{"id":"F2006L03497","name":"AD/AS 355/88 Amdt 1 - Cabin Vibration Damper Assembly","slug":"ad-as-355-88-amdt-1-cabin-vibration-damper-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":61017,"registerId":"commonwealth-F2006L03497-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter AS 355 (Twin Ecureuil) Series","sectionType":"division","heading":"Eurocopter AS 355 (Twin Ecureuil) Series Helicopters","content":"### Eurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\n| AD/AS 355/88 Amdt 1 | Cabin Vibration Damper Assembly | 12/2006 |\n| ------------------- | ------------------------------- | ------- |\n\n| Applicability: | 1. Eurocopter AS 355 E, F, F1, F2 and N helicopters fitted with:a. a cabin vibration damper assembly installed on the right hand (RH) side of the helicopter; andb. an automatic flight control system.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Visually check the visible areas of the blade of the vibration damper assembly, installed on the RH side of the helicopter, for cracks, in accordance with paragraph 2.B.1 of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.46 or any later EASA approved revisions.2. If a crack is found, remove the RH vibration damper assembly, replace the cracked blade and re-install the vibration damper assembly fitted with a new blade, and adjust the vibration damper in accordance with paragraph 2.B.1 of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.46 or any later EASA approved revisions.3. For helicopters modified per MODs 072262, 071543 and OP1055 install a vibration damper/casing assembly on the RH side of the helicopter, in accordance with paragraph 2 of Eurocopter ASB No. 53.00.22 or any subsequent EASA approved revisions, as is applicable.Terminating Action.Compliance with Requirements 2 provides terminating action to the repetitive inspections detailed in Requirement 1 of this AD.Note: EASA AD 2006-0273 dated 4 September 2006 refers. |\n| Compliance:    | 1. Repetitively before the first flight of the day after the effective date of this AD.2. Before further flight.3. No later than 30 June 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n\n|             | This Amendment becomes effective on 23 November 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Background: | In the event of a failure of the blade of the RH cabin vibration damper assembly, for helicopters fitted with an automatic flight control system, the failed part that remains trapped in the bottom structure lower fairing can interfere with the trim actuator rod which is installed nearby. Such interference could jam the flight controls.This amendment introduces a mandatory modification to the vibration damper assembly which terminate the repetitive inspection called up in this AD.The original issue of this AD became effective 20 June 2005. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n13 October 2006","sortOrder":0},{"sectionNumber":"AD/AS 355/88 Amdt 1","sectionType":"part","heading":"AD/AS 355/88 Amdt 1","content":"## AD/AS 355/88 Amdt 1","sortOrder":1},{"sectionNumber":"Cabin Vibration Damper Assembly","sectionType":"part","heading":"Cabin Vibration Damper Assembly","content":"## Cabin Vibration Damper Assembly","sortOrder":2},{"sectionNumber":"12/2006","sectionType":"part","heading":"12/2006","content":"## 12/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment adds a mandatory modification (installation of an updated vibration damper/casing assembly) that, once done, terminates the repetitive daily inspection called for in the original AD. The original AD (effective 20 June 2005) required repetitive inspections; this amendment imposes a one‑off modification with a compliance deadline (no later than 30 June 2007) to remove the inspection burden."},"complexity_factors":["Model‑ and equipment‑specific applicability: applies only to AS 355 E, F, F1, F2 and N helicopters fitted with a RH cabin vibration damper and an automatic flight control system (Applicability).","Multiple actions with different timings: repetitive before‑first‑flight inspections, immediate replacement before further flight if a crack is found, and a one‑off modification by a fixed deadline (Compliance).","References to external technical documents: requires compliance with Eurocopter ASB Nos. 05.00.46 and 53.00.22 or later EASA‑approved revisions, creating dependency on external approvals (Requirement 1–3).","Terminating action mechanic: installing the updated damper/casing assembly terminates the repetitive inspection obligation, creating a trade‑off between ongoing labour cost and one‑off modification cost (Requirement 3, Terminating Action).","Interaction with specific aircraft modifications: the mandatory installation applies to helicopters modified per MODs 072262, 071543 and OP1055 (Requirement 3).","Safety consequence linkage: the rule targets a particular failure mode (damper blade failure interfering with trim actuator rod) which ties inspection/modification costs to a specific mechanical risk (Background)."],"plain_english_summary":"This amendment requires operators of certain Eurocopter AS 355 variants fitted with a right‑hand cabin vibration damper and an automatic flight control system to perform daily visual checks of the damper blade and to replace any cracked blade before further flight. It also requires installing an updated damper/casing assembly (by 30 June 2007 for affected mods); installation removes the need for the repetitive daily inspections. Operators pay for inspections, parts and the mandatory modification intended to prevent jammed trim actuators from a failed damper blade."},"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":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original safety purpose — addressing the specific risk of vibration damper blade failure in AS 355 helicopters with automatic flight control systems. The amendment introduces a terminating modification (the permanent fix) but this is a natural evolution of the original inspection mandate rather than scope creep. The original 2005 AD required repetitive inspections; this 2006 amendment simply adds the option to permanently modify the aircraft to eliminate that recurring burden while maintaining safety."},"complexity_factors":["Short, single-purpose document focused on one mechanical component","Only 3 specific requirements with clear conditional logic (if crack found → replace)","Limited applicability criteria (5 helicopter models + 2 specific equipment conditions)","References to external technical documents (Eurocopter Alert Service Bulletins) rather than reproducing complex technical specifications inline","Simple compliance timeline: immediate repetitive checks, before-flight replacement if cracked, and one fixed deadline (30 June 2007) for terminating modification","No nested definitions section, no extensive cross-referencing to other legislation, no penalty provisions or enforcement mechanisms described"],"plain_english_summary":"Owners/operators of certain Eurocopter AS355 E/F/F1/F2/N helicopters with a right‑side cabin vibration damper and an automatic flight control system must perform daily visual inspections for cracks in the damper blade and replace any cracked blade before flight. A terminating modification is available (added by this amendment) that, once embodied, removes the need for repetitive inspections. The action prevents damper blade failure jamming flight controls."}},"importantCases":[],"_links":{"self":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly","history":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly/history","analysis":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly/analysis","conflicts":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly/conflicts","importantCases":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly/important-cases","documents":"/api/acts/ad-as-355-88-amdt-1-cabin-vibration-damper-assembly/documents"}}