{"id":"F2007L00120","name":"AD/B747/205 Amdt 2 - Lower Lobe Fuselage Frames","slug":"ad-b747-205-amdt-2-lower-lobe-fuselage-frames","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68218,"registerId":"commonwealth-F2007L00120-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/B747/205 Amdt 2 | Lower Lobe Fuselage Frames | 2/2007 |\n| ------------------ | -------------------------- | ------ |\n\n| Applicability: | Model 747-100, -100B, -100B SUD, -200B, -300, -400, -400D, and 747SR series aircraft, as listed in Boeing Alert Service Bulletin 747-53A2408 Revision 1, or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2006-09-06 R1 Amdt 39-14842.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of15 February 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | This Amendment becomes effective on 15 February 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background:    | The FAA received reports indicating that fatigue cracks were found in lower lobe frames on the left side of the fuselage. Undetected fatigue cracking of lower lobe fuselage frames could lead to fatigue cracks in the fuselage skin, and result in rapid decompression of the aircraft.Amendment 1 retained all the requirements of the original AD, while expanding aircraft applicability.Amendment 2 is issued in response to a revision of the related FAA AD, which specifies appropriate service information for certain corrective actions. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n3 January 2007","sortOrder":0},{"sectionNumber":"AD/B747/205 Amdt 2","sectionType":"part","heading":"AD/B747/205 Amdt 2","content":"## AD/B747/205 Amdt 2","sortOrder":1},{"sectionNumber":"Lower Lobe Fuselage Frames","sectionType":"part","heading":"Lower Lobe Fuselage Frames","content":"## Lower Lobe Fuselage Frames","sortOrder":2},{"sectionNumber":"2/2007","sectionType":"part","heading":"2/2007","content":"## 2/2007","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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Compared with the original AD, the instrument's scope has expanded. Amendment 1 (retained by this instrument) broadened the aircraft applicability to include additional 747 variants as listed in the Boeing service bulletin. Amendment 2 does not materially broaden the population of affected aircraft further; its primary effect is to align the Australian requirement with a revised FAA AD that specifies the correct service information for corrective actions. In other words, the significant scope expansion occurred with Amendment 1 (expanded applicability), while Amendment 2 is mainly a technical alignment to updated FAA/Boeing service instructions."},"complexity_factors":["Short instrument with limited standalone text (primarily references other documents)","Single external cross-reference to FAA AD 2006-09-06 R1 (Amdt 39-14842)","Reference to Boeing Alert Service Bulletin 747-53A2408 Revision 1 (or later FAA‑approved revision) to define affected aircraft","Amendment history (original AD, Amendment 1 expanded applicability; Amendment 2 aligns with revised FAA AD)","Compliance and technical detail delegated to external documents (FAA AD and Boeing service bulletin) rather than contained in the AD itself"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- This is an airworthiness directive (AD) that requires operators of certain Boeing 747 aircraft to carry out the inspections and corrective actions set out in the related FAA AD 2006-09-06 R1 (as amended) and the Boeing Alert Service Bulletin 747-53A2408 Revision 1 (or any later FAA‑approved revision). (Requirement / Applicability)\n- The AD applies to Model 747-100, -100B, -100B SUD, -200B, -300, -400, -400D, and 747SR series aeroplanes listed in the Boeing service bulletin. (Applicability)\n- Compliance must be performed according to the technical requirements of the FAA AD, with this Australian amendment becoming effective 15 February 2007. (Compliance / Effective date)\n\nWhy it was issued (stated reason)\n\n- The FAA reported fatigue cracks in lower lobe fuselage frames on the left side of affected 747s. The declared safety concern is that undetected fatigue cracking could progress to the fuselage skin and could result in rapid decompression. This amendment aligns the Australian requirement with a revision of the related FAA AD that specifies appropriate service information for corrective actions. (Background)\n\nWho is directly affected\n\n- Airlines and operators that own or operate the listed Boeing 747 models (the set is defined by the Boeing Alert Service Bulletin referenced).\n- Maintenance organisations that perform inspections and repairs on those aircraft.