of the tail rotor assembly.
  • Page 126 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-6. Tail Rotor Installation Orientation Rev. 11 MM-10-18 Oct 25/19...

  • Page 127: Inspection

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-1. Inspection Requirements – Tail Rotor Assembly Figure 10-1 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # ≤ .001 deep 28-150074-11, -13 Spindle Surface scratches, None Allowed Polish with Scotch Brite...
  • Page 128 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-1. Inspection Requirements – Tail Rotor Assembly Figure 10-1 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-150076-15 Journal Journal I.D. .4995 to +.0002 Not Repairable Replace Journal .4998 Journal O.D. .7509 to -.0002...
  • Page 129 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-1. Inspection Requirements – Tail Rotor Assembly Figure 10-1 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # MR-18, Bearing Bearing O.D. 1.6250 +.0000 Not Repairable Replace Bearing -.0005 ECD001-11 Visible wear of the...
  • Page 130 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-1. Inspection Requirements – Tail Rotor Assembly Figure 10-1 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # ≤ .005 deep SL61W5P Lockwasher Nicked locking tabs None Allowed Blend and polish out smooth ≤...
  • Page 131 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-1. Inspection Requirements – Tail Rotor Assembly Figure 10-1 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-150001-5 Blade and Grip Blade: Assembly (Cont'd) Doubler Separation None Allowed See para.10-1, G See para.10-1, G...
  • Page 132 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Note 1 - If the blade is attached to the grip using 1/4" bolts, a new grip or blade can be installed by Enstrom. The blade and grip assembly will have 5/16"bolts installed. Both of the blade and grip assemblies must have the same size retaining bolts. Do not intermix blade and grip assemblies that have different size retaining bolts.

  • Page 133: Balance Procedure

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-2 STATIC BALANCE Balance Procedure (See Figure 10-1 for items listed by number) Remove bolt (26), washers (27), and nut (28) from the pitch arms if installed. Install the balance mandrel, T-0087-15, through the hub (2). Align the plates of the mandrel with the flats of the spindle and with the recesses in the plates in toward the hub.
  • Page 134 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-7. Tail Rotor Static Balancing Rev. 11 MM-10-26 Oct 25/19...

  • Page 135: Tracking And Dynamic Balance

    TRACKING AND DYNAMIC BALANCE NOTE: It is not necessary to track the tail rotor blades on Enstrom tail rotor assemblies. Earlier tail rotor assemblies with the 3 piece pitch links should be set to an overall length of 4.26 in/10.82 cm in accordance with Figure 10-5.
  • Page 136 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-8. Velocimeter and T-0152 Installation Figure 10-9. Reflective Tape Installed on the Target Blade Rev. 11 MM-10-28 Oct 25/19...

  • Page 137: Tail Rotor Balance Procedure

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Tail Rotor Balance Procedure: WARNING: The following steps are to be performed by authorized personnel. Position the helicopter so the tail rotor transmission output shaft is pointing into the wind (either upwind or downwind). Ground run the aircraft at 350 rotor RPM with the tail rotor pedals neutral.
  • Page 138 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-10. Tail Rotor Balancing Chart Rev. 11 MM-10-30 Oct 25/19...

  • Page 139: Clock Angle Correction Procedure

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL “Clock Angle Correction” Procedure Obtain the ips reading and clock angle using the procedure in paragraph B. As an example, the following results were obtained: Run 1, ips .55 @ 4:30 clock angle. Plot Run 1 on the tail rotor polar chart (Figure 10-11).
  • Page 140 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-11. Tail Rotor Clock Angle Correction Example Rev. 11 MM-10-32 Oct 25/19...
  • Page 141 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-12. Tail Rotor Clock Angle Correction Example Rev. 11 MM-10-33 Oct 25/19...
  • Page 142 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-13. Tail Rotor Clock Angle Correction Example Rev. 11 MM-10-34 Oct 25/19...
  • Page 143 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-14. Tail Rotor Clock Angle Correction Example Rev. 11 MM-10-35 Oct 25/19...

  • Page 144: Teeter Trunnion Shimming Procedure

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Teeter Trunnion Shimming Procedure (Figure 10-1) NOTE: If more than five harper washers are required to balance the tail rotor in the chordwise axis, it may be necessary to shift the teeter hub to move the balance fulcrum.

  • Page 145: Tail Rotor Pitch Control Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-4 Tail Rotor Pitch Control Assembly Removal – Pitch Control (Figure 10-15) Disconnect the pitch change links from the pitch link retainer (18). Remove bolt (1), washer (2), spacers (3), washer (5), and nut (6) to disconnect the pitch change link (4) (Figure 10-3, right).
  • Page 146 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Upper Bracket Lower Bracket Seal Screw Seal Retainer Washer Pitch Control Bearing Bolt Bearing Washer Retaining Ring Bearing Housing Spring Washer Washer Pitch Link Retainer Cotter Pin Cotter Pin Figure 10-15. Tail Rotor Pitch Control Assembly Rev.
  • Page 147 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL WARNING: Use extreme caution when removing or installing the blade and grip assemblies to prevent from injuring personnel. WARNING: Use protective gloves when handling heated parts. Heat the bearing housing (7) to approximately 250°/121°C. Gently tap the bearing (15) from the housing.
  • Page 148 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Press dowel pin (19) into pitch link retainer (18). Rotate retainer and repeat. NOTE: Seat dowel pins into the pitch link retainer far enough that the cotter pins can be installed. The pins must not extend through the pitch control bearing.
  • Page 149 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install seal (12) into the seal retainer (13). Install the seal retainer into the recessed area of pitch control bearing (14) using tool T-0140. Alternatively, the seal may be installed by tapping it with a small punch.
  • Page 150 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-10-42 Oct 25/19...
  • Page 151 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-2. Inspection Requirements – Tail Rotor Pitch Control Assembly Part No. Fig. 10-15 Part Name Inspect* Serviceable Limits* Repair Limits* Repair or Action Item No. 28-16331-1 Bearing bore 2.6774 to +.0002 Not Repairable Replace Housing Bearing 2.6779...
  • Page 152 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 10-2. Inspection Requirements – Tail Rotor Pitch Control Assembly Part No. Fig. 10-15 Part Name Inspect* Serviceable Limits* Repair Limits* Repair or Action Item No. 107-KSZZ6, Bearing O.D. 2.6772 +.0000/-.0005 Not Repairable Replace Bearing ECD016-11 I.D.

