{"id":"F2006B08410","name":"AD/CESSNA 525/1 - Main Landing Gear Trunnion Bearings","slug":"ad-cessna-525-1-main-landing-gear-trunnion-bearings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115869,"registerId":"commonwealth-F2006B08410-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 525/1 - Main Landing Gear Trunnion Bearings","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)  \nCessna 525 Series Aeroplanes\n\nAD/CESSNA 525/1 Main Landing Gear Trunnion Bearings 4/97 DM\n\nApplicability: Model 525 Serial numbers 525-0001 to 525-0153.\n\nRequirement: 1. Inspect the main landing gear trunnion pins in accordance with Cessna SLA 525- 32-11.\n\n2. Modify in accordance with Cessna SB.525-32-08 Rev 1.\n\nNote: FAA AD 97-01-02 refers.\n\nCompliance: 1. Inspect within 25 hours time in service after 19 February 1997, and thereafter at intervals not exceeding 25 hours time in service until modified.\n\n2. Unless already accomplished as a result of Requirement 1, modify within 75 hours time in service after 19 February 1997.\n\nThis Airworthiness Directive becomes effective on 19 February 1997.\n\nBackground: This Directive is the result of a MLG collapse during landing roll out, due to trunnion bearing failure caused by loss of dry film lubricant on the MLG trunnion bearings.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive confines its scope to Cessna 525 aircraft with serial numbers 525-0001 through 525-0153 and prescribes inspection and modification actions to address trunnion bearing lubricant loss and failure. The text supplied shows no change in scope from that stated intent: it targets a specific fleet subset and mandates inspection intervals and a modification procedure to remediate the identified failure mode. (Applicability; Requirement 1–2; Background; Compliance 1–2)"},"complexity_factors":["Narrow applicability limited to specific serial numbers (525-0001 to 525-0153) (Applicability)","Two discrete technical actions: repeated inspection (SLA 525-32-11) and a required modification (SB.525-32-08 Rev 1) (Requirement 1–2)","Short compliance windows (inspect within 25 hours; modify within 75 hours) that create scheduling pressure (Compliance 1–2)","Technical procedures are defined by manufacturer service documents, requiring qualified maintenance personnel and possible parts procurement (Requirement 1–2)","Cross-reference to an FAA AD increases multi-jurisdictional technical alignment but requires checking parallel guidance (Note)"],"plain_english_summary":"This AD requires owners/operators of Cessna 525 aircraft (serials 525‑0001 to 525‑0153) to inspect and then modify main landing gear trunnion bearings using Cessna SLA 525‑32‑11 and SB.525‑32‑08 Rev 1 after reports of bearing lubricant loss and a gear collapse. Inspections are required within 25 hours TIS (and every 25 hours until modified) and the modification must be done within 75 hours after 19 February 1997.\n\nIt matters because operators bear the cost, scheduling impact and must use certified maintenance to reduce collapse risk."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted airworthiness directive addressing a specific mechanical failure mode in a defined aircraft population. It remains focused on its original safety purpose with no scope creep."},"complexity_factors":["Single, specific aircraft model and limited serial number range","Only two requirements: inspect and modify","Clear, fixed compliance times (25 hours and 75 hours)","No nested exceptions or conditional logic","References external technical documents (Cessna SLA and SB) rather than incorporating complex internal provisions","Background explanation is straightforward and single-issue focused"],"plain_english_summary":"This is a **safety order for specific Cessna jet aircraft** (the CitationJet 525 series, serial numbers 525-0001 through 525-0153).\n\n**What it does:**\n- **Requires urgent inspections** of the main landing gear trunnion pins (the pivot points that attach the wheels to the aircraft) every 25 flight hours\n- **Mandates a permanent fix** (modification) within 75 flight hours\n\n**Why it matters:**\nA Cessna 525 had its main landing gear collapse during landing because the dry film lubricant on these bearings failed. This directive prevents the same dangerous failure from happening to other aircraft.\n\n**Who must comply:**\n- Owners and operators of Cessna 525 aircraft with serial numbers 525-0001 to 525-0153 (approximately the first 153 aircraft built)\n\n**Key deadlines:**\n- First inspection: within 25 flight hours after 19 February 1997\n- Ongoing inspections: every 25 flight hours until modified\n- Permanent modification: within 75 flight hours after 19 February 1997\n\n**What operators must follow:**\n- Cessna Service Letter 525-32-11 (for inspections)\n- Cessna Service Bulletin 525-32-08 Revision 1 (for the modification)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings","history":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings/history","analysis":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings/analysis","conflicts":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings/conflicts","importantCases":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings/important-cases","documents":"/api/acts/ad-cessna-525-1-main-landing-gear-trunnion-bearings/documents"}}