AD/B747/394 - Thrust Reverser Control System 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.

Boeing 747 Series Aeroplanes AD/B747/394 Thrust Reverser Control System Wiring 9/2009 DM

Applicability: Model 747-400 and -400F series aeroplanes, powered by Rolls-Royce RB211 series engines. Requirement: Modify the thrust reverser control system wiring to the flap control unit (FCU) in the P414 and P415 panels in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin (ASB) 747-78A2181, dated 8 June 2009. Later revisions of the above ASB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-13-03, are considered acceptable for compliance with the equivalent Requirements of this Directive. Note: FAA AD 2009-13-03 Amdt 39-15942 refers. Compliance: Within 60 days after the effective date of this Directive. This Airworthiness Directive becomes effective on 6 July 2009. Background: The FAA has received a report of automatic retraction of the leading edge flaps during takeoff due to indications transmitted to the FCU from the thrust reverser control system.

This Directive is issued to prevent automatic retraction of the leading edge flaps during takeoff, which could result in reduced climb performance and consequent collision with terrain and obstacles or forced landing of the aeroplane.