  • Page 153: Tail Rotor Gearbox

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-5 TAIL ROTOR GEARBOX General Description – Tail Rotor Gearbox The tail rotor gearbox consists of an aluminum cast housing for a 90° degree miter gear drive, with integral cast mount and control pivot bosses. The gearbox mechanical input is an independently mounted shaft and gear assembly that is retained by a matched pair of duplex ball bearings.
  • Page 154 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL C. Removal – Tail Rotor Gearbox Remove tail rotor assembly (para. 10-1, C). Disconnect tail rotor pitch change cables at the gearbox or remove the pivot control brackets (Figure 10-15) from the tail rotor gearbox with the cables attached.
  • Page 155 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-16. TIR Indicator for the Output Shaft Rev. 11 MM-10-47 Oct 25/19...

  • Page 156: Tail Rotor Driveshaft And Flex Coupling

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-6 TAIL ROTOR DRIVESHAFT AND FLEX COUPLING General Information – Flex Coupling The alignment of the tail rotor flex couplings is a very important factor in achieving the full service life of the flex pack. Large offsets on the tension side of the pack usually indicate improper spacing of the coupling sections, and will promote premature distortion or degradation of the flex pack.
  • Page 157 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Tail Rotor Driveshaft Coupling Hub (Forward Flange) Bolt Coupling Hub (Rear Flange) Washer Sleeve Taper Pin Flex Pack Taper Pin Cable Tie Cup Washer Plug Washer (If Item 7 is not present) Flex Coupling Washer (Beveled) Figure 10-17.
  • Page 158 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL The elements are all deformed evenly, with no separation or voids between the elements. The offset is less than .060 inch as shown in Figure 10-21. The coupling hubs which hold the flex elements must be flat within .010 inch as shown in Figure 10-22.
  • Page 159 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-19. Tail Rotor Drive Shaft Coupling Installation, Rear Coupling Shown; Forward Coupling Similar Figure 10-20. Acceptable Limits of Bowed Flex Packs Rev. 11 MM-10-51 Oct 25/19...
  • Page 160 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-21. Acceptable Limits for Flex Packs with Offset Bends Figure 10-22. Acceptable Limits for Bent Coupling Hub Flanges Rev. 11 MM-10-52 Oct 25/19...

  • Page 161: Installation - Flex Coupling

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Installation – Flex Coupling (Figure 10-17) NOTE: Proper attention during installation and alignment must be taken to permit couplings to operate to full capacity and provide good service life. Install rain slinger on tail rotor gearbox (Figure 10-18).

  • Page 162: Disassembly - Pillow Block

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Mark the pillow blocks to the tailcone to assist with alignment during installation. Remove bolts and washers attaching pillow blocks to tailcone. NOTE: Save shims for reinstallation. Temporarily tape the shims to the tailcone in the respective positions.
  • Page 163 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-23 Figure 10-24 Rev. 11 MM-10-55 Oct 25/19...

  • Page 164: Assembly - Pillow Block

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Assembly – Pillow Block Heat bearing housing to approximately 250°F/121°C. Lubricate the bore of the housing and install the bearing into position. NOTE: The open side of the bearing is installed inboard toward the grease fitting.
  • Page 165 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Temporarily slide forward coupling half on the forward end of the driveshaft and place the driveshaft on the tailcone. Reassemble the couplings together such that the flanges are in alignment. Install equal thickness spacers between the flex pack and the flanges. An alternate method is to use a .235 in aluminum block.

  • Page 166: Alignment - Driveshaft

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Alignment – Driveshaft Clamp piano wire attachment tools T-0088 to each end of the driveshaft. Attach the piano wire between the tools and center it vertically down the centerline of the driveshaft. NOTE: If the alignment tools differ in height greater than allowable, it is not possible to obtain proper alignment of the tail rotor drive shaft.
  • Page 167 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL M. Final Assembly – Driveshaft Install the tach drive pulley on the driveshaft. Disconnect the forward coupling and install the tach drive O-rings and cover. Connect the coupling. Install the vertical stabilizer on 280F models only.

  • Page 168: Tail Rotor Control System

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10-7 TAIL ROTOR CONTROL SYSTEM Tension Check – Tail Rotor Cable Control System Install the tail rotor rigging tool T-0080 (0.590 in/15 mm side) between the bearing retainer and the output shaft seal retainer to hold the tail rotor pitch controls in the neutral position (Figure 10-26).

