{"id":"F2006B09852","name":"AD/F50/26 Amdt 1 - Forward Passenger Door Frame to Torsion Box Connection","slug":"ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54923,"registerId":"commonwealth-F2006B09852-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/26 Amdt 1 - Forward Passenger Door Frame to Torsion Box Connection","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)  \nFokker F50 (F27 Mk 50) Series Aeroplanes\n\nAD/F50/26\n\nAmdt 1\n\n  \n\nForward Passenger Door Frame to Torsion Box Connection\n\n  \n5/92\n\nApplicability: Serial numbers 20103 \\- 20152 inclusive.\n\nRequirement: 1. Inspect in accordance with Part 1 of Fokker SB F50-53-031, dated 23 July 1990.\n\nNote: RLD AD(BLA) 90 \\- 089 refers.\n\n    2. For aircraft serial numbers 20103 and 20108 to 20152 inclusive, accomplish Part 2 of Fokker SB F50-53-031, dated 23 July 1990.\n\n    3. For aircraft serial numbers 20104 to 20107 inclusive:\n\n    (a) Accomplish SB F50-53-005.\n\nNote: RLD AD (BLA) 89-58 refers.\n\n    (b) Accomplish Part 3 of Fokker SB F50-53-031.\n\n| Compliance: | For paragraph 1. | Prior to accomplishing paragraphs 2 or 3.   |\n| ----------- | ---------------- | ------------------------------------------- |\n|             | For paragraph 2. | Prior to accumulating 20 000 flight cycles. |\n|             | For Paragraph 3. | Prior to accumulating 10 000 flight cycles  |\n\nBackground: Full scale fatigue tests revealed cracks in frame 4110 near the connection to the upper torsion box above the forward passenger entrance door. The original issue of this Directive required the installation of a steel reinforcement plate. Subsequent fatigue tests revealed even this connection to have an insufficient fatigue life.\n\nThis amendment requires an additional reinforcement which should give the structure above the passenger door a crack-free life of 45 000 flight cycles.","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":3,"scope_assessment":{"changed":true,"description":"This is Amendment 1 to an existing directive. The original directive only required installation of a steel reinforcement plate. This amendment expands the scope to require 'additional reinforcement' after further testing revealed the original fix was insufficient. The scope has grown from a one-time modification to a multi-stage inspection and reinforcement regime with different requirements for different aircraft sub-groups."},"complexity_factors":["Multiple conditional requirements based on aircraft serial numbers (three distinct groups with different compliance paths)","Cross-references to external technical documents (Fokker Service Bulletins F50-53-031 and F50-53-005)","Cross-reference to Dutch aviation authority directive (RLD AD(BLA) 90-089 and 89-58)","Tiered compliance deadlines tied to flight cycle accumulation rather than calendar dates","Technical aviation terminology requiring specialised knowledge (torsion box, fatigue cycles, service bulletins)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Fokker F50 aircraft (S/N 20103–20152) to inspect and strengthen the forward passenger door frame connection to the upper torsion box after fatigue tests found early cracking. An initial inspection is mandatory before any repair.\n\nMost affected aircraft must receive the additional reinforcement by 20,000 flight cycles, while four aircraft with an earlier modification require a different repair by 10,000 cycles. Non‑compliance grounds the aircraft from Australian airspace."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment expands the original directive by requiring an additional reinforcement beyond the prior steel plate and by prescribing serial-number-specific inspection and repair actions with defined flight-cycle compliance limits to achieve a 45,000 flight-cycle target (see Requirement and Background)."},"complexity_factors":["Multiple serial-number cohorts with different mandated actions (Requirement paragraphs 1–3 differentiate S/N groups 20103–20152, 20103 & 20108–20152, and 20104–20107).","Several referenced Service Bulletins and parts: Fokker SB F50-53-031 (Parts 1–3) and SB F50-53-005 (Requirement).","Staggered compliance timings and triggers (Compliance table: 'prior to accomplishing paragraphs 2 or 3', 'prior to accumulating 20,000 flight cycles', 'prior to accumulating 10,000 flight cycles').","Technical basis and revision history: original AD installed a steel reinforcement plate; subsequent fatigue tests required an additional reinforcement to reach 45,000 flight cycles (Background).","Cross-references to earlier RLD ADs increase traceability needs for operators (Notes referencing RLD AD(BLA) 90-089 and 89-58)."],"plain_english_summary":"This Airworthiness Directive mandates inspections and the installation of additional reinforcement at the forward passenger door frame–to–torsion-box connection on specified Fokker F50 serial numbers. It follows fatigue tests that found cracking; the amendment requires added reinforcement (beyond a prior steel plate) and sets serial-number-specific inspections and repair deadlines intended to give the area a crack-free life of 45,000 flight cycles."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection","history":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection/history","analysis":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection/analysis","conflicts":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection/conflicts","importantCases":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection/important-cases","documents":"/api/acts/ad-f50-26-amdt-1-forward-passenger-door-frame-to-torsion-box-connection/documents"}}