{"id":"F2005L03568","name":"AD/B737/263 - Krueger Flap Actuator Support Fittings","slug":"ad-b737-263-krueger-flap-actuator-support-fittings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39124,"registerId":"commonwealth-F2005L03568-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/263 | Krueger Flap Actuator Support Fittings | 13/2005 |\n| ----------- | -------------------------------------- | ------- |\n\n| Applicability: | Model 737-100 and -200 series aircraft, line numbers 1 through 813.                                                                                                                                                                                                                                                                        |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2000-15-18Amdt 39-11851.Note: Boeing Service Bulletin (SB) 737-57-1129 Revision 1, Notice of Status Change (NSC) 1, NSC 2, NSC 3, and SB 737-57-1129 Revision 2, or later FAA approved revision or NSC, refer.                                                              |\n| Compliance:    | For the repeat inspection requirement:As specified in paragraph (a) of the Requirement document.For the replacement requirement specified in paragraph (b) of the Requirement document:Before 31 January 2006, unless already accomplished.                                                                                                |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                        |\n| Background:    | The FAA received reports of cracking due to stress corrosion of the support fittings of the Krueger flap actuator. This Directive requires inspections to detect cracking of the support fittings of the actuator and replacement of the existing fittings with new steel fittings and modification of the aft attachment of the actuator. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n10 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/263","sectionType":"part","heading":"AD/B737/263","content":"## AD/B737/263","sortOrder":1},{"sectionNumber":"Krueger Flap Actuator Support Fittings","sectionType":"part","heading":"Krueger Flap Actuator Support Fittings","content":"## Krueger Flap Actuator Support Fittings","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety-focused scope: detect and mitigate stress-corrosion cracking of Krueger flap actuator support fittings. It does not broaden the regulatory reach beyond inspection and mandatory replacement/modification of the specified fittings on the listed aircraft. The instrument mainly enforces the FAA AD and Boeing SB technical remedy, rather than adding new, unrelated requirements."},"complexity_factors":["Short instrument focused on a single technical problem (Krueger flap actuator support fittings)","Single applicability definition (Model 737-100 and -200, line numbers 1–813)","Two primary obligations: recurring inspections and one-time replacement/modification","Cross-references to external technical documents (FAA AD 2000-15-18A and Boeing SB 737-57-1129 with multiple revisions/NSCs)","A fixed compliance deadline for the replacement (31 January 2006) and an effective date (22 December 2005)","No large interpretation/definitions section and no nested exceptions in the AD text provided"],"plain_english_summary":"**What this instrument does (mechanics)\n\n- This Airworthiness Directive (AD) applies to Boeing 737-100 and 737-200 aeroplanes, line numbers 1–813.\n- It requires operators to follow the technical requirements of FAA AD 2000-15-18A (amendment 39-11851) for inspections of the Krueger flap actuator support fittings, and to replace the existing (aluminium/alloy) support fittings with new steel fittings and modify the aft actuator attachment. Boeing Service Bulletin (SB) 737-57-1129 (and its listed revisions/Notices of Status Change) are the referenced repair/installation documents.\n- There are two distinct obligations: recurring inspections (the repeat-inspection requirement) to look for cracking, and a one-time replacement/modification. The replacement obligation had to be completed by 31 January 2006 unless it was already done.\n- The AD was made effective on 22 December 2005.\n\nWhy the AD was issued (stated reason)\n\n- The FAA had reports of stress-corrosion cracking in the Krueger flap actuator support fittings. The directive’s stated purpose is to detect cracking early by inspection and to remove the susceptible fittings by replacing them with steel fittings and modifying the aft attachment.\n\nWho is affected\n\n- The immediate legal duty-bearers are the owners/operators of Boeing 737-100 and -200 aircraft with the specified line numbers. Maintenance organisations that work on these aircraft must carry out the inspections and replacement work to the specified standard documents.\n\nWho pays, who decides, and what behaviour changes\n\n- Aircraft operators pay for inspection labour, parts (steel fittings and hardware), possible downtime, and any required certification/maintenance paperwork.