  • Page 169: Tail Rotor Control Cables

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Verify that the pedals are in alignment. If not aligned, adjust the cable tension in accordance with para. 10-7, A. Move the pedals to the full left position. Insert the tail rotor rigging tool T-0080 (narrow profile) between the output shaft seal housing and the face of the brass bushing in the pitch control assembly (Figure 10-26).
  • Page 170 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-26. Rigging Tool T-0080 Installation Figure 10-27. Wooden Wedges Installed Rev. 11 MM-10-62 Oct 25/19...
  • Page 171 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-28. Tail Rotor Pedal Adjustment Stops Rev. 11 MM-10-63 Oct 25/19...
  • Page 172 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Advisory Circular 43.13-1B, paragraph 7-149, Cable System Inspection. If the pulleys are rubbing on the mounting brackets, AN960-10L washers may be used as shims to eliminate the interference. CAUTION: In older aircraft, turnbuckles located near the turbocharger have a high susceptibility to rapid deterioration.
  • Page 173 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Clamp the tail rotor pedals in neutral position using two wood blocks and C-clamps. Install the tail rotor rigging tool T-0080 (0.590 in/15 mm) between the bearing retainer and the output shaft seal retainer to hold the tail rotor pitch controls in the neutral position (Figure 10-26).
  • Page 174 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Cut the cable forward of the turnbuckle in the engine compartment (Detail Attach a string to the aft end of the cable and pull it out forward through the firewall and the seat assembly. Attach a new cable to the string and pull it back through the firewall.
  • Page 175 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 10-29. Tail Rotor Cables Rev. 11 MM-10-67 Oct 25/19...
  • Page 176 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 11 MM-10-68 Oct 25/19...
  • Page 177 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 12 FLIGHT CONTROLS TABLE OF CONTENTS Paragraph Description Page 12-1 Troubleshooting the Articulated Rotor System ........MM-12-3 A. General ....................MM-12-3 B. Problems, Checks, Solutions ..............MM-12-3 12-2 Main Rotor Blade Tracking ............... MM-12-5 A.
  • Page 178 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 12 FLIGHT CONTROLS TABLE OF CONTENTS Paragraph Description Page D. Cyclic Rigging to Swashplate ............. MM-12-39 E. Main Rotor Hub – Cyclic and Collective Rigging ........ MM-12-39 12-8 Cyclic Azimuth Check ................MM-12-42 A. Verification of Rigging ................. MM-12-42 B.

  • Page 179: Troubleshooting The Articulated Rotor System

    NOTE: Replacement blades must be matched by Enstrom Helicopter Service. Provide serial numbers of good blades and helicopter serial number. Blade repairs must be performed by an authorized blade repair facility. (e) Main rotor blade...
  • Page 180 “Blade Information Sheet”, or replace tabs if damaged. NOTE: If tab angles are not available, contact Enstrom Helicopter Service for original angles. Provide aircraft serial number. (f) Main rotor blades Inspect blades for evidence of Extent of damage will suffered “hangar...

  • Page 181: Main Rotor Blade Tracking

    16-digit series, XXXX-YZZ-ZZZZZ-Z, where XXXX is the blade S/N, and Y is the spar code, and ZZ-ZZZZZ-Z is the Enstrom part number; or a 5- digit series, XXXX-Y where XXXX is the blade S/N, and Y is the spar code.
  • Page 182 For this reason, Enstrom recommends that the strobe light only be used on the ground for initial ground track or for initial hover track if the initial ride is unacceptably rough.

  • Page 183: Installation Of Equipment

    Install the vertical velocimeter on the right side of the instrument panel pedestal (Figure 12-3). NOTE: Enstrom recommends not using a strobe light to track blades. Three-blade rotor systems do not necessarily fly in track and the strobe may produce misleading information and lengthen the tracking procedure.
  • Page 184 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-2. Optical Sensor Installation (280FX) Figure 12-3. Velocimeter Installation (280FX) Rev. 11 MM-12-8 Oct 25/19...

  • Page 185: Tabbing Out Feedback

    Enstrom helicopters with minimum cyclic vibration. Less than optimum outboard tabbing will result in excessive inboard tab to achieve a smooth ride and also excessive cyclic stick vibration.

  • Page 186: Hover Tracking

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Run the helicopter again and using the same procedure, compare the magnitude of the cyclic feedback. Again, it should either be eliminated, stay the same or get worse. If it stays the same or gets worse, then set the #1 blade outboard tab back to zero, and add two degrees up to the #2 blade outboard tab.
  • Page 187 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-4. Vertical Accelerometer Channel “B” Polar Chart Rev. 11 MM-12-11 Oct 25/19...

  • Page 188: Lateral Balancing

    If work has been done to the blades as per paragraph 12-1, follow the procedures listed below. It is not recommended to change tip weights in the Enstrom rotor system because there is no centering mechanism in the hydraulic lead-lag dampers. Changing tip weights usually results in the blade flying in different lead-lag position but will not cure the underlying cause of a lateral imbalance.
  • Page 189 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-5. Lateral Accelerometer Channel “A” Polar Chart Rev. 11 MM-12-13 Oct 25/19...

