{"id":"F2006B06420","name":"AD/R22/13 - Tail Rotor Drive Shaft - Replacement","slug":"ad-r22-13-tail-rotor-drive-shaft-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47787,"registerId":"commonwealth-F2006B06420-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/R22/13 - Tail Rotor Drive Shaft - Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Robinson R22 Series Helicopters\n\n \n\nAD/R22/13 Tail Rotor Drive Shaft - Replacement 8/82\n\nApplicability: Models R22 with S/Nos. 0002 to 0282. Document:  Robinson SB.21.\n\nCompliance: Within 100 hours time in service after 30 September 1982.\n\n \n\nBackground:  There have been reported cases of tail rotor drive shaft whipping, due to inadvertent rotor overspeed. A higher frequency shaft is introduced to reduce the possibility of drive shaft whip, and subsequent failure.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive from 1982 addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating a hardware replacement for a defined aircraft population."},"complexity_factors":["Extremely short document — approximately 150 words total","Only one defined term (S/Nos. = serial numbers, implicitly understood)","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Single, unambiguous compliance requirement with clear deadline","No conditional logic, exceptions, or nested provisions","Straightforward applicability test (serial number range)"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Robinson R22 helicopters.\n\n**What it requires:** Owners and operators of early-model R22 helicopters (serial numbers 0002 to 0282) must replace the tail rotor drive shaft with an improved, higher-frequency version within 100 hours of flight time after 30 September 1982.\n\n**Why it matters:** The original drive shafts could develop dangerous \"whipping\" (vibration-induced bending) if the main rotor was accidentally spun too fast. This vibration could cause the shaft to fail, leading to loss of tail rotor control and potentially a crash. The replacement shaft is designed to resist this problem.\n\n**Who must comply:** Anyone operating the affected helicopter models — essentially, maintenance organisations and owners of these specific serial numbers. Non-compliance means the aircraft cannot legally fly."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive text prescribes a specific replacement for the listed Robinson R22 serial numbers, cites the maker's service bulletin for the technical procedure, and sets a single compliance window. Nothing in the instrument indicates a change from that stated scope; the AD enforces replacement for the stated fleet within the stated timeframe (Applicability; Compliance; Document; Background)."},"complexity_factors":["Narrow applicability limited to Robinson R22 S/N 0002–0282 (Applicability)","Single, specific mandated action: replacement of the tail rotor drive shaft (Compliance)","Clear compliance deadline expressed as hours-in-service after a date (Compliance)","Reliance on an external manufacturer document for technical procedure (Document)","Technical nature of the work requires certified maintenance but the AD contains no procedural branching or multiple compliance options (Document; Compliance)"],"plain_english_summary":"Mandates replacement of the tail-rotor drive shaft on Robinson R22 helicopters, serial Nos. 0002–0282, installed per Robinson SB.21 and completed within 100 hours TIS after 30 September 1982. Owners/operators and maintenance organisations must procure, install, and certify the higher‑frequency shaft and bear associated costs and downtime.\n\nThe measure is intended to reduce tail-rotor drive‑shaft whipping and failure following inadvertent rotor overspeed; compliance follows the manufacturer’s service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement","history":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement/history","analysis":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement/analysis","conflicts":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement/conflicts","importantCases":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement/important-cases","documents":"/api/acts/ad-r22-13-tail-rotor-drive-shaft-replacement/documents"}}