{"id":"F2006B02915","name":"AD/B737/219 - Rudder Front Spar Flange Bolts","slug":"ad-b737-219-rudder-front-spar-flange-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42257,"registerId":"commonwealth-F2006B02915-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 737 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B737/219 Rudder Front Spar Flange Bol","sectionType":"part","heading":"AD/B737/219 Rudder Front Spar Flange Bolts 2/2004","content":"# AD/B737/219 Rudder Front Spar Flange Bolts 2/2004\n\nApplicability: All Model 737-100, \\-200, \\-200C, \\-300, \\-400, and \\-500 series aircraft.\n\nRequirement: Inspect in accordance with the technical requirements of FAA AD 2003-26-01 Amdt 39-13397.\n\nFor any aluminium/fibreglass rudder assembly having an identification plate indicating a graphite assembly, or for any graphite assembly having an identification plate indicating an aluminium assembly, and the alert service bulletin specifies to contact Boeing for appropriate action: Before further flight, contact the Manager, Seattle ACO, FAA; or a Boeing Designated Engineering Representative who has been authorised by the Manager, Seattle ACO, to make such findings.\n\nNote: Boeing Alert Service Bulletin 737-55A1087 refers.\n\nCompliance: As specified in the Requirement document, with a revised effective date of 19 February 2004.\n\nThis Airworthiness Directive becomes effective on 19 February 2004.\n\nBackground: The manufacturer advised the FAA of two reports of loose bolts common to the flange of the rudder front spar and main thrust hinge and actuator assembly, as well as auxiliary actuator support fitting, on Model 737 series aircraft. No additional damage was reported in the first case. In the second case, the holes common to the flange of the rudder front spar had become elongated. A further nine reports of loose flange bolts have been received. Such loose bolts could cause the rudder actuator to separate from the rudder during certain flight conditions, and could result in loss of rudder control and consequent loss of control of the aircraft.\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 8 January 2004\n\n![](image.001.png)","sortOrder":1}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD remains narrowly targeted at correcting the unsafe condition described (loose or elongated flange bolts on the rudder front spar and associated fittings). It requires inspections per FAA AD 2003-26-01 and prescribes escalation where identification-plate mismatches exist. There is no expansion beyond that safety remediation purpose in this text."},"complexity_factors":["Short, focused document (one primary safety issue)","Single external normative reference: FAA AD 2003-26-01 (requires reader to consult another instrument for detailed procedures)","Cross-reference to Boeing Alert Service Bulletin 737-55A1087 for technical detail","One conditional escalation: identification-plate mismatch triggers requirement to contact FAA Seattle ACO or authorised Boeing DER before further flight","Limited number of defined elements (applicability, requirement, compliance, background) and no layered exceptions"],"plain_english_summary":"**What this Airworthiness Directive (AD) does**\n\n- **Applies to:** All Boeing 737 series aircraft of models 737-100, -200, -200C, -300, -400 and -500. (Applicability)\n\n- **Required action:** Operators must inspect the rudder front spar flange bolts and related fittings in accordance with the FAA Airworthiness Directive 2003-26-01 and the technical instructions referenced there. (Requirement)\n\n- **Special instruction about mismatched identification plates:** If a rudder assembly is marked as aluminium but is a graphite assembly (or vice versa), and the Boeing alert service bulletin tells you to \"contact Boeing for appropriate action,\" you must, before the aircraft flies again, contact either the Manager of the Seattle Aircraft Certification Office (FAA) or a Boeing Designated Engineering Representative (DER) authorised by that Manager to make the necessary findings. (Requirement)\n\n- **When to comply:** The AD took effect on 19 February 2004; inspections and any corrective actions are required as set out in the FAA AD. (Compliance)\n\n- **Why it's required:** The manufacturer reported incidents of loose flange bolts at the rudder front spar that in some cases had elongated bolt holes. Loose or failed flange bolts could allow the rudder actuator to separate from the rudder, possibly causing loss of rudder control. (Background)\n\nHow it works mechanically\n\n- The AD does not itself set out step-by-step inspection procedures but makes compliance with