{"id":"F2008L03126","name":"AD/B747/128 Amdt 3 - Lower Lobe Lap Joints at Wing to Body Fairing","slug":"ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":75168,"registerId":"commonwealth-F2008L03126-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 747 Series Aeroplanes","sectionType":"division","heading":"Boeing 747 Series Aeroplanes","content":"### Boeing 747 Series Aeroplanes\n\n| AD/B747/128 Amdt 3 | Lower Lobe Lap Joints at Wing to Body Fairing | 11/2008 DM |\n| ------------------ | --------------------------------------------- | ---------- |\n\n| Applicability: | Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007 or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2008-16-14 Amdt39-15632.Note: Boeing Alert Service Bulletin (ASB) 747-53A2312 Revision 3 or later FAA approved revision refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Compliance:    | As specified in the requirement document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n|                | This Amendment becomes effective on 17 September 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | This Directive was prompted by reports of cracking in the stringer 34 lap joint near the interface with the wing-to-body fairing. This condition, if not corrected, could result in an in-flight depressurisation of the aircraft.Amendment 1 reduced the number of aircraft to be inspected and widened the inspection area to include all lap splice upper rows under the wing-to-body fairing.Amendment 2 allowed use of ASB 747-53A2312 Revision 3 as an alternative method of compliance with the requirements of FAA AD 94-15-06.Amendment 3 is issued to change the requirement document. FAA AD 94-15-06 Amdt 39-8977 is superseded by FAA AD 2008-16-14 Amdt 39-15632. This results in a change to the High Frequency Eddy Current inspection method due to possible faulty results when inspecting Alodine-coated rivets; adds an additional one time inspection for cracking; and terminates the adjusting factor for the inspection compliance times based on cabin differential pressure. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n18 August 2008","sortOrder":0},{"sectionNumber":"AD/B747/128 Amdt 3","sectionType":"part","heading":"AD/B747/128 Amdt 3","content":"## AD/B747/128 Amdt 3","sortOrder":1},{"sectionNumber":"Lower Lobe Lap Joints at Wing to Body Fa","sectionType":"part","heading":"Lower Lobe Lap Joints at Wing to Body Fairing","content":"## Lower Lobe Lap Joints at Wing to Body Fairing","sortOrder":2},{"sectionNumber":"11/2008 DM","sectionType":"part","heading":"11/2008 DM","content":"## 11/2008 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 3 replaces the earlier FAA requirement document (FAA AD 94-15-06) with FAA AD 2008-16-14, resulting in specific scope changes: it modifies the HFEC inspection method (to address Alodine-coated rivet issues), adds an additional one‑time inspection for cracking, and removes the previous adjusting factor for inspection compliance times based on cabin differential pressure (Background)."},"complexity_factors":["Cross-reference to an external FAA AD as the operative requirement (Requirement: \"Action in accordance with the technical requirements of FAA AD 2008-16-14\").","Multiple prior amendments and supersession history that change compliance obligations (Background: \"Amendment 3 is issued to change the requirement document... FAA AD 94-15-06 ... is superseded by FAA AD 2008-16-14\").","Technical change to inspection method (High Frequency Eddy Current) to address unreliable results on Alodine-coated rivets, which affects inspection procedure and equipment choice (Background: \"change to the High Frequency Eddy Current inspection method due to possible faulty results when inspecting Alodine-coated rivets\").","Addition of a mandated one-time inspection in the new requirement document, creating an extra compliance action for operators (Background: \"adds an additional one time inspection for cracking\").","Termination of an existing compliance-time adjustment factor tied to cabin differential pressure, altering scheduling and interval calculations for inspections (Background: \"terminates the adjusting factor for the inspection compliance times based on cabin differential pressure\").","Broad aircraft applicability across many 747 variants increases logistical coordination for operators and maintainers (Applicability: lists multiple 747 models and references Boeing ASB 747-53A2312 Revision 3).","Allowance of an alternative method of compliance by referencing a Boeing Alert Service Bulletin (ASB) introduces dependency on manufacturer documentation and potential FAA-approved revisions (Background & Applicability: reference to ASB 747-53A2312 Revision 3 as alternative)."],"plain_english_summary":"This Airworthiness Directive requires operators of the listed Boeing 747 models to perform inspections and corrective actions on the lower-lobe lap joints at the wing-to-body fairing in line with FAA AD 2008-16-14. It affects aircraft owners, operators and maintenance organisations because reported cracking could cause in-flight depressurisation; the AD changes inspection technique and timing and adds a one‑time inspection."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The directive has evolved significantly from its original purpose. Amendment 1 expanded the inspection area beyond the original scope. Amendment 2 introduced alternative compliance methods. Amendment 3 fundamentally changed the underlying technical requirements by switching from FAA AD 94-15-06 to FAA AD 2008-16-14, altered the inspection methodology due to discovered technical flaws in the previous method, added new inspection requirements, and removed the pressure-based compliance adjustment system. The current scope is substantially broader and more technically demanding than the original 1994 directive."},"complexity_factors":["Heavy reliance on external technical documents — the actual requirements are contained in FAA AD 2008-16-14 and Boeing Alert Service Bulletin 747-53A2312, not in the directive itself","Multiple amendment history (Amendments 1, 2, and 3) with cumulative changes to inspection scope, methods, and compliance calculations","Specific technical terminology requiring aviation engineering knowledge (lap joints, stringer 34, High Frequency Eddy Current inspection, Alodine-coated rivets)","Cross-referencing between Australian directive and US FAA regulations creates jurisdictional complexity","Conditional applicability based on aircraft model variants and certification categories"],"plain_english_summary":"This directive orders operators of classic Boeing 747 models (‑100/200/300/400, 747SR, 747SP) to inspect and repair lower‑lobe lap joints near the wing‑to‑body fairing after cracks were found at stringer 34 that could cause sudden cabin depressurisation. Amendment 3 aligns the rules with a newer FAA AD, revises the inspection method to avoid false readings on coated rivets, adds an extra inspection and removes a pressure‑differential scheduling exemption."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing","history":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing/history","analysis":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing/analysis","conflicts":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing/conflicts","importantCases":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing/important-cases","documents":"/api/acts/ad-b747-128-amdt-3-lower-lobe-lap-joints-at-wing-to-body-fairing/documents"}}