AD/B737/176 - Inspection and Replacement of Engine and APU Fire Detection System Assemblies or Elements (Cth)

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

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Boeing 737 Series Aeroplanes

AD/B737/176 Inspection and Replacement of Engine and APU Fire Detection System Assemblies or Elements

4/2002

Applicability: Model 737-700 and -800 series aeroplanes, line numbers 1 to 81 inclusive, except line numbers 73 to 80.

Requirement: 1. Inspect the Auxiliary Power Unit (APU) and engine fire detection assemblies and replace, as applicable, any fire detector assembly or element in accordance with the technical requirements of FAA AD 98-21-11 amendment 39-10819.

2. No person shall install, on any aeroplane, an Auxiliary Power Unit (APU) or engine fire detector assembly or element having a serial number listed in paragraphs (b)(1), (b)(2), or (b)(3) of FAA AD 98-21-11.

Compliance: As of the effective date of this Airworthiness Directive.

This Airworthiness Directive becomes effective on 18 April 2002.

Background: The FAA received a report from the manufacturers indicating that certain fire detector assemblies and elements were not checked for helium gas leaks during manufacture and therefore may have incorrect set points for the fire warning indicating system. The requirements of this Directive are intended to prevent failure of the APU or the engine fire detector system to detect a fire in a timely manner.