{"id":"F2009L01557","name":"AD/ECUREUIL/133 Amdt 1 - Collective Pitch Lever Locking Stud","slug":"ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":78266,"registerId":"commonwealth-F2009L01557-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter AS 350 (Ecureuil) Series Heli","sectionType":"division","heading":"Eurocopter AS 350 (Ecureuil) Series Helicopters","content":"### Eurocopter AS 350 (Ecureuil) Series Helicopters\n\n| AD/ECUREUIL/133 Amdt 1 | Collective Pitch Lever Locking Stud | 5/2009 |\n| ---------------------- | ----------------------------------- | ------ |\n\n| Applicability: | EUROCOPTER (formerly EUROCOPTER FRANCE, AEROSPATIALE) AS350 B, BA, BB, B1, B2, B3, D helicopters:- Delivered before embodiment of modification 073175; or- Helicopters on which the locking studs or the collective pitch levers or the locking strips have been reworked or modified in service; or- Helicopters having accomplished Revision 0 or Revision 1 of EUROCOPTER SB No. 67.00.37, corresponding to modification 073237; or- Helicopters with a serial number equal to: 3972, 3973, 3982, 3987, 4003, 4023, 4046, 4050, 4086, 4120, 4122, 4132, 4143, 4152, 4172, 4194, 4259, 4314, 4324, 4378, 4392, 4447, 4452, 4477, 4489, 4490, 4501, 4523, 4546, 4560, 4589, 4594, 4599, 4632, 4659, 4666, 4671.Note 1: Refer to the Aircraft Individual Inspection Record (RIC), the Log Cards (FM) or the aircraft logbook to identify the actual configuration of the helicopter.                                                                                                                                                                                                               |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Required as indicated, in accordance with EUROCOPTER Emergency Alert Service Bulletin No. 05.00.58.The use of later approved revisions of this document is acceptable for compliance with the requirements of this AD.1. Helicopters having embodied modification 073237:a) Measure the clearance between the end of the locking stud and the locking strip in accordance with paragraph 2.B.2.a.b) If the clearance is equal to or more than 3 mm return the helicopter to flight configuration.c) If the clearance is less than 3 mm and the helicopter has not embodied modification 073175, accomplish the instructions of paragraph 2.B.2.b.d) If the clearance is less than 3 mm and the helicopter has already embodied modification 073175, accomplish the instructions of paragraph 2.B.2.c.                                                                                                                                                                                                                                                                                              |\n|                | 2. Helicopters not having embodied modification 073237:a) Measure the clearance between the end of the locking stud and the locking strip in accordance with paragraph 2.B.3.a.b) If the clearance is equal to or more than 3 mm return the helicopter to flight configuration.c) If the clearance is less than 3 mm and the helicopter has not embodied modification 073175, accomplish the instructions of paragraph 2.B.3.b.d) If the clearance is less than 3 mm and the helicopter has already embodied modification 073175, suspend flights, contact EUROCOPTER for instructions and follow their corrective actions.3. Repeat the clearance measurement detailed in Requirement 1 or 2 of this AD, depending on the helicopter configuration.Ferry FlightsIf a flight is necessary to ferry the helicopter to a repair station or a place where the maintenance can be performed in order to comply with Requirements 1 or 2 of this AD, the flight is permitted with no passenger on board.Note 2: EASA AD 2009-0019 dated 3 February 2009 refers. This AD supersedes EASA AD 2008-0205-E. |\n| Compliance:    | For Requirements 1 and 2 - Remains unchanged as detailed in the original issue of this AD as: After the last flight of the day from 5 December 2008 (the effective date of the original issue of this AD).For Requirement 3 - At each time the collective pitch lever, the locking stud or the locking pitch are replaced; andeach time the locking strip setting is readjusted; andat intervals not exceeding 660 flight hours or 2 years, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Amendment becomes effective on 7 May 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | EUROCOPTER has developed modification 073237 which prevents wear of the locking stud and thus precludes the risk of untimely unlocking of the collective pitch lever during the engine starting phase.This modification has introduced a new locking stud which is longer than the previous one.