{"id":"F2006B02859","name":"AD/B737/156 - Fuel Tank Vent System","slug":"ad-b737-156-fuel-tank-vent-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42201,"registerId":"commonwealth-F2006B02859-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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 737 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B737/156 Fuel Tank Vent System 8/2001","sectionType":"part","heading":"AD/B737/156 Fuel Tank Vent System 8/2001","content":"# AD/B737/156 Fuel Tank Vent System 8/2001\n\nApplicability: All Boeing 737-100, \\-200, \\-300, \\-400 and \\-500 series aircraft.\n\nRequirement: Incorporate a flame arrestor and pressure relief valve in the fuel tank vent system in accordance with either:\n\n    (a) Boeing Service Bulletin 737-28-1131, Revision 2 and Boeing Information Notice 737-28-1131 IN 01, or\n\n    (b) Shaw Aero Devices, Inc. STC No. SA00859SE, dated December 14, 2000.\n\nNote 1: FAA AD 99-03-04, Paragraph (b) refers.\n\nNote 2: AD/B737/158 addresses the fuel system wiring provision of FAA AD 99-03- 04, Paragraph (a).\n\nNote 3: FAA letter, Reference No. 140S-00-569, approves Shaw Aero Devices, Inc. STC No. SA00859SE, dated December 14, 2000, as an alternative means of compliance for FAA AD 99-03-04.\n\nNote 4: Aircraft modified in accordance with previous issues of Boeing SB 737-28- 1131 satisfy the intent of this Airworthiness Directive.\n\nCompliance: No later than 10 March 2003.\n\nThis Airworthiness Directive becomes effective on 9 August 2001.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD aligns Australia’s requirement with the referenced FAA AD by mandating installation of specific vent-system hardware for the listed 737 series and by accepting the same alternative compliance means (Boeing SB or Shaw STC). It does not broaden applicability beyond the named aircraft types and expressly recognises prior Boeing SB modifications as compliant (Applicability; Requirement; Notes 1–4)."},"complexity_factors":["Single, specific technical retrofit required (flame arrestor + pressure relief valve) — clear technical scope (Requirement).","Two named compliance pathways: Boeing SB 737-28-1131 Rev 2 or Shaw STC SA00859SE — permits an alternative installation route (Requirement).","Cross-references to external FAA material and other ADs (FAA AD 99-03-04; AD/B737/158) introduce regulatory linkage to foreign directives (Notes 1–3).","Compliance deadline and effective date create a fixed scheduling and operational constraint for operators (Compliance; effective date line).","Acknowledgement that earlier Boeing SB revisions satisfy intent means record review/verification of prior modifications may be needed (Note 4).","Applicability to multiple 737 series concentrates costs on operators/owners of those fleets; parts, labour and downtime are probable compliance costs (Applicability; Requirement)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737-100/200/300/400/500 aircraft to install a flame arrestor and a pressure-relief valve in the fuel-tank vent system by 10 March 2003 (effective 9 August 2001). Operators can comply by following Boeing Service Bulletin 737-28-1131 Rev 2 or by installing Shaw Aero Devices STC SA00859SE; aircraft modified to earlier issues of the Boeing service bulletin are treated as compliant. (Requirement; Notes; Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — mandating specific safety modifications to fuel tank vent systems on particular Boeing 737 models. The inclusion of an alternative compliance path (Shaw Aero STC) does not expand scope but provides flexibility in meeting the same safety objective."},"complexity_factors":["Single, clearly defined applicability (5 specific Boeing 737 series)","Straightforward requirement with only 2 alternative compliance paths","4 brief notes providing cross-references to related FAA directives and approvals","Single, unambiguous compliance date","No defined terms section, no nested conditions, no exceptions","Total length: approximately 250 words"],"plain_english_summary":"This AD mandates installation of a flame arrestor and pressure relief valve to the fuel-tank vent system on Australian-operated Boeing 737-100/200/300/400/500 aircraft to mitigate a fuel‑tank fire/explosion hazard.  \n\nWork must follow Boeing Service Bulletin 737-28-1131 Rev 2 or an approved Shaw Aero Devices STC (SA00859SE) and be completed by 10 March 2003; it responds to risks highlighted by the TWA 800 disaster."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-156-fuel-tank-vent-system","history":"/api/acts/ad-b737-156-fuel-tank-vent-system/history","analysis":"/api/acts/ad-b737-156-fuel-tank-vent-system/analysis","conflicts":"/api/acts/ad-b737-156-fuel-tank-vent-system/conflicts","importantCases":"/api/acts/ad-b737-156-fuel-tank-vent-system/important-cases","documents":"/api/acts/ad-b737-156-fuel-tank-vent-system/documents"}}