{"id":"F2006B03130","name":"AD/B747/232 Amdt 1 - Crew Rest Area Heat Exchanger - 2","slug":"ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42502,"registerId":"commonwealth-F2006B03130-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/232 Amdt 1 - Crew Rest Area Heat Exchanger - 2","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/B747/232 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/B747/232\n\nAmdt 1\n\n  \nCrew Rest Area Heat Exchanger \\- 2 13/2001\n\nApplicability: Model 747-400 series aircraft, line numbers 1 through 1205; equipped with dual crown skin heat exchangers.\n\nRequirement: Inspect in accordance with the technical requirements of FAA AD 2001-18-04 Amdt 39-12430.\n\nNote: Boeing Alert Service Bulletins 747-21A2412 and 747-21A2412 Revision 2 refer.\n\nCompliance: As specified in the Requirement document with a revised effective date of 27 December 2001.\n\nThis amendment becomes effective on 27 December 2001.\n\nBackground: The FAA received reports of cracking and buckling of the front edge of the crew rest heat exchanger on several aircraft. Investigation revealed that certain heat exchangers were manufactured with material that is too thin. On one aircraft, the heat exchanger buckled and bulged enough to make contact with the rudder and elevator cables located below the heat exchanger.\n\nAmendment 1 is issued in response to a new FAA AD which adds a new requirement for a one-time inspection to determine the part number and shop code of the shell of the crew rest heat exchanger, and follow-on actions if necessary, which terminate the currently required repetitive inspections.\n\nThe original issue of this Airworthiness Directive became effective on 10 August 2000.\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 November 2001\n\nPage 1 of 1\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 5 December 2001.\n\nPage 2 of","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: addressing the unsafe condition of crew rest area heat exchangers in specific Boeing 747-400 aircraft. The amendment adds a new inspection requirement and terminates repetitive inspections, but this is a refinement of the existing safety measure rather than an expansion beyond the original scope. The affected aircraft population and the fundamental safety concern (defective heat exchangers) remain unchanged from the original August 2000 directive."},"complexity_factors":["Very short document (2 pages, approximately 300 words)","Only 4 defined structural sections (Applicability, Requirement, Compliance, Background)","Single cross-reference to external FAA directive (AD 2001-18-04) and two Boeing service bulletins","No nested conditional logic or exceptions — straightforward 'inspect in accordance with X' structure","Clear, unambiguous applicability criteria (specific aircraft model and line number range)","No interpretation section or defined terms requiring legal parsing"],"plain_english_summary":"This AD replaces the previous order and mandates inspections of crew-rest area heat exchangers on Boeing 747‑400 (line numbers 1–1205) after discovery of thin metal shells that can crack, buckle and bulge into rudder/elevator control cables. It adds a one‑time check of part and manufacturing codes (per FAA AD 2001‑18‑04) and requires corrective action if defects are found. It affects owners, operators and maintenance organisations and prevents potential control‑cable jamming."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the AD's compliance mechanics compared with the original AD by adding a new one-time inspection to identify the part number and shop code of the crew rest heat exchanger shell, and by introducing follow-on actions that, if taken, terminate the previously required repetitive inspections. In practical terms, the amendment moves the compliance regime from ongoing repetitive inspections toward a targeted identification-and-corrective-action approach tied to specific part/shop-code findings (Background; Amendment 1 description)."},"complexity_factors":["Short, single-aircraft-type directive limited to Boeing 747-400 series line numbers 1–1205 with dual crown skin heat exchangers","Direct cross-reference to an external FAA AD (FAA AD 2001-18-04) for technical requirements and compliance timing","Cross-reference to external manufacturer service bulletins (Boeing Alert Service Bulletins 747-21A2412 and Revision 2)","Replaces and revokes a prior AD (administrative replacement element)","One-time inspection that determines part number/shop code with conditional follow-on actions terminating prior repetitive inspections (single layer of conditionality)","Relies on external documents for procedural detail rather than containing technical steps in the AD itself"],"plain_english_summary":"**What this AD changes (mechanical requirement)**\n\n- The Civil Aviation Safety Authority (CASA) revokes the earlier AD/B747/232 and issues an amended Airworthiness Directive that requires operators of certain Boeing 747-400 aeroplanes to perform inspections and any follow-up actions specified by the referenced FAA Airworthiness Directive (FAA AD 2001-18-04).