{"id":"F2006B02847","name":"AD/B737/145 Amdt 1 - Flightcrew Seat Locks and Seat Tracks","slug":"ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42189,"registerId":"commonwealth-F2006B02847-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/145 Amdt 1 - Flightcrew Seat Locks and Seat Tracks","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/B737/145 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\nBoeing 737 Series Aeroplanes\n\nAD/B737/145\n\nAmdt 1\n\n  \nFlightcrew Seat Locks and Seat Tracks 5/2004\n\nApplicability: Model 737-300, \\-400, and \\-500 series aircraft, equipped with IPECO flightcrew seats; as listed in Boeing Alert Service Bulletin ASB 737-25A1363 Revision 1, dated 28 March 2002.\n\nRequirement: Inspect in accordance with the technical requirements of FAA AD 2004-04-03 Amdt 39-13483.\n\nCompliance: For Group 1 aircraft listed in ASB 737-25A1363 Revision 1: Before 10 November 2000; in accordance with ASB 737-25A1363. For Group 2 aircraft listed in ASB 737-25A1363 Revision 1:\n\nWithin 90 days after 13 May 2004; in accordance with ASB 737-25A1363 Revision 1.\n\nThe compliance time remains unchanged for Group 1 aircraft. This Amendment becomes effective on 13 May 2004.\n\nBackground: The FAA received reports of instances of the pilot seat sliding to the aft-most position during acceleration and take-off on certain Model 737 series aircraft. Investigation revealed that the screws attaching the rear tracklock bracket to the seat track had broken, allowing excessive lateral movement and disengagement of the locking pin from the floor-mounted seat track.\n\nBoeing 737 Series Aeroplanes\n\nAD/B737/145 Amdt 1 (continued)\n\nAmendment 1 is issued in response to a new FAA AD, which revises applicability of the existing AD by adding aircraft with the introduction of Revision 1 of the related service bulletin.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 2 April 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 21 April 2004.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is an amendment to an existing Airworthiness Directive. The original AD addressed flightcrew seat lock failures. Amendment 1 simply expands applicability to additional aircraft (Group 2) covered by a revised Boeing service bulletin. The core safety purpose — preventing seat track failures — remains unchanged."},"complexity_factors":["Short, single-purpose directive (approximately 300 words)","Only 2 defined groups (Group 1 and Group 2) with clear compliance dates","Single cross-reference to FAA AD 2004-04-03 and Boeing Service Bulletin ASB 737-25A1363 Revision 1","No nested exceptions or conditional logic beyond the two aircraft groups","Technical content is incorporated by reference rather than reproduced in full"],"plain_english_summary":"This Airworthiness Directive covers certain Boeing 737-300/-400/-500 airplanes equipped with IPECO pilot seats, required because screws in the seat locking mechanism can break and allow the seat to slide rearward during takeoff, risking loss of pilot control.  \n\nIt mandates inspection and corrective action per Boeing ASB 737-25A1363 Rev. 1 (and FAA AD 2004-04-03); Group 2 airplanes must comply within 90 days of May 13, 2004, while Group 1 compliance remains unchanged."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 1 adjusts the AD's applicability by adding aircraft listed in Boeing ASB 737-25A1363 Revision 1 and sets the compliance window for the added Group 2 aircraft. This is an incremental expansion to ensure additional serials/aircraft are covered; it stays within the original safety purpose (preventing unintended seat movement) rather than growing the AD's objective beyond that safety issue."},"complexity_factors":["Short document (single AD with clear Applicability, Requirement, Compliance, Background sections)","Direct cross-reference to two external technical documents: FAA AD 2004-04-03 and Boeing ASB 737-25A1363 Revision 1 (necessitates consulting those documents for technical detail)","Two-group structure with different compliance times (Group 1 and Group 2)","A regulatory cross-reference to CASR subregulation 39.1(1) (legal basis is external)","Date inconsistency potential (Group 1 compliance deadline predates the AD's amendment date, which may confuse readers)"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- This Airworthiness Directive (AD) requires operators of certain Boeing 737-300/ -400/ -500 aeroplanes equipped with IPECO flightcrew seats to inspect the seat locks and seat tracks.  