AD/B737/149 - Autothrottle Computer (Cth)

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

Boeing 737 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/B737/149 Autothrottle Computer 1/2001

Applicability: All Model 737-300, -400, and -500 series aeroplanes.

Requirement: 1. Replace the existing autothrottle computer with a new, improved autothrottle computer in accordance with Boeing Alert Service Bulletin 737-22A1130 dated 24 September 1998.

2. Autothrottle computers with Part Numbers 10-62017-1, -2, -3, -4, -5, -11, -21, -23, -25, or -27 may not be fitted to any aeroplane to replace an installed computer.

Note: FAA AD 2000-23-34 Amdt 39-12007 refers.

Compliance: For Requirement 1 - Within 18 months after the effective date of this Directive.

For Requirement 2 - As of the effective date of this Directive.

This Airworthiness Directive becomes effective on 25 January 2001.

Background: The aircraft manufacturer has received several reports of asymmetric thrust conditions during flight caused by irregular autothrottle operation in which the thrust levers slowly move apart causing the aeroplane to bank excessively and go into a roll.