1AD/B747/141 - Pylon - Inboard and Outboard Strut Forward Lower Spar

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 747 Series Aeroplanes

AD/B747/141 Pylon - Inboard and Outboard Strut Forward Lower Spar

5/95

Applicability: B747 L/N 001 - 510 powered by JT9D-3 or -7 series engines, excluding JT9D-70 engines.

Requirement: Perform a detailed visual inspection of the Inboard and Outboard Strut Forward Lower Spar Chords, Stiffeners and Web to detect cracks and loose fasteners. Inspect in accordance with Boeing Service Bulletin 747-54-2160.

Note: FAA AD 94-17-17 refers.

Compliance: Initially inspect before 2 February 1996 or before exceeding 6000 landings, whichever is the later.

Aircraft that have accumulated between 6000 and 15000 landings shall be inspected before 2 October 1995.

Aircraft which have accumulated more than 15000 landings shall be inspected before 2 July 1995.

Reinspect at intervals not to exceed 2000 landings or 8000 hours time in service, whichever occurs first.

Background: There have been five reports of cracks in the subject web. In addition it is suspected that a web crack may have contributed to a recent engine separation.