{"id":"F2006L03944","name":"AD/DAUPHIN/89 - Main Rotor Head Frequency Adapters","slug":"ad-dauphin-89-main-rotor-head-frequency-adapters","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":60893,"registerId":"commonwealth-F2006L03944-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter SA 360 and SA 365 (Dauphin) S","sectionType":"division","heading":"Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters","content":"### Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\n| AD/DAUPHIN/89 | Main Rotor Head Frequency Adapters | 2/2007 TX |\n| ------------- | ---------------------------------- | --------- |\n\n| Applicability: | Model SA 365 N, SA 365 N1, AS 365 N2, AS 365 N3, SA 365 C, SA 365 C1,SA 365 C2, and SA 365 C3 helicopters, all serial numbers, if a main rotor head (MRH) fitted with frequency adapters and frequency adapter bushes is installed, as referenced below:- pre MOD 0762C39 and used in hot climatic conditions and/or tropical and damp atmosphere, or- post Mod 0762C39.The part numbers of the affected frequency adapters and frequency adapter bushes are listed in paragraph 2.B.2.v and paragraph 2.B.5 of Eurocopter AS 365 Alert Service Bulletin (ASB) No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.Note 1: The use of a helicopter in tropical and damp atmosphere is defined as follows:A helicopter operated in climatic conditions with outside air temperatures from28 degrees centigrade upward combined with relative humidity from 75% upward.Note 2: The use of a helicopter in hot climatic conditions is defined as follows:A helicopter operated in areas with high solar radiation temperatures above40 degrees centigrade. |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. A MRH fitted with frequency adapters pre MOD 0762C39 and operated in hot climatic conditions and/or in tropical and damp atmosphere:Modify the frequency adapters and frequency adapter bushes per MOD 0762C39, in accordance with paragraphs 2.B.1, 2.B.2 and 2.B.3 of AS 365 ASBNo. 62.00.24 and SA 365 ASB No. 65.45, as applicable.2. A MRH fitted with frequency adapters post MOD 0762C39:Check that the lockwire is in place and that the holes in the frequency adapters and in the frequency adapter bushes are not blocked, in accordance with paragraph 2.B.6 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | If the lockwire is in place on the trailing edge of the frequency adapter and if the four holes are not blocked, flights may be resumed.If the lockwire is not in place, before further flight, re-position the bush if it has turned, and fit the lockwire.If one hole or more is/are blocked, before further flight, unblock the hole(s).After the effective date of this Directive, no person may install any of the following equipment held as spares and intended for use in hot climatic conditions and/or in tropical and damp atmosphere:- MRHs fitted with frequency adapters,- Frequency adapter assemblies,- Non-drilled frequency adapter bushes,on a helicopter as a replacement part, unless it has been modified in accordance with paragraph 2.B.2 or 2.B.4 or 2.B.5 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.Note: EASA Emergency AD 2006-0362-E refers.                                                                                                                                                     |\n| Compliance:    | 1. Within 110 flight hours after 2 December 2006.2. Within 10 flight hours after application of MOD 0762C39, or within 10 flight hours after 2 December 2006, whichever occurs later, and thereafter at intervals not to exceed 10 flight hours.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 2 December 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | The EASA received reports of deterioration and two reports of failure of Starflex star arm ends. Such deterioration generated high-amplitude vibrations in flight, compelling the pilot to carry out a precautionary landing, in both cases. A failure of the Starflex star arm end could make it impossible to control the helicopter.The deteriorations are due to the strong effect of temperature on the strength of the Starflex star arm end attachment.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n1 December 2006","sortOrder":0},{"sectionNumber":"AD/DAUPHIN/89","sectionType":"part","heading":"AD/DAUPHIN/89","content":"## AD/DAUPHIN/89","sortOrder":1},{"sectionNumber":"Main Rotor Head Frequency Adapters","sectionType":"part","heading":"Main Rotor Head Frequency Adapters","content":"## Main Rotor Head Frequency Adapters","sortOrder":2},{"sectionNumber":"2/2007 TX","sectionType":"part","heading":"2/2007 TX","content":"## 2/2007 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety‑focused scope: it targets specific MRH frequency adapters and bushes on defined Dauphin helicopter models to address temperature‑related deterioration and risk of Starflex star arm end failure. It does not expand beyond that technical safety purpose — it prescribes modifications, checks, and limits on fitting unmodified spares in hot/tropical operations, consistent with the stated hazard and the referenced manufacturer and EASA guidance."