  • Page 190: Clock Angle Corrections

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL G. Clock Angle Corrections NOTE: The clock angle correction is seldom the same in hover as it is in forward flight so when the tracking progresses to the forward flight phase, a new chart should be used, and the correction will have to be figured again.
  • Page 191 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-6. Main Rotor Clock Angle Correction Example Rev. 11 MM-12-15 Oct 25/19...
  • Page 192 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-6.1. Main Rotor Clock Angle Correction Example Rev. 11 MM-12-16 Oct 25/19...
  • Page 193 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-6.2. Main Rotor Clock Angle Correction Example Rev. 11 MM-12-17 Oct 25/19...
  • Page 194 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-6.3. Main Rotor Clock Angle Correction Example Rev. 11 MM-12-18 Oct 25/19...

  • Page 195: Collective Pitch Control Stick

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-3 COLLECTIVE PITCH CONTROL STICK A. Description The collective pitch control stick controls rate of climb when pulled upward by increasing the pitch of all three main rotor blades simultaneously and to the same degree. Downward movement of the collective stick decreases the pitch of the blades which decreases lift on the rotor and allows for a controlled descent.

  • Page 196: Removal - Copilot Collective

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install bolt (1), washers, nut and torque. Connect the electrical wiring, as applicable. Connect the wire terminals for the starter button. (Illuminated collective control only) Connect the electrical harness to the connector on the forward side of the seat deck.
  • Page 197 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Bolt Threaded Shaft Bolt Check nut DU Washer Spring Capsule Assembly Expando Pin Pivot Retainer Strap Control Rod Figure 12-7. Collective Control System Rev. 11 MM-12-21 Oct 25/19...

  • Page 198: Collective Trim System

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-4 COLLECTIVE TRIM SYSTEM NOTE: Refer to Service Information Letter SIL 0184, latest revision, regarding a collective trim system update to simplify collective balance adjustment. A. Collective Trim Capsule Removal (Figure 12-9) Remove the fiberglass seat deck.
  • Page 199 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-8. Collective Spring Capsule in Holding Tool T-0022 (As removed from the collective trim system) Rev. 11 MM-12-23 Oct 25/19...
  • Page 200 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Washer Washer Capsule Pivot Spacer Bracket Bellcrank Bolt Bolt Washer Spacer Check Nut Pivot Retainer Strap Tie Rod Bolt Link Washer Spring Housing Spring Spacer Washer Bolt Spring Retainer Washer Link Assembly Figure 12-9. Collective Trim, Spring Capsule Assembly Rev.
  • Page 201 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL B. Collective Trim – Disassembly Carefully place the spring capsule assembly horizontally between jaws of bench vise. Cut safety wire from special tool T-0022. Slowly rotate the vise handle to release spring pressure until all tension is relieved.
  • Page 202 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install spacer (17) into bellcrank (18). Place washers (16) on each side of bellcrank (18) and carefully slide the spring capsule assembly into position. Attach the spring capsule to bellcrank (18) with bolt (13), washers (14), and nut (15).

  • Page 203: Cyclic Pitch Control Stick

    RPM. USE EXTREME CARE. NOTE: If needed, contact Enstrom Product Support for additional assistance regarding collective trim adjustments. To correct for an out-of-balance condition, a light collective (easier up than down), release tension on the spring in the trim capsule.

  • Page 204: Lateral And Longitudinal Trim Actuators

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-6 LATERAL AND LONGITUDINAL TRIM ACTUATORS A. Troubleshooting Problem Cause Required Action Trim Actuator (1) Faulty motor Remove the actuator assembly. Inoperative Troubleshoot in the following order to (2) Faulty microswitch determine which area is causing (3) Spring capsule binding on problem.
  • Page 205 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Housing Housing Spring Capsule Spring Capsule Bolt Bolt Light Washer Heavy Washer Spacer Spacer Bolt Bolt Harper (ECD050) Washer Spacer Figure 12-10. Trim Motor Installation Rev. 11 MM-12-29 Oct 25/19...

  • Page 206: Removal - Longitudinal Trim Actuator

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL C. Removal – Longitudinal Trim Actuator (Figure 12-10) Identify wires and their location before disconnecting from the microswitches. (12V) Disconnect wires from the microswitches and from the quick disconnect attached to ground wire. (24V) Disconnect the trim actuator electrical connector from TSU.
  • Page 207 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Screw Coupling Washer Snap Ring Switch Assembly Worm Gear Assembly Housing Washer Spring Capsule Assembly Lock Washer (ACME) Shaft and Cover Assembly Motor Figure 12-11. Trim Motor Assembly Rev. 11 MM-12-31 Oct 25/19...

  • Page 208: Assembly - Trim Actuator

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Spring capsule assembly – Acme nut replacement is accomplished by removing the three screws at base of capsule. Remove and replace nut. Reinstall the switch activator and screws to the base of the capsule. The rubber bumper at base of capsule is attached by applying contact cement adhesive to both the bumper and acme nut.

  • Page 209: Installation - Lateral Trim Actuator

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL G. Installation – Lateral Trim Actuator (Figure 12-10) Install spacer (8) into housing (1). Install spacer (5) into spring capsule (2). Install the actuator assembly into the seat structure and align with mounts. Install bolt (7) through light washer (4), seat structure mount and spacer (8).

  • Page 210: Flight Control Rigging

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-7 FLIGHT CONTROL RIGGING NOTE: Cyclic and collective rigging must be done in sequence starting with the cyclic pitch controls. A rigging check must be accomplished any time components of the control system have been removed and exact dimensions such as rod lengths or bellcrank angles are not available prior to re-installation of that component.
  • Page 211 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-12. Cyclic Rigging Chart Rev. 11 MM-12-35 Oct 25/19...

