{"id":"F2006B03241","name":"AD/B747/61 Amdt 2 - Rear Pressure Bulkhead","slug":"ad-b747-61-amdt-2-rear-pressure-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42665,"registerId":"commonwealth-F2006B03241-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/61 Amdt 2 - Rear Pressure Bulkhead","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![](image.002.png)  \nBoeing 747 Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/61 Amdt 1 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\nAD/B747/61\n\nAmdt 2\n\n  \nRear Pressure Bulkhead 11/2000\n\nApplicability: Model 747 series aircraft, line positions 1 through 671.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2000-15-08 Amdt 39-11840.\n\nNote: Boeing Service Bulletin 747-53-2275 through Revision 5 and 747-53A2275 Revision 6 refer.\n\nCompliance: As specified in the Requirement document with a revised effective date of 2 November 2000.\n\nThis Amendment becomes effective on 2 November 2000.\n\nBackground: Damage including dents, tears, nicks, gouges, and scratches, has been found on some aircraft. Fatigue cracking may occur on high time aircraft and undetected damage may lead to premature fatigue cracking. The required inspections are intended to ensure the continued structural integrity of the bulkhead.\n\nAmendment 1 was prompted by reports indicating that the inspections required by FAA AD 87-23-10 may not detect cracking of the bulkhead web in a timely manner, and certain inspection changes were introduced.\n\nAmendment 2 is issued in response to a new FAA AD which requires that a currently required one-time inspection to detect cracking of the upper segment of the bulkhead web be accomplished repetitively, and adds additional repetitive inspections to detect cracking of the upper and lower segments of the aft bulkhead web.\n\nAmendment 1 to this Airworthiness Directive became effective on 31 December 1998.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nThe original issue of this Airworthiness Directive became effective on 24 March 1998.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 13 September 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 4 October 2000.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The legislation maintains its original narrow scope — ensuring structural integrity of the rear pressure bulkhead on specific Boeing 747 models. Amendment 2 expands the inspection frequency (from one-time to repetitive) and coverage (upper and lower segments), but this is a technical enhancement within the existing safety purpose, not a scope creep into new regulatory areas."},"complexity_factors":["Short, single-purpose instrument (approximately 400 words)","Only 4 defined structural elements (damage types: dents, tears, nicks, gouges, scratches)","Heavy reliance on external technical documents — compliance requires reference to FAA AD 2000-15-08 and Boeing Service Bulletins 747-53-2275 and 747-53A2275","Simple conditional structure: applicability → requirement → compliance → background","No nested exceptions or complex definitional sections","Clear lineage (Amendment 2 of an existing AD) with explicit revocation of previous version"],"plain_english_summary":"Australia's regulator revokes and replaces an earlier safety order, mandating repeated inspections of the Boeing 747 rear pressure bulkhead and requiring compliance with FAA AD 2000-15-08. It applies to owners/operators of early-production 747s (line positions 1–671).\n\nThis targets dents, tears or scratches that can cause premature fatigue cracking of the bulkhead web; undetected cracking could lead to catastrophic loss of cabin pressurisation."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. Amendment 2 expands the original scope. The original AD required inspections (initially a one‑time inspection and then inspection changes in Amendment 1). Amendment 2 converts the previously required one‑time inspection of the upper bulkhead web into repetitive inspections and adds additional repetitive inspections covering both upper and lower segments of the aft bulkhead web. Mechanically, that moves the instrument from a mainly one-off corrective check to a continuing maintenance obligation for affected operators, increasing recurring compliance costs and inspection frequency compared with the original intent."},"complexity_factors":["Short single-issue AD focused on rear pressure bulkhead","Direct cross-reference to FAA AD 2000-15-08 for technical procedures (external dependency)","Note referencing Boeing Service Bulletin 747-53-2275 revisions 5 and 6 (additional external documents to consult)","Clear applicability limitation: Model 747 series, line positions 1–671 (simple scope boundary)","Amendment history: original AD, Amendment 1, and Amendment 2 (some historical layering)","Change from one-time to repetitive inspections (introduces ongoing conditionality but described in the external FAA AD)"],"plain_english_summary":"**What this Airworthiness Directive (AD) does**\n\n- Revokes the earlier AD/B747/61 Amendment 1 and replaces it with Amendment 2. (See: heading and signature block.)