Commonwealth legislation

AD/B737/39 - APU Fire Detector Element

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legislative instrument

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This Airworthiness Directive requires operators of Boeing 737s fitted with Walter Kidde APU fire-detection systems to inspect the APU compartment and confirm the correct Walter Kidde detector element (identified by a perforated shield or specific part numbers) is installed; if not visible, the lower APU shroud must be opened for verification. It affects aircraft operators and maintenance organisations and matters because an incorrect Systron‑Donner element can give a cockpit test pass while failing to detect an actual APU fire. Compliance was required by 19 July 1990.

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AD/B737/39 - APU Fire Detector Element

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 737 Series Aeroplanes

AD/B737/39 APU Fire Detector Element 7/90

Applicability: All model 737 series aircraft equipped with Walter Kidde APU fire detection systems.

Requirement: Inspect to ensure a Walter Kidde fire detector element is installed in the APU compartment. This inspection may be performed by viewing through the APU cooling air exhaust outlet. The Walter Kidde element is protected by a perforated shield surrounding the length of the element. If the perforated shield is not seen, open the lower APU shroud and verify that for 737-300 and 737-400 series aircraft, the fire detector element installed is Boeing P/N 10-61096-316 / Walter Kidde P/N 894481, and for 737-100 and 737-200 series aircraft, the fire detector element installed is Boeing P/N 10-62061-6 or P/N 10-61096-116.

Compliance: Prior to 19 July 1990.

Background: Boeing has advised that several aircraft with Walter Kidde APU fire detection systems were found to have a Systron-Donner fire detector element fitted instead of the correct Walter Kidde element. This would result in a positive flight deck fire detector test even though the system would not have detected an actual fire.

Source text

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

1 AD/B737/39 - APU Fire Detector Element

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Boeing 737 Series Aeroplanes

AD/B737/39 APU Fire Detector Element 7/90

Applicability: All model 737 series aircraft equipped with Walter Kidde APU fire detection systems.

Compliance: Prior to 19 July 1990.