  • Page 212: Collective Rigging - Seat Deck Area

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Secure jam nuts and move the cyclic stick laterally to assure the rod ends do not bind. Adjustment check - Rotate the pilot's cyclic stick around the cyclic stop ring. Check that both left and right bellcranks maintain contact with the stop ring through 360 degrees of travel.
  • Page 213 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-13. Cyclic Stick Rigging, Tool T-1775 Installed Rev. 11 MM-12-37 Oct 25/19...
  • Page 214 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-14. Cyclic Bellcranks Parallel to Mount Figure 12-15. Collective Housing to Seal Housing Clearance Rev. 11 MM-12-38 Oct 25/19...

  • Page 215: Cyclic Rigging To Swashplate

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL D. Cyclic Rigging – To Swashplate Install rigging tool T-1775 in the cyclic stop ring (Figure 12-13). NOTE: Run the trim motors to slightly preload cyclic stick against tool. Install swashplate centering tools T-1575 to hold the swashplate perpendicular to the main rotor shaft (Figure 12-16).
  • Page 216 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-16. Installation of Swashplate Rigging Tool T-1575 Rev. 11 MM-12-40 Oct 25/19...
  • Page 217 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-17. Main Rotor Azimuth Positions Rev. 11 MM-12-41 Oct 25/19...

  • Page 218: Cyclic Azimuth Check

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Remove tool T-1575. Place the collective control stick in full up position. Rotate #1 blade to the 97° azimuth position (Figure 12-17). Set protractor at +19° and position it on top of the flat area of the blade grip. Adjust the collective up stop at the seat deck until the bubble is centered, giving +19 degrees ±...

  • Page 219: Autorotative Rpm Adjustment

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Move the cyclic stick to full right position. Measure the blade grip angle. Measurement to be 14.5 degrees ± .5 degree. NOTE: If adjustments are required, adjust rod (13) (Figure 12-12). Move the cyclic stick to full left position. Measure blade grip angle. Measurement to be - 2.5 degrees ±...

  • Page 220: Cyclic Trim Springs Rigging Procedure

    NOTE: The lateral bias spring installation is configured one of two ways. Helicopters certified to 2350 lb gross weight are configured as shown in Figure 12-18(a); Helicopters certified to 2600 lb gross weight (configured to Enstrom Specification Drawing 28-100015) are configured as shown in Figure 12-18(b).
  • Page 221 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-18. Lateral Bias Spring Installation (a) Applicable to 2350 lb gross weight helicopters (b) Applicable to 2600 lb gross weight helicopters configured to Enstrom Specification 28-100015 Figure 12-19. Longitudinal Bias Spring Installation Rev. 11...

  • Page 222: Lower Swashplate Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-10 LOWER SWASHPLATE ASSEMBLY A. Removal – Lower Swashplate Assembly (Figure 12-20) Remove both side panel cowls. Drain fuel tanks. Disconnect fuel lines and remove the left side fuel tank (para. 13-10). Disconnect the longitudinal cyclic rod (2) from lower bearing housing (1) by removing bolt (3), washers (4) and (5), spacer (6) and nut (7).
  • Page 223 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 10. Pull the bolt (1) and bearing assembly (3) and (4) from the lower universal housing (7). 11. Press the bolt (1) from the bearing (3) and remove slinger (6) and spacer (5). 12. Remove the retaining ring (2) and grease fitting from the housing (4).
  • Page 224 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Lower Bearing Housing Lateral Push-Pull Rod Longitudinal Push-Pull Rod Nut (P/N AN320-4) Bolt Washer Washer Spacer 1/4 Harper Washer Rod End (Dog Leg) Spacer Bolt Lower Swashplate Housing Bolt Bolt Washer Washer Cotter Pin Figure 12-20. Lower Swashplate Installation Rev.

  • Page 225: Lower Swashplate Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Bolt (Shaft) Washer Retaining Ring DU Washer Bearing Shim Bearing Housing DU Bearing Spacer Sleeve Slinger Universal Shaft Lower (Universal) Housing Upper Housing Washer Tie Rod Assembly Spacer Cotter Pin Light Washer Set Screw (if equipped) Figure 12-21.
  • Page 226 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 1) Inspect the universal joint for looseness/play by twisting and pushing and pulling the upper and lower housings of the lower swashplate against each other. 2) Inspect the tie rod and universal shaft axis for end play by attempting to move the upper and lower housings against each other along the tie rod and universal shaft axes.
  • Page 227 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Lubricate (MIL-PRF-81322) the bolt (1) and install into the lower universal housing (7). Install the washer (8) and nut (9). Torque the nut and install a cotter pin. Apply VC3 Vibra-Tite over the end of the bolt, nut, and cotter pin.
  • Page 228 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install the tie rod (19) into the universal shaft (17) to prevent the shaft from rotating and install a nut (11). Ensure the DU washer is properly seated on the retention pin on the washer (12). Torque the nut to 110-150 in-lb/12.5-17.0 Nm and check that the cotter pin hole is aligned.
  • Page 229 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL CAUTION: Ensure that the spacers (20) used on the tie rod are the correct length (Refer to Table 12-1). Failure to install the correct length spacers can result in premature wear of the tie rod and universal shaft.
  • Page 230 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install spacer (6) in the longitudinal push-pull rod (2). With washers (5) on each side of spacer (6), insert push-pull rod (2) into the lower bearing housing (1). Install bolt (3), washers (4) and nut (7) to secure the rod in place. Torque (30-40 in-lb/3.4- 4.5 Nm) the nut and install the cotter pin (20).
  • Page 231 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-1. Inspection Requirements – Lower Swashplate Assembly Fig. 12-21 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-16123-1 Bolt Bearing surface Dia. -.0002 Not Repairable Replace Bolt .4723 to .4726...
  • Page 232 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-1. Inspection Requirements – Lower Swashplate Assembly Fig. 12-21 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # ≤ .003 deep 28-16228-1 Spacer Nicks and gouges None Allowed Polish out smooth...
  • Page 233 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-1. Inspection Requirements – Lower Swashplate Assembly Fig. 12-21 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-16223-19 Universal Shaft O.D. .4991 to .4995 -.0003 Not Repairable Replace Shaft Tie Rod Bore +.0005...

