{"id":"F2006B03074","name":"AD/B747/172 Amdt 1 - Nose Wheel Well Vertical Beams and Fuselage Frames","slug":"ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42433,"registerId":"commonwealth-F2006B03074-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/172 Amdt 1 - Nose Wheel Well Vertical Beams and Fuselage Frames","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/172 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\n![](image.001.png)\n\nBoeing 747 Series Aeroplanes\n\nAD/B747/172\n\nAmdt 1\n\n  \n\nNose Wheel Well Vertical Beams and Fuselage Frames\n\n  \n11/2001\n\nApplicability: Model 747 series aircraft, line numbers 1 through 685; except for aircraft excluded by the applicability table specified in the Requirement document.\n\nRequirement: Inspect in accordance with the technical requirements of FAA AD 2001-14-18 Amdt 39-12329.\n\nReplacement of vertical beams and frames, as applicable, in accordance with the applicable procedure in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2293 Revision 8, constitutes terminating action for the requirements of this Directive.\n\nCompliance: As specified in the Requirement document with a revised effective date of 1 November 2001.\n\nThis Amendment becomes effective on 1 November 2001.\n\nBackground: The FAA received a report of severed fuselage frames at BS 300 and BS 320 approximately 10 inches outboard of the nose wheel well side panel, which resulted in accelerated fatigue cracking and subsequent failure of the adjacent nose wheel well vertical beams.\n\nAmendment 1 is issued in response to a new FAA AD which expands applicability to include additional aircraft, and adds new requirements for repetitive inspections to detect fatigue cracking of the webs and frames from BS 260 to BS 320. The AD also provides for optional terminating action.\n\nBoeing 747 Series Aeroplanes\n\nAD/B747/172 Amdt 1 (Continued)\n\nThe original issue of this Airworthiness Directive became effective on 27 March 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 19 September 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 10 October 2001.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original March 2001 directive has expanded significantly. Amendment 1 adds: (1) broader applicability covering additional aircraft line numbers, (2) new requirements for repetitive (ongoing) inspections rather than one-time checks, and (3) an optional terminating action pathway. The scope has grown from a targeted inspection to a comprehensive fatigue monitoring and repair program."},"complexity_factors":["Short, single-purpose document (approximately 300 words)","Only 2 defined technical references (FAA AD 2001-14-18 and Boeing Service Bulletin 747-53A2293 Rev 8)","Simple conditional structure: inspect, and if damaged, repair","Clear applicability criteria (Model 747, line numbers 1-685, with explicit exclusions)","No nested exceptions or complex cross-referencing within the document itself","Relies on external technical documents for detailed procedures rather than embedding them"],"plain_english_summary":"This Airworthiness Directive mandates inspections and repairs on Boeing 747s (s/n 1–685) to detect and fix cracked or broken fuselage frames near the nose wheel well, preventing spread to vertical beams and dangerous structural failure. Effective 1 November 2001, the amendment expands affected aircraft, adds repeated inspections to catch new cracks, and permits a permanent repair that terminates the inspection requirement — a safety-critical action for operators."},"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":6,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the original AD's scope by adding additional aircraft to applicability and introducing repetitive inspections for webs and frames from BS 260 to BS 320; it also formalises an optional terminating action via replacement per Boeing Alert Service Bulletin 747-53A2293 Rev 8. (See Background: \"expands applicability...adds new requirements for repetitive inspections...provides for optional terminating action\"; Requirement; Applicability.)"},"complexity_factors":["Cross-reference to FAA AD 2001-14-18 for the technical inspection requirements rather than reproducing procedures in this instrument (Requirement).","Use of Boeing Alert Service Bulletin 747-53A2293 Revision 8 as the prescribed replacement procedure and as optional terminating action (Requirement).","Applicability scope covers line numbers 1–685 but allows exclusions by an applicability table in the Requirement document, creating conditional coverage (Applicability; Requirement).","Added repetitive inspection scope covering frames and webs from BS 260 to BS 320, requiring targeted structural inspections along specific station lines (Background / Amendment 1).","Compliance timing set by reference to the Requirement document with a revised effective date, requiring operators to conform to external documents and timelines (Compliance).","Revocation of the prior AD and adoption of the FAA-expanded measures creates coordination and compliance-management tasks for fleet operators and regulators (opening paragraph; Background)."],"plain_english_summary":"### What this AD does\nRequires Boeing 747 aeroplanes (line numbers 1–685, except those excluded by the Requirement table) to be inspected for fatigue cracking around the nose wheel well vertical beams and nearby fuselage frames following FAA AD 2001-14-18. Replacement of affected beams/frames per Boeing Alert Service Bulletin 747-53A2293 Revision 8 is an optional terminating action. The directive responds to reports of severed frames and accelerated fatigue and takes effect 1 November 2001."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames","history":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames/history","analysis":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames/analysis","conflicts":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames/conflicts","importantCases":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames/important-cases","documents":"/api/acts/ad-b747-172-amdt-1-nose-wheel-well-vertical-beams-and-fuselage-frames/documents"}}