},"complexity_factors":["Two primary conditional branches based on MOD 0762C39 status (pre‑MOD vs post‑MOD)","Multiple specific model variants listed (8 model codes) covering all serial numbers","Several short compliance windows: 110 flight hours for one action; 10 flight hours initial and recurring 10‑flight‑hour interval for inspections","Explicit climatic definitions that require operational judgement (tropical/damp: ≥28°C + ≥75% RH; hot climatic conditions: >40°C solar temperature)","Direct prohibition on installing certain unmodified spare parts for specified climate uses","References and dependence on external documents (Eurocopter ASB No. 62.00.24 and No. 65.45; MOD 0762C39; EASA Emergency AD 2006‑0362‑E) that contain the detailed procedures and part numbers","Mixed types of required work: one‑off modification actions and recurring, frequent inspections (operational and logistical complexity)","Operational decision points with binary outcomes (lockwire present and holes clear = flight OK; otherwise grounding and corrective action required)"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires specific maintenance actions on the main rotor head (MRH) frequency adapters and bushes on certain Eurocopter Dauphin helicopters (SA/AS 365 series) when those MRHs are fitted with frequency adapters.  The required action depends on whether the MRH has already been modified by MOD 0762C39 or not:\n  - If the MRH is *pre‑MOD 0762C39* and the helicopter is used in hot or tropical/damp climates: the frequency adapters and bushes must be modified in accordance with the Eurocopter Alert Service Bulletins (ASBs) referenced (paragraphs 2.B.1, 2.B.2 and 2.B.3 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45).\n  - If the MRH is *post‑MOD 0762C39*: perform a recurring check that lockwire is present and that the holes in the frequency adapters and bushes are clear (per paragraph 2.B.6 of the same ASBs). Flights may continue if lockwire is fitted and holes are clear; if not, corrective work is required before further flight.\n- Prohibits fitting certain spare parts (MRHs with frequency adapters, frequency adapter assemblies, and non‑drilled frequency adapter bushes) into helicopters intended for use in hot or tropical/damp climates unless those spares have been modified per the ASB paragraphs listed.\n- Sets compliance times: one action within 110 flight hours after 2 December 2006; the post‑MOD checks must be done within 10 flight hours after MOD 0762C39 or within 10 flight hours after 2 December 2006 (whichever is later) and then at intervals not exceeding 10 flight hours.\n\n**Which aircraft and people are affected\n\n- Affected aircraft: Eurocopter SA 365 N, SA 365 N1, AS 365 N2, AS 365 N3, SA 365 C, SA 365 C1, SA 365 C2 and SA 365 C3 — all serial numbers — but only those fitted with MRHs that have frequency adapters and bushes of the part numbers listed in the Eurocopter ASBs.\n- Affected persons and organisations: aircraft operators (particularly those operating in hot climates or tropical/damp atmospheres), maintenance organisations and engineers, and spare parts suppliers.\n\n**Why it matters (official rationale + operational effect)\n\n- Officially, the measure responds to reports of deterioration and two failures of Starflex star arm ends. The manufacturer and regulator link the deterioration to temperature effects that reduce the strength of the star arm end attachment, producing high‑amplitude vibration and, in the reported cases, a precautionary landing.\n\n**Operational consequences, costs and incentives (analyst’s lens)\n\n- Who pays: aircraft operators or owners pay for the modification, the recurring inspections, any rework (repositioning bushes, refitting lockwire, unblocking holes), and for modifying or replacing spare parts to meet the ASB requirements.\n- Who decides: maintenance engineers (under approved maintenance procedures) carry out inspections and modifications per the referenced ASBs. The regulator (delegate of CASA) enforces compliance with the AD.\n- Behaviour changes required: operators must (a) determine which MRHs/spares are affected, (b) schedule and complete modifications or recurring inspections within the specified flight‑hour windows, and (c) stop fitting unmodified spares into helicopters intended for hot/tropical use.