{"id":"F2008L02877","name":"AD/HS 748/34 - Fuel Tank Safety - Airworthiness Limitations","slug":"ad-hs-748-34-fuel-tank-safety-airworthiness-limitations","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74759,"registerId":"commonwealth-F2008L02877-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"British Aerospace (Hawker Siddeley) HS 7","sectionType":"division","heading":"British Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes","content":"### British Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes\n\n| AD/HS 748/34 | Fuel Tank Safety - Airworthiness Limitations | 9/2008 |\n| ------------ | -------------------------------------------- | ------ |\n\n| Applicability: | HS.748 aircraft, all models, all serial numbers. |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | Amend the approved aircraft maintenance schedule to incorporate the instructions and limitations of HS.748 Aircraft Maintenance Manual (AMM) Chapter 05-10-00 “Critical Design Configuration Control Limitations (CDCCL) - Fuel System” at AMM Revision 19 dated 15 January 2008. |\n| | The use of later European Aviation Safety Agency (EASA) approved revisions of the above document is acceptable for compliance with the requirements of this Directive. |\n| | Note: EASA AD 2008-0125 refers. |\n| Compliance: | Within the next 3 months after the effective date of this Directive. |\n| | This Airworthiness Directive becomes effective on 28 August 2008. |\n| Background: | Resulting from the assessment of fuel tank wiring installations required by SFAR 88 and equivalent JAA/EASA policy, BAE Systems (Operations) Limited has revised the HS.748 AMM, now at Revision 19, to introduce Chapter 05-10-00 “Critical Design Configuration Control Limitations (CDCCL) - Fuel System”. The CDCCLs provide instructions to retain critical ignition source prevention features during configuration changes that may be caused by modification, repair or maintenance actions.The CDCCLs have been identified as requirements for continued airworthiness to address the risk of fuel vapour ignition sources remaining undetected. This condition, if not corrected, could result in a fuel tank explosion and consequent loss of the aircraft. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n16 July 2008","sortOrder":0},{"sectionNumber":"AD/HS 748/34","sectionType":"part","heading":"AD/HS 748/34","content":"## AD/HS 748/34","sortOrder":1},{"sectionNumber":"Fuel Tank Safety - Airworthiness Limitat","sectionType":"part","heading":"Fuel Tank Safety - Airworthiness Limitations","content":"## Fuel Tank Safety - Airworthiness Limitations","sortOrder":2},{"sectionNumber":"9/2008","sectionType":"part","heading":"9/2008","content":"## 9/2008","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive implementing international fuel tank safety standards (SFAR 88) for a specific aircraft type. The scope remains precisely limited to fuel system CDCCL incorporation for the HS.748 fleet, consistent with the original regulatory intent of addressing fuel tank ignition source risks."},"complexity_factors":["Single, specific aircraft type (HS.748) with clear applicability","One primary compliance action (incorporate specific manual chapter)","Cross-reference to external document (EASA AD 2008-0125) but no complex legislative cross-referencing","Simple temporal compliance requirement (3 months from effective date)","Minimal defined terms (only CDCCL requires explanation, provided in context)","No nested exceptions or conditional logic — straightforward mandate","Short document (approximately 250 words of substantive content)"],"plain_english_summary":"This CASA Airworthiness Directive requires Australian operators and maintainers of HS.748 aircraft to update their approved maintenance manuals to include the fuel‑system Critical Design Configuration Control Limitations (CDCCL) in Chapter 05-10-00 (AMM Rev 19, 15 Jan 2008) — or equivalent later EASA-approved versions — within three months of 28 Aug 2008. It implements post‑TWA Flight 800 fuel‑tank wiring safeguards to prevent ignition sources and reduce risk of tank explosion."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive implements a specific corrective step (making CDCCL provisions mandatory in the maintenance schedule) that aligns with the original safety objective identified by SFAR 88/EASA policy: preventing fuel tank ignition sources introduced or left during maintenance or modification. It does not broaden the regulation beyond that objective; rather, it converts manufacturer AMM guidance (Revision 19) into a mandatory continuing airworthiness requirement. There is no evidence in this text that the scope was expanded beyond that original safety purpose."},"complexity_factors":["Single, narrowly framed prescriptive action: amend approved maintenance schedule to incorporate AMM Chapter 05-10-00 (CDCCL) Revision 19.","Reference to a technical chapter (CDCCL) requiring maintenance organisations to interpret and implement configuration‑control instructions.","Acceptable alternative clause: later EASA‑approved revisions of the AMM chapter are permitted, creating a dependency on external agency approvals.","Cross-reference to EASA AD 2008-0125 and SFAR 88 / JAA/EASA policy in the background, requiring readers to consult other documents for full context.","Short 3‑month compliance deadline adds an operational timing constraint.","Applies to all models and serial numbers (broad applicability) but contains no model‑specific exceptions."