The inspection must be done in accordance with the technical requirements of FAA AD 2004-04-03 and Boeing Alert Service Bulletin ASB 737-25A1363 Revision 1.  \n\n- The AD divides affected aeroplanes into groups and sets deadlines: Group 1 aircraft must already have met the earlier compliance requirement (the compliance time for Group 1 remains \"before 10 November 2000\"); Group 2 aircraft must be inspected within 90 days after 13 May 2004.  \n\n- The AD becomes effective on 13 May 2004 and is issued under CASA's regulatory power to require actions necessary to correct an unsafe condition (CASR subregulation 39.1(1)).\n\nWho is affected\n\n- Aircraft operators/owners of Boeing 737-300, -400 and -500 series aeroplanes that are fitted with IPECO flightcrew seats and that are listed in Boeing ASB 737-25A1363 Revision 1.  \n\n- Maintenance organisations and engineers who must carry out the inspections and any corrective work required by the FAA AD and the Boeing service bulletin.  \n\nWhat specific actions are required\n\n- Inspect the rear tracklock bracket, screws and the locking pin engagement on the flightcrew seat tracks, following the procedures, tolerances and follow-up corrective actions set out in FAA AD 2004-04-03 and Boeing ASB 737-25A1363 Revision 1.  \n\n- If the inspection finds broken screws, excessive lateral movement, or disengagement of the locking pin, corrective action must be taken as specified in the referenced FAA AD/Boeing service bulletin (this typically means repair or replacement of tracklock hardware and associated parts).\n\nWhy CASA issued this AD (stated rationale)\n\n- The FAA reported pilots' seats sliding to the aft-most position during acceleration/take-off because screws attaching the rear tracklock bracket to the seat track had broken.  The AD (as amended) updates applicability to include aircraft added by Revision 1 of the Boeing service bulletin so that all affected serials/aircraft are covered.\n\nOperational and economic mechanics (who pays, who decides, and how behaviour changes)\n\n- Who pays: aircraft operators (or their insurers) pay for inspections, labour, parts and any aircraft downtime caused by the work.  \n\n- Who decides: CASA (via its delegate) mandates the action; the technical content and corrective steps are those set out in the FAA AD and Boeing service bulletin, which maintenance organisations must follow.  \n\n- Behaviour change: operators must schedule the mandated inspections within the specified compliance windows, perform the work to the technical instructions, and document compliance with the AD.  If defects are found, operators must remove defective parts and install approved replacements before further flight as required by the referenced documents.\n\nTrade-offs, risks and implementation notes\n\n- Immediate safety benefit: inspection and corrective action reduce the risk of an uncontrolled aft movement of the pilot seat during critical flight phases.  \n\n- Costs/opportunity cost: inspections, parts and labour impose direct costs and may take aircraft out of service temporarily. The AD does not specify compensation; those costs fall to operators.  \n\n- Reliance on external documents: compliance requires consulting FAA AD 2004-04-03 and Boeing ASB 737-25A1363 Revision 1. That creates dependency on those documents for precise steps, parts, and acceptable repairs.  \n\n- Enforcement and recordkeeping: operators must retain evidence of compliance as required under CASA maintenance and continuing airworthiness rules.  \n\n- Implementation risk: if operators misunderstand grouping or applicable serial numbers, an affected aeroplane could be missed; the AD amends applicability to capture aircraft added by the service bulletin revision.  \n\nSummary of the amendment's mechanical change\n\n- Amendment 1 does not introduce a new type of remedy. It expands the applicability by adding aircraft identified in Boeing ASB 737-25A1363 Revision 1 and sets the compliance window for the newly identified Group 2 aircraft (90 days after 13 May 2004). The previously required compliance for Group 1 remains unchanged (before 10 November 2000)."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks","history":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks/history","analysis":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks/analysis","conflicts":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks/conflicts","importantCases":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks/important-cases","documents":"/api/acts/ad-b737-145-amdt-1-flightcrew-seat-locks-and-seat-tracks/documents"}}