\n- Compliance burden & timing risk: the AD sets short inspection intervals for post‑MOD components (every 10 flight hours) which can materially increase maintenance workload and downtime. The 110 flight‑hour window for one required action could force near‑term maintenance planning and possible grounding if parts or qualified maintenance capacity are scarce.\n- Market effects: spare parts suppliers face a constraint — unmodified spare MRHs or bushes cannot legally be fitted in helicopters used in the defined climates, reducing the utility of existing unmodified inventory in those markets and creating demand for modified spares or post‑modification services. That can raise replacement costs or create supply friction in hot/tropical regions.\n- Implementation risk & inspection ambiguity: the AD relies on visual checks (presence of lockwire; holes not blocked) and correct repositioning of bushes. Those tasks are routine but rely on correct interpretation of the ASBs by maintenance staff. The definitions of ‘‘tropical and damp atmosphere’’ and ‘‘hot climatic conditions’’ are provided (28°C with ≥75% RH; or >40°C solar temperature), but real‑world borderline cases will require operator judgment and recordkeeping.\n- Contract and operational freedom: operators retain freedom to continue operations provided they comply with the checks and modifications; however, restrictions on fitting certain unmodified spare parts constrain how operators procure and install replacements.\n\n**References and cross‑checks\n\n- The AD implements actions mandated to follow Eurocopter ASB No. 62.00.24 and No. 65.45 (specific paragraphs cited in the AD) and references EASA Emergency AD 2006‑0362‑E and MOD 0762C39. The AD’s practical work instructions and part numbers are contained in those ASBs, so access to and compliance with those external documents is required.\n\n**Net summary sentence\n\nOperators and maintainers of the listed Eurocopter Dauphin models who use helicopters in hot or tropical/damp climates must modify specified frequency adapters and bushes (or, if already modified, perform frequent lockwire/hole checks), cannot fit certain unmodified spare parts in those climatic operations, and bear the cost and scheduling burden of those measures to reduce the risk of MRH‑related vibration and possible loss of control."},"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 a standard Airworthiness Directive format. The scope remains tightly focused on the specific safety defect (frequency adapter deterioration in hot/humid conditions) and does not appear to have expanded beyond its original safety purpose. The environmental conditions and modification status distinctions are necessary to target the specific failure mode identified, not scope creep."},"complexity_factors":["Multiple overlapping applicability conditions combining aircraft model, serial number range, specific part modifications (MOD 0762C39), and environmental operating conditions (hot climate vs tropical/damp atmosphere)","Cross-references to external Eurocopter Alert Service Bulletins (ASB No. 62.00.24 and 65.45) for detailed technical procedures","Dual compliance pathways with different deadlines (110 flight hours vs 10 flight hours) depending on modification status","Nested conditional logic: different requirements apply based on (a) whether adapters are pre- or post-modification, AND (b) operating environment, AND (c) inspection findings (lockwire status, blocked holes)","Specific technical definitions for environmental conditions with precise temperature and humidity thresholds (28°C/75% humidity, 40°C solar radiation)","Prohibition on installation of unmodified spare parts with additional conditions"],"plain_english_summary":"This CASA Airworthiness Directive mandates repairs/inspections on Eurocopter Dauphin helicopters to address failing frequency adapters in the main rotor head that deteriorate in hot (>40°C) or tropical/humid (>28°C/≥75% RH) conditions, causing severe vibrations and potential loss of control.\n\nIt requires older adapters be upgraded within 110 flight hours (from Dec 2006), frequent checks on newer adapters, and prohibits installing unmodified spare parts for helicopters operating in those climates — an urgent safety measure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters","history":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters/history","analysis":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters/analysis","conflicts":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters/conflicts","importantCases":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters/important-cases","documents":"/api/acts/ad-dauphin-89-main-rotor-head-frequency-adapters/documents"}}