{"id":"F2006B11105","name":"AD/LEARJET 35/26 - Forward Engine Mounts","slug":"ad-learjet-35-26-forward-engine-mounts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56765,"registerId":"commonwealth-F2006B11105-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET 35/26 - Forward Engine Mounts","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nGates Learjet 35 and 36 Series Aeroplanes\n\nAD/LEARJET 35/26 Forward Engine Mounts 5/87\n\nDM\n\nApplicability: All models 35 and 36 series aircraft with S/Nos. 35-001 to 35-522 and 36-001 to 36- 053 which do not incorporate forward engine mounts P/N 2651034.\n\nRequirement: Inspect the forward engine mounts in accordance with Gates Learjet SB 35/36-71-3.\n\nNote 1: Aircraft known to have unrepaired cracks shall not be returned to service without the prior approval of the Secretary.\n\nNote 2: It is requested that inspections which result in no defects being discovered are reported to the Secretary, in order that the need for this requirement may be reviewed in the future.\n\nNote 3: FAA AD 86-02-06 refers.\n\nCompliance: (a) Visual Inspection \\- Part 2A of the SB:\n\nPrior to exceeding 2400 hours total time in service or within 75 hours time in service after 18 March 1987, whichever occurs later, and thereafter at intervals not exceeding 420 hours time in service.\n\n(b) Magnetic Particle Inspection \\- Part 2B of the SB:\n\nPrior to exceeding 2400 hours total time in service or within 1500 hours time in service after 18 March 1987, whichever occurs later, and thereafter at intervals not exceeding 1500 hours time in service.\n\nBackground: The manufacturer has reported a case of cracking in both engine mounts on a Model 35 aircraft. Further testing revealed that one of the engine mounts would not sustain the required regulatory loads.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in defined aircraft. It has not expanded beyond its original purpose of ensuring engine mount integrity through mandated inspections."},"complexity_factors":["Multiple applicability criteria (model series, serial number ranges, part number exclusions)","Dual compliance pathways with different thresholds (visual vs magnetic particle inspection)","Time-based calculations using 'whichever occurs later' logic","Cross-reference to external technical document (Gates Learjet Service Bulletin 35/36-71-3)","Conditional prohibition on return to service requiring administrative approval","Reference to corresponding foreign aviation regulation (FAA AD 86-02-06)"],"plain_english_summary":"This CASA Airworthiness Directive orders mandatory inspections of forward engine mounts on specific Gates Learjet 35/36 (serials 35‑001–35‑522, 36‑001–36‑053) to detect cracks. Aircraft with upgraded mounts (P/N 2651034) are exempt. It requires recurring visual and magnetic‑particle checks at defined flight‑hour intervals; any cracked mount must be repaired before flight unless special permission is granted. The AD prevents catastrophic engine separation by catching fatigue cracks early."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD confines obligations to the listed Model 35/36 serials lacking P/N 2651034 and specifies inspection types, intervals and reporting/approval conditions (Applicability; Requirement; Compliance; Notes). The instrument does not expand applicability beyond those aircraft or add new operational prohibitions; it imposes inspection, reporting and Secretary‑approval steps consistent with addressing the reported cracking."},"complexity_factors":["Applicability limited to specific serial number ranges and excludes aircraft already fitted with P/N 2651034 (Applicability).","Two inspection methods with different requirements: visual inspection (Part 2A) and magnetic particle inspection (Part 2B) (Compliance (a) & (b)).","Conditional compliance deadlines using service hours and a fixed date (e.g. ‘prior to exceeding 2400 hours or within X hours after 18 March 1987, whichever occurs later’) create timing complexity (Compliance (a) & (b)).","Discretionary requirement: aircraft with known unrepaired cracks must obtain prior approval from the Secretary before return to service (Note 1) — creates an approval bottleneck.","Administrative reporting request for inspections that find no defects (Note 2) increases paperwork and monitoring workload.","Dependency on manufacturer service bulletin for inspection procedures (Requirement) — operators must follow external technical material.","Cross-reference to FAA AD 86-02-06 may require operators to reconcile multiple regulatory documents (Note 3)."],"plain_english_summary":"This AD requires owners/operators of Gates Learjet 35 and 36 series (S/N 35‑001 to 35‑522 and 36‑001 to 36‑053) that do not have forward engine mounts P/N 2651034 to inspect the forward engine mounts in accordance with Gates Learjet SB 35/36‑71‑3. It prescribes specific visual and magnetic‑particle inspection types and recurring intervals, and prohibits returning aircraft with unrepaired cracks without the Secretary’s approval."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-35-26-forward-engine-mounts","history":"/api/acts/ad-learjet-35-26-forward-engine-mounts/history","analysis":"/api/acts/ad-learjet-35-26-forward-engine-mounts/analysis","conflicts":"/api/acts/ad-learjet-35-26-forward-engine-mounts/conflicts","importantCases":"/api/acts/ad-learjet-35-26-forward-engine-mounts/important-cases","documents":"/api/acts/ad-learjet-35-26-forward-engine-mounts/documents"}}