{"id":"F2008L00492","name":"AD/J4100/3 - Aileron Quadrant Bearing","slug":"ad-j4100-3-aileron-quadrant-bearing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":119304,"registerId":"commonwealth-F2008L00492-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"BAe Systems (Operations) Jetstream 4100 ","sectionType":"division","heading":"BAe Systems (Operations) Jetstream 4100 Series Aeroplanes","content":"### BAe Systems (Operations) Jetstream 4100 Series Aeroplanes\n\n| AD/J4100/3 | Aileron Quadrant Bearing | 4/2008 DM |\n| ---------- | ------------------------ | --------- |\n\n| Applicability: | Jetstream Series 4100 aircraft, constructor’s number 41004 and subsequent which do not have modification JM41307A or modification JM41307B embodied.                                                                                                                       |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Jetstream Alert Service Bulletin J41-A-27-026 or later NAA approved revisions.Note: UK CAA AD 005-12-93 dated 18 January 1994 refers.                                                                                                            |\n| Compliance:    | As detailed in Jetstream Alert Service Bulletin J41-A-27-026 or later NAA approved revisions with an effective as the effective date of this AD.                                                                                                                           |\n|                | This Airworthiness Directive becomes effective on 20 February 2008.                                                                                                                                                                                                        |\n| Background:    | An incident occurred where abnormal backlash of the pilot’s aileron control required the second pilot to take control and land the aircraft. The abnormal backlash was found to be caused by the failure of a bearing in a quadrant in the pilot’s aileron control system. |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n14 February 2008","sortOrder":0},{"sectionNumber":"AD/J4100/3","sectionType":"part","heading":"AD/J4100/3","content":"## AD/J4100/3","sortOrder":1},{"sectionNumber":"Aileron Quadrant Bearing","sectionType":"part","heading":"Aileron Quadrant Bearing","content":"## Aileron Quadrant Bearing","sortOrder":2},{"sectionNumber":"4/2008 DM","sectionType":"part","heading":"4/2008 DM","content":"## 4/2008 DM","sortOrder":3}],"analysis":{"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":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (constructor's number range and specific modification exclusions)","Single requirement referencing an external technical document (Service Bulletin)","No nested conditional logic or exceptions beyond the modification exclusions","No cross-references to other legislation or regulations","Straightforward compliance deadline (single fixed date)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and corrective action on the aileron-quadrant bearing on BAe Jetstream 4100-series aircraft (serials 41004 and up), unless modified by JM41307A/B. Operators must follow Jetstream Alert Service Bulletin J41-A-27-026 (or later approved versions). The AD addresses a bearing failure that caused dangerous control backlash and prevents potential loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument sets a targeted corrective requirement for a defined fleet subset and refers operators to a specified service bulletin; the text contains no indication that the scope has been expanded or narrowed from an earlier version."},"complexity_factors":["Narrow, technical applicability limited to Jetstream 4100 aircraft from constructor’s number 41004 onward and absence of mods JM41307A/JM41307B (Applicability).","Mandates compliance with an external technical document (Jetstream Alert Service Bulletin J41-A-27-026) or later NAA‑approved revisions, creating reliance on another instrument for procedural detail (Requirement; Compliance).","Specified effective date creates a firm compliance timetable and immediate operator responsibility (Compliance: effective 20 February 2008).","Concrete safety trigger from an operational incident (bearing failure causing control backlash) that limits scope to a known failure mode (Background).","Administrative/oversight element: directive issued by the Civil Aviation Safety Authority delegate, implying regulator enforcement but no discretionary exemptions in the text (signature/date)."],"plain_english_summary":"This Airworthiness Directive requires operators of BAe Systems Jetstream 4100 aeroplanes (constructor’s number 41004 and later) that do not have modification JM41307A or JM41307B to carry out the actions in Jetstream Alert Service Bulletin J41-A-27-026 (or later NAA‑approved revisions). It responds to a failed aileron quadrant bearing that caused abnormal control backlash; operators must follow the service bulletin by the AD effective date (20 February 2008)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-j4100-3-aileron-quadrant-bearing","history":"/api/acts/ad-j4100-3-aileron-quadrant-bearing/history","analysis":"/api/acts/ad-j4100-3-aileron-quadrant-bearing/analysis","conflicts":"/api/acts/ad-j4100-3-aileron-quadrant-bearing/conflicts","importantCases":"/api/acts/ad-j4100-3-aileron-quadrant-bearing/important-cases","documents":"/api/acts/ad-j4100-3-aileron-quadrant-bearing/documents"}}