\n- The Civil Aviation Safety Authority (CASA) enforces the AD in Australia; the AD requires compliance with the FAA AD and Boeing Service Bulletins (so the technical approach is decided by those documents and approved revisions).\n- Operators must schedule and perform recurring inspections, and plan/complete the one-time replacement and aft-attachment modification by the stated deadline (or earlier). That changes maintenance planning and can temporarily remove aircraft from service.\n\nCosts, incentives, and trade-offs\n\n- Direct costs: parts, skilled labour, and aircraft downtime. Those are concentrated on operators of affected models (a finite set of older 737s).\n- Benefits: reduced risk of in-service failure of the Krueger flap actuator support fittings (safety benefit). The benefit is concentrated on passengers, crew and operators who continue to fly the affected aircraft.\n- Opportunity cost: maintenance hours and hangar space diverted from other tasks; some operators might choose to retire or cannibalise older airframes rather than retrofit them if retrofit cost and downtime exceed expected remaining economic life.\n- Implementation risk: availability of replacement fittings and approved mod kits, accuracy and consistency of inspections (detecting stress-corrosion cracks early depends on inspection thoroughness), and scheduling bottlenecks at maintenance providers.\n- Compliance burden: moderate — operators must track recurring inspections, source parts that meet the SB requirements, and document compliance to the regulator.\n\nEffects on private enterprise and market choices\n\n- Independent maintenance organisations that can perform this work may gain business; operators that cannot or will not invest may ground or retire aircraft, shifting market supply of older 737s.\n- The AD does not prescribe who pays or fund replacements; that cost falls to aircraft owners/operators. It does not alter ownership rights or contractual freedoms beyond imposing a mandatory maintenance requirement to continue flying legally.\n\nCross-references and dependencies\n\n- The AD is largely a cross-reference instrument: it imposes legal force on the actions described in the FAA AD and the Boeing SBs. Any later FAA-approved revisions or SB revisions (listed in the AD) are incorporated for technical compliance.\n\nPractical implementation notes\n\n- Operators should follow the FAA AD and the Boeing SB precisely for inspection intervals, inspection methods, and the detailed replacement/modification steps.\n- Record-keeping of inspections and the replacement/modification work is required to demonstrate compliance to CASA.\n\nSource claim and analyst test\n\n- The AD’s stated aim is safety (detect and eliminate fittings prone to stress-corrosion cracking). The costs and behavioural effects are concrete: inspection/replacement costs, aircraft downtime, parts procurement and potential fleet-level decisions (repair versus retirement). The instrument centralises technical decision-making in the FAA AD and Boeing SBs, reducing CASA’s need to draft technical procedures but increasing operator dependence on those external documents for the exact method of compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific safety purpose — addressing a known defect in particular aircraft components. It has not expanded beyond its original intent of ensuring the structural integrity of Krueger flap actuator fittings on affected Boeing 737 aircraft."},"complexity_factors":["Short, single-purpose directive with one main technical requirement","Relies entirely on external technical documents (FAA AD 2000-15-18 and Boeing Service Bulletins) rather than spelling out procedures in the text itself","Only 2 compliance deadlines to track (inspections and replacement)","Limited applicability (specific aircraft models and line numbers only)","No nested exceptions or conditional logic within the directive text itself"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and corrective action on Krueger flap actuator support fittings on Boeing 737-100/-200 (line numbers 1–813) due to stress-corrosion cracking risk. Operators must inspect, replace cracked or corroded fittings with steel parts and modify the actuator rear attachment to ensure flap reliability. It affects Australian operators and foreign aircraft under CASA; compliance deadlines include mandatory work by 31 January 2006 (effective 22 December 2005)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings","history":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings/history","analysis":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings/analysis","conflicts":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings/conflicts","importantCases":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings/important-cases","documents":"/api/acts/ad-b737-263-krueger-flap-actuator-support-fittings/documents"}}