{"id":"F2006B03044","name":"AD/B747/143 - Fuselage Section 41 Skin Stringer Joints","slug":"ad-b747-143-fuselage-section-41-skin-stringer-joints","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42403,"registerId":"commonwealth-F2006B03044-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/143 - Fuselage Section 41 Skin Stringer Joints","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/143 Fuselage Section 41 Skin Stringer Joints 5/95\n\nApplicability: Boeing 747 aircraft line numbers 001 to 430 inclusive.\n\nRequirement: 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.\n\nInspect, using close visual and eddy current methods in accordance with Boeing Service Bulletin (SB) 747-53A2321, Revision 5.\n\n2. Inspect using high frequency Eddy Current, and, if required modify, any external repair doublers that overlap the skin-stringer fastener locations.\n\nInspect and modify in accordance with Boeing SB 747-53A2321, Revision 5, Fig 3.\n\nNote 1: FAA AD 90-26-10 refers.\n\nCompliance: 1. Inspect in accordance with Requirement 1 before 12 000 flights, or before 1000 flights after 27 April 1995, whichever occurs later.\n\nRe-inspect at intervals not to exceed 2000 flights.\n\n2. 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.\n\nRe-inspect at intervals not to exceed 1500 flights.\n\nModify doublers before 15 000 flights, or within 1000 flights after 27 April 1995, whichever is the later.\n\nNote 2: For the purposes of this AD a flight shall be where the cabin pressure differential equals or exceeds 2.0 psi.\n\nBackground: 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.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1928},"content_quality":"ok","complexity_score":5,"scope_assessment":{"changed":false,"description":"This appears to be the original 1995 airworthiness directive focused specifically on addressing fuselage skin cracking issues in early-model Boeing 747s. The scope remains tightly focused on the stated safety issue without expansion into unrelated areas."},"complexity_factors":["Technical aviation terminology requiring specialized knowledge (Body Stations, stringers, doublers, eddy current testing)","Multiple conditional compliance deadlines using 'whichever occurs later' logic","External cross-references to Boeing Service Bulletin 747-53A2321 and FAA AD 90-26-10","Specific applicability limited to aircraft line numbers 001-430","Custom definition of 'flight' for compliance calculation (pressure differential ≥2.0 psi)","Multiple inspection methods specified for different scenarios (visual vs. eddy current vs. high frequency eddy current)"],"plain_english_summary":"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.\n\nThis matters because discovered cracks—up to ~0.5\"—can grow and cause sudden loss of cabin pressure, creating a serious in‑flight safety hazard."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints","history":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints/history","analysis":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints/analysis","conflicts":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints/conflicts","importantCases":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints/important-cases","documents":"/api/acts/ad-b747-143-fuselage-section-41-skin-stringer-joints/documents"}}