{"id":"F2006B09888","name":"AD/F50/6 - Control Cables in Accessory Compartment","slug":"ad-f50-6-control-cables-in-accessory-compartment","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55026,"registerId":"commonwealth-F2006B09888-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/6 - Control Cables in Accessory Compartment","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/F50/6 Control Cables in Accessory Compartment 3/89\n\nDM\n\n \n\nApplicability: F27-050 S/Nos 20103 to 20108 and 20110 to 20138. Requirement:  Action in accordance with Fokker SB F50-27-010.\n\nNote: RLD AD 88-84 refers.\n\n \n\nCompliance: Prior to 31 March 1989.\n\n \n\nBackground: Freezing of cable systems has occurred at high altitude. Rain, high humidity and low OAT were factors. Installation of a cover is to prevent moisture from falling onto the cables pulleys etc.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive addressing a specific technical defect in specific aircraft. It has not expanded beyond its original purpose of mandating a physical modification to prevent cable freezing."},"complexity_factors":["Very short document (under 200 words)","Only one substantive requirement (comply with referenced service bulletin)","Single applicability criterion (specific serial number range)","Single compliance deadline with no conditional extensions","No defined terms section","No nested exceptions or conditional logic","Cross-references only to external technical document (Fokker SB) and related Dutch aviation authority directive"],"plain_english_summary":"**What this is:** 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:** It requires owners or operators of certain Fokker F50 aeroplanes to install protective covers over control cables in the accessory compartment. This prevents moisture (from rain or humidity) from freezing on the cables at high altitude, which could jam the flight controls.\n\n**Who it affects:** Operators of Fokker F50 aircraft with serial numbers 20103–20108 and 20110–20138.\n\n**What must be done:** Follow the instructions in Fokker Service Bulletin F50-27-010 (a technical notice from the manufacturer) to install the protective cover.\n\n**When:** Before 31 March 1989.\n\n**Why it matters:** Frozen control cables can prevent pilots from steering the aircraft properly — a serious safety risk. This directive fixes a known problem where moisture was freezing on cables during high-altitude flight in cold, humid conditions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD applies only to the serial-numbered aircraft listed (Applicability) and requires a specified corrective action per the manufacturer service bulletin (Requirement) to be completed by the stated date (Compliance). The text does not indicate any change to that original applicability or requirement."},"complexity_factors":["Narrow and explicit applicability limited to specific serial numbers (Applicability)","Substantive technical steps delegated to an external manufacturer service bulletin rather than contained in the AD text (Requirement)","Fixed compliance deadline which creates scheduling and potential downtime costs for operators (Compliance)","Cross-reference to another airworthiness directive (RLD AD 88-84) adds contextual linkage (Note)","Technical factual causation (freezing due to moisture and low OAT) requires maintenance/engineering work to mitigate (Background)"],"plain_english_summary":"This airworthiness directive requires owners/operators of specified Fokker F50 serial numbers to fit a moisture‑preventing protective cover in the accessory compartment, using Fokker Service Bulletin F50‑27‑010, to reduce control‑cable freezing caused by moisture and low temperatures. Compliance (at the operator’s expense) was mandatory by 31 March 1989."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment","history":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment/history","analysis":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment/analysis","conflicts":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment/conflicts","importantCases":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment/important-cases","documents":"/api/acts/ad-f50-6-control-cables-in-accessory-compartment/documents"}}