Commonwealth legislation

AD/B747/143 - Fuselage Section 41 Skin Stringer Joints

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

5/10 complexity

A safety order requires operators of early Boeing 747s (line numbers 001–430) to inspect the upper front fuselage for cracking around rivets using close visual and eddy‑current techniques, and to inspect or modify any external repair patches. Inspections are recurring with specified flight‑cycle deadlines; only pressurized flights (≥2.0 psi) count.

This matters because discovered cracks—up to ~0.5"—can grow and cause sudden loss of cabin pressure, creating a serious in‑flight safety hazard.

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Current sections

Direct links to the current provisions in AD/B747/143 - Fuselage Section 41 Skin Stringer Joints.

AD/B747/143 - Fuselage Section 41 Skin Stringer Joints

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/B747/143 Fuselage Section 41 Skin Stringer Joints 5/95

Applicability: Boeing 747 aircraft line numbers 001 to 430 inclusive.

Requirement: 1. Inspect the Section 41 upper fuselage skin at the skin to stringer fastener rows in the areas between Body Stations (BS) 220 and BS 520 left and right hand sides, between stringers S-6 and S-14, excluding the lap joints.

Inspect, using close visual and eddy current methods in accordance with Boeing Service Bulletin (SB) 747-53A2321, Revision 5.

Inspect using high frequency Eddy Current, and, if required modify, any external repair doublers that overlap the skin-stringer fastener locations.

Inspect and modify in accordance with Boeing SB 747-53A2321, Revision 5, Fig 3.

Note 1: FAA AD 90-26-10 refers.

Compliance: 1. Inspect in accordance with Requirement 1 before 12 000 flights, or before 1000 flights after 27 April 1995, whichever occurs later.

Re-inspect at intervals not to exceed 2000 flights.

Inspect doublers in accordance with Requirement 2 before 10 000 flights after doubler installation, or before 1000 flights after 27 April 1995, whichever occurs later.

Re-inspect at intervals not to exceed 1500 flights.

Modify doublers before 15 000 flights, or within 1000 flights after 27 April 1995, whichever is the later.

Note 2: For the purposes of this AD a flight shall be where the cabin pressure differential equals or exceeds 2.0 psi.

Background: A number of operators have reported skin cracks at skin-stringer fastener locations. Some cracks were up to 0.5" long. Skin cracks that reach critical length can cause an in flight de-pressurization.

Source text

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

1 AD/B747/143 - Fuselage Section 41 Skin Stringer Joints