{"id":"F2007L03997","name":"AD/LEARJET 35/41 - Engine Firewall","slug":"ad-learjet-35-41-engine-firewall","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":160791,"registerId":"commonwealth-F2007L03997-current","compilationNumber":null,"startDate":"2026-04-04","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Gates Learjet 35 and 36 Series Aeroplane","sectionType":"division","heading":"Gates Learjet 35 and 36 Series Aeroplanes","content":"### Gates Learjet 35 and 36 Series Aeroplanes\n\n| AD/LEARJET 35/41 | Engine Firewall | 11/2007 |\n| ---------------- | --------------- | ------- |\n\n| Applicability: | Model 35, 35A, 36, and 36A aircraft, as identified in Learjet Service Bulletin35/36-54-3 original issue, or later FAA approved revision.                                                                                                                                                                                 |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Inspect for unsealed gaps on the engine pylon side of the engine firewall, and clean and seal any unsealed gap in accordance with Learjet Service Bulletin 35/36-54-3 original issue, 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\n7 September 2007","sortOrder":0},{"sectionNumber":"AD/LEARJET 35/41","sectionType":"part","heading":"AD/LEARJET 35/41","content":"## AD/LEARJET 35/41","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":{"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":2,"scope_assessment":{"changed":false,"description":"The instrument implements a targeted corrective maintenance requirement for the specified Learjet models as described in the source. It does not broaden applicability beyond the listed models, nor extend obligations beyond inspection and sealing per the stated service bulletin and the 12‑month compliance window (see Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow applicability: limited to Model 35, 35A, 36 and 36A aircraft (Applicability).","Single, discrete required action: inspect and, if necessary, clean and seal unsealed gaps on the engine pylon side of the engine firewall (Requirement).","Dependency on an external technical document: work is to follow Learjet Service Bulletin 35/36-54-3 or later FAA‑approved revision, creating reliance on FAA/Learjet-approved procedures (Requirement).","Fixed compliance window: a single 12‑month deadline after 25 Oct 2007 reduces ongoing regulatory complexity but concentrates workload (Compliance).","Low regulatory discretion: the AD specifies the action and timing, leaving limited interpretive room for regulators, though approval of later SB revisions is an external control point (Requirement/Applicability).","Operational cost and scheduling impact: maintenance/repair costs and aircraft downtime fall on operators—this is an explicit, immediate private cost (Requirement/Compliance)."],"plain_english_summary":"This directive requires owners/operators of Gates Learjet 35, 35A, 36 and 36A aeroplanes to inspect the engine firewall on the engine pylon side for any unsealed gaps and to clean and seal any gaps in accordance with Learjet Service Bulletin 35/36-54-3 (or a later FAA‑approved revision). Compliance is required within 12 months after 25 October 2007. The stated purpose is to stop flammable liquids or fire from passing the firewall into the pylon and potentially causing a fire inside the aircraft; it places inspection and repair costs and scheduling obligations on operators."},"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 specific aircraft models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words of substantive content)","Only 4 defined aircraft models in applicability section","Single, straightforward requirement with one referenced technical standard (Learjet Service Bulletin 35/36-54-3)","Simple compliance deadline (12 months from effective date)","No nested exceptions, conditional logic, or cross-references to other legislation","Clear, single-purpose safety directive with no policy ambiguities"],"plain_english_summary":"CASA requires operators of Gates Learjet 35/35A/36/36A to inspect the engine firewall-to-pylon interface and clean and seal any unsealed gaps per Learjet Service Bulletin 35/36-54-3 (or later FAA-approved revision) within 12 months of 25 October 2007. Unsealed gaps could admit flammable fluids or fire into the fuselage; compliance is mandatory."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-35-41-engine-firewall","history":"/api/acts/ad-learjet-35-41-engine-firewall/history","analysis":"/api/acts/ad-learjet-35-41-engine-firewall/analysis","conflicts":"/api/acts/ad-learjet-35-41-engine-firewall/conflicts","importantCases":"/api/acts/ad-learjet-35-41-engine-firewall/important-cases","documents":"/api/acts/ad-learjet-35-41-engine-firewall/documents"}}