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n\n|     | As a result, the clearance between the locking stud and the locking strip is reduced and in some cases it proves to be insufficient when the collective pitch lever is positioned on the \"low pitch\" stop.In fact, on a helicopter during an autorotation test in flight, it was found that the collective pitch lever rubbed against the locking strip in the \"low pitch\" position (low position). This rubbing is due to insufficient clearance and could result in untimely locking of the collective pitch lever and consequent loss of control of the helicopter.To preclude the risk of untimely locking, this AD required an inspection to verify the presence of the required minimum clearance between the end of the locking stud and the locking strip and provides a repair solution in case the clearance is insufficient. This was extended as a precautionary measure also to helicopters with locking system configuration prior to modification 073237.Amendment 1requires repeat inspections to be conducted at intervals as defined in this AD.The original issue of this AD became effective 5 December 2008. |\n| --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n27 March 2009","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/133 Amdt 1","sectionType":"part","heading":"AD/ECUREUIL/133 Amdt 1","content":"## AD/ECUREUIL/133 Amdt 1","sortOrder":1},{"sectionNumber":"Collective Pitch Lever Locking Stud","sectionType":"part","heading":"Collective Pitch Lever Locking Stud","content":"## Collective Pitch Lever Locking Stud","sortOrder":2},{"sectionNumber":"5/2009","sectionType":"part","heading":"5/2009","content":"## 5/2009","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":4,"scope_assessment":{"changed":false,"description":"This is an amendment (Amendment 1) to an existing Airworthiness Directive. The original AD addressed an immediate safety issue regarding collective pitch lever locking studs. This amendment adds recurring inspection requirements (Requirement 3) that were not in the original issue, but this is a natural evolution of airworthiness oversight rather than scope creep. The core purpose — ensuring safe operation of the collective pitch locking mechanism — remains unchanged."},"complexity_factors":["Multiple applicability criteria requiring cross-checking against aircraft logbooks, service bulletins, and serial numbers","Conditional logic based on whether specific modifications (073175, 073237) have been embodied","Nested decision tree in Requirements section (4 sub-paragraphs each for Requirements 1 and 2)","Reference to external technical documents (Eurocopter Emergency Alert Service Bulletin No. 05.00.58) without reproducing their content","Dual compliance timelines (one-time inspection vs. recurring inspections)","Cross-reference to European Aviation Safety Agency (EASA) AD 2009-0019"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of specified Eurocopter AS350 (Ecureuil/Squirrel) helicopters to inspect the collective pitch lever locking stud that secures the main rotor collective during engine start. If the clearance to the locking strip is under 3 mm corrective action or grounding applies; 3 mm or more is acceptable. Repeat inspections are required periodically. The measure prevents unexpected locking or release of the collective (after a reported rubbing incident). Empty ferry flights to a repair facility are permitted."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 1 expanded the instrument beyond the original single-inspection requirement by adding mandatory repeat inspections at defined triggers and intervals (each time the collective pitch lever, locking stud or locking strip is replaced; each time the locking strip is readjusted; and at intervals not exceeding 660 flight hours or 2 years). It also extended the precautionary inspection requirement to helicopters with the pre-modification 073237 locking-system configuration. These additions broaden the ongoing maintenance burden and monitoring scope compared with the original issue."},"complexity_factors":["Conditional branching by helicopter configuration (has modification 073237 or not; has modification 073175 or not)","Specific numeric clearance threshold (3 mm) that determines different mandatory actions","List of specific serial numbers included in applicability","Cross-reference to EUROCOPTER Emergency Alert Service Bulletin No. 05.00.58 for procedural detail","Different corrective pathways (return to flight, accomplish service bulletin instructions, or suspend flights and contact manufacturer)","Repeat-inspection regime with multiple triggers (on part replacement, on readjustment, and periodic intervals: 660 flight hours or 2 years)","Reference to and superseding of prior EASA ADs (cross-jurisdictional provenance)","Operational exception for ferry flights with constraint (no passengers)","Amendment history (this is Amendment 1) and extension of requirements compared with original AD"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It requires operators of certain Eurocopter AS350 (Ecureuil) series helicopters to measure and, if necessary, correct the clearance between the end of the collective pitch locking stud and the locking strip. The required minimum clearance is 3 mm.\n- The required action depends on the helicopter's configuration: whether it has modification 073237 embodied, and whether it has modification 073175 embodied. Different measurement and corrective steps apply in each case (see \"Requirement\" below).\n- If the clearance is adequate (>= 3 mm) the helicopter can be returned to service. If the clearance is insufficient (< 3 mm) the AD prescribes either a repair action, or (in some configurations) suspension of flights and contacting EUROCOPTER for corrective instructions.\n- The AD mandates repeat inspections: whenever the collective pitch lever, locking stud or locking strip is replaced; whenever the locking strip setting is readjusted; and at intervals not exceeding 660 flight hours or 2 years, whichever comes first.\n- Ferry flights to reach a place of repair are permitted, but only with no passengers on board.