FAA AD 2003-26-01 mandatory for Australian operators and points to Boeing Alert Service Bulletin 737-55A1087 for technical detail. (Requirement / Note)\n\n- If inspections reveal an uncertainty caused by incorrect identification plates on the rudder assembly, the AD requires an immediate escalation to the FAA Seattle ACO or an authorised Boeing DER to determine the correct repair or disposition before further flight. (Requirement)\n\nWho pays, who decides, and what changes in behaviour\n\n- Operators pay for inspections, any corrective work (repairs or bolt/part replacement), and the administrative cost of contacting FAA/DER where plate mismatches occur. (Requirement / Compliance)\n\n- The FAA Seattle ACO Manager or an authorised Boeing DER makes required technical findings when identification-plate mismatches arise; operators must follow their determinations. (Requirement)\n\n- Behavioural change: operators must incorporate the specified inspections into maintenance actions, possibly grounding affected aircraft until inspections or repairs are completed; they must follow the FAA/Boeing determinations for ambiguous parts. (Requirement / Compliance)\n\nCosts, trade-offs and implementation risks (practical testing of the AD’s stated purpose)\n\n- Compliance burden: The AD creates an immediate, safety-driven inspection requirement. Costs are largely concentrated on operators (inspection labour, parts, and potential out-of-service time). (Requirement / Compliance)\n\n- Operational trade-offs: Because some findings require action \"before further flight,\" there is a risk of aircraft being removed from service on short notice, affecting schedules and revenue. (Requirement)\n\n- Administrative burden and delay risk: When identification plates are inconsistent, operators must escalate to the FAA or an authorised DER. That escalation centralises technical decision-making outside the operator, which can delay corrective action depending on FAA/DER availability. (Requirement)\n\n- Supply and repair capacity: If inspections identify parts that must be replaced, availability of authorised repair parts or qualified technicians can affect how long an aircraft is grounded. The AD itself does not provide alternatives; it defers to FAA/Boeing decisions where ambiguity exists. (Requirement / Note)\n\n- Benefits and concentration of effect: The benefit (reduced risk of rudder actuator separation) accrues broadly to flight safety for all users and the public; the direct costs fall mainly on aircraft operators who must perform inspections and repairs. (Background / Requirement)\n\n- Implementation risk: The AD relies on cross-jurisdictional technical documents (the FAA AD and a Boeing service bulletin). Clear, timely access to those documents and prompt FAA/DER responses are necessary for smooth compliance. (Requirement / Note)\n\nSource citations within the AD: Applicability; Requirement; Compliance; Background; Note (Boeing Alert Service Bulletin 737-55A1087)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope: addressing a specific mechanical defect (loose rudder bolts) on specific Boeing 737 models. The reference to material identification plate mismatches is an ancillary check to ensure correct repair procedures, not an expansion beyond the original safety purpose."},"complexity_factors":["Short document (approximately 300 words)","Only 4 defined structural sections (Applicability, Requirement, Compliance, Background)","Single cross-reference to external FAA directive (FAA AD 2003-26-01)","One conditional scenario requiring special action (material mismatch on identification plate)","No nested exceptions or complex conditional logic","Technical aviation terminology used but explained through context"],"plain_english_summary":"Australia's aviation regulator (CASA) issued a safety order requiring operators of Boeing 737-100/200/200C/300/400/500 series to inspect rudder attachment bolts after loose bolts and stretched bolt holes were found. Following FAA AD 2003-26-01 procedures is mandatory; if rudder material differs from its identification plate, operators must contact Boeing or the FAA before further flight. The directive took effect 19 February 2004."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts","history":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts/history","analysis":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts/analysis","conflicts":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts/conflicts","importantCases":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts/important-cases","documents":"/api/acts/ad-b737-219-rudder-front-spar-flange-bolts/documents"}}