{"id":"F2006B10245","name":"AD/GAZELLE/26 - Flexible Disks of Tail Rotor Drive Shafts","slug":"ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55914,"registerId":"commonwealth-F2006B10245-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the 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\n![](image.001.png)  \n\nEurocopter SA341 and SA342 (Gazelle) Series Helicopters","sortOrder":0},{"sectionNumber":"AD/GAZELLE/26 Flexible Disks of Tail Rot","sectionType":"part","heading":"AD/GAZELLE/26 Flexible Disks of Tail Rotor Drive Shafts 13/2003","content":"# AD/GAZELLE/26 Flexible Disks of Tail Rotor Drive Shafts 13/2003\n\nApplicability: SA 341 G and SA 342 J helicopters.\n\nRequirement: 1. Inspect the flexible discs in both the inclined and horizontal tail rotor drive shafts for correct installation of the disc jo-bolt washers in accordance with Eurocopter Alert Telex Number 65.63.\n\n    2. Carry out repetitive inspection of flexible disc assemblies found to have jo-bolt washes incorrectly assembled in accordance with Requirement 1 of this directive.\n\n    3. Replace flexible disc assemblies found to have jo-bolt washes incorrectly assembled in accordance with Requirement 1 of this directive.\n\nNote: DGAC Airworthiness Directive U2003-394(A) refers.\n\nCompliance: 1. Unless previously accomplished; within 10 hours time in service from the effective date of this directive.\n\n    2. At intervals not to exceed 10 hours time in service.\n\n    3. No later than 1 May 2004.\n\nCompliance with Requirement 3 provides a terminating action for this directive. This Airworthiness Directive becomes effective on 25 December 2003.\n\nBackground: This directive has been issued in response to a report of the tail rotor drive shaft flexible disc jo-bolt washers being found installed back to front. Incorrect installation of the washes may result in cracking of the flexible disc and loss of tail rotor drive.\n\n![Signature of Jim Coyne](image.002.png)  \n\nJim Coyne\n\n![](image.001.png)Delegate of the Civil Aviation Safety Authority 14 November 2003\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 3 December 2003.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific mechanical defect (incorrectly installed jo-bolt washers) in specific helicopter models (SA 341 G and SA 342 J). The three requirements (inspect, repetitive inspection if needed, replace by deadline) form a complete, self-contained safety response without scope creep."},"complexity_factors":["Very short document (approximately 300 words)","Only 3 defined requirements with clear sequential numbering","Single cross-reference to French aviation authority directive (DGAC U2003-394(A)) and Eurocopter Alert Telex 65.63","No nested conditional logic — requirements apply straightforwardly based on inspection findings","Simple temporal compliance structure (fixed dates and flight hours)","Minimal defined terms (only 'time in service' used in standard aviation sense)"],"plain_english_summary":"This CASA safety order addresses a dangerous installation error of jo-bolt washers in the tail rotor drive shafts of Eurocopter SA 341 G and SA 342 J Gazelle helicopters. Incorrect washer fitment can crack flexible discs and cause total loss of tail rotor control, so owners, operators and maintenance engineers must inspect affected discs within 10 flight hours, perform recurring checks if misinstalled, and fit replacement assemblies by 1 May 2004 to eliminate the risk."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope remains focused on correcting incorrectly assembled jo‑bolt washers in flexible discs of the tail‑rotor drive shafts for the specified Gazelle models. The directive prescribes inspections, repeat inspections if faults are found, and replacement as a terminating action without broadening applicability or adding unrelated requirements."},"complexity_factors":["Narrow applicability: limited to Eurocopter SA341G and SA342J helicopters (Applicability).","Clear, prescriptive actions: inspect, repeat inspect if defects found, and replace faulty assemblies (Requirement 1–3).","Short compliance windows and recurring inspection interval: initial inspection within 10 hours TIS, repeat interval 10 hours, replacement required by 1 May 2004 (Compliance).","Terminates on replacement of assemblies (Compliance provides terminating action).","Relies on manufacturer service information: Eurocopter Alert Telex No. 65.63 (Requirement).","Regulatory basis and delegated authority: issued under subregulation 39.1(1) of CASR 1998 (preamble).","Operational impact concentrated on operators: inspection labor, potential part costs and aircraft downtime borne by owners/operators."],"plain_english_summary":"Mandates inspection and, if necessary, replacement of flexible disc assemblies and jo‑bolt washers in the inclined and horizontal tail‑rotor drive shafts of Eurocopter SA341G and SA342J helicopters. The measure responds to reports of jo‑bolt washers installed backwards; incorrect installation can crack the flexible disc and cause loss of tail‑rotor drive. Operators must inspect quickly (short‑hour windows), perform repeat inspections if faults are found, and replace affected assemblies by a set date to terminate the directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts","history":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts/history","analysis":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts/analysis","conflicts":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts/conflicts","importantCases":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts/important-cases","documents":"/api/acts/ad-gazelle-26-flexible-disks-of-tail-rotor-drive-shafts/documents"}}