\n- Requires operators of affected Boeing 747 aeroplanes to carry out the inspections and related actions described in the referenced FAA AD 2000-15-08. (See: \"Requirement\".)\n- Changes a previously required one‑time inspection of the aft (rear) pressure bulkhead web into a schedule of repetitive inspections, and adds further repetitive inspections of the upper and lower segments of the aft bulkhead web. (See: \"Background\" and \"Requirement\".)\n- Becomes effective 2 November 2000. (See: \"Compliance\".)\n\n**Who this affects**\n\n- Operators and maintenance organisations responsible for Boeing 747 series aircraft at line numbers 1 through 671. (See: \"Applicability\".)\n- Maintenance planners, certifying engineers and airline compliance officers who must schedule, perform and record the inspections and any required repairs.\n\n**Why this matters (mechanics and safety rationale)**\n\n- The rear pressure bulkhead is a primary structural component that seals the pressurised fuselage from the unpressurised tail area. Damage (dents, tears, nicks, gouges, scratches) and fatigue cracking of the bulkhead web have been found on some 747s. The AD is intended to detect cracking before it grows to an unsafe size. (See: \"Background\".)\n- The AD does not itself set the inspection method or intervals in full detail; it directs operators to follow the technical requirements of FAA AD 2000-15-08 (and notes Boeing Service Bulletin 747-53-2275 revisions). That means the FAA AD and the Boeing service bulletin contain the specific inspection procedures, intervals and thresholds for corrective action. (See: \"Requirement\" and Note.)\n\n**How it works in practice**\n\n- The regulator (the CASA delegate) requires compliance by reference: Australian operators must follow the FAA AD’s inspection and repeat-inspection schedule and any repair instructions. (See: \"Requirement\", \"Compliance\".)\n- If inspections find damage or cracking, operators must carry out the corrective actions specified in the referenced FAA AD/Boeing service bulletin (which typically include repair or replacement and possibly more frequent inspections until fixed).\n- Compliance timing is governed by the referenced FAA AD, but the Australian AD sets a revised effective date (2 November 2000). (See: \"Compliance\".)\n\n**Costs, incentives, trade-offs and implementation considerations**\n\n- Who pays: the aircraft operator bears the direct costs — labour, inspection equipment, downtime, and any repairs or part replacements. (Implicit from the AD’s requirement that operators perform inspections and repairs.)\n- Bureaucratic discretion and reliance: CASA’s AD adopts the FAA-required actions by reference, so Australian operators must access and follow external documents (FAA AD 2000-15-08 and the Boeing service bulletin revisions). That creates a dependence on foreign regulator/ manufacturer documents for procedural details. (See: \"Requirement\" and Note.)\n- Ongoing vs one‑off burden: Amendment 2 converts a previously one‑time inspection into a set of repetitive inspections and adds inspection locations. That increases ongoing maintenance workload and recurring costs compared with the original one‑time measure. (See: \"Background\".)\n- Substitution or operational choices: operators can respond by scheduling inspections into regular maintenance checks, taking aircraft out of service for inspections, or performing repairs/parts replacement that may change future inspection needs — the AD requires the actions in the FAA AD but does not mandate a single way to comply. (Inferred from the AD’s structure and typical AD practice.)\n- Compliance risk and access to instructions: the AD requires following external documents. Operators must maintain access to those documents (FAA AD and Boeing service bulletins) and ensure maintenance staff are trained on the specified inspection techniques. Failure to follow the referenced documents would be non-compliance with the AD.\n\n**Practical note**\n\n- The AD applies only to Boeing 747s with line positions 1–671. Later-built aircraft (beyond line 671) are outside this AD’s applicability and so are not required by this instrument to follow this particular inspection regime unless another AD applies. (See: \"Applicability\".)\n\n(References in the text: Applicability; Requirement; Note referencing Boeing Service Bulletin 747-53-2275 revisions; Compliance with revised effective date 2 November 2000; Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead","history":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead/history","analysis":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead/analysis","conflicts":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead/conflicts","importantCases":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead/important-cases","documents":"/api/acts/ad-b747-61-amdt-2-rear-pressure-bulkhead/documents"}}