{"id":"F2006B01955","name":"AD/A320/67 - MLG Free Fall Extension System","slug":"ad-a320-67-mlg-free-fall-extension-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41177,"registerId":"commonwealth-F2006B01955-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A320/67 - MLG Free Fall Extension System","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAirbus Industrie A319, A320 and A321 Series Aeroplanes\n\nAD/A320/67 MLG Free Fall Extension System 6/96\n\nApplicability: Serial numbers 002 to 008, 010 to 014, 016 to 078, 080 to 104, and 106 and 107 with Airbus Industrie SB A320-53-1023 Rev. 6 or earlier Revisions incorporated.\n\nRequirement: Action in accordance with Airbus Industrie AOT 53-08 Rev.1 dated 15 January 1996.\n\nNote: DGAC AD 96-053-077(B) refers.\n\nCompliance: Inspect within 1000 flights after 23 May 1996, and where the minimum clearance between the MLG free fall extension system bellcrank installation and the reinforcement bracket is:\n\n    greater than 3mm with no interference,\n\n    \\- within 5 years’ time in service after 23 May 1996 reinstall the reinforcement brackets in accordance with SB A320-53-1023 Rev. 7;\n\n    b. less than 3mm with no interference,\n\n    \\- within 18 months after 23 May 1996 reinstall the reinforcement brackets in accordance with SB A320-53-1023 Rev. 7; or\n\n    c. less than 3mm with evidence of interference,\n\n    i) prior to further flight reinstall the reinforcement brackets in accordance with SB A320-53-1023 Rev. 7, or\n\n    ii) prior to further flight rework the bellcrank lever in accordance with the instructions specified in the Requirement Document, subsequently, and within 5 years’ time in service after 23 May 1996, reinstall the reinforcement bracket fasteners in accordance with SB A320-53-1023 Rev. 7.\n\nFull incorporation of Airbus Industrie SB A320-53-1023 Rev. 7 cancels the requirements of this Directive.\n\nNote: AD/A320/47 Amdt 2 cross refers.\n\nBackground: This Directive is issued in order to detect possible interference between the attaching fasteners of the reinforcement bracket, and the MLG free fall extension system bellcrank and its tie-rod attachment nut, which could interfere with the operation of the MLG free fall system.","sortOrder":0}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a focused, single-purpose scope: addressing a specific mechanical interference issue on specific Airbus aircraft. It has not expanded beyond its original safety intent."},"complexity_factors":["Multiple conditional branches based on inspection findings (3 distinct scenarios: >3mm, <3mm no interference, <3mm with interference)","Cross-references to external technical documents (Airbus Industrie AOT 53-08 Rev.1, SB A320-53-1023 Rev. 7, DGAC AD 96-053-077(B), and AD/A320/47 Amdt 2)","Specific serial number applicability with gaps (excludes 009, 015, 079, 105)","Dual timeline requirements (flight cycles and calendar time — '1000 flights' vs '5 years' time in service')","Technical aviation terminology requiring domain knowledge (bellcrank, tie-rod, free fall extension system, service bulletins)","Cancellation clause dependent on future action (full incorporation of SB Rev. 7 cancels the directive)"],"plain_english_summary":"This Airworthiness Directive requires operators of certain Airbus A319/A320/A321 aircraft to inspect—and where needed, correct—a potential interference between a reinforcement-bracket bolt and the main landing gear free-fall bellcrank. It applies to planes without a specific service update and sets short deadlines for remedial action when clearances are inadequate or parts are contacting. The measure protects the emergency gravity-extension system and prevents possible gear-up landings."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Directive remains narrowly focused on the original technical problem: detecting and remedying interference between the MLG free-fall extension bellcrank/tie-rod nut and reinforcement bracket fasteners. It prescribes inspection and corrective work methods tied to Airbus technical documents and sets compliance timelines. There is no indication the instrument expanded beyond that original safety mitigation purpose; the cancellation mechanism (full incorporation of SB Rev.7) is a standard way to retire an AD once the manufacturer’s fix is fully applied."},"complexity_factors":["Short document but multiple conditional branches based on measured clearance (three outcome paths).","Time-based deadlines with several different windows (inspect within 1,000 flights; corrective actions within 18 months or 5 years; some actions required prior to further flight).","Specific dimensional threshold (3 mm) and an additional reference to 5 mm in text structure increases measurement precision requirements.","Dependence on external technical documents: Airbus AOT 53-08 Rev.1 and Airbus SB A320-53-1023 (Rev.6 and Rev.7 referenced).","Cancellation clause linking full incorporation of SB Rev.7 to automatic cancellation of the AD.","Applicability defined by multiple serial-number ranges, which requires cross-checking operator records.","Some subjective language: “evidence of interference” introduces inspector judgement and potential inconsistency."