{"id":"F2006B09917","name":"AD/F50/87 - Pitot & Static Port Heating Wiring","slug":"ad-f50-87-pitot-static-port-heating-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55127,"registerId":"commonwealth-F2006B09917-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nFokker F50 (F27 Mk 50) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/F50/87 Pitot & Static Port Heating Wi","sectionType":"part","heading":"AD/F50/87 Pitot & Static Port Heating Wiring 8/2004","content":"# AD/F50/87 Pitot & Static Port Heating Wiring 8/2004\n\nApplicability: Model F.27 Mk.050, Mk.0502 and Mk.604 aeroplanes, all serial numbers. Requirement: Modify the wiring of the pitot and static port heating in accordance with Section 2 \\-\n\nAccomplishment Instructions of Fokker Service Bulletin F50-30-028 dated 4 March 2004 or Revision 1 dated 26 April 2004.\n\nNote 1: Fokker Services Manual Change Notification \\- Maintenance Documentation (MCNM) F50-048 dated 4 March 2004 also pertains to this subject.\n\nNote 2: CAA-NL AD 2004-038 (A) Corr refers.\n\nCompliance: Within the next 36 months after the effective date of this Directive. This Airworthiness Directive becomes effective on 5 August 2004.\n\nBackground: The Netherlands CAA has received a report from a Fokker 50 operator of intermittent events where, during autopilot engagement in IAS-Mode decent, the aircraft suddenly pitched nose down resulting in an overspeed situation. Investigation revealed a failed heater element in the left hand upper pitot-static tube, which was not detected by the current sensor, and as a result no “PITOT HEAT” alert was generated. In a single air data computer (ADC) configuration only pressure from the left hand upper pitot head is used. In this instance freezing of the pitot head resulted in erroneous ADC airspeed output","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific safety defect identified through incident investigation. The scope remains tightly focused on the wiring modification required to prevent undetected pitot heater failures."},"complexity_factors":["Single, specific technical requirement referencing an external manufacturer document","No defined terms section — uses standard aviation terminology","Simple applicability (three specific aircraft models, all serial numbers)","Single compliance deadline (36 months from effective date)","No nested exceptions or conditional logic","Background narrative is straightforward incident description"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires owners/operators of certain Fokker F50 aircraft (affecting Fokker F.27 Mk.050, Mk.0502 and Mk.604 models) to modify the electrical wiring for pitot and static port heaters per Fokker Service Bulletin F50‑30‑028. The change, to be done within 36 months of 5 August 2004, prevents undetected heater failure that can give false airspeed data and provoke dangerous autopilot responses."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive enforces a corrective wiring modification for the specified Fokker F.27/F50 models to address a reported unsafe condition. It does not expand or narrow the set of affected models beyond the stated applicability and aligns with the referenced service and authority documents."},"complexity_factors":["Single, safety-critical electrical modification to pitot/static heating wiring (requires qualified maintenance personnel and access to pitot/static tubes).","Mandatory incorporation of external technical instructions (Fokker Service Bulletin F50-30-028, MCNM F50-048) — work depends on those documents' detail and availability.","Applicability to multiple airframe variants and all serial numbers increases fleet-wide coordination.","Fixed compliance window (36 months) imposes scheduling and possible aircraft downtime costs on operators.","Cross-reference to a foreign authority AD (CAA-NL AD 2004-038 (A) Corr) requires alignment with prior investigations and corrective action."],"plain_english_summary":"This Airworthiness Directive requires operators of Fokker F.27 Mk.050, Mk.0502 and Mk.604 aeroplanes to modify pitot and static-port heating wiring in accordance with Fokker Service Bulletin F50-30-028, with compliance required within 36 months of 5 August 2004.\n\nIt responds to a reported incident where a failed pitot heater went undetected, producing erroneous airspeed from the air data computer and an uncommanded nose-down/overspeed during IAS-mode autopilot; operators and maintainers bear the cost and scheduling burden of the mandated wiring change."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring","history":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring/history","analysis":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring/analysis","conflicts":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring/conflicts","importantCases":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring/important-cases","documents":"/api/acts/ad-f50-87-pitot-static-port-heating-wiring/documents"}}