\n\nWho pays, who decides, and what behaviour changes\n\n- Operators pay the direct costs: inspections, any non-routine repairs, parts, and aircraft downtime while work is carried out. Maintenance organisations incur labour costs and must follow the specified service procedures. The regulator (Civil Aviation Safety Authority, via this AD) decides the mandatory inspection and repair standard by adopting the FAA AD and Boeing service bulletin as the required method of compliance.\n- Behaviour change: operators must schedule and perform the mandated inspections and corrective actions within the intervals and methods set by the FAA AD/service bulletin; they cannot ignore or substitute different procedures without regulator approval.\n\nTesting the stated purpose against practical effects, incentives and trade-offs\n\n- Purpose-claim: the AD aims to detect and fix fatigue cracks early to prevent fuselage-skin cracking and reduce the risk of decompression. The instrument achieves that by mandating inspections and corrective actions specified in an established FAA AD and Boeing service bulletin (Requirement / Background).\n- Costs and implementation burden: the cost to operators will be the labour, parts and aircraft out-of-service time required for inspections and any required repairs. These costs are concentrated on operators of the listed 747 models; the benefit (reduced structural failure risk) accrues broadly to passengers, crew and the operator’s continuing ability to fly the aircraft.\n- Incentives and trade-offs: operators are incentivised to comply to keep aircraft airworthy and avoid enforcement action; there is also a private incentive to avoid more expensive repairs later. The trade-off is near-term expenditure and downtime versus the avoided safety and operational risk of unaddressed fatigue cracking.\n- Implementation risk and discretion: the AD binds compliance to FAA technical requirements and Boeing service information. That reduces regulatory discretion in method but creates dependency on the accuracy and completeness of the referenced FAA AD and Boeing service bulletin. Operators must follow the specified documents unless an alternative method of compliance is approved by the regulator.\n- Substitution and operational effects: affected aircraft may need to be grounded temporarily for inspections/repairs, possibly affecting schedules or requiring aircraft substitutions. There is no change to ownership, price regulation, or broader market competition directly; the main commercial effect is on operating costs for operators of the listed 747s.\n\nConcrete mechanism summary\n\n- The AD: (1) identifies the fleet (by model and Boeing service bulletin listing), (2) requires the technical steps set out in FAA AD 2006-09-06 R1 (and associated Boeing service bulletin), and (3) fixes the effective date of the Australian amendment at 15 February 2007. Non-compliance with the AD would expose operators to regulator enforcement for operating an unairworthy aircraft. (Applicability / Requirement / Compliance)\n\nSources in the instrument: Applicability, Requirement, Compliance and Background sections of AD/B747/205 Amdt 2."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original directive has expanded through amendments. Amendment 1 'expanded aircraft applicability' (covered more aircraft models than originally). Amendment 2 does not further expand scope but updates the technical content. The instrument has evolved from its original form through two amendments, though it remains focused on the same safety issue (lower lobe fuselage frame cracking)."},"complexity_factors":["Very short document (approximately 250 words of substantive content)","Only 2 defined technical references (the Boeing Service Bulletin and FAA AD numbers)","Single clear requirement: comply with external FAA document","No nested exceptions or conditional logic — applicability is a straightforward list of aircraft models","Cross-references to external technical documents rather than internal legislative provisions","Simple amendment structure (Amendment 2 updates reference to match revised FAA AD)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and repairs for fatigue cracks in lower-lobe fuselage frames of certain Boeing 747s listed in Boeing Alert Service Bulletin 747-53A2408 Revision 1 (or later). It adopts the technical instructions of FAA AD 2006-09-06 R1 into Australian law, effective 15 February 2007.\n\nThis second amendment updates the required repair procedures; compliance is mandatory to prevent crack growth that could lead to rapid decompression and unsafe flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames","history":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames/history","analysis":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames/analysis","conflicts":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames/conflicts","importantCases":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames/important-cases","documents":"/api/acts/ad-b747-205-amdt-2-lower-lobe-fuselage-frames/documents"}}