Commonwealth legislation

AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket

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Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

5/10 complexity

Requires operators of Boeing 747s (line numbers 202–886) with GE CF6‑45/50 engines to inspect the engine thrust‑control idler pulley support bracket for cracking, permits a temporary repair for a single crack under 2.0 inches, and mandates replacement of aluminium brackets with Inconel 625 parts per Boeing service bulletins. Inspections and replacements must meet specified flight‑hour and date deadlines; replacing with Inconel 625 removes the inspection requirement. Operators pay for inspections, repairs and parts and must follow the Boeing SB procedures.

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Direct links to the current provisions in AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket.

AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket

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/B747/144 Engine Thrust Control - Idler Cable Pulley Support Bracket

5/95

Applicability: B747 Line numbers 202 to 886 inclusive equipped with GE CF6-45/50 engines.

Requirement: 1. Visually inspect number 1 strut engine thrust control cable idler pulley support bracket for cracking in accordance with Boeing SB 747-76A2083. Brackets with a single crack less than 2.0 inches long may remain in service provided the interim repair is installed in accordance with Boeing SB 747-76A2083 Revision 1.

Replace the aluminium alloy idler pulley support bracket with one made of Inconel 625 in accordance with Boeing SB 747-76A2083 Revision 2.

Note: FAA AD 93-17-06 refers.

Compliance: 1. a. Inspect in accordance with Requirement 1 before 9000 hours time in service or within 600 hours time in service from 27 April 1995, whichever is the later.

Re-inspect at intervals not to exceed 600 hours time in service.

b. Inspect brackets with the interim repair installed in accordance with Requirement 1 at intervals not to exceed 100 hours time in service.

2. a. Replace interim repaired brackets in accordance with Requirement 2 within 750 hours time in service from repair installation.

2. b. Replace brackets in accordance with Requirement 2 before 10 November 1995.

Note: Replacement with brackets manufactured from Inconel 625 cancels the inspection requirements of this AD.

Background: Five operators have reported cracks in the thrust control cable idler pulley support brackets. Failure of the brackets could result in loss of control of engine thrust.

Source text

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

1 AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket