{"id":"F2006L00144","name":"AD/R22/53 - Main Rotor Blades","slug":"ad-r22-53-main-rotor-blades","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58032,"registerId":"commonwealth-F2006L00144-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Robinson R22 Series Helicopters","sectionType":"division","heading":"Robinson R22 Series Helicopters","content":"### Robinson R22 Series Helicopters\n\n| AD/R22/53 | Main Rotor Blades | 2/2006 |\n| --------- | ----------------- | ------ |\n\n| Applicability: | R22 helicopters fitted with P/N A016-2 Main Rotor Blades.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Remove and replace P/N A016-2 Main Rotor Blades with P/N A016-4 Main Rotor Blades.2. P/N A016-2 blades are not to be returned to service under any circumstances.Accomplishment of this Airworthiness Directive is terminating action for the requirements of AD/R22/31 Amdt 11, which will be cancelled after 1 April 2006.                                                                                                                                                                                                                                                                                                                                   |\n| Compliance:    | 1. Prior to 1 April 2006.2. After 1 April 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 16 February 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Background:    | There have been several accidents in Australia and overseas caused by failure of the Part Number A016-2 main rotor blade. The subsequent investigations showed that the design of the blade is not tolerant to certain environmental conditions that may allow moisture ingress and corrosion pits to develop in the inboard spar/root fitting attachment bolt hole. The corrosion pits can allow fatigue cracks to develop which may proceed to rapid failure of the main rotor blade within a few flights, with subsequent loss of the helicopter. This AD requires replacement of the P/N A016-2 main rotor blades with new improved design blades P/N A016-4. |\n\n![](image.001.png)  \nNeville Probert  \nDelegate of the Civil Aviation Safety Authority\n\n20 December 2005","sortOrder":0},{"sectionNumber":"AD/R22/53","sectionType":"part","heading":"AD/R22/53","content":"## AD/R22/53","sortOrder":1},{"sectionNumber":"Main Rotor Blades","sectionType":"part","heading":"Main Rotor Blades","content":"## Main Rotor Blades","sortOrder":2},{"sectionNumber":"2/2006","sectionType":"part","heading":"2/2006","content":"## 2/2006","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — a targeted safety replacement of a specific defective helicopter part. It has not expanded beyond its initial purpose of addressing the A016-2 blade failure risk."},"complexity_factors":["Single, unambiguous requirement with no conditional exceptions","Only one defined term of significance (P/N A016-2 vs P/N A016-4)","Clear binary compliance deadline (before/after 1 April 2006)","No cross-references to other legislation except cancellation of one prior AD","Straightforward cause-and-effect background explanation","Total length is approximately 200 words of substantive content"],"plain_english_summary":"This AD mandates that owners/operators of Robinson R22 helicopters fitted with main rotor blades marked P/N A016-2 must replace them with improved A016-4 blades by 1 April 2006; A016-2 blades are permanently prohibited.  \n\nIt addresses a design flaw where moisture-induced corrosion causes hidden cracks that can lead to in‑flight blade separation and fatal accidents, so the order affects flight schools, private owners, charter operators and maintenance organisations."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive stays within the original safety objective: eliminate a known failure mode of a specific rotor-blade part by mandating replacement with an improved-design part. It does not broaden applicability to other components, helicopter models, or introduce ongoing monitoring obligations beyond the one-off replacement. The only scope change relative to prior ADs is that this action is declared terminating action for the earlier AD/R22/31 Amdt 11, i.e. it replaces earlier measures rather than expanding the regulator's reach."},"complexity_factors":["Single model applicability (R22 helicopters fitted with P/N A016-2 blades)","One primary mandatory action: replace P/N A016-2 with P/N A016-4","Clear prohibition: P/N A016-2 blades not to be returned to service","Single compliance deadline (by 1 April 2006) and effective date (16 February 2006)","Reference to one prior AD as being terminated on compliance (AD/R22/31 Amdt 11)","Short text, no nested exceptions, few defined terms and no staged/conditional inspections"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- This is a mandatory airworthiness directive for Robinson R22 helicopters that are fitted with main rotor blades Part Number (P/N) A016-2.  \n- Owners/operators must remove and replace every P/N A016-2 blade with the improved-design P/N A016-4 blade. (Requirement)\n- P/N A016-2 blades are prohibited from being returned to service under any circumstances after the replacement requirement takes effect. (Requirement)\n- The directive took effect on 16 February 2006, and the replacement must be done by 1 April 2006. After 1 April 2006 P/N A016-2 blades are not permitted in service. (Compliance)\n- Completing this replacement satisfies (is \"terminating action\" for) the requirements of a prior directive (AD/R22/31 Amdt 11), which will be cancelled after 1 April 2006. (Requirement)\n\n**Why the regulator requires this (official rationale)**\n\n- Investigations of several accidents showed that the A016-2 blade design can allow moisture to enter the inboard spar/root fitting attachment bolt hole, creating corrosion pits. These pits can develop into fatigue cracks that may grow quickly and cause a sudden blade failure within a few flights. The directive requires replacement with the P/N A016-4 blade, which has an improved design intended to prevent that failure mode. (Background)\n\n**Who this affects and who pays**\n\n- Affected: owners and operators of R22 helicopters that currently have P/N A016-2 main rotor blades fitted (Applicability).  \n- Costs: the owner/operator is responsible for the blade replacement expense, any labour/maintenance costs, and any aircraft downtime while the work is done. If replacement blades are scarce, operators may also incur additional delay or opportunity costs (grounding, rescheduling flights, chartering, or selling the aircraft).  \n\n**What behaviour changes are required**\n\n- Operators must remove the legacy A016-2 blades and install A016-4 blades by the specified compliance date.  \n- After the compliance date, operators may no longer operate R22s fitted with A016-2 blades or reinstall them.  \n- After compliance is accomplished, operators no longer need to meet the earlier AD/R22/31 Amdt 11 requirements (the new action terminates that AD).  \n\n**Implementation and practical risks / trade-offs**\n\n- Safety vs cost: the directive exchanges an immediate replacement cost and potential operational disruption for a reduced risk of sudden main-rotor failure. (Requirement; Background)\n- Supply and scheduling risk: the effectiveness of the rule depends on availability of the P/N A016-4 blades and of maintenance capacity before the deadline. Scarcity could concentrate costs on operators who must ground aircraft or pay premium installation rates.  \n- Enforcement and discretion: the directive is prescriptive (replace by a date; do not return old parts), leaving little regulator discretion in individual cases, but inspectors must verify compliance.  \n- Concentrated benefits and diffuse costs: manufacturers or suppliers of the A016-4 blade realise concentrated sales; a broad set of small operators bear distributed replacement costs.  \n\n**Net mechanical effect**\n\n- The rule removes the option to keep the older blades in service, forces retrofit to a single improved part-number blade, and ends the requirements imposed by the previous AD once operators comply. (Requirement; Compliance)\n\n\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-r22-53-main-rotor-blades","history":"/api/acts/ad-r22-53-main-rotor-blades/history","analysis":"/api/acts/ad-r22-53-main-rotor-blades/analysis","conflicts":"/api/acts/ad-r22-53-main-rotor-blades/conflicts","importantCases":"/api/acts/ad-r22-53-main-rotor-blades/important-cases","documents":"/api/acts/ad-r22-53-main-rotor-blades/documents"}}