{"id":"F2006B09840","name":"AD/F50/15 - Engine Air Intake Seal","slug":"ad-f50-15-engine-air-intake-seal","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54882,"registerId":"commonwealth-F2006B09840-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/15 - Engine Air Intake Seal","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/F50/15 Engine Air Intake Seal 5/89 DM\n\n \n\nApplicability: Model F27 mark 050 with serial numbers: 20103 through 20108\n\n20110 through 20144\n\n \n\n20146 and 20147\n\n \n\n20150 through 20152\n\n \n\n20155 through 20161\n\n \n\nRequirement: Action in accordance with Fokker 50 Service Bulletin No. F50-30-004.\n\n \n\nNote: RLD AD BLA 89-32 refers.\n\n \n\nCompliance: Prior to 31 May 1989.\n\n \n\nBackground:  The manufacturer has determined that ice accumulating at the rear of the engine air intake and on the flexible seal, can shed into the engine and cause a momentary flame-out.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued for a specific technical defect. It has not expanded beyond its original purpose of addressing ice accumulation in engine air intakes on specific Fokker F50 aircraft."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative sections: Applicability, Requirement, Note, and Compliance","Single technical reference to external document (Fokker Service Bulletin)","No defined terms section","No conditional logic or nested exceptions","Simple date-based compliance deadline with no alternatives or extensions mentioned","Straightforward applicability limited to specific serial number ranges"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain Fokker F50 aeroplanes to carry out a specific maintenance action to fix a dangerous ice buildup problem.\n\n**Who it affects:**\nOwners and operators of Fokker F50 model aircraft with specific serial numbers (roughly 40-50 individual planes, built in the late 1980s).\n\n**The safety problem:**\nIce can accumulate at the back of the engine air intake and on a flexible seal. If this ice breaks off (\"sheds\"), it can get sucked into the engine and cause a **flame-out** — where the engine suddenly stops producing power. This is obviously very dangerous during flight.\n\n**What must be done:**\nOperators must follow the instructions in **Fokker Service Bulletin F50-30-004** (a technical notice from the manufacturer) to fix this problem.\n\n**Deadline:**\nThe work had to be completed before **31 May 1989**.\n\n**Why it matters:**\nThis directive prevents engine failures that could lead to emergency landings or crashes. Airworthiness directives are legally binding — operators cannot fly these aircraft without complying."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as supplied, sets a limited and specific scope: a defined set of Fokker F50 serial numbers must comply with the manufacturer’s service bulletin by a fixed date to address a stated ice-ingestion hazard. There is no text in the supplied instrument indicating an amendment or expansion of that scope from the original directive."},"complexity_factors":["Narrow applicability: specific aircraft identified by serial number (Applicability)","Single required action tied to an external document (Fokker 50 Service Bulletin No. F50-30-004) rather than detailed steps within the AD (Requirement)","Firm, short compliance deadline (Prior to 31 May 1989) (Compliance)","Minimal text in the AD leaves technical detail to the service bulletin, creating dependency on that external document (Requirement)","Cross-reference to another AD (RLD AD BLA 89-32) increases traceability requirements for full context (Note)"],"plain_english_summary":"This AD requires owners/operators of specified Fokker F50 (F27 Mk 50) aircraft (listed by serial number) to carry out the work in Fokker Service Bulletin F50-30-004 to mitigate ice build-up at the engine intake that can cause engine flame‑outs. Issued by the Civil Aviation Safety Authority, compliance is mandatory by 31 May 1989 and imposes downtime, parts and labour costs on the affected operators, who must rely on the manufacturer’s bulletin for technical details."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-15-engine-air-intake-seal","history":"/api/acts/ad-f50-15-engine-air-intake-seal/history","analysis":"/api/acts/ad-f50-15-engine-air-intake-seal/analysis","conflicts":"/api/acts/ad-f50-15-engine-air-intake-seal/conflicts","importantCases":"/api/acts/ad-f50-15-engine-air-intake-seal/important-cases","documents":"/api/acts/ad-f50-15-engine-air-intake-seal/documents"}}