Commonwealth legislation

AD/B737/149 - Autothrottle Computer

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

This Airworthiness Directive requires operators of Boeing 737-300, -400 and -500 aeroplanes to replace the autothrottle computer with a new, improved unit and forbids fitting certain listed autothrottle part numbers. It responds to reports of irregular autothrottle behaviour that produced asymmetric thrust and a risk of loss of control. Replacement must follow Boeing Alert Service Bulletin 737-22A1130 and be completed within 18 months; the prohibition on listed parts is effective immediately, so operators must procure and install the approved unit and meet the compliance timeframe.

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AIRWORTHINESS DIRECTIVE

View image in the official source

View image in the official source
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.

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.

This Directive requires replacement of the existing autothrottle computer with a new, improved autothrottle computer. This action is intended to prevent a severe asymmetric thrust condition developing during flight, which could result in loss of control of the aeroplane.

Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.

Eugene Paul Holzapfel

Delegate of the Civil Aviation Safety Authority 11 December 2000

View image in the official source

The above AD is notified in the Commonwealth of Australia Gazette on 20 December 2000.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

AIRWORTHINESS DIRECTIVE AIRWORTHINESS DIRECTIVE

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.