{"id":"F2006B03063","name":"AD/B747/160 - Fuselage Skin Above Main Entry Doors - 2","slug":"ad-b747-160-fuselage-skin-above-main-entry-doors-2","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42422,"registerId":"commonwealth-F2006B03063-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/160 - Fuselage Skin Above Main Entry Doors - 2","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/B747/160 Fuselage Skin Above Main Entry Doors \\- 2 8/96\n\nApplicability: B747 aircraft, line numbers 207 to 1088.\n\nNote. AD/B747/149 refers to a similar problem for line numbers 1 to 206.\n\nRequirement: 1. Remove stringers S-15, S-14E, S-14 between STA 460 and 480, and move STA 460 frame aft to gain internal access to the skin and doublers above main entry door 1. Perform an internal visual inspection for cracking of doublers along fastener holes up to stringer S-14E. Perform open-hole High Frequency Eddy Current (HFEC) inspections of skin and doublers up to stringer S-14 for cracking. Gain access and conduct inspections in accordance with Boeing Service Bulletin (SB) 747-53A2396, Revision 1.\n\n    2. If cracks are found, repair and reinforce the skin joint in accordance with the Structural Repair Manual, or if no cracks are found, install an external doubler in accordance with Boeing SB 747-53A2396, Revision 1.\n\n    3. After modification or repair in accordance with Requirement 2, reinspect the affected area using internal High Frequency Eddy Current (HFEC) or external Low Frequency Eddy Current (LFEC) inspections, in accordance with Boeing Service Bulletin 747-53A2396, Revision 1.\n\nNote: For the purposes of this AD, a flight-cycle may be taken as only those flights which achieve a cabin pressure differential of 2.0 psi or greater.\n\nCompliance: Inspect, and reinforce the skin joint by repair or modification, before 10000 flight cycles or within 3000 flight cycles after 18 July 1996, whichever occurs last.\n\nInitially reinspect within 15000 flight cycles after modification or repair, and thereafter reinspect at intervals not to exceed 6000 flight cycles if using internal HFEC, or at intervals not to exceed 3000 flight cycles if using external LFEC inspectors.\n\nBackground: An operator has reported numerous skin cracks found in internal skin doublers under the outer flange of STA 460 frame above main entry door 1. Boeing's subsequent inspection of 747-100SR fuselage and 747-400 section 41 and 42 fatigue test articles also revealed multiple cracking. Further inspection of 5 in-service aircraft revealed 4 aircraft with multiple cracking at times as low as 15,000 flights. Skin cracks that are not found and reinforced may lead to sudden loss of cabin pressurisation.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"This AD addresses Boeing 747 line numbers 207–1088 for skin cracking above main entry door 1; a separate AD (AD/B747/149) covered line numbers 1–206. The two instruments together extend the inspection/repair requirement to the broader fleet by covering the remainder of serial ranges (Applicability; Note)."},"complexity_factors":["Technical inspection mix: internal visual inspection, open-hole High Frequency Eddy Current (HFEC) and external Low Frequency Eddy Current (LFEC) options with differing detection capability and intervals (Requirement 1; Requirement 3).","Access-modifying structural work required to gain inspection access: removal of stringers S-15, S-14E, S-14 and moving STA 460 frame aft (Requirement 1).","Repair/mitigation choices: either repair/reinforce per the Structural Repair Manual or install an external doubler per Boeing SB (Requirement 2).","Prescriptive compliance timing and reinspection cadence tied to flight-cycle counts and inspection method: initial compliance before 10,000 flight cycles or within 3,000 after 18 July 1996; reinspect initially within 15,000 cycles after modification/repair and thereafter every 6,000 cycles (internal HFEC) or 3,000 cycles (external LFEC) (Compliance).","Flight-cycle definition depends on cabin pressure exposure (only flights with cabin differential ≥ 2.0 psi count), which affects compliance accounting (Note).","Narrow applicability by serial/line numbers (207–1088) and cross-reference to a separate AD for line numbers 1–206, which affects which operators must comply (Applicability; Note).","Dependence on external documents and manufacturer procedures (Boeing Service Bulletin 747-53A2396 Rev 1 and the Structural Repair Manual) creates implementation reliance on those materials and any required approvals (Requirement 1; Requirement 2).","Operational and maintenance burden: requires skilled nondestructive testing, structural access work and possible reinforcement/repair downtime and parts, creating direct costs for operators (Requirement 1–3; Compliance).","Safety consequence if not corrected: potential sudden loss of cabin pressurisation motivating the AD's prescriptive measures (Background)."],"plain_english_summary":"This AD requires operators of Boeing 747 aeroplanes (line numbers 207–1088) to open up and inspect the fuselage skin and internal doublers above main entry door 1, remove specific stringers and shift a frame for access, then repair or install external doublers per Boeing Service Bulletin 747-53A2396 Rev 1. It sets deadlines and reinspection intervals to detect and fix cracking that the AD says can lead to sudden loss of cabin pressurisation."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope: addressing a specific structural fatigue issue in a defined subset of Boeing 747 aircraft. The directive does not expand beyond its original purpose of mandating inspection and repair of fuselage skin cracking above main entry door 1."},"complexity_factors":["Technical aviation terminology throughout (e.g., 'stringers', 'STA 460', 'doublers', 'flight cycles') requiring specialised knowledge","Multiple compliance pathways contingent on inspection findings (crack found vs. no crack found)","Cross-reference to external technical documents (Boeing Service Bulletin 747-53A2396, Structural Repair Manual) without reproducing their content","Nested timing requirements with alternative calculation methods (10,000 flight cycles OR 3,000 cycles after specific date, whichever is later)","Different re-inspection intervals based on method chosen (6,000 vs 3,000 flight cycles)","Specific definition of 'flight cycle' provided in a note (cabin pressure differential of 2.0 psi or greater)","Applicability limited by manufacturing line numbers requiring cross-checking against aircraft records"],"plain_english_summary":"This Airworthiness Directive orders owners/operators of Boeing 747s (line numbers 207–1088) to inspect and fix cracking in the fuselage skin above the main passenger door. It targets cracks around doubler fastener holes that can grow and cause sudden cabin depressurisation.\n\nCompliance requires inspection, repair or reinforcement, and recurring checks. It matters because undetected crack growth has already been found on multiple aircraft and could lead to catastrophic loss of cabin pressure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2","history":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2/history","analysis":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2/analysis","conflicts":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2/conflicts","importantCases":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2/important-cases","documents":"/api/acts/ad-b747-160-fuselage-skin-above-main-entry-doors-2/documents"}}