{"id":"F2006B10678","name":"AD/HU 369/15 - Tail Rotor Blades - Inspection","slug":"ad-hu-369-15-tail-rotor-blades-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116620,"registerId":"commonwealth-F2006B10678-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/15 - Tail Rotor Blades - Inspection","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 369/15 Tail Rotor Blades \\- Inspection 5/75\n\nApplicability: All 369 series with 369A1613 \\- basic or \\-3 metal tail rotor blades with S/Nos. prior to 1310.\n\nDocument: Hughes SIN No. HN-83.\n\nCompliance: For Part 1 \\- Within 50 hours time in service after 2 May 1975.\n\nFor Part 2 \\- Before 2 May 1975.\n\nFor Part 3 \\- At each daily inspection.\n\nNote: For aircraft maintained in accordance with ANO 100.5.1 Part 3 of this Directive shall be entered on the maintenance release as maintenance required. The Part 3 inspection may be performed by the pilot in command, in which case certification is not required. In all other cases certification may be made on the maintenance release. This inspection may also be performed and certified by any Licensed Aircraft Maintenance Engineer.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a historical airworthiness directive from 1975 (as indicated by '5/75' in the reference). It has not expanded beyond its original purpose of mandating specific tail rotor blade inspections for a defined fleet of helicopters. The scope remains precisely targeted at the safety issue identified in Hughes SIN HN-83."},"complexity_factors":["Very short document (under 200 words)","Only 3 defined compliance timeframes (Part 1, 2, 3)","Single applicability criterion (specific part numbers and serial number range)","One reference document (Hughes SIN HN-83)","Simple conditional note regarding pilot-performed inspections vs engineer certification","No nested definitions, no cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires specific inspections of tail rotor blades on certain Hughes/Kawasaki 369 series helicopters.\n\n**What it does:**\n- **Mandates three different inspection requirements** for metal tail rotor blades on affected helicopters:\n  - **Part 1:** A one-time inspection within 50 flight hours after 2 May 1975\n  - **Part 2:** An inspection that should have been completed before 2 May 1975\n  - **Part 3:** An ongoing daily inspection requirement\n\n**Who it affects:**\n- Owners and operators of **McDonnell Douglas (Hughes) and Kawasaki 369 series helicopters**\n- Specifically those with **metal tail rotor blades** (part numbers 369A1613 or 369A1613-3) with **serial numbers below 1310**\n\n**Why it matters:**\n- Tail rotor failures can cause catastrophic helicopter crashes\n- This AD addresses a known safety issue identified in **Hughes Service Information Notice HN-83**\n- **Part 3 is particularly notable:** pilots can perform this daily check themselves without needing an engineer's certification, though licensed engineers can also do it\n- The directive must be recorded on the aircraft's **maintenance release** (the official document showing an aircraft is airworthy)\n\n**Key practical point:** This is a **retrospective safety order** — it imposes ongoing obligations on aircraft that may be decades old, reflecting how aviation safety law works: once an airworthiness directive is issued, it remains binding until explicitly cancelled."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text does not indicate any amendment to or narrowing/expansion from a prior instrument; it sets specific applicability and compliance obligations for the stated blade model and serial-number range. There is no language in the provided text that changes the directive's scope beyond what is expressly stated (Applicability; Compliance; Note)."},"complexity_factors":["Serial-number-limited applicability (only 369A1613 blades with S/Ns prior to 1310) narrows but complicates identification of affected aircraft (Applicability).","Multiple compliance deadlines with different timeframes: Part 1 (within 50 hours after 2 May 1975), Part 2 (before 2 May 1975), and recurring Part 3 (at each daily inspection) (Compliance).","Cross-reference to an external technical source (Hughes SIN No. HN-83) for inspection procedures, requiring users to consult another document (Document).","Different certification and performance options for Part 3 (pilot may perform without certification; otherwise LAME may perform and certify), creating alternative compliance paths and allocation of responsibility (Note).","Requirement to record Part 3 on the maintenance release where ANO 100.5.1 applies introduces an administrative compliance element (Note)."],"plain_english_summary":"- What this directive does, mechanically:\n  - It requires inspections of tail rotor blades on certain McDonnell Douglas (Hughes) and Kawasaki 369 series helicopters (Applicability). Specifically, it applies to helicopters fitted with 369A1613 (\"-basic\" or \"-3\") metal tail rotor blades with serial numbers prior to 1310 (Applicability).