{"id":"F2005L03964","name":"AD/B737/273 - Air Leakage into the Fuel Feed Lines","slug":"ad-b737-273-air-leakage-into-the-fuel-feed-lines","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39841,"registerId":"commonwealth-F2005L03964-current","compilationNumber":null,"startDate":"2026-04-01","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/B737/273 | Air Leakage into the Fuel Feed Lines | 1/2006 |\n| ----------- | ------------------------------------ | ------ |\n\n| Applicability: | All Model 737-100 and 737-200 series aeroplanes, line number 001 through line number 900.                                                                                                                                                                                                                                                                                                                                                                                                               |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Unless previously accomplished, institute an inspection program in accordance with Boeing Service Bulletin 737-28-1047, Revision 3, dated 19 November 1987, or earlier FAA-approved revisions.Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 92-09-02, is considered acceptable for compliance with the equivalent Requirements of this Directive.Note: FAA AD 92-09-02 Amdt 39-8227refers. |\n| Compliance:    | Prior to the accumulation of 20,000 flight hours or within 30 days after the effective date of this AD, whichever occurs later.                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 19 January 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | This actions detailed in this AD are intended to prevent air leakage into the fuel feed lines within the wing tanks during fuel system suction feed operation at low fuel levels.                                                                                                                                                                                                                                                                                                                       |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n30 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/273","sectionType":"part","heading":"AD/B737/273","content":"## AD/B737/273","sortOrder":1},{"sectionNumber":"Air Leakage into the Fuel Feed Lines","sectionType":"part","heading":"Air Leakage into the Fuel Feed Lines","content":"## Air Leakage into the Fuel Feed Lines","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD applies to the specific Boeing 737-100/200 line numbers 001–900 and requires implementing the inspection program in the referenced Boeing Service Bulletin (Applicability; Requirement). It does not expand the set of aircraft beyond that applicability and allows earlier FAA‑approved SB revisions or AMOCs (Requirement), so there is no observable expansion of scope from the directive's stated purpose. The 'Unless previously accomplished' clause narrows immediate obligations for aircraft with completed actions (Requirement)."},"complexity_factors":["Narrow applicability to specific aircraft models and line-number range (Applicability).","Mandates following an external technical document (Boeing Service Bulletin 737-28-1047 Rev 3) rather than prescribing inspection steps in the AD itself (Requirement).","Accepts multiple FAA‑approved revisions or AMOCs as alternatives, requiring regulator/operator coordination on acceptable revisions (Requirement: 'FAA-approved revisions' and 'AMOC').","Timing rule with a 'whichever occurs later' clause: compliance prior to 20,000 flight hours or within 30 days after effective date, creating two parallel triggers to track (Compliance).","Provision 'Unless previously accomplished' introduces record-checking and evidence requirements to establish prior compliance (Requirement).","Technical inspection content is delegated to Boeing SB; operators must interpret and implement technical instructions, creating operational compliance complexity (Requirement)."],"plain_english_summary":"**What it does:** Requires owners/operators of Boeing 737-100 and 737-200 aeroplanes (line numbers 001–900) to start an inspection program per Boeing Service Bulletin 737-28-1047 (Rev 3 or earlier FAA‑approved revisions) to stop air leaking into wing-tank fuel feed lines during suction-feed at low fuel. **Who pays/when:** Operators must comply before 20,000 flight hours or within 30 days of the AD taking effect; they bear inspection and scheduling costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft models. It has not expanded beyond its original purpose of preventing air leakage into fuel feed lines."},"complexity_factors":["Very short document (under 300 words)","Only 2 defined technical references (Boeing Service Bulletin and FAA AD)","Single primary requirement with one straightforward alternative compliance path (AMOC)","Simple conditional compliance deadline (whichever occurs later of two dates)","No nested exceptions or cross-references to other legislation","Clear, unambiguous applicability clause (specific aircraft models and line numbers)"],"plain_english_summary":"This AD mandates a specific inspection program for Boeing 737-100 and -200 series (built through line 900) to prevent air ingress into wing tank fuel feed lines that can cause engine fuel starvation. Operators must follow Boeing Service Bulletin 737-28-1047 (Revision 3) or FAA-approved equivalents.\n\nIt applies to all owners/operators of the affected aircraft, with compliance before 20,000 flight hours or within 30 days of the AD taking effect, whichever is later."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines","history":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines/history","analysis":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines/analysis","conflicts":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines/conflicts","importantCases":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines/important-cases","documents":"/api/acts/ad-b737-273-air-leakage-into-the-fuel-feed-lines/documents"}}