  • Page 234: Upper Swashplate Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-11 UPPER SWASHPLATE ASSEMBLY A. Removal – Upper Swashplate Assembly (Figure 12-22) Remove the screws and fiberglass cover over the collective push-pull rod located above the seat deck in the cabin. If required, remove screws (19) and washers (18) to remove the magnetic pickup bracket (17) (Figure 12-23).
  • Page 235 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Bolt Bushing (ref. SIL 0178) Push-Pull Rod Pivot Strap Dogleg Pivot Strap Bushing Push-Pull Rod Bolt Bolt Walking Beam Washer Bolt NOTE: See Figure 12-23 if equipped with optional magnetic pickup bracket. Figure 12-22. Upper Swashplate Installation Rev.
  • Page 236 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 13. Slide bell of the upper swashplate up and down to tap the swashplate assembly from the lower end of the mast. B. Disassembly – Upper Swashplate Assembly (Figure 12-23) Install blocks (T-1758) on each side of the control housing (14) and clamp blocks in a vise with the nuts (1) facing up for removal.

  • Page 237: Upper Swashplate Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Spacer Lock Plate Bushing Bell Housing Control Housing Bolt Bushing Washer Retainer and Guide Shaft Assembly Bearing Retainer (Guide Tube Assembly) Shims Magnetic Pickup Bracket Bearing Washer Bearing Housing Screw Lube Fitting Slinger Interrupter Figure 12-23. Upper Swashplate Assembly Rev.
  • Page 238 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL D. Inspection – Upper Swashplate Assembly Inspect the swashplate rod end (dog leg) (10, Figure 12-22) assemblies for excessive bearing play/wear. Using a suitable light source and inspection mirror, as required, visually inspect each of the dog leg assemblies for condition and/or excessive radial play/wear between the bearing uni-ball and the uni-ball bearing race (Figure 12-22).
  • Page 239 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Place the shims (7) on the face of housing (9). Install the bearing retainer (6) in place and secure with washers (5) and screws (4). Torque (12-15 in-lb/1.4-1.7 Nm) the screws in an alternating sequence and lockwire in pairs with .025 safety wire.
  • Page 240 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL F. Installation – Upper Swashplate Assembly and Guidetubes (Figure 12-22) Lubricate (MIL-PRF-81322) the bore of main rotor mast at the lower end. Align the slot in the control housing (14) with the locking pin in lower end of the mast and install the upper swashplate assembly into the mast.
  • Page 241 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Insert stainless steel spacer (7) into the end of the push-pull rods (6) and spacer (8) into the center pivot of the pitch change bellcrank (5). Install push-pull rods (6) into mast and connect to the pitch change bellcrank (5) with bolts (3), washers, and nuts.
  • Page 242 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-24. Alignment Tool T-0054 for Dog Leg Installation Rev. 11 MM-12-66 Oct 25/19...
  • Page 243 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-2. Inspection Requirements – Upper Swashplate Assembly Fig. 12-22 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-16132-4 Pivot Strap Bushing I.D. .3750 to .3755 +.0005 Not Repairable Replace Bushing Fig.
  • Page 244 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-2. Inspection Requirements – Upper Swashplate Assembly Fig. 12-23 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-16108-2, -11 Bearing Housing Bearing bore Dia. No Tolerance Not Repairable Replace Housing 3.9365 to 3.9371...
  • Page 245 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-2. Inspection Requirements – Upper Swashplate Assembly Fig. 12-23 Part Name Inspection* Serviceable Limits* Repair Limits* Repair or Action Item # 28-16260-1 Retainer and Guide Sheared or worn rivets None Allowed If rivet is sheared...

  • Page 246: Main Rotor Push Pull Rods

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-12 MAIN ROTOR PUSH PULL RODS NOTE: The following was formerly contained in Section 23 and includes data incorporated from SIL 0156. See also SDB 0096. A. Removal – Main Rotor Push-Pull Rods Remove the push-pull rod in accordance with para. 12-11, A, steps 7 through 11.
  • Page 247 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Push-Pull Rod Assembly Washer Teflon Bearing Insert Bushing Pitch Change Bellcrank Washer Bushing Bolt Bushing Figure 12-25. Main Rotor Push-Pull Rod Installation Rev. 11 MM-12-71 Oct 25/19...
  • Page 248 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL a) Inspection Area Identification b) Push-Pull Rod Runout Inspection c) Lower Fitting Contact Wear Limits Figure 12-26. Main Rotor Push-Pull Rod Inspections Rev. 11 MM-12-72 Oct 25/19...
  • Page 249 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-27. Main Rotor Push-Pull Rod Corrosion Pitting Rev. 11 MM-12-73 Oct 25/19...
  • Page 250 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Table 12-3. Inspection Requirements – Main Rotor Push-Pull Rod Part Name Inspection Serviceable Limits Repair Limits Repair or Action Push-Pull Rod Cracks or Dents No Tolerance Allowed Not Repairable Replace Push-Pull Rod Assembly Assembly Nicks, scratches, or corrosion .007 in /.18mm...

