{"id":"F2006B03164","name":"AD/B747/268 - Trailing Edge Flap Transmission Torque Brake","slug":"ad-b747-268-trailing-edge-flap-transmission-torque-brake","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42536,"registerId":"commonwealth-F2006B03164-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\n![](image.001.png)  \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 CAR 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\nBoeing 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/268 Trailing Edge Flap Transmiss","sectionType":"part","heading":"AD/B747/268 Trailing Edge Flap Transmission Torque Brake 5/2002","content":"# AD/B747/268 Trailing Edge Flap Transmission Torque Brake 5/2002\n\nApplicability: Model 747 series aeroplanes line numbers 0001 to 1207, excluding line number 1174 and Model 747SP series aeroplanes.\n\nRequirement: 1. Action in accordance with the technical requirements of CORRECTION FAA AD 2001-23-13 Amendment 39-12512 issued in Renton, Washington, on 7 February 2002.\n\n2. No person shall install on any aircraft any transmission or torque brake assembly of the trailing edge flaps at positions 2 or 7 as identified in the “Existing Part Number” column of paragraph 2.E of Boeing Service Bulletin 747-27-2374 dated 18 November, 1999.\n\nCompliance: Requirement 1: Within 13 months or 5,400 flight hours after the effective date of this Airworthiness Directive, whichever occurs later.\n\nRequirement 2: From the date when this Directive becomes effective. This Airworthiness Directive becomes effective on 16 May 2002.\n\nBackground: The manufacturer raised a Service Bulletin after it was found that the trailing edge flap transmission torque brake (Belleville spring design) does not lockout at the intended torque levels. If a flap jam occurred, and the torque brake failed to limit the torque of the transmission, the resultant force may cause the transmission mounts to fail. This Airworthiness Directive has therefore been raised to remove, rework or replace such torque brakes to prevent damage to the flap system, adjacent systems, or structural components; or excessive skew of the trailing edge flap, that could result in flap asymmetry and consequent reduced controllability of the aeroplane.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 27 March 2002\n\n![](image.001.png)","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific mechanical defect in a specific aircraft type with targeted remedial action. There is no evidence of scope creep; the instrument remains focused solely on the trailing edge flap torque brake issue identified in the background."},"complexity_factors":["Short, single-purpose instrument (approximately 400 words)","Only 2 substantive requirements with clear compliance deadlines","Minimal defined terms (only 'line numbers' and specific part references require external lookup)","Single cross-reference to external technical document (FAA AD 2001-23-13 and Boeing Service Bulletin 747-27-2374)","No nested exceptions or conditional logic beyond the applicability carve-out (excluding line number 1174)","Straightforward temporal compliance structure (date OR flight hours, whichever is later)"],"plain_english_summary":"This CASA safety order requires urgent corrective action on specific Boeing 747/747SP aircraft to fix faulty trailing-edge flap torque brakes that can fail to lock, risking broken mounts, flap asymmetry and loss of control.  \n\nAffected operators must comply with the referenced FAA directive to repair, replace or remove the brakes within 13 months or 5,400 flight hours, and are banned from installing the implicated brake assemblies from the effective date to prevent catastrophic flap failure."},"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":"No. The Directive implements corrective actions identified by the manufacturer and adopted from FAA AD 2001-23-13 (Requirement 1) and enforces a parts-installation prohibition matching Boeing Service Bulletin 747-27-2374 (Requirement 2). It does not expand the fleet affected beyond the stated applicability (line numbers 0001–1207, excluding 1174, and excluding 747SP), though it does impose an immediate ban on installing the listed assemblies (Requirement 2)."},"complexity_factors":["Cross-references to external authorities: adopts FAA AD 2001-23-13 as the required technical action (Requirement 1).","Dependency on manufacturer service data: prohibits parts identified in Boeing Service Bulletin 747-27-2374 para 2.E (Requirement 2).","Specific applicability carve-outs: applies to 747 line numbers 0001–1207 but excludes line 1174 and the 747SP (Applicability).","Dual compliance metric: compliance deadline is the later of 13 months or 5,400 flight hours after the AD’s effective date (Compliance — Requirement 1).","Immediate-effect prohibition: ban on installing specified assemblies is effective from the AD’s date (Requirement 2 / Compliance).","Technical work scope: requires removal, rework or replacement of torque brakes (Requirement 1), which may trigger parts sourcing and maintenance planning.","Safety rationale tied to specific failure mode: torque brake (Belleville spring design) may not lock out, risking transmission mount failure and flap asymmetry (Background)."],"plain_english_summary":"This Airworthiness Directive orders operators of Boeing 747 aeroplanes (line numbers 0001–1207, excluding 1174, and excluding 747SP) to remove, rework or replace certain trailing-edge flap transmission torque brakes because they may not lock at the intended torque and could cause flap asymmetry. It adopts the FAA’s technical remedy and immediately prohibits installing the listed torque-brake assemblies at positions 2 or 7. It matters because it forces specific maintenance and parts controls to address a mechanical safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake","history":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake/history","analysis":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake/analysis","conflicts":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake/conflicts","importantCases":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake/important-cases","documents":"/api/acts/ad-b747-268-trailing-edge-flap-transmission-torque-brake/documents"}}