{"id":"F2006B09896","name":"AD/F50/67 - Main Landing Gear Drag Stay Tubes","slug":"ad-f50-67-main-landing-gear-drag-stay-tubes","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55052,"registerId":"commonwealth-F2006B09896-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/67 - Main Landing Gear Drag Stay Tubes","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)  \nFokker F50 (F27 Mk 50) Series Aeroplanes\n\nAD/F50/67 Main Landing Gear Drag Stay Tubes 8/95\n\nApplicability: Fokker F27 Mk050 series aircraft fitted with main landing gear drag stay tube P/N 200684001.\n\nRequirement: 1. Do an ultrasonic inspection of the drag stay tube in accordance with Dowty Aerospace Service Bulletin F50-32-50 to confirm that a straight bore tube is installed.\n\n    2. Remove all stepped bore tubes from service.\n\n    3. Re-identify all straight bore tubes with P/N 200684004.\n\nNote 1: RLD AD 93-169/2 and Fokker SB F50-32-029 refer.\n\nCompliance: 1. Inspect in accordance with Requirement 1 before 20 September 1995.\n\nInspect spare tubes before installation on an aircraft.\n\n2. Remove from service in accordance with Requirement 2 or re-identify in accordance with Requirement 3 before further flight.\n\nBackground: One instance of a failed drag stay tube has been reported on F27 aircraft, F50 aircraft utilise an identical drag stay tube. The failure caused the landing gear to collapse and was attributed to a crack originating at an incorrectly machined step on the tube interior. This AD will ensure that all such tubes are identified and removed from service.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2417},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope targeting a specific safety-critical manufacturing defect in identified landing gear components. There is no indication of scope expansion beyond the initial safety concern regarding drag stay tube failures."},"complexity_factors":["Use of undefined technical aviation terminology (drag stay tubes, stepped bore, straight bore, ultrasonic inspection)","Reliance on external technical standard (Dowty Aerospace Service Bulletin F50-32-50) for compliance procedures","Multiple specific part numbers and aircraft model designations requiring cross-referencing","Technical conditional applicability based on aircraft configuration"],"plain_english_summary":"This mandatory safety directive requires owners and operators of Fokker F27 Mk050 aircraft with main landing gear drag stay tubes P/N 200684001 to ultrasonic‑inspect those tubes per Dowty Aerospace SB F50‑32‑50, remove any “stepped bore” tubes immediately, and re‑identify approved straight‑bore tubes as P/N 200684004.  \n\nIt responds to a stepped‑bore tube failure that caused a landing‑gear collapse traced to an internal manufacturing defect; the actions prevent similar in‑service failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes","history":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes/history","analysis":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes/analysis","conflicts":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes/conflicts","importantCases":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes/important-cases","documents":"/api/acts/ad-f50-67-main-landing-gear-drag-stay-tubes/documents"}}