{"id":"F2007L03996","name":"AD/LJ45/11 - Engine Firewall","slug":"ad-lj45-11-engine-firewall","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":160790,"registerId":"commonwealth-F2007L03996-current","compilationNumber":null,"startDate":"2026-04-04","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Learjet 45 Series Aeroplanes","sectionType":"division","heading":"Learjet 45 Series Aeroplanes","content":"### Learjet 45 Series Aeroplanes\n\n| AD/LJ45/11 | Engine Firewall | 11/2007 |\n| ---------- | --------------- | ------- |\n\n| Applicability: | Model 45 aircraft, as identified in Bombardier Service Bulletin 45-54-3 Revision 2, or later FAA approved revision.                                                                                                                                                                                                      |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Inspect the engine pylon trailing edge for unsealed gaps, and clean and seal any unsealed gap in accordance with Bombardier Service Bulletin 45-54-3 Revision 2, or later FAA approved revision.Note: FAA AD 2007-17-17 Amdt 39-15175 refers.                                                                            |\n| Compliance:    | Within 12 months after 25 October 2007, unless already accomplished.                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 25 October 2007.                                                                                                                                                                                                                                                       |\n| Background:    | The FAA received a report of unsealed gaps (penetration points) of the engine firewall that were discovered during production. Such a condition, unless corrected, could allow penetration of flammable liquids or fire through the engine firewall into the engine pylon, which could lead to fire inside the aircraft. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n10 September 2007","sortOrder":0},{"sectionNumber":"AD/LJ45/11","sectionType":"part","heading":"AD/LJ45/11","content":"## AD/LJ45/11","sortOrder":1},{"sectionNumber":"Engine Firewall","sectionType":"part","heading":"Engine Firewall","content":"## Engine Firewall","sortOrder":2},{"sectionNumber":"11/2007","sectionType":"part","heading":"11/2007","content":"## 11/2007","sortOrder":3}],"analysis":{"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 model. The scope remains tightly focused on the original safety issue — sealing engine firewall gaps in Learjet 45 aircraft."},"complexity_factors":["Single, specific technical requirement (inspect and seal gaps)","Only one defined applicability criterion (Model 45 aircraft per specific service bulletin)","Simple compliance deadline (12 months from effective date)","No nested exceptions or conditional logic","Short document (approximately 200 words of substantive content)","Single cross-reference to FAA AD 2007-17-17 for context only"],"plain_english_summary":"Owners and operators of certain Learjet 45 aircraft must inspect and, if needed, clean and seal unsealed gaps in the engine pylon trailing edge to restore the engine firewall’s integrity, following Bombardier Service Bulletin 45‑54‑3 Revision 2 (or FAA‑approved later). Compliance was required within 12 months of 25 October 2007 to eliminate the risk of fire or fuel intrusion into the cabin."},"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":3,"scope_assessment":{"changed":false,"description":"The instrument as presented targets a specific fleet subset (Learjet Model 45 identified by the Bombardier service bulletin) and mandates a defined corrective action within a fixed timeframe. The text does not indicate any expansion or narrowing of scope beyond that defined applicability and the referenced service bulletin; therefore no scope change from the document itself is apparent."},"complexity_factors":["Narrow applicability to Model 45 aircraft as identified in Bombardier Service Bulletin 45-54-3 Rev 2 (Applicability) — reduces scope complexity.","Mandated inspect-and-seal action following the manufacturer's service bulletin (Requirement) — prescriptive technical remedy.","12‑month compliance deadline from 25 October 2007 (Compliance) — creates a fixed implementation timeframe and scheduling pressure.","Cross-reference to FAA AD 2007-17-17 and allowance for later FAA‑approved SB revisions (Requirement/Applicability) — introduces dependency on external regulatory approvals.","Costs and operational work fall to aircraft owners/operators (Requirement/Compliance) — clear who pays and who must act.","No alternative compliance methods or delegations stated in the text (Requirement) — limited administrative discretion noted.","Technical work (inspection, cleaning, sealing) may require specialist skills/parts and transient aircraft downtime (Background/Requirement)."],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier Learjet 45 aircraft (as identified in Bombardier Service Bulletin 45-54-3 Rev 2 or later FAA‑approved revisions) to inspect the engine pylon trailing edge for unsealed gaps and to clean and seal any found gaps in accordance with the service bulletin. Compliance is required within 12 months of 25 October 2007. The rule assigns inspection and repair costs to aircraft owners/operators and cross‑references FAA AD 2007‑17‑17."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lj45-11-engine-firewall","history":"/api/acts/ad-lj45-11-engine-firewall/history","analysis":"/api/acts/ad-lj45-11-engine-firewall/analysis","conflicts":"/api/acts/ad-lj45-11-engine-firewall/conflicts","importantCases":"/api/acts/ad-lj45-11-engine-firewall/important-cases","documents":"/api/acts/ad-lj45-11-engine-firewall/documents"}}