{"id":"F2006L00726","name":"AD/B747/258 Amdt 1 - Engine Pylon Diagonal Brace Underwing Fitting","slug":"ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":136750,"registerId":"commonwealth-F2006L00726-current","compilationNumber":null,"startDate":"2026-04-03","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/B747/258 Amdt 1 | Engine Pylon Diagonal Brace Underwing Fitting | 4/2006 |\n| ------------------ | --------------------------------------------- | ------ |\n\n| Applicability: | Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SR, and 747SP series aircraft, as listed in Boeing Alert Service Bulletin747-57A2312 Revision 1, or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2005-14-08Amdt 39-14185.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Compliance:    | As specified in the Requirement document with a revised effective date of13 April 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n|                | This Amendment becomes effective on 13 April 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | The FAA requires certain inspections/actions to prevent loss of the underwing fitting load path due to missing or damaged alloy-steel taperlock fasteners, which could result in separation of the engine and strut from the aircraft.Amendment 1 is issued in response to a new FAA AD, which expands applicability to include additional aircraft models and requires a new inspection to determine fastener material. The FAA received reports indicating that cracked fasteners made of A286 material were found on aircraft that had only fasteners made of A286 material installed in the area common to the diagonal brace underwing fittings. |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n27 February 2006","sortOrder":0},{"sectionNumber":"AD/B747/258 Amdt 1","sectionType":"part","heading":"AD/B747/258 Amdt 1","content":"## AD/B747/258 Amdt 1","sortOrder":1},{"sectionNumber":"Engine Pylon Diagonal Brace Underwing Fi","sectionType":"part","heading":"Engine Pylon Diagonal Brace Underwing Fitting","content":"## Engine Pylon Diagonal Brace Underwing Fitting","sortOrder":2},{"sectionNumber":"4/2006","sectionType":"part","heading":"4/2006","content":"## 4/2006","sortOrder":3}],"analysis":{"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":3,"scope_assessment":{"changed":true,"description":"This Amendment 1 explicitly expands the scope compared to the original AD/B747/258. The Background section states it 'expands applicability to include additional aircraft models' and 'requires a new inspection to determine fastener material' — broadening both the aircraft covered and the technical requirements."},"complexity_factors":["Short, single-purpose document (1 page)","Only 1 defined term implicitly referenced (the FAA AD number)","No nested conditional logic — simple 'comply with external document' structure","Heavy reliance on external technical reference (FAA AD 2005-14-08) — actual requirements not spelled out in this document","Straightforward applicability table referencing specific Boeing models and service bulletin","No exceptions or exemptions listed in this instrument itself"],"plain_english_summary":"This airworthiness directive orders operators of Boeing 747s to inspect and remediate engine-pylon diagonal-brace fasteners (per FAA AD 2005-14-08) after finding cracked or missing bolts that could allow in-flight engine separation. Amendment 1 widens which 747 series are covered and adds inspections for the suspect fastener material. It affects airlines, maintenance organisations and CASA — a targeted, preventive safety action to stop catastrophic engine loss."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the AD's applicability to additional 747 models and adds a new inspection to identify the material of taperlock fasteners after reports of cracked A286 fasteners were found on aircraft with A286 fasteners installed in the diagonal-brace underwing fitting area."},"complexity_factors":["Cross-reference to FAA AD 2005-14-08 and Boeing Alert Service Bulletin 747-57A2312 Rev 1 (requires obtaining and following external technical documents)","Applicability covers a wide range of Boeing 747 models (selection and identification of affected aircraft required)","Technical requirement to determine fastener material (may need material tests or records checks)","Operational impact from inspections and any resulting repairs or part replacements","Compliance tied to a revised effective date (administrative tracking and scheduling)"],"plain_english_summary":"This amendment tells operators of specified Boeing 747 variants to carry out the inspections and corrective actions set out in FAA Airworthiness Directive 2005-14-08 and Boeing Alert Service Bulletin 747-57A2312 Rev 1, effective 13 April 2006. It targets the diagonal-brace underwing fitting fasteners because cracked A286 alloy taperlock fasteners were found. Aircraft operators must inspect and, if necessary, replace fasteners; the regulator adopts and enforces the FAA requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting","history":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting/history","analysis":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting/analysis","conflicts":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting/conflicts","importantCases":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting/important-cases","documents":"/api/acts/ad-b747-258-amdt-1-engine-pylon-diagonal-brace-underwing-fitting/documents"}}