\n  - It sets three inspection actions with deadlines: Part 1 must be done within 50 hours time-in-service after 2 May 1975; Part 2 must be done before 2 May 1975; and Part 3 must be done at each daily inspection (Compliance).\n  - It cites Hughes Service Information Note HN-83 as the referenced document for the inspections (Document).\n\n- Who is affected:\n  - Owners and operators of 369 series helicopters that have the specified tail rotor blade model and serial numbers (Applicability).\n  - Maintenance personnel and pilots who carry out, certify, or record inspections (Note).\n\n- Who decides and who pays:\n  - The aircraft operator/owner is responsible for ensuring inspections are performed and for any associated costs (the Directive imposes the obligation; see Compliance and Note).\n  - Certification of the inspection results is done either by the pilot in command (for the Part 3 daily inspection, where certification is not required if performed by the pilot), or by the person holding maintenance certification (Licensed Aircraft Maintenance Engineer) and recorded on the maintenance release where required (Note). Where maintenance is performed under ANO 100.5.1, Part 3 must be entered on the maintenance release (Note).\n\n- How it changes behaviour:\n  - Operators must schedule and perform specific inspections within the stated timeframes (Compliance).\n  - Daily inspections must include the Part 3 check and either be carried out by the pilot in command (no certification required) or be certified on the maintenance release by a Licensed Aircraft Maintenance Engineer or other authorised person (Note).\n  - Maintenance records must reflect the Part 3 inspection when aircraft are maintained under ANO 100.5.1 (Note).\n\n- Documented source and scope mechanics:\n  - The directive relies on Hughes SIN No. HN-83 as the technical source for the inspection procedures (Document).\n  - The directive's applicability is limited to a specific blade model and serial-number range, so it does not apply to all 369 helicopters universally (Applicability).\n\n- Practical trade-offs, incentives, costs and risks (source-grounded):\n  - Direct costs: Operators pay for the labour and any replacement or corrective maintenance arising from the inspections (Compliance; Note).\n  - Time cost and operational opportunity cost: Part 1 and Part 2 impose one-off deadlines (within 50 hours after 2 May 1975 and before 2 May 1975 respectively), and Part 3 imposes an ongoing daily inspection obligation, which allocates pilot or maintenance time each day (Compliance).\n  - Compliance burden and paperwork: Where aircraft are maintained under ANO 100.5.1, the Part 3 inspection must be entered on the maintenance release, adding administrative work (Note).\n  - Choice and substitution effects: Allowing the pilot in command to perform Part 3 without certification can reduce immediate maintenance costs and reliance on Licensed Aircraft Maintenance Engineers, but shifts responsibility for performing and judging the inspection to pilots (Note).\n  - Discretion and certification: Certification is not required when the pilot performs Part 3; otherwise, certification can be made on the maintenance release by a Licensed Aircraft Maintenance Engineer, which creates a clear compliance pathway and a role for licensed maintenance personnel (Note).\n  - Implementation risk: Failure to perform, record, or properly certify the inspections within the stated timeframes may lead to regulatory non-compliance; the directive sets explicit time-based and recurring compliance points to manage that risk (Compliance; Note).\n\n- Where to look in the instrument for each point:\n  - Applicability: identifies which helicopters and blade serial numbers are covered.\n  - Document: cites Hughes SIN No. HN-83 as the technical source to follow.\n  - Compliance: lists the deadlines and frequency for Parts 1, 2 and 3.\n  - Note: explains who may perform and certify Part 3, and the requirement to enter Part 3 on the maintenance release when ANO 100.5.1 applies.\n\n(References in parentheses refer to the corresponding labeled sections of the directive as provided.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection","history":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection/history","analysis":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection/analysis","conflicts":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection/conflicts","importantCases":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection/important-cases","documents":"/api/acts/ad-hu-369-15-tail-rotor-blades-inspection/documents"}}