{"id":"F2005L02781","name":"AD/EMB-120/39 - APU Firewall","slug":"ad-emb-120-39-apu-firewall","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":37674,"registerId":"commonwealth-F2005L02781-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Embraer EMB-120 (Brasilia) Series Aeropl","sectionType":"division","heading":"Embraer EMB-120 (Brasilia) Series Aeroplanes","content":"### Embraer EMB-120 (Brasilia) Series Aeroplanes\n\n| AD/EMB-120/39 | APU Firewall | 11/2005 |\n| ------------- | ------------ | ------- |\n\n| Applicability: | All Model EMB-120 aircraft.                                                                                                                                                                  |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Embraer Service Bulletin No. 120-53-0080 original issue, or later CTA approved revision.Note: CTA AD 2005-08-03 Amdt 39-1087 refers.                               |\n| Compliance:    | Within 4,000 flight hours or 2 calendar years after 27 October 2005, whichever occurs first.                                                                                                 |\n|                | This Airworthiness Directive becomes effective on 27 October 2005.                                                                                                                           |\n| Background:    | During production, the manufacturer discovered that an opening in the APU firewall was not sealed. This condition, if not corrected, will compromise the isolating function of the firewall. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n15 September 2005","sortOrder":0},{"sectionNumber":"AD/EMB-120/39","sectionType":"part","heading":"AD/EMB-120/39","content":"## AD/EMB-120/39","sortOrder":1},{"sectionNumber":"APU Firewall","sectionType":"part","heading":"APU Firewall","content":"## APU Firewall","sortOrder":2},{"sectionNumber":"11/2005","sectionType":"part","heading":"11/2005","content":"## 11/2005","sortOrder":3}],"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 remains focused on correcting an identified production defect in the APU firewall for all EMB-120 aeroplanes (Applicability; Background). The AD mandates compliance via a specific Embraer Service Bulletin (Requirement) within a set timeframe (Compliance) and does not expand obligations beyond inspection/repair per that technical instruction; allowing later CTA‑approved revisions only moderates how the mandated fix may be implemented."},"complexity_factors":["Narrow technical scope: targets a single manufacturing defect (unsealed APU firewall opening) affecting all EMB-120s (Applicability).","Dependency on external technical document: mandates action \"in accordance with Embraer Service Bulletin No. 120-53-0080\" (Requirement), creating reliance on a non-statutory document for compliance details.","Regulatory tolerance for revisions: permits later CTA/CSA-approved revisions of the service bulletin (Requirement), introducing limited administrative discretion about acceptable corrective methods.","Fixed compliance window: specifies a binary compliance trigger (4,000 flight hours or 2 calendar years after 27 October 2005) (Compliance), which concentrates scheduling and maintenance burden on operators within that period.","Administrative cross-reference: note referring to CTA AD 2005-08-03 Amdt 39-1087 creates regulatory linkage that operators must track.","Operational cost and logistics: inspecting/sealing the firewall will impose direct maintenance costs, parts/labour scheduling and possible aircraft downtime for all operators."],"plain_english_summary":"This Airworthiness Directive requires all Embraer EMB-120 aircraft to have a discovered unsealed opening in the APU firewall corrected by following Embraer Service Bulletin No. 120-53-0080 (or a later Civil Aviation Safety Authority‑approved revision). It imposes a compliance deadline (4,000 flight hours or 2 years after 27 October 2005), so aircraft owners/operators must arrange inspection and repair within that window to restore the firewall’s isolating function."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive addressing a specific manufacturing defect in a specific aircraft type. The scope remains tightly focused on the original safety issue — sealing an APU firewall opening — with no expansion beyond this technical remedy."},"complexity_factors":["Single, specific technical requirement referencing an external service bulletin","No defined terms section — uses standard aviation terminology","Simple binary applicability (all Model EMB-120 aircraft)","Straightforward compliance deadline with clear alternative triggers (flight hours OR calendar time)","No nested exceptions, conditional logic, or cross-references to other legislation beyond the referenced service bulletin and related foreign AD","Total length: approximately 150 words of substantive content"],"plain_english_summary":"This AD requires owners and operators of Embraer EMB‑120 aircraft in Australia to correct an unsealed opening in the APU firewall by following Embraer Service Bulletin 120‑53‑0080 (or later approved). The repair must be done within 4,000 flight hours or 2 years from 27 Oct 2005. It addresses the risk that an unsealed firewall could allow an APU fire to spread."}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-120-39-apu-firewall","history":"/api/acts/ad-emb-120-39-apu-firewall/history","analysis":"/api/acts/ad-emb-120-39-apu-firewall/analysis","conflicts":"/api/acts/ad-emb-120-39-apu-firewall/conflicts","importantCases":"/api/acts/ad-emb-120-39-apu-firewall/important-cases","documents":"/api/acts/ad-emb-120-39-apu-firewall/documents"}}