{"id":"F2006B02903","name":"AD/B737/203 - Pressure Fuelling System","slug":"ad-b737-203-pressure-fuelling-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42245,"registerId":"commonwealth-F2006B02903-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.002.png)![](image.001.png)AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)For 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\nBoeing 737 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B737/203 Pressure Fuelling System 2/2","sectionType":"part","heading":"AD/B737/203 Pressure Fuelling System 2/2003","content":"# AD/B737/203 Pressure Fuelling System 2/2003\n\nApplicability: Model 737-600, \\-700, \\-700C, \\-800 and \\-900 series aeroplanes, as listed in Boeing Alert Service Bulletin (ASB) 737-28A1142, Revision 2, dated 26 November 2002.\n\nRequirement: Replace the existing fuelling float switch and conduit assemblies in the main and centre fuel tanks with new, improved assemblies (includes a new float switch and a new conduit assembly with a liner system inside the conduit), in accordance with Work Packages I and II of the Accomplishment Instructions of Boeing ASB 737- 28A1142, Revision 2.\n\nReplacements carried out before the effective date of this Directive in accordance with Boeing ASB 737-28A1142, dated 7 February 2002, are considered acceptable for compliance with this Directive.\n\nNote 1: Due to the lack of sleeving on the existing electrical wire installations of the centre fuel tank, it is recommended that Work Package II be completed before Work Package I.\n\nNote 2: FAA AD 2002-26-18 Amdt 39-13006 refers.\n\nCompliance: For aeroplanes that have accumulated fewer than 5,000 total hours time in service (TIS) as of the effective date of this Directive \\- Within 2 years after the effective date of this Directive.\n\nFor aeroplanes that have accumulated 5,000 total hours TIS or more, but fewer than 10,000 total hours TIS as of the effective date of this Directive \\- Within 1 year after the effective date of this Directive.\n\nFor aeroplanes that have accumulated 10,000 total hours TIS or more as of the effective date of this Directive \\- Within 180 days after the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 20 February 2003.","sortOrder":1}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope aligns with the Boeing ASB 737-28A1142 Revision 2 applicability (Model 737-600/700/700C/800/900) and requires the specific part replacements in main and centre fuel tanks. The Directive explicitly accepts earlier replacements performed under Boeing ASB dated 7 February 2002, indicating no expansion of obligations beyond the ASB’s listed models and replacement work."},"complexity_factors":["Model-specific applicability tied to Boeing ASB 737-28A1142, Revision 2 (restricts affected fleet).","Technical requirement: replace float switch and conduit assemblies (Work Packages I and II of the ASB).","Tiered compliance deadlines based on total hours TIS ( <5,000: 2 years; 5,000–<10,000: 1 year; ≥10,000: 180 days).","Recommendation sequencing: complete Work Package II before I due to lack of sleeving in centre tank wiring (operational constraint).","Accepts prior replacements performed under Boeing ASB dated 7 February 2002 (grandfathers earlier compliant work).","References FAA AD 2002-26-18 (regulatory cross-reference).","Effective date specified (20 February 2003) — creates fixed compliance windows from that date.","Operational and maintenance burden rests on aircraft operators to schedule and perform replacements (cost/time impact on operators)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737-600/700/700C/800/900 series aeroplanes to replace fuel tank float switches and conduit assemblies in the main and centre tanks with improved parts, following Boeing Alert Service Bulletin (ASB) 737-28A1142 Revision 2. It sets staged compliance deadlines based on each aeroplane’s total hours in service and accepts earlier replacements done per the February 2002 ASB. The work prevents an identified unsafe condition in fuel tanks."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific unsafe condition in specific Boeing 737 fuel tank components. There is no evidence of scope creep; it remains a targeted safety intervention for a defined technical problem."},"complexity_factors":["Single, specific technical requirement (component replacement) with clear reference to external Boeing service bulletin","Three-tier compliance schedule based on aircraft flight hours (TIS — Time in Service)","One grandfathering provision allowing earlier repairs to count as compliance","Two non-mandatory notes providing technical guidance on sequencing of work","No defined terms section, no cross-references to other legislation beyond the enabling regulation (CAR 1998 subreg 39.1(1))","Limited conditional logic (only the compliance deadlines vary by aircraft hours)"],"plain_english_summary":"CASA has ordered operators and maintenance organisations of Boeing 737-600/700/700C/800/900 series to replace faulty fuel‑tank float switches and wiring conduits in main and centre tanks with improved, sleeved components to mitigate a fire/explosion risk. Compliance is required on a tiered schedule by airframe hours (high/medium/low time: 180 days / 1 year / 2 years); repairs already done per Boeing’s February 2002 instructions are accepted."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-203-pressure-fuelling-system","history":"/api/acts/ad-b737-203-pressure-fuelling-system/history","analysis":"/api/acts/ad-b737-203-pressure-fuelling-system/analysis","conflicts":"/api/acts/ad-b737-203-pressure-fuelling-system/conflicts","importantCases":"/api/acts/ad-b737-203-pressure-fuelling-system/important-cases","documents":"/api/acts/ad-b737-203-pressure-fuelling-system/documents"}}