Commonwealth legislation

AD/B747/159 - Forward Pressure Bulkhead

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Commonwealth

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legislative instrument

Plain English Summary

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This Airworthiness Directive requires operators of most Boeing 747s (line numbers 1–886, except 80, 85 and 151) to inspect the forward pressure bulkhead using Boeing Service Bulletin 747-53-2355 at the specified flight thresholds and intervals; repairs or modifications done per that Service Bulletin remove the inspection requirement for the repaired area. Flights with cabin differential ≤2.0 psi are excluded from the flight-counting rule.

The objective claimed is to limit fatigue cracking from repeated pressurisation. Operators pay inspection and repair costs, must track qualifying flights, and follow the technical procedures set out in the Boeing Service Bulletin while CASA enforces the AD.

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AD/B747/159 - Forward Pressure Bulkhead

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/B747/159 Forward Pressure Bulkhead 8/96

Applicability: All model 747s, line numbers 1 to 886 excepting 80, 85 and 151.

Requirement: Inspect the forward pressure bulkhead structure in accordance with Boeing SB 747- 53-2355.

Note: This Service Bulletin supersedes Boeing SB 747-53-2210.

Compliance: Inspect at the flight thresholds and intervals specified in Boeing SB 747-53-2355, Paragraph D. Aircraft over these times must be inspected within 500 flights after 18 July 1996.

Modification or repair of each area in accordance with Boeing SB 747-53-2355 cancels the inspection requirements for that area.

Note: For the purposes of this AD, flights on which the cabin pressure differential does not exceed 2.0 psi need not be counted.

Background: Numerous cracks caused by cyclic pressure loads have been found in the forward pressure bulkhead on aircraft in service and on both the 747 forward fuselage fatigue test articles. A series of inspections and structural changes are required to limit the fatigue damage to the bulkhead. This Directive replaces outer ring chord inspections previously specified in AD/B747/46 Amdt 4.

Source text

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

1 AD/B747/159 - Forward Pressure Bulkhead