{"id":"F2007L02685","name":"AD/B737/237 Amdt 1 - Passenger Cabin Conditioned Air Overhead Ducts","slug":"ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68579,"registerId":"commonwealth-F2007L02685-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/237 Amdt 1 | Passenger Cabin ConditionedAir Overhead Ducts | 10/2007 |\n| ------------------ | --------------------------------------------- | ------- |\n\n| Applicability: | Model 737-300, -400, and -500 series aircraft, listed in Boeing Special Attention Service Bulletin 737-21-1131 Revision 3, or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2005-03-02 Amdt 39-13958.The action (i.e. inspection or modification) defined in Boeing Special Attention Service Bulletin 737-21-1131 Revision 3 may be used as an alternative method of compliance to the requirements of paragraph (b) of FAA AD 2005-03-02.                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of14 April 2005.The compliance time remains unchanged by this issue of the Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n|                | This Amendment becomes effective on 27 September 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| Background:    | The manufacturer received a substantial number of reports of leaking air conditioning overhead ducts on Model 737 and Model 757 aircraft from multiple airlines. Two of these reports described overhead duct failures that caused the ceiling panels to fall into the passenger cabin. This Directive requires overhead duct lanyard installations, to prevent a disconnected overhead duct from causing ceiling panels to drop below the minimum height of the evacuation zone for the passenger cabin, which could result in inadequate height for safe exit in the event of an emergency evacuation.Amendment 1 is issued to allow use of the latest Boeing service bulletin as an alternative method of compliance to the requirements of paragraph (b) of FAA AD 2005-03-02. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n14 August 2007","sortOrder":0},{"sectionNumber":"AD/B737/237 Amdt 1","sectionType":"part","heading":"AD/B737/237 Amdt 1","content":"## AD/B737/237 Amdt 1","sortOrder":1},{"sectionNumber":"Passenger Cabin ConditionedAir Overhead ","sectionType":"part","heading":"Passenger Cabin ConditionedAir Overhead Ducts","content":"## Passenger Cabin Conditioned  \nAir Overhead Ducts","sortOrder":2},{"sectionNumber":"10/2007","sectionType":"part","heading":"10/2007","content":"## 10/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Amendment 1 changes scope by explicitly permitting Boeing Special Attention Service Bulletin 737-21-1131 Revision 3 (or later FAA-approved revisions) as an alternative method of compliance to paragraph (b) of FAA AD 2005-03-02. The amendment does not alter which aircraft are covered (737-300/-400/-500 listed in the service bulletin) and leaves the original compliance times unchanged, but it expands the approved technical means by which operators may meet the AD's requirements (Requirement; Background; Compliance)."},"complexity_factors":["Cross-reference to FAA AD 2005-03-02 Amdt 39-13958 requiring inspection/modification (Requirement).","Allowance of an alternative method of compliance via Boeing Service Bulletin 737-21-1131 Rev 3 or later FAA-approved revision (Requirement, Amendment 1).","Applicability limited to specific Boeing 737-300/-400/-500 series aircraft listed in the Boeing service bulletin (Applicability).","Safety-critical, technical maintenance tasks that must be executed by qualified maintenance organisations (Background/Requirement).","Administrative changes only: revised effective date and unchanged compliance times (Compliance), which requires tracking by operators.","Delegation and approval dynamics between CASA, FAA AD, and Boeing service bulletin introduce inter-jurisdictional coordination and reliance on external technical documents (Background/Requirement)."],"plain_english_summary":"**What it does:** Requires operators of Boeing 737-300/-400/-500 series to inspect and, where required, install lanyards or otherwise secure conditioned-air overhead ducts so a disconnected duct cannot pull ceiling panels down into passenger evacuation zones. This is implemented by mandating the actions of FAA AD 2005-03-02, but allows Boeing Special Attention Service Bulletin 737-21-1131 Revision 3 (or later FAA-approved revisions) as an alternative method of compliance. It affects aircraft operators and maintenance organisations and keeps the original compliance deadlines unchanged."},"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":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope. It is a technical update that adds an alternative compliance pathway (newer Boeing service bulletin) without expanding the aircraft models covered, the safety issue addressed, or the fundamental remedial action required."},"complexity_factors":["Short, single-purpose directive (approximately 250 words of substantive content)","Only 3 defined/model references (737-300, -400, -500 series)","Single cross-reference to FAA AD 2005-03-02 and Boeing Service Bulletin 737-21-1131 Revision 3","Simple conditional structure: one primary requirement with one alternative method of compliance","No nested exceptions or complex temporal provisions — compliance date references external document unchanged by this amendment","Minimal legislative machinery — operates as a delegated legislative instrument under aviation safety law"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of certain Boeing 737‑300/‑400/‑500 aircraft to address leaking and potentially detached overhead air‑conditioning ducts—installation of restraining lanyards or equivalent corrective action is mandated to prevent ceiling panels falling and obstructing emergency evacuation. Amendment 1 permits compliance using a newer Boeing service bulletin as an approved alternative to the referenced FAA AD; the safety requirement and compliance timing remain unchanged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts","history":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts/history","analysis":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts/analysis","conflicts":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts/conflicts","importantCases":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts/important-cases","documents":"/api/acts/ad-b737-237-amdt-1-passenger-cabin-conditioned-air-overhead-ducts/documents"}}