Accessories And Utilities Description; Accessories And Utilities - Safety Precautions; Accessories And Utilities Inspection And Overhaul Time Limits - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
SECTION XIV
ACCESSORIES AND UTILITIES
14-1. INTRODUCTION. This section coven accessories which are available in this airplane and are not
covered in other sections of this Service Manual. This information provides instructions for remedying
difficulties which may arise in any of the accessories and the instructions are organized so the mechanic may
refer to whichever component or system he must repair or adjust.
14-2. OXYGEN SYSTEM.
1-3. DESCRIPTION AND PRINCIPLE OF OPERATION. The oxygen system consists of an oxygen
cylinder and regulator, charging valve, pressure gauge, outlets and masks and an ON/OFF control. High
pressure is routed from the cylinder and regulator to the pressure gauge. Low pressure oxygen is routed from
the cylinder and regulator to the outlets and masks whenever the control knob is pulled to the ON position.
Each outlet has a springloaded valve which prevents the flow of oxygen until a mask hose is engaged in the
outlet.
144.
TROUBLESHOOTING. A troubleshooting chart is located at the back of the oxygen system portion
of this section.
14-5. SAFETY PRECAUTIONS. Utmost care must be exercised in servicing, handling and inspection of the
oxygen system. A fully charged oxygen cylinder contains enough pressure to cause serious injury to personnel
and damage to equipment. Keep hands, tools and working area clean and post NO SMOKING signs. Keep all
components of the system free from oil, grease, gasoline and all readily combustible material. Never allow
electrical equipment to come in contact with the oxygen cylinder. Keep fire and heat away from oxygen
equipment and take care not to generate sparks with carelessly handled tools.
14-6. INSPECTION AND OVERHAUL TIME LIMITS. It is recommended that inspection and overhaul be
conducted by an FAA Approved Station or the manufacturer, Scott Aviation. The following checks and chart
gives recommended inspection and overhaul time for the various parts of the oxygen system.
a. The oxygen cylinder can be identified by the ICC or DOT identification stamped on the cylinder.
The standard weight cylinder (ICC or DOT 3AA 1800) must be hydrostatic tested at the end of each 5 year
period. The lightweight cylinder (ICC or DOT 3HT 1850) must be hydrostatic tested every 3years and must be
retired from service after 24 years, or 4,380 pressurizations, whichever occurs first. The month and year of the
last test is stamped on the cylinder beneath the ICC or DOT identification.
b. The outlets should be checked for leakage both in the non-use condition, and for leakage around an
inserted connector.
c. The high pressure gauge may be checked for accuracy by comparing its indicated pressure with that
of a gauge of known accuracy.
d. Inspection of the regulator may be effected by introducing into an outlet a mask connector to which
is attached a 100 psi gauge. With one other outlet flowing through a plugged in mask, the indicated regulator
output pressure shall be not less than 45 psig at sea level with 200 psig supply cylinder pressure. It should be
noted that the permissible leakage through the 1/16 diameter vent hole in the side of the upper regulator housing
is 10 cc/min. maximum, when the regulator is turned on. There shall be no external leakage anywhere on the
regulator when it is turned off. All fittings shall be leak free.
Revised: 3/31/94
ACCESSORIES AND UTILITIES
4E5