82-21-04 JET ELECTRONICS AND TECHNOLOGY, INC.: Amendment 39-4475. Applies to all Model PS-835 series Emergency Power Supply installations.
NOTE: This power supply is usually used to supply electrical power for third (standby) attitude indicators, emergency lighting, radio communications and other equipment critical to the safety of the airplane.
Compliance: Required as indicated unless already accomplished.
To prevent a false indication, that emergency power is available, accomplish the following:
a) Within the next 25 hours time-in-service after the effective date of this AD check to determine whether the emergency power supply installation incorporates a panel located battery test switch.
1) If the installation incorporates a panel located battery test switch, prior to further flight install a temporary placard near the test switch which reads as follows:
TO TEST EMER PWR SUPPLY
1. DISREGARD EMER PWR SW TEST POSITION
2. A/C MASTER/BATTSW-OFF
3. EMER PWR SW-ON
4. CK OPERATION OF ACCESSORY/INSTR
b) On or before October 1, 1983, examine the aircraft manufacturer's records and/or emergency power supply installation to determine whether the emergency power supply is a J.E.T. model PS-835A, -835B, -835C or -835D. If the power supply is a PS-835A not incorporating a Mod 6, a PS-835B not incorporating a Mod 7, a PS-835C not incorporating Mod 1 or a PS-835D not incorporating a Mod 1, modify the J.E.T. power supply in accordance with J.E.T. Service Bulletin SB501-1228-7 dated May 20, 1982. Remove the temporary placard if required by paragraph a) of this AD when the modification required by this paragraph is incorporated.
c) Paragraph a) of this AD may be accomplished by the owner/operator on any airplane owned or operated by the person. This person must make the prescribed aircraft record entry indicating compliance with paragraph a) of this AD.
d) The modification required by paragraph b) of this AD must be accomplished by an appropriately rated, FAA certificated repair station on those power supplies used as a source of power for flight instruments.
e) Aircraft may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished.
f) An equivalent method of compliance with this AD may be used if approved by the Chief, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018; telephone (312) 694-7127.
This amendment becomes effective on October 21, 1982.