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It requires certain Airbus A319/A320/A321 aeroplanes (listed by serial number) to have the main landing gear (MLG) free-fall extension system inspected and, depending on the measurement results, to have parts reinstalled or reworked following Airbus technical instructions.\n- The inspection must be done within 1,000 flights after 23 May 1996 (see “Compliance”).\n- Actions depend on the measured minimum clearance between the free-fall extension system bellcrank and the reinforcement bracket:\n  - If clearance is greater than 3 mm with no evidence of interference: reinstall the reinforcement brackets per Airbus Service Bulletin (SB A320-53-1023 Rev.7) within 5 years after 23 May 1996.\n  - If clearance is less than 3 mm with no interference: reinstall the reinforcement brackets per SB Rev.7 within 18 months after 23 May 1996.\n  - If clearance is less than 3 mm with evidence of interference:\n    - Either reinstall the reinforcement brackets per SB Rev.7 before further flight, or\n    - Rework the bellcrank lever per the Airbus AOT instructions before further flight and then reinstall the reinforcement bracket fasteners per SB Rev.7 within 5 years after 23 May 1996.\n- The required inspection and any corrective work must be carried out in accordance with Airbus Industrie AOT 53-08 Rev.1 (the “Requirement” document) and Service Bulletin A320-53-1023 (various revisions are referenced).\n- Once an operator has fully incorporated Airbus SB A320-53-1023 Rev.7, this Airworthiness Directive (AD) is cancelled for those aeroplanes.\n\n**Who it affects**\n\n- Aeroplane operators who own or operate the listed Airbus A319/A320/A321 serial numbers.\n- Maintenance organisations and approved maintenance engineers who must perform the inspection and the corrective work.\n- Parts suppliers and MROs that provide the reinforcement brackets, fasteners or bellcrank rework services.\n\n**Why it matters (safety and operational mechanics)**\n\n- The Directive’s stated purpose is to detect and correct possible physical interference between the reinforcement bracket fasteners and the MLG free-fall extension bellcrank/tie-rod nut (see “Background”). Interference could impede the free-fall operation of the main landing gear—a safety-critical mechanism for gear extension if primary systems fail.\n\n**Implementation mechanics, incentives and trade-offs**\n\n- Implementation requires measurement (clearance in mm), judgement (what constitutes “evidence of interference”), and compliance with Airbus technical documents (AOT 53-08 Rev.1 and SB A320-53-1023 Rev.7). (Applicability; Requirement; Compliance.)\n- Costs and who pays: aircraft operators pay for inspections, any rework, parts and associated downtime. Maintenance providers and parts suppliers gain the work (concentrated benefit). The measure does not directly change market structure or competition among carriers but creates predictable demand for MRO services.\n- Timing trade-offs: where interference is detected (clearance < 3 mm with interference), the AD requires corrective action before further flight, which can force immediate grounding or removal from service for repairs. Where there is no interference but small clearance, the AD allows a deferred window (18 months or 5 years) to schedule work, reducing immediate disruption but imposing future maintenance planning costs.\n- Operational risk and uncertainty: the 3 mm threshold and the term “evidence of interference” require clear measurement and judgement by maintenance personnel—different inspectors could reach different conclusions, which affects fleet availability and may increase conservative (grounding) decisions.\n- Regulatory linkage: compliance depends on following Airbus service documents. Full incorporation of the manufacturer’s Service Bulletin Rev.7 cancels the AD for affected aeroplanes, so the AD is a temporary regulatory backstop until the manufacturer’s fix is fully adopted.\n\n**Compliance burden and implementation risk**\n\n- Burden: an inspection within a fleet scheduling window (1,000 flights) plus potential repair work that may need parts, shop time and certification by an approved maintenance organisation.\n- Risk: parts or approved repair instructions might be back-ordered or require specialised shop skills; subjective inspection criteria could cause unnecessary groundings or, conversely, failure to detect marginal interference.\n\n**Net operational effect (concrete, not ideological)**\n\n- Operators must inspect and, if necessary, fix or rework components to ensure the MLG free-fall mechanism is not obstructed. The rule shifts direct costs and scheduling impacts onto operators and maintenance providers, while addressing a specific mechanical risk to safe gear operation (Background). The AD does not rewrite commercial contracts or market rules; it prescribes a safety inspection and corrective path tied to manufacturer instructions and timelines.\n\n(References in the instrument: Applicability; Requirement; Compliance; Note; Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-67-mlg-free-fall-extension-system","history":"/api/acts/ad-a320-67-mlg-free-fall-extension-system/history","analysis":"/api/acts/ad-a320-67-mlg-free-fall-extension-system/analysis","conflicts":"/api/acts/ad-a320-67-mlg-free-fall-extension-system/conflicts","importantCases":"/api/acts/ad-a320-67-mlg-free-fall-extension-system/important-cases","documents":"/api/acts/ad-a320-67-mlg-free-fall-extension-system/documents"}}