{"id":"F2006B04624","name":"AD/BELL 407/1 Amdt 5 - Never Exceed Speed Reduction","slug":"ad-bell-407-1-amdt-5-never-exceed-speed-reduction","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44376,"registerId":"commonwealth-F2006B04624-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 407/1 Amdt 5 - Never Exceed Speed Reduction","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)  \n![](image.002.png)  \nBell Helicopter Textron Canada (BHTC) 407 Series Helicopters\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BELL 407/1 Amdt 4 and issues the following AD under subregulation 39.1 (1) of CAR 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\nAD/BELL 407/1\n\nAmdt 5\n\n  \n\nNever Exceed Speed Reduction 6/2001 DM\n\nApplicability: All BHTC Model 407 helicopters.\n\nRequirement: 1. Remove the copy of AD/BELL 407/1 Amdt 4 from the front of the Flight Limitations section of the Aircraft Flight Manual and advise all pilots of its removal.\n\n    2. Remove the Vne limitation placard and airspeed indicator redline limits which were installed in accordance with AD/BELL 407/1 Amdt 4.\n\n    3. Unless already accomplished, install an airspeed actuated pedal stop in accordance with BHTC Alert Service Bulletin (ASB) 407-99-33.\n\n    4. Unless already accomplished, Replace the Vne placards in accordance with ASB 407-99-33, remove the temporary instrument markings and install new airspeed limitations decals in accordance with Part II of ASB 407-99-33, and remove all Temporary Revisions to the AFM inserted by previous Directive amendments and insert Temporary Revision titled Vne Increase to 140 KIAS dated 17 December 1999.\n\nNote 1: Requirements 3 and 4 were originally required by AD/BELL 407/1 Amdt 3 with a compliance time of 31 January 2001. As AD/BELL 407/1 Amdt 4 had an effective date of 11 January 2001, the compliance time of amendment 3 was never met.\n\nNote 2: Transport Canada AD CF-2001-01R1 refers.\n\nCompliance: Before 31 May 2001.\n\nThis Amendment becomes effective on 26 April 2001.\n\nBackground: Transport Canada had received three reports of Model 407 helicopter accidents in which the aft section of the tail boom was severed by the tail rotor. In two of the cases an unexpected right yaw, followed by a large left directional control input, were reported prior to the tail boom strike. The actions required by this Directive were to minimise the risk of a tail boom strike during flight; pending further engineering towards reinstatement of 140 KIAS Vne.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nAmendment 1 mandated the technical provisions of ASB 407-99-27, and allowed an increased Vne of 130 KIAS up to 20 degrees C and 125 KIAS above 20 degrees C.\n\nAmendment 2 allowed an increase in Vne to 130 KIAS above 20 degrees C, as a result of flight tests at elevated temperatures.\n\nAmendment 3 required installation (before 31 January 2001) of a pedal stop which repositioned itself relative to airspeed, and so provided terminating action for the Directive.\n\nAmendment 4 was prompted by an accident in which a helicopter flying at 140 knots was destroyed by suspected tail rotor strike to the tail boom. Pending further evaluation of the accident, to minimise the risk of a tail boom strike during flight, the never-exceed speed (Vne) is to be reduced.\n\nAmendment 5 is issued in response to a revision of the related Transport Canada AD which removes the current Vne restriction imposed as a result of an accident. The accident investigation has revealed no data to confirm a tail rotor strike as the cause.\n\nAmendment 4 of this Directive became effective on 12 January 2001\\. Amendment 3 of this Directive became effective on 18 May 2000.\n\n![](image.003.png)The original issue of this Directive became effective on 20 May 1999.\n\n![](image.004.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 19 April 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 26 April 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Yes. Earlier amendments (notably Amendment 4) reduced the Vne to minimise tail‑boom strike risk; Amendment 5 revokes Amendment 4 and directs removal of the reduced‑Vne placards and AFM markings, installation of an airspeed‑actuated pedal stop, and insertion of the Temporary Revision titled “Vne Increase to 140 KIAS dated 17 December 1999,” thereby restoring the higher Vne subject to the specified equipment and placard changes. (Requirement: 1–4; Background; Note 2; Compliance)"},"complexity_factors":["Wide applicability to the entire fleet: “Applicability: All BHTC Model 407 helicopters.” (Applicability)","Multiple coordinated actions required from operators: removal of prior AD from the AFM and pilot notification; removal of placards and instrument markings; installation of an airspeed‑actuated pedal stop; replacement of placards and AFM temporary revisions in accordance with ASB 407-99-33. (Requirement: 1–4)","Technical work must follow a manufacturer Alert Service Bulletin (ASB) rather than being purely procedural, creating a parts/maintenance dependency. (Requirement: 3–4 — ASB 407-99-33; Part II of ASB 407-99-33)","Compliance deadline imposes time pressure: “Compliance: Before 31 May 2001.” (Compliance)","Regulatory change reverses a prior restriction and revokes a previous amendment, creating potential operational confusion for operators who implemented Amendment 4. (Opening paragraph revoking AD/BELL 407/1 Amdt 4; Background; Requirement 1)","Cross-jurisdictional linkage: the AD responds to and references Transport Canada AD CF-2001-01R1, so international regulatory coordination affects scope. (Note 2; Background)","Safety rationale tied to accident reports with unresolved causation: background cites accidents and subsequent reevaluation, which affects the evidentiary basis for the change. (Background)"],"plain_english_summary":"This Airworthiness Directive applies to all Bell 407 helicopters. It revokes the prior amendment that reduced the never-exceed speed (Vne), requires removal of the temporary reduced-Vne placards and markings, and mandates installation of an airspeed‑actuated pedal stop plus updated Vne decals and a Flight Manual revision. CASA says the change follows Transport Canada’s revised AD and accident review; mechanically it alters equipment, cockpit markings and pilot information with a set compliance deadline."},"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 stays within the original scope of addressing tail boom strike risks in Bell 407 helicopters. While it reverses a temporary speed restriction from Amendment 4, it does not expand beyond the original safety purpose. The directive maintains the same applicability (all Model 407 helicopters) and continues the same regulatory thread."},"complexity_factors":["Multiple amendments referenced (Amendments 1-5) creating a layered history that must be understood to follow current requirements","Cross-references to external technical documents: Bell Helicopter Alert Service Bulletin (ASB) 407-99-33 and Transport Canada AD CF-2001-01R1","Conditional requirements ('Unless already accomplished') requiring operators to check compliance status against previous amendments","Specific technical terminology (Vne, KIAS, pedal stop, tail boom strike) requiring aviation knowledge","Precise compliance deadline (31 May 2001) with retrospective effective dates mentioned for context"],"plain_english_summary":"This AD from CASA lifts a temporary low-speed restriction on Bell 407 helicopters and restores Vne to 140 kt, but only after operators remove prior warning materials, install an airspeed-linked mechanical pedal stop (if not already fitted), update the flight manual and markings. It affects all Bell 407 owners/operators in Australia and must be complied with by 31 May 2001."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction","history":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction/history","analysis":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction/analysis","conflicts":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction/conflicts","importantCases":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction/important-cases","documents":"/api/acts/ad-bell-407-1-amdt-5-never-exceed-speed-reduction/documents"}}