  • Page 251: Flight Test Procedure

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 12-13 FLIGHT TEST PROCEDURE A. Preliminary Checks NOTE: Whenever a helicopter has had work accomplished to the flight controls, it is recommended that a flight test be conducted before returning the helicopter to service. Perform a preflight inspection. See Rotorcraft Flight Manual, Section 4.

  • Page 252: Hover Test

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Retard throttle to idle position and check for disengagement of sprag clutch by observing tachometer needle split. Smoothly rejoin tach needles and set engine RPM at 3050. Perform normal run-up procedures. Check throttle for false limit at 3050 RPM. No stop should be contacted prior to 3050 RPM.
  • Page 253 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: Do not adjust for minor trim conditions until necessary adjustments for autorotation, V , and cruise procedures have been completed which are discussed later in this test procedure. For left pedal and collective rigging low rpm check, proceed as follows: Stabilize aircraft at 1 foot hover and normal operating range with heading into the wind.
  • Page 254 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Visually check static ring for cyclic position on pilot's side. Cyclic stick should be centered and slightly aft in the ring. Trim aircraft to neutral forces. Release cyclic to ensure adequate trim is available. Change collective setting to check spring forces of collective bungee. Record if other than "0"...

  • Page 255: Hne

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL F. V and V Checks Fly aircraft to 1000 feet AGL. Record pressure altitude, temperature, and gross weight information. Adjust engine RPM to 3050 with 39" manifold pressure in level flight. Allow two minutes for aircraft to stabilize. Record airspeed.
  • Page 256 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 12-28. Autorotational RPM Correction Chart – Sea Level Base Altitude Rev. 11 MM-12-80 Oct 25/19...
  • Page 257 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SECTION 13 POWERPLANT AND ASSOCIATED SYSTEMS TABLE OF CONTENTS Paragraph Description Page 13-1 Powerplant ..................... MM-13-1 A. General Description ................MM-13-1 B. Operating Specifications ..............MM-13-1 13-2 Engine ....................MM-13-3 A. Engine and Turbocharger Troubleshooting ........MM-13-3 B.
  • Page 258 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Paragraph Description Page 13-7 Primary Airflow System ..............MM-13-52 A. General Information ................ MM-13-52 B. Air Filter and Housing ..............MM-13-55 13-8 Cooling System ................... MM-13-57 A. General Information ................ MM-13-57 B. Fan Assembly ................. MM-13-57 C.
  • Page 259 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Master Switch – On Boost Pump – On Observe open fitting for evidence of fuel leakage. NOTE: Fuel leakage indicates scored (a) mixture control jet, (b) rotating plates or a damaged "O" ring on the jet.
  • Page 260 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Disconnect throttle (5) and wastegate (6) controls. Remove four attachment bolts (7). Disconnect air inlet hose (8) from injector adapter. Disconnect injector and air inlet adapter (9) by removing the four connecting bolts, two of which attach these components to the mounting bracket.
  • Page 261 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Lean engine until the RPM rise just before shut down is 0 to 25 RPM. NOTE: If the linkage rod bottoms out or disengages at either end during adjustments, it will be necessary to remove, adjust and reassemble...
  • Page 262 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (9) Injector Repairs Lapping idle valve and mixture control valve Disconnect mixture control cable from the injector mixture control lever. Remove the following: Two screws holding the mixture control lever assembly. Mixture control level assembly.
  • Page 263 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Mixture Control (1) General Information The mixture control cable is manually operated by depressing the knob in end of control handle and pushing inward to richen mixture and pulling out to lean mixture. The mixture control handle also has a vernier adjustment to complete fine mixture adjustments.
  • Page 264 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 13-6. Mixture Control Rigging Rev. 7 MM-13-38 Aug 22/16...

  • Page 265: General Information

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Connect exhaust collar and steel gasket to the turbocharger exhaust inlet. Rotate the collar for correct alignment. Install exhaust inlet clamp, torque to 70-80 in-lb/7.9-9.0 Nm and safety. NOTE: Slip clamp over end of tube to assemble. Do not spread.
  • Page 266 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 13-9. Turbocharger Installation Rev. 8 MM-13-50 Sep 20/17...

  • Page 267: Magneto Operation Check

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Release the starter button. Turn the magneto switch to OFF. Check the system, replace or adjust components as necessary. (10) Repeat checking procedure before reconnecting the starter. D. Magneto Operation Check Start the engine and engage the rotor.
  • Page 268 Observe at this time that the pointer in the rotor viewing window aligns with the “L” marked on the rotor. If internal timing of the magneto is required, refer to the Enstrom Tech Tip or Bendix Operation and Maintenance Manual No. L-928.
  • Page 269 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 13-15 Rev. 11 MM-13-69 Oct 25/19...
  • Page 270 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Rotate the magneto in the opposite direction until the first set of contacts opens. Tighten the magneto clamps and install the plug in the viewing hole. Back the engine up approximately 20° to 30° and then carefully bump the engine forward while observing the timing light.

