{"id":"F2006B03199","name":"AD/B747/306 - Passenger Service Unit Panel Rail Tie Bar","slug":"ad-b747-306-passenger-service-unit-panel-rail-tie-bar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42571,"registerId":"commonwealth-F2006B03199-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/306 Passenger Service Unit Panel","sectionType":"part","heading":"AD/B747/306 Passenger Service Unit Panel Rail Tie Bar 7/2004","content":"# AD/B747/306 Passenger Service Unit Panel Rail Tie Bar 7/2004\n\nApplicability: Model 747-400 and \\-400D series aircraft, identified as Group 2 aircraft in Boeing Special Attention Service Bulletin 747-25-3111 Revision 2, dated 24April 2003.\n\nRequirement: Install tie bars in Zone A on the rails of the centre passenger service unit panels in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-25-3111 Revision 2.\n\nNote: FAA AD 2004-09-04 Amdt 39-13593 refers.\n\nCompliance: Within 18 months after 8 July 2004.\n\nThis Airworthiness Directive becomes effective on 8 July 2004.\n\nBackground: The FAA received a report that, during manufacture, panel tie bars were not installed on the rails of the centre passenger service units (PSU) panel in Zone A on certain Model 747-400 series aircraft. If the tie bars in Zone A are not installed, the PSU panels can move from their location on the PSU rails during flexure of the rails. This condition, if not corrected, could result in PSU panels falling from the PSU support rails during takeoff or landing, which could result in injury to passengers and could impede an evacuation in an emergency situation.\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 26 May 2004\n\n![](image.001.png)","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive addressing a specific manufacturing defect in a specific aircraft model. The scope remains tightly focused on the original safety issue — missing tie bars on PSU panels — with no expansion beyond the original technical problem."},"complexity_factors":["Single, specific mechanical action required (install tie bars)","Only one defined term of note ('Zone A' — a location reference in the aircraft)","No nested exceptions or conditional logic","Clear, single compliance deadline (18 months from effective date)","Narrow applicability (specific Boeing model series and specific aircraft group)","References only one external technical document (Boeing Service Bulletin) and one related FAA directive for context"],"plain_english_summary":"This Airworthiness Directive requires operators of certain Boeing 747-400/747-400D aircraft identified in Boeing Service Bulletin 747‑25‑3111 Rev 2 to install missing tie bars on Passenger Service Unit (PSU) overhead panels. It addresses a factory omission that could allow panels to fall onto passengers during critical phases, posing injury and evacuation hazards. The mandated repair must be completed within 18 months of 8 July 2004."},"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD is narrowly corrective and limited to aircraft where tie bars were missing (Group 2 per the Boeing service bulletin). It does not expand beyond that original safety-fix purpose: it prescribes a single retrofit on a defined subset of 747-400/-400D aeroplanes. There is no material growth of scope beyond the original intent to remedy missing tie bars identified in manufacture."},"complexity_factors":["Short single-subject AD (one physical correction: install tie bars).","Single, narrow applicability: Model 747-400 and -400D Group 2 aircraft per Boeing Service Bulletin.","One compliance action delegated to an external document (Boeing Special Attention Service Bulletin 747-25-3111 Rev 2).","Single compliance timeframe (18 months) and single effective date (8 July 2004).","Cross-reference to FAA AD (note), increasing external-document reliance but not adding internal procedural complexity.","Minimal conditional logic and no nested exceptions or multiple compliance options."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires installation of tie bars on the centre passenger service unit (PSU) panel rails in Zone A on certain Boeing 747-400 and 747-400D aeroplanes (those identified as Group 2 in Boeing Special Attention Service Bulletin 747-25-3111 Revision 2). (Requirement / Applicability)\n- Directs that the work be done in accordance with the Accomplishment Instructions in Boeing Special Attention Service Bulletin 747-25-3111 Revision 2. (Requirement)\n- Sets the compliance deadline at within 18 months after 8 July 2004. The AD became effective on 8 July 2004. (Compliance / Effective date)\n\n**Who is affected**\n\n- Operators and owners of Boeing Model 747-400 and 747-400D aircraft that are identified as Group 2 in the referenced Boeing Service Bulletin. These operators are required to carry out the retrofit on each affected aircraft.\n- Maintenance organisations or mechanics who perform the installation must follow the Boeing service bulletin instructions.\n\n**Why it matters (stated safety concern and how the AD addresses it)**\n\n- The underlying safety report found that, during manufacture, some centre PSU rails in Zone A were left without tie bars. Without the tie bars, PSU panels can shift when the rails flex and could fall during takeoff or landing. Falling panels risk passenger injury and could impede evacuation. (Background)\n- The AD fixes that unsafe condition by mandating installation of the missing tie bars, using the manufacturer's detailed instructions.\n\n**How it works in practice**\n\n- The regulator (the CASA delegate) mandates the action and sets the deadline; the operator arranges for the installation according to the Boeing service bulletin. The AD explicitly relies on the Boeing Accomplishment Instructions for technical steps.\n- Compliance will typically require parts (tie bars if not present), labour, and aircraft out-of-service time while the work is completed. Costs and downtime fall on the aircraft owner/operator.\n\n**Implementation, incentives and trade-offs**\n\n- The AD delegates the exact technical method to Boeing’s service bulletin, reducing CASA’s need to set technical detail but making compliance dependent on that external document (Requirement).  \n- Costs are concentrated on affected operators (parts, labour, aircraft downtime). Benefits (reduced risk of falling PSU panels) are safety-related and accrue to passengers and crew.  \n- Practical risks include parts availability, variability in maintenance-provider experience, and the need to correctly identify which aeroplanes are in “Group 2” per the service bulletin (Applicability).  \n- The compliance window (18 months) balances urgency against operator scheduling and resource constraints; shorter windows would raise immediate grounding or accelerated maintenance costs, longer windows would delay hazard mitigation.\n\n**Enforcement and recordkeeping**\n\n- The AD is issued under CASR subregulation 39.1(1) and becomes legally mandatory for the identified aircraft. Operators must keep maintenance records showing the AD action was completed in accordance with the service bulletin.\n\n**Cross-references**\n\n- The AD incorporates Boeing Special Attention Service Bulletin 747-25-3111 Revision 2 and refers to FAA AD 2004-09-04 for related action. Compliance requires consulting those external documents (Requirement / Note)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar","history":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar/history","analysis":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar/analysis","conflicts":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar/conflicts","importantCases":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar/important-cases","documents":"/api/acts/ad-b747-306-passenger-service-unit-panel-rail-tie-bar/documents"}}