{"id":"F2006B09881","name":"AD/F50/53 - Fuselage Skin Above Forward Passenger Door","slug":"ad-f50-53-fuselage-skin-above-forward-passenger-door","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55008,"registerId":"commonwealth-F2006B09881-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/53 - Fuselage Skin Above Forward Passenger Door","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n \n\nAD/F50/53 Fuselage Skin Above Forward Passenger Door 4/92\n\nApplicability: Serial numbers 20103 - 20108 inclusive, 20110 - 20149 inclusive and 20151 - 20155 inclusive.\n\n \n\nRequirement: Modify in accordance with Fokker SB F50-53-032 dated 23 July 1990.\n\n \n\nNote: RLD AD (BLA) 90-090 refers.\n\n \n\nCompliance: Prior to accumulating 15 000 flight cycles.\n\n \n\nBackground: During full scale fatigue tests, cracks were found in the skin above the passenger door at frame STA.3670. To increase the fatigue life of the fuselage in this area to more than 90 000 flight cycles install a reinforcement plate.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope remains targeted to a specific set of Fokker F50 serial numbers and a specific fuselage location. The instruction is to perform a single retrofit (install a reinforcement plate) per the cited service bulletin before 15,000 flight cycles to address cracking discovered in fatigue tests. There is no indication in the text that the scope has been broadened beyond that original technical fix. (Applicability, Requirement, Compliance, Background)"},"complexity_factors":["Technical nature of the required modification (requires following a specific service bulletin and installation of a reinforcement plate). (Requirement)","Serial‑number specific applicability limits the population but requires accurate fleet identification and record checks. (Applicability)","Compliance trigger based on flight cycles requires reliable flight‑cycle tracking systems. (Compliance)","Dependency on obtaining the referenced service bulletin and any parts called up in it (external document dependency). (Requirement)","Operational scheduling and potential aircraft downtime while modification is performed (logistical complexity). (Compliance)","Regulatory stickiness: AD is prescriptive with no alternative method stated, limiting flexibility for operators. (Requirement, Compliance)"],"plain_english_summary":"This directive mandates installing a reinforcement plate on the fuselage skin above the forward passenger door of specific Fokker F50 (F27 Mk 50) aircraft (listed serial numbers) per Fokker Service Bulletin F50‑53‑032, to be done before each affected aeroplane reaches 15,000 flight cycles. Owners/operators must fund and schedule the work to prevent fatigue cracking and extend the door‑area life (claimed >90,000 cycles); non‑compliance renders the aircraft non‑conforming."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural fatigue issue identified during testing. It has not expanded beyond its original purpose of mandating a reinforcement modification for identified aircraft."},"complexity_factors":["Single, specific modification requirement with clear reference to manufacturer service bulletin","Narrow applicability limited to specific serial number ranges","Simple compliance deadline (flight cycle threshold)","No nested exceptions, conditional logic, or extensive cross-referencing","Minimal defined terms (only standard aviation terminology like 'flight cycles' and 'STA.3670' which is a frame station reference)","Short document length (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nRequires owners/operators of certain Fokker F50 aeroplanes to install a reinforcement plate on the fuselage skin above the forward passenger door. This modification prevents cracks from developing in that area.\n\n**Who it affects:**\nOperators of Fokker F50 aircraft with specific serial numbers: 20103–20108, 20110–20149, and 20151–20155.\n\n**Why it matters:**\nDuring fatigue testing, engineers discovered cracks forming in the fuselage skin near the passenger door after repeated pressurisation cycles. Without this fix, the structural integrity of the aircraft could be compromised over time. The reinforcement extends the aircraft's safe service life beyond 90,000 flight cycles.\n\n**Key requirements:**\n- **What to do:** Install a reinforcement plate following Fokker Service Bulletin F50-53-032 (dated 23 July 1990)\n- **When to do it:** Before the aircraft reaches 15,000 flight cycles\n- **Reference:** This aligns with a Dutch aviation safety directive (RLD AD 90-090)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door","history":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door/history","analysis":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door/analysis","conflicts":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door/conflicts","importantCases":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door/important-cases","documents":"/api/acts/ad-f50-53-fuselage-skin-above-forward-passenger-door/documents"}}