{"id":"F2006B10749","name":"AD/HU 369/84 - Tail Rotor Blades","slug":"ad-hu-369-84-tail-rotor-blades","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116759,"registerId":"commonwealth-F2006B10749-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/84 - Tail Rotor Blades","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 369/84 Tail Rotor Blades 1/92 DM\n\nApplicability: Model 369 Series fitted with the following tail rotor blades: P/N 369D21613\n\nS/Ns 0646, 1165,1821.\n\nP/N 369D21613M S/Ns 1357, 1809, 1855\\. P/N 369D21613-11 S/Ns 2465, 2466, 2683\\. P/N 369D21613-51\n\nS/Ns 4025, 4026, 4453, 4514, 4515, 4683, 02222-6097. P/N 369D21613-501\n\nS/N 5308.\n\nRequirement: Remove from service any tail rotor blade identified by the above serial number listing.\n\nNote 1: Removed blades need to be returned to Rotor Blades (NZ) Ltd for rework. Note 2: Air Transport NZ AD DCA/HU 369/59 refers.\n\nCompliance: Unless already accomplished; prior to further flight after 20 November 1991.\n\nBackground: This Directive is issued in response to a NZ AD which was issued as the result of a recent accident in New Zealand where a tail rotor blade abrasion strip separated in flight. Initial investigation has indicated a defect with the tail rotor blade abrasion strip attachment. The abrasion strips may appear free of bond separation or voids, but this does not assure their airworthiness. The above identified tail rotor blades are of the same batch as the accident blade.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific manufacturing defect in a specific batch of helicopter components. It has not expanded beyond its original purpose of grounding suspect tail rotor blades."},"complexity_factors":["Very short document (under 300 words)","Only 5 defined part numbers with specific serial number lists","Single, unambiguous compliance requirement (remove before flight)","No cross-references to other legislation except a related NZ directive mentioned in a note","No conditional logic or exceptions — applies to listed items, full stop","Clear deadline (20 November 1991)","Plain language background explaining the safety rationale"],"plain_english_summary":"This AD legally requires immediate removal from service of 16 specific tail-rotor blades (Model 369 Series) because an abrasion strip detached in flight, causing an accident; the listed blades came from the same batch and may have faulty bonding even if visually intact.  \n\nOperators with any affected serial-numbered blade must not fly after 20 Nov 1991 and must send removed blades to Rotor Blades (NZ) Ltd for rework."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope remains narrowly focused on the specific blade part numbers and serial numbers from the same production batch as the accident blade; the directive directs removal and return for rework rather than expanding to broader inspections or other models (Applicability, Requirement, Background)."},"complexity_factors":["Narrow, explicit applicability by part numbers and serial numbers — requires positive identification of affected blades (Applicability, Requirement).","Immediate compliance deadline: removal prior to further flight after 20 November 1991 — operational scheduling and potential short‑term grounding (Compliance).","Logistics and cost of returning removed blades to a single rework provider (Rotor Blades (NZ) Ltd) — transport, repair cost and turnaround time (Note 1).","No alternative corrective actions, deferrals, or exemptions specified — operators must remove listed blades (Requirement, Compliance).","Cross‑reference to an existing New Zealand AD introduces regulatory coordination and traceability requirements (Background; Note 2).","Verification and record‑keeping burden on operators and the regulator to show removal and rework have occurred (implicit in Requirement and Compliance).","Cause identified as abrasion‑strip attachment defect from an accident investigation — immediate risk mitigation rather than long‑term monitoring (Background)."],"plain_english_summary":"This Airworthiness Directive requires operators of McDonnell Douglas (Hughes) / Kawasaki 369‑series helicopters fitted with the listed tail‑rotor blade part and serial numbers to remove those specific blades from service before the next flight. The action responds to an in‑flight abrasion‑strip separation; removed blades must be returned to Rotor Blades (NZ) Ltd for rework, so operators bear the grounding, logistics and rework costs and must verify compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-84-tail-rotor-blades","history":"/api/acts/ad-hu-369-84-tail-rotor-blades/history","analysis":"/api/acts/ad-hu-369-84-tail-rotor-blades/analysis","conflicts":"/api/acts/ad-hu-369-84-tail-rotor-blades/conflicts","importantCases":"/api/acts/ad-hu-369-84-tail-rotor-blades/important-cases","documents":"/api/acts/ad-hu-369-84-tail-rotor-blades/documents"}}