\n\n**Who this affects**\n\n- Owners/operators and maintenance organisations responsible for EUROCOPTER (formerly AEROSPATIALE/Eurocopter France) AS350 B, BA, BB, B1, B2, B3 and D helicopters meeting the listed applicability criteria (including specific serial numbers and helicopters delivered before modification 073175, those with parts reworked in service, and helicopters having embodied revision 0 or 1 of Eurocopter SB No. 67.00.37 / mod 073237).\n- Maintenance personnel who must perform the clearance measurements, adjustments and any corrective work in accordance with EUROCOPTER Emergency Alert Service Bulletin No. 05.00.58 (or later approved revisions).\n- Manufacturers (EUROCOPTER) insofar as some configurations require operators to contact them for corrective instructions.\n\n**Why it matters (claimed purpose and mechanical effect)**\n\n- EUROCOPTER developed modification 073237 introducing a longer locking stud to reduce wear and the risk of unintended unlocking of the collective pitch lever during engine starting. The AD says this change can reduce the clearance between the stud and the locking strip in the \"low pitch\" position; insufficient clearance can cause rubbing that may lead to untimely locking of the collective lever and loss of control.\n- The AD’s mechanical effect is to detect inadequate clearance and to mandate either repair or grounding/contact with the manufacturer so the risk of the collective lever locking unexpectedly is reduced.\n\n**Who pays, who decides, and what behaviour changes**\n\n- Who pays: aircraft owners/operators pay for the inspections, measurements, any repairs or embodiment of modifications, and for downtime while work is carried out. If EUROCOPTER supplies parts or instructions, parts and labour costs remain the operator's responsibility unless otherwise arranged with the manufacturer.\n- Who decides/enforces: the Civil Aviation Safety Authority (CASA) delegate issued the AD and enforces compliance. EUROCOPTER provides the service bulletin that details the measurement and corrective procedures; in some cases operators must contact EUROCOPTER for instructions.\n- Behaviour changes required of operators: perform the specified clearance checks, carry out the corrective actions if clearance is below 3 mm (or suspend flights and contact EUROCOPTER for affected configurations), record compliance, and repeat inspections on the stated events and intervals. Ferry flights to reach a repair facility may be made but must be flown with no passengers on board.\n\n**Testing the stated purpose against costs, incentives and risks**\n\n- Direct costs and burdens: recurring inspections (every 660 flight hours or 2 years, and on component replacement/adjustment), measurement labour, and corrective work if clearance is insufficient. There is potential aircraft downtime and associated loss of revenue.\n- Incentives created: operators may choose to incorporate modifications (e.g. 073175 or 073237) or adopt more frequent maintenance to reduce future inspection failures. Conversely, where the AD permits flight after a >=3 mm measurement, operators may prioritise quick checks to minimise grounding time.\n- Trade-offs and opportunity costs: strict compliance reduces the risk of in-flight control loss but diverts maintenance resources and aircraft availability to inspections and possible corrective works. Operators must weigh retrofit/repair costs against operational disruption.\n- Implementation risks: accurate measurement depends on maintenance competence and consistent procedures (the AD references the EUROCOPTER service bulletin for technique). Parts availability or manufacturer response times (for configurations requiring contact with EUROCOPTER) can extend grounding periods.\n- Compliance burden and discretion: the AD sets objective thresholds (3 mm) and explicit actions, limiting discretionary interpretation by operators, but it delegates corrective-method detail to EUROCOPTER service documents and, for some cases, to direct EUROCOPTER instructions.\n\n**Concrete mechanisms that produce effects**\n\n- Safety effect: by mandating measurement and repair, the AD reduces the mechanical condition (insufficient clearance) that the AD links to untimely locking of the collective lever.\n- Operational effect: increases maintenance workload and may cause temporary grounding; allows an empty ferry flight to a repair facility but forbids passenger carriage in that flight.\n\n**Where to look for the exact steps**\n\n- Applicability and serial-number list (who must comply).\n- Requirement paragraphs (1 and 2) that set measurement and corrective steps depending on whether modification 073237 and/or 073175 has been embodied.\n- Compliance paragraph for repeat inspection triggers and intervals (component replacement, readjustment, 660 flight hours or 2 years).\n- EUROCOPTER Emergency Alert Service Bulletin No. 05.00.58 (and any later approved revisions) for procedural detail on measurement and repair.\n\n(References are the AD sections labelled \"Applicability\", \"Requirement\", \"Compliance\" and \"Background\".)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud","history":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud/history","analysis":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud/analysis","conflicts":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud/conflicts","importantCases":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud/important-cases","documents":"/api/acts/ad-ecureuil-133-amdt-1-collective-pitch-lever-locking-stud/documents"}}