AD/B747/229 - Engine Thrust Control Cables (Cth)

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

Boeing 747 Series Aeroplanes

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.

AD/B747/229 Engine Thrust Control Cables 7/2000

Applicability: Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, SR and SP series aircraft fitted with P&W JT9D-3 or -7 series engines, CF6-45 or -50 series engines or RB211-524B, C or D series engines.

Requirement: Action in accordance with the technical requirements specified in FAA AD 2000-05- 30 Amendment 39-11640.

Note: FAA AD 2000-05-30 Amendment 39-11640 refers.

Compliance: At the time specified in the FAA AD except for a revised effective date of 13 July 2000.

This Airworthiness Directive becomes effective on 13 July 2000.

Background: The FAA have identified an unsafe condition that relates to the effect of a thrust control cable failure on controllability of the aircraft. Should an engine control thrust "B" cable fail during landing, it changes the position of the thrust reverser directional control valve, causing the thrust reverser to stow and the engine to accelerate while the other engines remain in full reverse. This will result in a severe asymmetric condition during landing.