{"id":"F2006B09887","name":"AD/F50/59 - Engine Electronic Control System","slug":"ad-f50-59-engine-electronic-control-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55024,"registerId":"commonwealth-F2006B09887-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/59 - Engine Electronic Control System","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/F50/59 Engine Electronic Control System 2/93\n\nApplicability: F27 Mk 050 aircraft Serial Numbers 20103 to 202427 inclusive.\n\nRequirement: Action in accordance with Fokker Service Bulletin F50-73-013 dated 6 July 1992.\n\nFokker Component Service Bulletin F7941-006-73-03 also refers.\n\nNote: RLD Airworthiness Directive BLA 92-086 dated 18 September 1992 refers.\n\nCompliance: Prior to 4 February 1994.\n\nBackground: The engine electronic control (EEC) is designed in such a way that if an EEC failure occurs the affected engine fuel control will remain at the last selected power setting. This means that there is no power response from the affected engine when the power levers are moved forward (fail-fixed feature) unless manual mode is selected by the pilot. This Directive requires that the EEC be replaced with a modified version which automatically selects manual mode if an EEC failure occurs below the 17 degrees power lever angle (approach position).","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1802},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow, technical scope—a targeted safety modification addressing a specific failure mode in a single aircraft system. It does not expand beyond the original intent of remedying the EEC fail-fixed hazard during approach phases."},"complexity_factors":["Technical aviation terminology requiring domain knowledge (EEC, fail-fixed feature, power lever angle)","External cross-references to manufacturer service bulletins (Fokker Service Bulletin F50-73-013)","Precise mechanical measurement thresholds (17 degrees power lever angle)","Specific serial number applicability ranges rather than generic aircraft categories"],"plain_english_summary":"This mandatory Airworthiness Directive requires operators of Fokker F50 aircraft (s/n 20103–202427) to replace the Engine Electronic Control (EEC) because the original “fail‑fixed” design could lock an engine at its last power setting, preventing throttle response and jeopardizing go‑around capability on approach. The retrofit EEC will auto‑select manual backup on failure. Compliance was required by 4 February 1994 per Fokker Service Bulletin F50‑73‑013."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-59-engine-electronic-control-system","history":"/api/acts/ad-f50-59-engine-electronic-control-system/history","analysis":"/api/acts/ad-f50-59-engine-electronic-control-system/analysis","conflicts":"/api/acts/ad-f50-59-engine-electronic-control-system/conflicts","importantCases":"/api/acts/ad-f50-59-engine-electronic-control-system/important-cases","documents":"/api/acts/ad-f50-59-engine-electronic-control-system/documents"}}