{"id":"F2015L01496","name":"AD/OH-58/8 Amdt 1 - Main Rotor Mast Cracking","slug":"ad-oh-58-8-amdt-1-main-rotor-mast-cracking","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":154598,"registerId":"commonwealth-F2015L01496-current","compilationNumber":null,"startDate":"2026-04-04","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/OH-58/8 Amdt 1 - Main Rotor Mast Cracking","content":"COMMONWEALTH OF AUSTRALIA Civil Aviation Safety Regulations 1998 (CASR 1998)\n\nCIVIL AVIATION SAFETY AUTHORITY Regulation 39.001\n\n![](image.001.png)![](image.001.png)AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below repeals Airworthiness Directive (AD) AD/OH-58/8 and issues the following AD under subregulation 39.001 (1) of CASR 1998 and subsection 33 (3) of the Acts Interpretation Act 1901. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct an unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nBell Helicopter Textron Canada (BHTC) 206A-1 (OH-58A) Series Helicopters\n\nAD/OH-58/8\n\nAmdt 1\n\n  \nMain Rotor Mast Cracking 20/2015\n\nApplicability: This AD applies to all Model OH-58A (Bell 206A-1) series helicopters, including\n\nAMT OH-58A and Osborne OH-58A.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2014-22-03. Compliance: Unless previously accomplished, the required actions in FAA AD 2014-22-03 must\n\nbe performed within the compliance time specified in FAA AD 2014-22-03. The effective date of this AD is 25 September 2015.\n\nBackground: This amendment to AD/OH-58/8 requires repetitive inspections (1200 hours TIS or\n\n3 years, whichever occurs earlier) of the Main Rotor Mast for a crack and expands the mast inspection area. The AD also requires periodic overhaul (1200 hours TIS or\n\n3 years, whichever occurs earlier) of the Main Rotor Mast Assembly and NDT Inspection of various Main Rotor Mast Assembly components.\n\nThis AD was prompted by two reported failures of the mast from corrosion-initiated fatigue cracking. The actions specified by this AD (with reference to FAA AD\n\n2014-22-04) are intended to prevent failure of the mast and subsequent loss of control of the helicopter.\n\nThe initial issue of this AD required compliance with FAA AD 2012-14-11 which has now been superseded by FAA AD 2014-22-03.\n\n![](image.003.png)\n\nNicholas Ward\n\nDelegate of the Civil Aviation Safety Authority\n\n21 September 2015\n\nPage 1 of 1","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Compared with the initial AD, this amendment expands the mast inspection area and adds mandatory repetitive inspections, periodic overhaul of the main rotor mast assembly, and NDT of mast components. It replaces reliance on FAA AD 2012-14-11 with FAA AD 2014-22-03, increasing maintenance and inspection obligations for all OH-58A operators."},"complexity_factors":["Cross-reference to an external FAA AD (FAA AD 2014-22-03): technical obligations are defined outside this instrument, requiring operators to obtain and follow another authority's document.","Repetitive inspection and overhaul intervals specified (1200 hours TIS or 3 years): creates ongoing compliance scheduling and record-keeping obligations.","Expanded inspection area and multiple inspection types (visual inspection plus NDT): increases technical scope and may require specialised tooling or certified NDT providers.","Applicability to all Model OH-58A variants (including AMT and Osborne): broad operator coverage increases the number of affected aircraft and potential logistics scaling.","Supersession of prior ADs (replaces compliance with FAA AD 2012-14-11): administrative tracking required to ensure operators transition to the new reference.","Safety-critical consequence (mast failure can cause loss of control): raises urgency and enforcement attention, increasing operational impact despite straightforward requirements."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Bell OH-58A (Bell 206A‑1) helicopters to perform repetitive inspections of the main rotor mast and to follow the technical instructions of FAA AD 2014‑22‑03, including periodic overhaul and nondestructive testing (NDT) of mast assembly components. It expands the area of the mast that must be inspected.\n\nOperators pay for inspections, overhauls and NDT. CASA (the delegate) sets the compliance timing (1200 hours TIS or 3 years) and mandates that actions be completed within the FAA AD’s compliance window, changing maintenance schedules and increasing inspection workload."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: preventing main rotor mast failures in OH-58A helicopters. The amendment simply updates the referenced FAA directive (from 2012-14-11 to 2014-22-03) and expands the inspection area, without broadening to other aircraft types or unrelated systems."},"complexity_factors":["Short, single-page document with clear structure (Applicability, Requirement, Compliance, Background)","Only 2 defined model variants mentioned (AMT OH-58A, Osborne OH-58A)","Single cross-reference to external technical document (FAA AD 2014-22-03) — compliance achieved by 'piggybacking' US requirements rather than rewriting them","Simple conditional logic: 'Unless previously accomplished' creates one exception","No nested definitions or interpretive provisions","Clear, unambiguous compliance timeframe (1200 hours TIS or 3 years, whichever occurs earlier)"],"plain_english_summary":"This mandatory Airworthiness Directive requires owners and operators of Bell OH-58A (Bell 206A-1) helicopters and their maintenance organisations to carry out regular inspections, NDT and scheduled overhauls of the main rotor mast to detect corrosion and fatigue cracking. \n\nIt follows two mast failures that can cause loss of control; the AD replaces the previous version and adopts updated FAA technical requirements to prevent catastrophic mast failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking","history":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking/history","analysis":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking/analysis","conflicts":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking/conflicts","importantCases":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking/important-cases","documents":"/api/acts/ad-oh-58-8-amdt-1-main-rotor-mast-cracking/documents"}}