{"id":"F2006B03464","name":"AD/BAe 146/111 Amdt 1 - APU - Insulation Blankets & Exhaust Drain Blank","slug":"ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43018,"registerId":"commonwealth-F2006B03464-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/111 Amdt 1 - APU - Insulation Blankets & Exhaust Drain Blank","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nOn the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BAe 146/111 and issues the following AD under subregulation 39.1 (1) of CASR 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\nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/111\n\nAmdt 1\n\n  \n\nAPU \\- Insulation Blankets & Exhaust Drain Blank\n\n  \n13/2004\n\nApplicability: BAe 146 Series and AVRO 146-RJ Series aeroplanes with Sundstrand APU installed (Modification HCM30373A) or Sundstrand APU installed with optional duct (Modification HCM30373A and HCM36166C).\n\nRequirement: Install modification HCM36244A in accordance with BAe Systems (Operations) Ltd Service Bulletin 49-072-36244A dated 11 October 2004.\n\nNote: UK CAA AD G-2004-0007 (EASA Ref No. 2004-2324) refers.\n\nCompliance: No later than 8 July 2005.\n\nThis Amendment becomes effective on 23 December 2004.\n\nBackground: APU exhaust duct skin temperatures within the ECS bay have been found to be higher than the certificated maximum. The ECS bay is not a designated fire zone hence there is no fire detection or suppression system and ventilation airflow around the APU exhaust is low. As fuel and hydraulic pipe work pass through the ECS bay a risk of flammable fluid ignition exists if leaking fluid contacts the APU exhaust duct skin.\n\nThis Directive originally required the embodiment of Mod HCM36240A insulation blankets. That modification has been found to be ineffective. This amendment requires the removal of that modification if fitted and the embodiment of Mod HCM36244A.\n\nThe original issue of this Directive became effective on 8 July 2004.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\n![](image.001.png)Delegate of the Civil Aviation Safety Authority 8 November 2004\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 1 December 2004.\n\n  \n\nPage 1 of 1","sortOrder":0}],"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":true,"description":"This amendment changes the original AD’s technical requirement. The original directive required embodiment of Mod HCM36240A; the amendment requires removal of that modification if fitted and embodiment of Mod HCM36244A instead (Requirement). Applicability and affected aircraft remain the same, but the specific corrective action and therefore compliance costs and work content are altered (Background; Requirement; Compliance)."},"complexity_factors":["Narrow applicability: specific to BAe 146 / AVRO 146‑RJ with Sundstrand APU (Modification HCM30373A ± HCM36166C)","Prescriptive technical actions identified by modification numbers (remove HCM36240A if fitted; install HCM36244A)","Dependence on an external service bulletin for implementation details (BAe Service Bulletin 49‑072‑36244A dated 11 Oct 2004)","Fixed compliance deadline (no later than 8 July 2005) imposing scheduling and downtime costs","Linkage to prior AD (revokes AD/BAe 146/111 original) and a foreign authority reference (UK CAA AD G‑2004‑0007 / EASA Ref No. 2004‑2324)","Implementation requires technical work and parts procurement but no complex legal interpretation"],"plain_english_summary":"Requires operators of BAe 146 and AVRO 146‑RJ aeroplanes fitted with a Sundstrand APU to remove a previously fitted insulation modification (HCM36240A, if present) and install modification HCM36244A following BAe Service Bulletin 49‑072‑36244A. (Requirement; Compliance by 8 July 2005.)\n\nCASA’s delegate issued the directive; affected operators bear the cost and must schedule work and any downtime. The mechanical change responds to higher-than-certified APU exhaust duct temperatures in the ECS bay that could ignite leaking flammable fluids."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing APU exhaust overheating in the ECS bay. It does not expand to new aircraft types, systems, or operational contexts. The amendment merely corrects the technical solution (replacing an ineffective modification with an effective one) while maintaining the same safety objective and applicability."},"complexity_factors":["Single, clearly defined applicability (two aircraft series with specific APU modifications)","One straightforward requirement (install specific modification per specific service bulletin)","Simple compliance deadline (single date, no conditional thresholds)","Minimal cross-referencing (only one referenced service bulletin and one related UK CAA AD)","Short document (1 page) with clear structure (Applicability, Requirement, Compliance, Background)","No nested exceptions or conditional logic — the amendment simply replaces an ineffective prior modification with a new one"],"plain_english_summary":"This AD mandates installation of BAe modification HCM36244A on BAe 146 and AVRO 146-RJ aircraft fitted with certain Sundstrand APUs to eliminate an overheated APU exhaust in the ECS bay that could ignite leaked fuel or hydraulic fluid. Previously required insulation blankets (HCM36240A) proved ineffective and must be removed if fitted.\n\nCompliance was required by 8 July 2005 to remove the fire hazard in an unprotected compartment."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank","history":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank/history","analysis":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank/analysis","conflicts":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank/conflicts","importantCases":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank/important-cases","documents":"/api/acts/ad-bae-146-111-amdt-1-apu-insulation-blankets-exhaust-drain-blank/documents"}}