AD/F28/89 APU Enclosure Drains and Wiring (Cth)

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 39.001(1) of CASR 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.

Fokker F28 Series Aeroplanes

AD/F28/89 APU Enclosure Drains and Wiring 7/2005

Applicability:

Fokker Aircraft Model F.28 Mk.1000 through 4000 series.

Requirement:

Perform a one-time inspection on the drain tubes and the wiring underneath the APU enclosure in accordance with the Accomplishment Instructions of Fokker Service Bulletin (SB) F28/49-038, dated 26 April 2004 or later CAA-NL / EASA approved revisions.

Note:  BLA (CAA - The Netherlands) Airworthiness Directive (AD) 2004-059 dated 29 April 2004, approved under EASA reference 2004-4045 dated 20 April 2004 refers.

Compliance:

Unless already accomplished, within the next 6 calendar months after the effective date of this Directive.

This Airworthiness Directive becomes effective on 7 July 2005.

Background:

Following an APU fire incident, inspection of the aircraft revealed that the fire had caused severe damage to the rear pressure bulkhead as well as the wiring and flight control cables that run between the APU enclosure and the rear pressure bulkhead.  Subsequent investigation showed that one of the APU drains was not connected to the APU enclosure feed-through, allowing fuel to accumulate underneath the APU enclosure.

Accumulated fuel in or under the APU enclosure may lead to fire and / or loss of aircraft.  The AD addresses the identified unsafe condition through a one-time inspection to verify that all drain tubes are correctly installed and that the wiring is not damaged.

James Coyne
Delegate of the Civil Aviation Safety Authority

23 May 2005