{"id":"F2006B03141","name":"AD/B747/243 Amdt 1 - Midspar Fuse Pin Retention","slug":"ad-b747-243-amdt-1-midspar-fuse-pin-retention","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42513,"registerId":"commonwealth-F2006B03141-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/243 Amdt 1 - Midspar Fuse Pin Retention","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)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/243 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nBoeing 747 Series Aeroplanes\n\nAD/B747/243\n\nAmdt 1\n\n  \nMidspar Fuse Pin Retention 3/2002\n\nApplicability: Model 747 series aircraft, line numbers 1 through 1046 that have accomplished FAA Airworthiness Directives 95-10-16 (AD/B747/153), 95-13-05 (AD/B747/154), 95-13-\n\n06, or 95-13-07; and line numbers 1047 through 1271.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2001-23-15 Amdt 39-12514.\n\nCompliance: As specified in the Requirement document with a revised effective date of 21 March 2002.\n\nThis amendment becomes effective on 21 March 2002.\n\nBackground: The FAA received several reports of loose primary retention nuts of the midspar fuse pins of the inboard and outboard engine struts of certain Model 747 series aircraft.\n\nLoss of primary retention capability could result in loss of secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the aircraft.\n\nAmendment 1 is issued in response to a new FAA AD which retains the current inspection requirements but mandates accomplishment of the previously optional terminating modification.\n\nThe original issue of this Airworthiness Directive became effective on 17 May 2001.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 February 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 February 2002.\n\n  \nPage 1 of 1","sortOrder":0}],"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Amendment 1 alters the scope of compliance: it retains the earlier inspection requirements but converts a previously optional terminating modification into a mandatory action, and it revokes the original AD. Operators must now accomplish the terminating modification in accordance with FAA AD 2001-23-15, with compliance effective from 21 March 2002."},"complexity_factors":["Cross-reference to an external FAA AD (FAA AD 2001-23-15) for technical requirements; the AD does not reproduce the technical steps.","Applicability is defined by aircraft line-number ranges and by whether earlier specific FAA ADs were accomplished (line numbers 1–1046 conditional, and 1047–1271 unconditional).","This instrument revokes a previous AD and issues an amendment that changes mandatory actions (previously optional terminating modification now required).","Compliance timing depends on the referenced FAA document and a revised effective date (21 March 2002), adding dependency on external compliance scheduling.","The AD states a safety consequence (possible loss of strut/engine) but leaves implementation details (inspection methods, modification procedure) to the FAA technical directive, increasing operational coordination needs."],"plain_english_summary":"**Airworthiness Directive:** This AD requires operators of affected Boeing 747s to carry out the technical actions in FAA AD 2001-23-15 — keeping existing inspections and making a previously optional terminating modification mandatory — to address reports of loose midspar fuse-pin retention nuts that could permit engine strut or engine loss. It applies to line numbers 1–1046 (where specified earlier FAA ADs have been accomplished) and 1047–1271, with compliance per the FAA AD and a revised effective date of 21 March 2002."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing midspar fuse pin retention issues on Boeing 747 aircraft. It tightens requirements by making a previously optional terminating action mandatory, but this is a natural evolution of the same safety issue rather than scope expansion."},"complexity_factors":["Short, single-page document with straightforward structure","Only 4 defined applicability categories (line number ranges and prior modification status)","Single requirement that cross-references an external FAA technical document rather than reproducing detailed instructions","No nested exceptions or conditional logic within the directive itself","Clear compliance date with reference to external document for detailed timing","Background section provides plain-language explanation of safety rationale"],"plain_english_summary":"This CASA safety order replaces the earlier directive and mandates owners/operators of specified Boeing 747s to follow FAA AD 2001‑23‑15 to inspect and permanently rectify loose midspar fuse pin retention nuts that could allow an engine to separate in flight. Effective 21 March 2002, the amendment removes the option of repeated inspections and requires the permanent modification to eliminate the risk of catastrophic engine detachment."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention","history":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention/history","analysis":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention/analysis","conflicts":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention/conflicts","importantCases":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention/important-cases","documents":"/api/acts/ad-b747-243-amdt-1-midspar-fuse-pin-retention/documents"}}