AD/B747/317 - Inadvertent Commanded Shutdown of the Engine Bleed Air Systems (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 39.1 (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.

Boeing 747 Series Aeroplanes

AD/B747/317 Inadvertent Commanded Shutdown of the Engine Bleed Air Systems

13/2004

Applicability: Boeing Model 747-400, -400D and –400F series aircraft as listed in Boeing Service Bulletin (SB) 747-36A2136 Revision 2, dated 13 May 2004.

Requirement: 1. Perform the following modifications and functional tests of the wiring of the wire integration unit (WIU) and the air supply control test unit (ASCTU) of the engine bleed air distribution system in accordance with the Accomplishment Instructions of Boeing SB 747-36A2136, Revision 2:

(a) remove the existing ASCTU,

(b) do the wiring changes between the WIU and ASCTU and the wiring changes to the WIU,

(c) do the resistance tests, and

(d) install a new or reworked ASCTU.

2. After accomplishing paragraphs 1(b), 1(c) and 1(d) of this AD perform the post- installation tests in accordance with SB 747-36A2136.

Note 1: Modifications and tests accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-36A2136, dated April 12, 2001; or Revision 1, dated January 17, 2002; are considered acceptable for compliance with the corresponding actions specified in Requirement 1 of this AD, provided the resistance tests were done with the ASCTU removed.