{"id":"F2006B02513","name":"AD/AS 355/63 Amdt 1 - Tail Servo Control Rod Eye End Fitting","slug":"ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41769,"registerId":"commonwealth-F2006B02513-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AS 355/63 Amdt 1 - Tail Servo Control Rod Eye End Fitting","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/63 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\n![](image.001.png)\n\nEurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\nAD/AS 355/63\n\nAmdt 1\n\n  \nTail Servo Control Rod Eye End Fitting 10/2002\n\nApplicability: All Model AS 355 E, F, F1, F2 and N helicopters, equipped with tail servocontrols not incorporating Mod 073139 or Eurocopter AS 355 Service Bulletin No. 67.00.22.\n\nRequirement: 1. Inspect the eye end fitting to servocontrol rod coupling for correct locking in accordance with instructions in Paragraph 2.A of Eurocopter AS 355 Alert Telex number 05.00.36.\n\n2. If play is found and/or the lockwasher is not correctly positioned carry out the maintenance procedure in paragraph 2B of Eurocopter AS 355 Alert Telex number 05.00.36.\n\nNote: DGAC AD 2001-581-063(A)R1 refers.\n\nCompliance: 1. a. For helicopters that have logged more than 500 flight hours, unless previously accomplished, within 50 flight ho urs, thereafter at intervals not to exceed 550 flight hours.\n\nb. For helicopters that have logged less than 500 flight hours, unless previously accomplished, inspect prior to 550 flight hours, thereafter at intervals not to exceed 550 flight hours.\n\n2. Prior to further flight.\n\nThis Airworthiness Directive becomes effective on 3 October 2002.\n\nBackground: Eurocopter received a report of the tail servo control rod eye end fitting disconnecting during flight. This condition led to the progressive reduction of the yaw control range and finally to the loss of servocontrol assistance. This Directive therefore requires an initial inspection followed by the repetitive inspections. Maintenance on the servocontrol rod eye end fitting will also need to be carried out should defects be found during the inspection.\n\nEurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\nAD/AS 355/63 Amdt 1 (continued)\n\nThis amendment reduces the applicability to servo controls incorporating Mod 073139 or SB 67.00.22.\n\n![](image.002.png)  \n\nJames Coyne\n\nDele gate of the Civil Aviation Safety Authority 23 August 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 11 September 2002.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment narrows (reduces) the scope of the original directive by excluding helicopters whose tail servocontrols incorporate Mod 073139 or have complied with Eurocopter AS 355 Service Bulletin No. 67.00.22. The practical effect is fewer helicopters remain subject to the inspection and repetitive maintenance requirement, because the amendment treats the modification/service-bulletin compliance as an alternative mitigation to the unsafe condition (amendment note; Applicability)."},"complexity_factors":["Short, single-topic directive focused on a specific component (tail servo control rod eye-end fitting)","Two-step requirement: inspection (Paragraph 2.A of Alert Telex 05.00.36) and corrective maintenance if defects found (Paragraph 2.B)","Two conditional timing branches based on total logged flight hours (>500 and <500) with repetitive 550 flight-hour interval","Exclusion for servocontrols incorporating Mod 073139 or Service Bulletin 67.00.22 (narrowed applicability)","Single external cross-reference to manufacturer Alert Telex 05.00.36 for procedural detail","One immediate grounding condition (repairs must be completed prior to further flight)","Minimal internal definitions or nested exceptions (keeps structure simple)","Reference to a foreign regulator AD (DGAC) but no heavy cross-referencing to multiple CASA instruments"],"plain_english_summary":"**What this directive does (mechanics):**\n\n- Applies to Eurocopter AS 355 E, F, F1, F2 and N helicopters that have tail servocontrols *without* Mod 073139 or without Eurocopter Service Bulletin 67.00.22 (Applicability).\n- Requires an initial inspection of the tail servocontrol rod eye-end fitting for correct locking, using the steps in Paragraph 2.A of Eurocopter Alert Telex 05.00.36 (Requirement 1).\n- If the inspection finds play or a lockwasher incorrectly positioned, it requires the maintenance procedure in Paragraph 2.B of the same Alert Telex and that the defect be fixed before the helicopter flies again (Requirement 2; Compliance 2).\n- Sets when inspections must occur (Compliance):\n  - If the helicopter already has more than 500 total flight hours: perform the inspection within the next 50 flight hours, then repeat at intervals not exceeding 550 flight hours.\n  - If the helicopter has logged less than 500 flight hours: inspect before reaching 550 flight hours, then repeat at intervals not exceeding 550 flight hours.\n- The directive relies on the Eurocopter Alert Telex 05.00.36 for the detailed inspection and repair steps and notes a related DGAC (French regulator) AD (Background).