\n- The AD applies to Boeing 747-400 series aircraft line numbers 1–1205 that are fitted with \"dual crown skin\" crew-rest heat exchangers (Applicability).\n- The technical inspection and any required corrective actions must be performed in accordance with FAA AD 2001-18-04 and the Boeing Alert Service Bulletins noted (Requirement; Note). The compliance timing is as specified in the FAA AD, with the Australian effective date of 27 December 2001 (Compliance).\n\n**Who is affected**\n\n- Aircraft owners/operators of affected 747-400s (those with the specified heat exchangers). Maintenance organisations that perform the inspections and repairs also must carry out the work to the technical standard cited.\n\n**Why the AD was issued (stated safety concern)**\n\n- The FAA reported cracking and buckling of the front edge of crew-rest heat exchangers. Some exchangers were found to have been manufactured with material that was too thin. On at least one airplane the exchanger bulged enough to contact rudder and elevator control cables located below it, creating a potential unsafe condition (Background).\n- Amendment 1 adds a one-time inspection to identify the exchanger shell's part number and shop code and requires follow-on actions where necessary. Those follow-on actions, if taken, will terminate the need for previously required repetitive inspections (Amendment 1 description in Background).\n\n**Who pays, who decides, and what behaviour changes**\n\n- Who pays: aircraft owners/operators pay for the inspections, any required repairs or replacement parts, and associated aircraft downtime.\n- Who decides: CASA (the Delegate who signed the AD) issues the mandatory requirement under subregulation 39.1(1) of the Civil Aviation Regulations 1998. The technical content and timing are set by reference to FAA AD 2001-18-04 and Boeing Alert Service Bulletins (Requirement; Note; Compliance).\n- Behaviour changes: operators must schedule and carry out the inspection(s) called up by the FAA AD; if a shell with certain part numbers/shop codes is found, follow-up actions (including repair or replacement) are required; completing the follow-on actions will stop the previous requirement for repeated inspections.\n\n**Practical implementation and trade-offs**\n\n- Compliance mechanics: the AD does not reproduce technical steps; operators must consult FAA AD 2001-18-04 and Boeing Alert Service Bulletins 747-21A2412 (and Revision 2) for the inspection procedure, criteria and corrective actions (Requirement; Note). That creates a dependency on external documents for the exact method and timing.\n- Costs vs benefits: the immediate cost to operators is labour, maintenance facility time and any replacement exchanger units. The stated safety benefit is reduced risk of control-cable interference from a buckled heat exchanger. If the one-time inspection plus corrective action terminates repetitive inspections, operators may save ongoing inspection costs in the future; whether that is net saving depends on the cost of the corrective action versus the prior inspection burden.\n- Concentrated vs diffuse effects: the cost is concentrated on operators of affected 747-400s; the safety benefit is concentrated in reducing the specific hazard (potential contact with control cables) but also benefits crew/passengers who rely on safe flight controls.\n- Implementation risk and compliance burden: operators must correctly identify affected exchangers by part number and shop code, which may require physical access or disassembly. Reliance on FAA and Boeing documents means operators must ensure they use the correct revision and effective dates specified by the AD.\n- Regulatory discretion: CASA's delegate enforces the technical requirement by reference to FAA/Boeing documents rather than reproducing procedures in full. That is standard practice for ADs but means interpretation and proof of compliance requires keeping records linking the work done to the referenced FAA AD/Boeing Service Bulletins.\n\n**Procedural notes**\n\n- The AD revokes the earlier AD/B747/232 and replaces it with this amended requirement (opening paragraph). The effective Australian compliance date is 27 December 2001 (Compliance). The original AD first took effect on 10 August 2000 (Background).\n\n(References in parentheses indicate the AD sections where the point is stated: Applicability; Requirement; Note; Compliance; Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2","history":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2/history","analysis":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2/analysis","conflicts":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2/conflicts","importantCases":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2/important-cases","documents":"/api/acts/ad-b747-232-amdt-1-crew-rest-area-heat-exchanger-2/documents"}}