Commonwealth legislation

AD/B737/81 Amdt 1 - Thrust Reverser Control System Inspection and Modification

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Commonwealth

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legislative instrument

Plain English Summary

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Mechanically, this directive requires operators of Boeing 737-300/‑400/‑500 aircraft (that have not installed Boeing SB 737‑78‑1053) to perform a specific Auto‑Restow test of the thrust‑reverser control system every 4,000 flight‑hours and to install thrust‑reverser sync‑locks by 31 December 1999. The stated goal is to reduce the risk of uncommanded in‑flight thrust‑reverser deployment after an accident. Operators bear inspection, repair and modification costs; they may either fix defects before flight or operate under an approved MEL, creating downtime and scheduling trade‑offs.

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Direct links to the current provisions in AD/B737/81 Amdt 1 - Thrust Reverser Control System Inspection and Modification.

AD/B737/81 Amdt 1 - Thrust Reverser Control System Inspection and Modification

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 737 Series Aeroplanes

AD/B737/81

Amdt 1

Thrust Reverser Control System Inspection and Modification

2/95

Applicability: All Boeing 737-300, -400, and -500 series aircraft not incorporating the intent of Boeing Service Bulletin 737-78-1053.

Requirement: 1. Carry out the test of the thrust reverser specified in the Boeing 737 Maintenance Manual, Section 78-31-00, titled “Auto-Restow Test” to verify proper operation of the thrust reverser Auto-Restow function.

The B737 Maintenance Manual contains test procedures for the Auto-Restow function dependent on thrust reverser modification standard and engine accessory unit configuration. Select the appropriate procedure for the particular thrust reverser/EAU configuration undergoing test.

If any discrepancy is found during this test either rectify the defect before further flight or operate the aircraft in accordance with an approved MEL.

Note: Boeing Message M-7272-94-6132 dated 7 December 1994 refers.

Incorporate thrust reverser sync-locks per Boeing Service Bulletin 737-78-1053 Revision 1, Revision 2, or Revision 3.

Incorporation of Boeing Service Bulletin 737-78-1053 is terminating action for Requirement 1 of this Directive. Following modification per S.B. 737-78-1053, subsequent test of the Auto-Restow function is to be in accordance with the requirements specified in the Boeing 737 Maintenance Planning Document (MPD).

Note: FAA AD 94-21-05 also refers.

Compliance: 1. Unless previously accomplished, prior to 31 March 1995, and thereafter at intervals not to exceed 4000 flight hours since the last inspection.

Not later than 31 December 1999.

Background: This Directive has been issued as a result of an on-going design review of thrust reverser systems following an accident that was attributed to an uncommanded in- flight deployment of a thrust reverser.

Amendment 1 has superseded the original issue of the Directive prior to the normal promulgation date due to the subsequent receipt of additional clarifying information which identifies a specific test of the thrust reverser control system in lieu of the previous requirement for a range of tests.

Source text

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

1 AD/B737/81 Amdt 1 - Thrust Reverser Control System Inspection and Modification