\n- The amendment narrows the group of helicopters covered by excluding those whose servocontrols incorporate Mod 073139 or Service Bulletin 67.00.22 (amendment note).\n\n**Who this affects:**\n\n- Aircraft operators/owners of the listed AS 355 models whose tail servocontrols have not been modified as above.\n- Maintenance organisations and licensed technicians who must perform the inspections and any remedial work to the eye-end fitting according to the manufacturer’s Alert Telex.\n- Less directly, operators who have already installed Mod 073139 or complied with SB 67.00.22 are excluded from these inspections (they no longer have this recurring obligation).\n\n**Why it matters (stated purpose and practical effects):**\n\n- Stated purpose: Eurocopter reported an in-flight disconnection of the tail servo control rod eye-end fitting that led to progressive loss of yaw control assistance (Background). The directive aims to detect incorrect locking or wear before a disconnect occurs by mandating inspections and corrective maintenance.\n\n**Costs, incentives and trade-offs (practical testing of the stated purpose):**\n\n- Who pays: operators pay for inspections, technician labour, parts, and any aircraft downtime while repairs are made (Requirement; Compliance).\n- Administrative burden: operators must track total flight hours accurately to meet the staged inspection deadlines and to schedule repetitive inspections every 550 flight hours.\n- Incentives created: because helicopters that have Mod 073139 or SB 67.00.22 are excluded, operators face a choice: continue with recurring inspections and possible repairs, or invest in the modification/service bulletin compliance to remove the recurring inspection obligation. That creates an incentive to adopt the modification if its one-off cost is lower than ongoing inspection and repair costs.\n- Implementation risk and dependence on manufacturer material: the AD requires following Eurocopter Alert Telex 05.00.36 for inspection and repair steps. Effective compliance depends on the clarity of that document, availability of required parts, and technician familiarity with the procedure (Requirement 1–2; Background).\n- Safety vs. cost trade-off: the directive sacrifices operator time and maintenance cost to reduce the risk of an in-flight servocontrol disconnect. The directive is prescriptive about inspection timing and requires immediate grounding until defects are fixed (Compliance 2).\n\n**Other practical notes:**\n\n- The directive revokes the prior AD and replaces it with this amendment (opening paragraph). The amendment narrows which aircraft are covered by exempting those with the specified modification or service bulletin (amendment note).\n- The AD cross-references the Eurocopter Alert Telex and a DGAC AD; operators must obtain and follow that manufacturer material to meet the AD requirements (Note; Requirement).\n\n(References: Applicability; Requirement paragraphs 1 and 2 citing Eurocopter Alert Telex 05.00.36; Compliance; Background; amendment note reducing applicability.)"},"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":true,"description":"This amendment reduces the scope compared to the original AD. The original directive applied more broadly; Amendment 1 specifically excludes helicopters that have already incorporated Mod 073139 or Eurocopter Service Bulletin 67.00.22. This is a narrowing of applicability rather than scope creep."},"complexity_factors":["Short, single-purpose document (2 pages) with clear structure","Only 4 defined applicability criteria (model variants and modification status)","Simple conditional logic: two compliance paths based on flight hours threshold (500 hours)","Cross-references to external technical documents (Eurocopter Alert Telex 05.00.36, DGAC AD 2001-581-063(A)R1) without reproducing their content","Single amendment narrows rather than expands scope","No nested exceptions or layered definitions"],"plain_english_summary":"This AD mandates inspections of the tail servo control rod eye end fitting on certain Eurocopter AS 355 models (E, F, F1, F2, N) that do not have Mod 073139 or SB 67.00.22, and immediate repair if the lock is loose or the lockwasher misaligned. Timed checks limit risk after a reported in‑flight disconnection that caused progressive loss of yaw control and hydraulic assistance.\n\nAmendment 1 narrows the scope by exempting helicopters already modified per Mod 073139 or SB 67.00.22."}},"importantCases":[],"_links":{"self":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting","history":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting/history","analysis":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting/analysis","conflicts":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting/conflicts","importantCases":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting/important-cases","documents":"/api/acts/ad-as-355-63-amdt-1-tail-servo-control-rod-eye-end-fitting/documents"}}