Commonwealth legislation

AD/B747/145 Amdt 1 - Outboard Engine Strut Spring Beam

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What this does: Requires operators of Boeing 747 aircraft (line numbers 202–396) fitted with Pratt & Whitney JT9D‑70 engines to carry out the technical actions set out in FAA AD 98‑21‑17, effective 28 January 1999.

Who it affects and why it matters: CASA enforces the directive; aircraft operators pay for compliance. The measure responds to titanium spring‑beam porosity that can cause fatigue cracking and possible engine loss, and updates the earlier 1995 directive to reflect an improved manufacturing process.

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AD/B747/145 Amdt 1 - Outboard Engine Strut Spring Beam

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/B747/145

Amdt 1

Outboard Engine Strut Spring Beam 1/99

Applicability: Model 747 series aircraft, line numbers 202 through 396, equipped with Pratt & Whitney Model JT9D-70 engines.

Requirement: Action in accordance with the technical requirements of FAA AD 98-21-17 Amdt 39- 10826.

Note: Boeing Service Bulletins 747-54A2171 and 747-54-2177 refer.

Compliance: As specified in the Requirement Document with a revised effective date of 28 January 1999.

This Amendment becomes effective on 28 January 1999.

Background: A failure of an outboard spring beam on a number 4 engine strut was reported. The failure was due to a material problem in the titanium spring beam which is only fitted to B747 aircraft with JT9D-70 engines. Continued operation with a damaged spring beam could result in loss of an engine.

Amendment 1 is issued in response to a new FAA AD which was prompted by the development of an improved process for manufacturing titanium spring beams that will eliminate the embedded porosity flaws in the existing spring beams, from which fatigue cracking can originate.

The original issue of this Airworthiness Directive became effective on 25 June 1995.

Source text

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

1 AD/B747/145 Amdt 1 - Outboard Engine Strut Spring Beam