{"id":"F2006B10746","name":"AD/HU 369/81 - Tail Rotor Swashplate Bearing Set","slug":"ad-hu-369-81-tail-rotor-swashplate-bearing-set","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116752,"registerId":"commonwealth-F2006B10746-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/81 - Tail Rotor Swashplate Bearing Set","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)  \nMcDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters\n\nAD/HU 369/81 Tail Rotor Swashplate Bearing Set 8/90\n\nDM\n\nApplicability: All model 369D, 369E and 369F/FF series helicopters.\n\nRequirement: Action in accordance with McDonnell Douglas SIN DN-167, EN-58 or FN-46 as applicable.\n\nCompliance: Part 1 of Requirement document-Prior to further flight after 30 June 1990. If bearing seals are green or yellow a certification which includes the bearing seal colour and a statement of compliance with this AD shall be entered on the Maintenance Release.\n\nNote: This inspection may be accomplished by the pilot in command.\n\nPart 2 of Requirement document-Within 10 hours time in service for applicable black seal bearing set and thereafter at intervals not exceeding 10 hours time in service.\n\nReplace bearing set before 300 hours time in service. Bearing sets that have exceeded 300 hours time in service by 30 June 1990 must be replaced before further flight.\n\nBackground: Inspection for defective tail rotor swashplate bearing sets is required to prevent failure of the bearing which could result in loss of control of the helicopter.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in 1990 for a specific mechanical defect. It has not expanded beyond its original purpose of addressing tail rotor swashplate bearing failures in the specified helicopter models."},"complexity_factors":["Single, specific mechanical component targeted (tail rotor swashplate bearing set)","Only three helicopter model variants affected (369D, 369E, 369F/FF)","Simple conditional logic based on visual indicator (seal colour: green/yellow vs black)","Clear compliance deadlines (fixed date of 30 June 1990, plus flight hour intervals)","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Single reference to manufacturer service instructions (SIN DN-167, EN-58, FN-46)","Total length: approximately 200 words"],"plain_english_summary":"This AD requires owners/operators of McDonnell Douglas/Kawasaki 369D, 369E and 369F/FF helicopters to inspect and ultimately replace tail rotor swashplate bearing sets to prevent in‑flight loss of control. It affects pilots, maintenance personnel and aircraft operators by mandating checks, documentation and replacement on a defined schedule to eliminate bearings known to have caused accidents."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"No. The AD applies specifically to all model 369D, 369E and 369F/FF helicopters named in 'Applicability' and confines measures to inspection, maintenance-release certification, and replacement schedules tied to bearing seal condition and hours-in-service (see 'Applicability', 'Requirement' and 'Background'). The instrument does not broaden applicability beyond those models or add other component types."},"complexity_factors":["Multiple and overlapping compliance deadlines: immediate action prior to further flight after 30 June 1990, 10‑hour intervals for black seal bearings, and mandatory replacement before 300 hours (Requirement: Part 1; Part 2).","Condition-based branching: different actions depend on bearing seal colour (green/yellow v. black) and on whether a set has already exceeded 300 hours by the 30 June 1990 cutoff (Requirement; Note).","Reference to external service documents (McDonnell Douglas SIN DN‑167, EN‑58 or FN‑46) creates dependency on technical manuals for correct procedures (Requirement).","Record‑keeping and certification: maintenance release must record seal colour and compliance statement, creating an administrative compliance burden for operators and certifying staff (Requirement: Part 1).","Operational discretion: inspection may be accomplished by the pilot in command, shifting some inspection responsibility from maintenance personnel to flight crew (Note).","Immediate economic impact on operators/owners: mandatory replacement before 300 hours and replacement of any set already over 300 hours by the specified date imposes replacement costs and downtime (Requirement: Part 2).","Safety‑purpose clarity but technical execution risk: the Background states the safety objective (prevent bearing failure leading to loss of control), but successful mitigation depends on consistent inspection quality and correct part replacement (Background; Requirement)."],"plain_english_summary":"This airworthiness directive requires inspection and replacement of the tail-rotor swashplate bearing set on McDonnell Douglas (Hughes) and Kawasaki 369D, 369E and 369F/FF helicopters, using the specified McDonnell Douglas service documents. It mandates immediate checks after 30 June 1990, more frequent inspection where bearing seals are black, a maintenance-release entry noting seal colour, and replacement before 300 flight hours; some inspections may be performed by the pilot."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set","history":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set/history","analysis":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set/analysis","conflicts":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set/conflicts","importantCases":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set/important-cases","documents":"/api/acts/ad-hu-369-81-tail-rotor-swashplate-bearing-set/documents"}}