{"id":"F2005L03564","name":"AD/B737/261 - Main Deck Floor Beams","slug":"ad-b737-261-main-deck-floor-beams","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39107,"registerId":"commonwealth-F2005L03564-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/B737/261 | Main Deck Floor Beams | 13/2005 |\n| ----------- | --------------------- | ------- |\n\n| Applicability: | Model 737-100 and -200 series aircraft as listed in Boeing Service Bulletin737-57-1210, or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2001-14-20Amdt 39-12331.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Compliance:    | As specified in the Requirement document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | This Directive is prompted by reports of incidents involving fatigue cracking and corrosion in transport category aircraft that are approaching or have exceeded their design life goal. The Directive implements recommendations of the Airworthiness Assurance Task Force assigned to review the Model 737 series aircraft, which determined that, to assure long term continued operational safety, various structural inspections should be accomplished. The actions specified by this Directive are intended to prevent failure of the main deck floor beams at certain body stations due to fatigue cracking, which could result in rapid decompression and consequent reduced controllability of the aircraft. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n10 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/261","sectionType":"part","heading":"AD/B737/261","content":"## AD/B737/261","sortOrder":1},{"sectionNumber":"Main Deck Floor Beams","sectionType":"part","heading":"Main Deck Floor Beams","content":"## Main Deck Floor Beams","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The Directive implements the Airworthiness Assurance Task Force recommendations to require structural inspections of main-deck floor beams on the specified 737-100/-200 aircraft. It does not expand applicability beyond aircraft listed in the referenced Boeing Service Bulletin and requires actions as set out in the cited FAA AD."},"complexity_factors":["Cross-references external instruments: compliance is specified by FAA AD 2001-14-20 and Boeing Service Bulletin 737-57-1210, requiring operators to track and apply those documents (Requirement).","Technical inspections: measures target fatigue cracking and corrosion of structural floor beams, requiring specialised inspection techniques and possible structural repairs (Background; Requirement).","Applicability determination: only applies to aircraft listed in the referenced Boeing Service Bulletin, so operators must confirm inclusion of individual airframes (Applicability).","Operational impact: inspections and corrective actions create maintenance downtime and direct costs for aircraft operators (Requirement; Background).","Regulatory layering and revision risk: reliance on later FAA-approved revisions and service bulletin updates creates ongoing compliance monitoring obligations (Applicability; Requirement)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737‑100 and ‑200 aircraft listed in Boeing Service Bulletin 737‑57‑1210 to carry out inspections and any corrective action on main-deck floor beams in accordance with FAA AD 2001‑14‑20. CASA says the measure responds to reported fatigue cracking and corrosion and aims to prevent floor‑beam failure that could cause rapid decompression and reduced controllability. Operators pay for inspections and repairs; CASA (by delegate) mandates compliance, effective 22 December 2005."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive implementing international safety recommendations. It maintains its original narrow scope: addressing specific structural fatigue issues in aging 737-100/-200 aircraft as identified by the Airworthiness Assurance Task Force. No scope creep is evident."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined applicability criterion (specific Boeing models)","Single cross-reference to external technical document (FAA AD 2001-14-20)","No nested conditions or exceptions within the directive itself","Technical complexity is outsourced to the referenced FAA document — the Australian instrument itself is a simple incorporation by reference"],"plain_english_summary":"This CASA Airworthiness Directive mandates that owners/operators of Boeing 737-100 and 737-200 aircraft carry out inspections of main deck floor beams per FAA AD 2001-14-20 to detect fatigue cracking and corrosion. It targets ageing structural risks that could lead to rapid decompression or loss of control, with compliance required by 22 December 2005."},"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-b737-261-main-deck-floor-beams","history":"/api/acts/ad-b737-261-main-deck-floor-beams/history","analysis":"/api/acts/ad-b737-261-main-deck-floor-beams/analysis","conflicts":"/api/acts/ad-b737-261-main-deck-floor-beams/conflicts","importantCases":"/api/acts/ad-b737-261-main-deck-floor-beams/important-cases","documents":"/api/acts/ad-b737-261-main-deck-floor-beams/documents"}}