  • Page 271: Harness Assembly

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install the bottom spark plugs and torque in accordance with Lycoming specifications (30-35 ft-lb/40.7-47.5 Nm). Harness Assembly (See Figure 13-16) Ignition wires are routed from the left magneto to all the cylinder top spark plugs and those from the right magneto to all the cylinder bottom spark plugs.

  • Page 272: Fuel System

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL 13-10 Fuel System General Information The fuel system consists of the fuel tanks, fuel boost pump, valve, filter, fuel lines, engine driven fuel pump and fuel pressure switch. Fuel is gravity fed from the tanks through the shut-off valve, boost pump, filter and fuel lines to the inlet side of the engine driven fuel pump.

  • Page 273: Scavenge Pump

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Install two screws and washers in top of heat shield. NOTE: It may be necessary to bend the heat shield slightly to facilitate installation of the top two screws. Install two screws and washers in the bottom of the heat shield.

  • Page 274: Correlator

    Operating Principles The mechanical correlator installed on the Enstrom Piston Engine helicopters automatically operates the throttle when the pilot moves the collective relieving the pilot of having to manipulate the throttle to maintain blade RPM in the green arc.

  • Page 275: Troubleshooting The Correlator

    (2) Correlator: If the actuator arm pivot shaft is still moving laterally (forward) after the throttle cable has been disconnected, there is a problem with the correlator. Contact Enstrom product support if the cause cannot be determined. Rev. 11 MM-13-94.1...
  • Page 276 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 13-22.1. (a) Clearance between the arm and the stop; (b) Open position Figure 13-22.2. Correlator Assembly Rev. 11 MM-13-94.2 Oct 25/19...

  • Page 277: Correlator Preflight Rigging

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (3) Wastegate: Disconnect the wastegate actuating arm from the throttle arm on the servo and operate the wastegate by hand. Operate the throttle and observe the throttle actuating arm for lateral movement on the pivot shaft, if the correlator now works correctly the issue is in the servo.

  • Page 278: Injector Rigging

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Injector Rigging (1) The injector shall be rigged as shown in Figure 13-26. The injector is at idle position. The lever may be repositioned in 15° increments by loosening the butterfly shaft nut. (2) The injector used for the “F” model shall be one of two types: Part No.
  • Page 279 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Set injector idle stop arm against stop pin (Figure 13-26). Set correlator summing lever at idle stop, point "A" (Figure 13-25). Remove bolt connecting throttle cable to throttle arm on servo and check that bolt is a slip fit and that the throttle stop is against the stop (Figure 13-26).

  • Page 280: Correlator Post-Flight Rigging

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL NOTE: Preflight rigging is now completed. Correlator will perform satisfactory until idle screw/mixture linkage adjustment has been made. Readjustment of correlator is then required for satisfactory and safe correlator function. Correlator Post-Flight Rigging (1) Readjust override stop, point "B" (Figure 13-27).

  • Page 281: Adjusting The Correlator After Maintenance

    ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL (3) Check wide open injector position: Raise collective stick 2" from down stop position and lock or .25 inch from stop (see Figure 13-29). Rotate twist grip to wide open position. Check if injector wide open stop arm is against stop pin.
  • Page 282 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL Figure 13-23. Forward Cable Attach Point Rev. 11 MM-13-100 Oct 25/19...
  • Page 283 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT Diagram 21-1 Rev. 11, Oct 25/19 MM-21-15...
  • Page 284 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT Diagram 21-2 Rev. 11, Oct 25/19 MM-21-16...
  • Page 285 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT SECTION 24 INSTRUMENTS TABLE OF CONTENTS Paragraph Description Page 24-1 Engine Monitor ..................MM-24-1 24-2 Description ..................MM-24-1 24-3 Maintenance ..................MM-24-2 24-4 Programming Alarm Limits ............... MM-24-2 24-5 Troubleshooting ................MM-24-2 24-6 Clock ...................... MM-24-7 24-7 Outside Air Temperature Indicator (OAT) ..........
  • Page 286 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT INTENTIONALLY LEFT BLANK Rev. 11 MM-24-0.2 Oct 25/19...
  • Page 287 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT 24-6. Clock A digital clock, if equipped, may be installed in the switch and circuit breaker panel or the instrument panel (F-28F S/N 833 and subsequent; 280FX S/N 2167 and subsequent). The clock is powered by an internal alkaline battery which should be replaced every 12 months.
  • Page 288 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT Table 24-3. Vendor Contact Information Component Vendor GEM 603 or 610 Insight Instrument Corporation Tel: 905-871-0733; Fax: 905-871-5460 www.insightavionics.com EDM 700 J.P. Instruments Tel: 1-800-345-4574 or 714-557-3805; Fax: 714-557-9840 sales@jpinstruments.com www.jpinstruments.com Clock - M800 Davtron Tel: 1-866-369-5588;...
  • Page 289 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT Inspection – Rotor RPM Magnetic Pick-up Inspect the magnetic pick-up for security of installation and condition and security the electrical wires and connectors. Using a multi-meter, check for 270-330 ohms across the leads. Repair – Rotor RPM Magnetic Pick-up Repair damaged wiring or electrical connectors.
  • Page 290 ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT Left: Inspection Plug; Right: Magnetic Pick-up Figure 24-2. Magnetic Pick-up Installation Rev. 11 MM-24-10 Oct 25/19...

This manual is also suitable for:

280f series

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