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires every operator of a British Aerospace (Hawker Siddeley) HS 748 aeroplane (all models and serial numbers) to update their approved aircraft maintenance schedule. Specifically, the maintenance schedule must incorporate the instructions and limits set out in the HS.748 Aircraft Maintenance Manual (AMM), Chapter 05-10-00 \"Critical Design Configuration Control Limitations (CDCCL) - Fuel System\", at AMM Revision 19 (dated 15 January 2008).\n- Gives operators the option to comply by using later revisions of that AMM chapter, but only if those later revisions are approved by the European Aviation Safety Agency (EASA).\n- Sets a firm compliance deadline: the change must be made within three months after the directive becomes effective.\n\n**Who this affects**\n\n- Aircraft operators and owners of HS.748 aeroplanes (every model and serial number).\n- Maintenance organisations and licensed maintenance personnel who prepare and implement the approved maintenance schedules for these aeroplanes.\n- Regulators and certifying authorities who verify compliance with airworthiness directives and approved maintenance schedules.\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The stated purpose (from the regulator/manufacturer) is to reduce the risk that fuel vapour could be ignited by electrical or other sources introduced, altered or left undetected during modification, repair or maintenance. The CDCCL chapter contains instructions meant to preserve features that prevent ignition sources from being introduced into fuel tanks.\n- Mechanically, the rule makes the CDCCL provisions a required part of the aircraft's continuing airworthiness obligations by embedding them in the operator's approved maintenance schedule. That means the CDCCL instructions become mandatory tasks/limitations for maintenance and modifications rather than advisory material.\n\n**Practical consequences and who pays, who decides, and what behaviour changes**\n\n- Who pays: the aircraft operator (or the maintenance organisation contracted by the operator) will bear the direct costs of updating the approved maintenance schedule, training or informing staff, and implementing any new or altered maintenance tasks or inspection regimes required by the CDCCLs. There may be indirect costs such as aircraft downtime if additional inspections or work items are introduced.\n- Who decides: the operator must amend its approved maintenance schedule to include the specified AMM chapter; the regulator enforces the directive. Operators may choose to adopt later EASA‑approved revisions where available.\n- Behaviour changes: maintenance organisations must follow the CDCCL rules when performing maintenance, repairs or modifications that could affect fuel system wiring or other features that prevent ignition sources. Record‑keeping and configuration control around fuel-system work are likely to be tightened.\n\n**Trade-offs, implementation risks and compliance burden**\n\n- Trade-offs: the directive increases mandatory maintenance controls (a cost to operators) in order to reduce a safety risk (potential fuel vapour ignition). The main trade is operator cost and possible additional maintenance time versus reduced risk of fuel tank ignition.\n- Implementation risks: operators must correctly interpret and embed the AMM CDCCL chapter into their approved schedules; inconsistency between maintenance providers or incomplete incorporation could leave gaps. Reliance on later EASA‑approved revisions introduces a dependency on external approvals for acceptable alternatives.\n- Compliance burden: procedural—amending approved documents, briefing/training maintenance staff, and ensuring future maintenance and modifications follow the CDCCL requirements. There is no indication of major discretionary regulatory judgement: the requirement is prescriptive (incorporate this AMM chapter) and time‑bound.\n\n**Source claims and how they map to costs/incentives**\n\n- Source claim: the change follows an assessment (SFAR 88 / EASA policy) that identified fuel tank wiring and related configuration changes as a risk. If the CDCCLs are not followed, the claimed risk is fuel vapour ignition and possible fuel tank explosion. Mechanically, the directive converts the CDCCLs into mandatory continuing airworthiness requirements. This shifts the incentive for operators from optional compliance to mandatory compliance, increasing their compliance costs but also reducing their legal and safety risk if implemented.\n\n(See the directive sections labelled \"Requirement\", \"Compliance\" and \"Background\" for the textual basis.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations","history":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations/history","analysis":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations/analysis","conflicts":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations/conflicts","importantCases":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations/important-cases","documents":"/api/acts/ad-hs-748-34-fuel-tank-safety-airworthiness-limitations/documents"}}