{"id":"F2006B10567","name":"AD/HS 748/31 Amdt 1 - Gust Lock Baulking Actuator","slug":"ad-hs-748-31-amdt-1-gust-lock-baulking-actuator","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116397,"registerId":"commonwealth-F2006B10567-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 748/31 Amdt 1 - Gust Lock Baulking Actuator","content":"![](image.001.png)\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/HS 748/31 and issues the following AD under subregulation 39.1 (1) of CASR 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\nBritish Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes\n\nAD/HS 748/31\n\nAmdt 1\n\n  \nGust Lock Baulking Actuator 1/2004\n\nApplicability: All HS748 aeroplanes.\n\nRequirement: 1. Modify the aeroplane’s gust lock system (Modification No 7673) in accordance with Parts 1 and 2 of BAe Systems Service Bulletin (SB) HS748-27-135 Revision 1 dated 10 December 2002.\n\n    2. Conduct an inspection of the baulk lever in accordance with Appendix 2 of SB HS748-27-135 Revision 1 or Revision 2 dated 2 October 2003.\n\n    3. Rework the Requirement 1 modification to the gust lock system in accordance with SB HS748-27-135 Revision 2.\n\nNote 1: CAA(UK) AD 003-12-2002 refers.\n\nCompliance: For Requirement 1 \\- Remains unchanged as ‘Before 1 September 2003’.\n\nFor Requirement 2 \\- Remains unchanged as ‘Initially within 750 hours time in service (TIS) or 240 days, whichever occurs first, after the installation of the baulking actuator and thereafter, repeat the inspection at intervals of 750 hours TIS or 240 days, whichever occurs first’.\n\nNote 2: 750 hours TIS or 240 days is the ‘C’ Check interval.\n\nFor Requirement 3 \\- Before 29 February 2004.\n\nThis Amendment becomes effective on 22 January 2004.\n\nBackground: BAe advises that there have been two incidents where re-engagement of the elevator gust-lock may have caused a flying control restriction. The original issue of this Directive required the installation of a rotary actuator at the elevator gust lock that will baulk the mechanism after gust-lock withdrawal so that an uncommanded re- engagement cannot occur.\n\nThis Amendment revises the wiring of the gust lock actuator to ensure correct operation.\n\nBritish Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes\n\nAD/HS 748/31 Amdt 1 (continued)\n\nThe original issue of this Airworthiness Directive became effective on 20 March 2003.\n\n![](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 4 December 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 December 2003.","sortOrder":0}],"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":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose — correcting a specific unsafe condition in the HS 748 gust lock system. It does not expand beyond the original aircraft type or safety issue; it merely refines the technical solution (updating wiring instructions) based on further manufacturer analysis."},"complexity_factors":["Short, single-purpose document (3 requirements only)","Minimal defined terms (only 'TIS' — Time In Service — is abbreviated)","Clear cross-references to manufacturer service bulletins (SB HS748-27-135) rather than internal legislative cross-references","Simple conditional logic: three distinct requirements with separate compliance dates","No nested exceptions or complex provisos","Straightforward applicability ('All HS748 aeroplanes') with no exclusions"],"plain_english_summary":"This mandatory Airworthiness Directive requires owners/operators of British Aerospace HS 748 aircraft in Australia to modify the gust‑lock system after incidents where the elevator gust lock could re‑engage after takeoff. Amendment 1 updates the actuator wiring to ensure the original fix works. Affected aircraft must have the modified system installed, the safety lever inspected every 750 flight hours or 240 days, and the original mod reworked by 29 February 2004."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment keeps the original AD's applicability to all HS748 aircraft but extends and clarifies the technical remedy: it revises the gust‑lock actuator wiring and requires a rework of the initial modification in accordance with a later SB revision, while maintaining the original installation and inspection mandates (Background; Requirements 1–3). Operational scope (which aircraft are affected) is unchanged, but the required technical remedy and wiring compliance were modified."},"complexity_factors":["Technical modification plus electrical wiring revision to the gust‑lock actuator (Requirement 1; Background).","Multiple service bulletin revisions referenced (SB HS748‑27‑135 Rev 1 and Rev 2) requiring staged compliance and rework (Requirements 1 and 3).","Recurring inspection regime with both an initial compliance window and repeating intervals tied to flight hours or days (750 hours TIS or 240 days) (Requirement 2; Compliance).","Different compliance deadlines for distinct actions (installation before 1 Sep 2003; inspections initially within 750 hours/240 days; rework before 29 Feb 2004) creating scheduling and record‑keeping burdens (Compliance).","Cross‑jurisdictional reference to CAA(UK) AD 003‑12‑2002 for context and technical basis (Note 1).","Requirement to rework an earlier modification introduces retrofit work and potential downtime for aircraft (Requirement 3)."],"plain_english_summary":"This Airworthiness Directive requires all British Aerospace (Hawker Siddeley) HS 748 aeroplanes to have their elevator gust‑lock system modified, inspected regularly, and the modification reworked to stop the gust‑lock re‑engaging unintentionally. It affects HS748 operators and maintenance providers, who must pay for and schedule the modification, recurring baulk‑lever inspections and the mandated rework; the AD sets specific deadlines and cites BAe service bulletin revisions and a UK AD as the instructional basis (Background; Requirements)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator","history":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator/history","analysis":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator/analysis","conflicts":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator/conflicts","importantCases":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator/important-cases","documents":"/api/acts/ad-hs-748-31-amdt-1-gust-lock-baulking-actuator/documents"}}