Commonwealth legislation

AD/B747/77 - APU Fire Detection

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

4/10 complexity

This directive mandates a modification to the APU electrical power circuitry on specified Boeing 747‑400s, to be carried out per Boeing Service Bulletin 747‑26‑2135 (or later), to prevent loss of APU fire‑detection power if the main battery switch is turned off. It affects owners/operators and maintenance organisations, who must fund and schedule the work by the compliance date (17 August 1990) to remove the identified safety vulnerability.

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AD/B747/77 - APU Fire Detection

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COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Boeing 747 Series Aeroplanes

AD/B747/77 APU Fire Detection 5/90

Applicability: All model Boeing 747-400 series aeroplanes as listed in Boeing SB 747-26-2135 Revision 1, or later revision.

Requirement: Modify the APU electrical power circuitry in accordance with Boeing SB 747-26- 2135 Revision 1 or later revision.

Compliance: Prior to 17 August 1990.

Background: In the current configuration if the main battery switch is turned off whilst the APU is operating, power to the APU fire detection system is removed. The APU goes through a 60 second cool down cycle with the fire detection system inoperative.

Compliance with this AD is required to correct this unacceptable condition.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.