{"id":"F2008L01212","name":"AD/F50/59 Amdt 1 - Engine Electronic Control System","slug":"ad-f50-59-amdt-1-engine-electronic-control-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":73450,"registerId":"commonwealth-F2008L01212-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F50 (F27 Mk 50) Series Aeroplanes","sectionType":"division","heading":"Fokker F50 (F27 Mk 50) Series Aeroplanes","content":"### Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n| AD/F50/59 Amdt 1 | Engine Electronic Control System | 5/2008 |\n| ---------------- | -------------------------------- | ------ |\n\n| Applicability: | F27 Mk 050 aircraft Serial Numbers 20103 to 20242 inclusive.                                                                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | If not previously accomplished, action in accordance with Fokker Service Bulletin F50-73-013 dated 6 July 1992 or later revision approved by the Rijksluchtvaartdienst (RLD) of The Netherlands or its successor. Fokker Component Service Bulletin F7941-006-73-03 also refers.                                                                                                                                                                             |\n|                | Note: RLD BLA 92-086 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Compliance:    | No later than 8 June 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Amendment becomes effective on 8 May 2008.                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background:    | 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.                                                                                                  |\n|                | The original issue of this Directive required 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). This Amendment continues that requirement and corrects a typographical error in the affected serial number range. At the same time the Amendment allows compliance with later approved revisions of the Fokker service bulletin. |\n|                | The original issue of this Directive became effective on 4 February 1993.                                                                                                                                                                                                                                                                                                                                                                                    |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n27 March 2008","sortOrder":0},{"sectionNumber":"AD/F50/59 Amdt 1","sectionType":"part","heading":"AD/F50/59 Amdt 1","content":"## AD/F50/59 Amdt 1","sortOrder":1},{"sectionNumber":"Engine Electronic Control System","sectionType":"part","heading":"Engine Electronic Control System","content":"## Engine Electronic Control System","sortOrder":2},{"sectionNumber":"5/2008","sectionType":"part","heading":"5/2008","content":"## 5/2008","sortOrder":3}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the 1993 directive. It corrects a typographical error in the serial number range and updates the compliance reference to allow later approved revisions of the service bulletin, but does not expand the safety issue being addressed or the aircraft covered."},"complexity_factors":["Single, specific technical requirement with clear reference to manufacturer service bulletin","Limited applicability (specific aircraft serial number range only)","Simple conditional logic (if not previously accomplished, then comply)","Minimal cross-referencing (only references one service bulletin and one Dutch aviation authority document)","Short document (approximately 250 words of substantive content)","No nested exceptions or complex defined terms"],"plain_english_summary":"This AD mandates modification or replacement of the engine electronic control system on Fokker F50 (F27 Mk 50) aircraft, serials 20103–20242, so a control failure below 17° power lever automatically reverts to manual instead of remaining “stuck.” It’s required per Fokker Service Bulletin July 1992 (or later approved revisions) to prevent loss of go‑around thrust during landing. Work deadline: 8 June 2008; this amendment corrects a typographical error and allows later approved SB versions."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The amendment does not materially change the scope of the original directive. It continues the original requirement to fit a modified EEC that automatically selects manual mode below the 17 degree power-lever angle after an EEC failure. The amendment only (a) corrects a typographical error in the serial-number range and (b) explicitly allows compliance using later revisions of the referenced Fokker service bulletin provided those revisions are approved by the RLD. These are corrective and procedural adjustments rather than an expansion of the directive's substantive scope."},"complexity_factors":["Short, single-subject directive focused on one aircraft system (EEC)","Single mandatory action: comply with a specified service bulletin (or later RLD-approved revision)","One defined applicability range (serial numbers 20103–20242)","One explicit compliance date and an effective date","Cross-references to two service bulletins and an RLD bulletin (minor cross-referencing)","Typographical correction of serial-number range noted (minor amendment detail)"],"plain_english_summary":"**What this directive does (in simple terms)**\n\n- **Who it applies to:** Owners/operators of Fokker F50 (F27 Mk 050) aeroplanes with serial numbers 20103 to 20242 inclusive (see \"Applicability\").\n\n- **Required action:** If the modification has not already been done, the aircraft must be modified in accordance with Fokker Service Bulletin F50-73-013 dated 6 July 1992, or a later revision of that service bulletin that has been approved by the Rijksluchtvaartdienst (RLD) of The Netherlands (or its successor). A related Fokker Component Service Bulletin (F7941-006-73-03) is also referenced (see \"Requirement\").\n\n- **What the modification changes mechanically:** The modification replaces the engine electronic control (EEC) with a version that will automatically switch the engine control to manual mode when an EEC failure happens below the 17 degree power-lever angle (the approach power setting). Before the modification, some EEC failures left the affected engine fuel control stuck at the last power setting (no automatic response to moving the power lever forward) unless the pilot selected manual mode themselves (see \"Background\").\n\n- **When it must be done:** The work must be completed no later than 8 June 2008. The amendment itself took effect on 8 May 2008 (see \"Compliance\").\n\n- **Why it matters (official rationale and practical effect):** The stated reason is to prevent a situation where, after an EEC failure, the engine does not respond to normal power-lever movements unless the pilot manually selects manual mode. The modification makes the system automatically go to manual mode in the identified failure condition below the 17 degree setting so that power response is available without the pilot first switching modes (see \"Background\").\n\n**Who pays, who decides, and what changes in behaviour**\n\n- **Who pays:** Aircraft owners/operators pay for the parts, labour and aircraft downtime to carry out the modification. Maintenance organisations will perform the work under the service bulletin instructions.\n\n- **Who decides/authorises compliance:** The Civil Aviation Safety Authority (CASA) delegate issued the directive; compliance is achieved by carrying out the work specified in the Fokker service bulletin or later RLD-approved revision. The RLD (or successor) must approve any later revision of the service bulletin for it to be acceptable under this directive.\n\n- **Behavioural change required:** Maintenance teams must replace or modify the EEC per the service bulletin. Pilots will no longer need to select manual mode in the specific failure scenario below 17 degrees because the modified EEC will select manual mode automatically.\n\n**Costs, trade-offs and implementation notes**\n\n- **Concentrated costs:** The direct and concentrated cost falls on the operators of the affected serial-numbered aircraft (parts, labour, downtime).\n\n- **Dependencies/risks for operators:** Compliance depends on availability of the modified EEC parts or kits, access to approved maintenance facilities, and timely approval of any later service-bulletin revisions by the RLD. If parts or approved revisions are not available, operators may face scheduling delays or an inability to comply by the stated date.\n\n- **Regulatory mechanism and paperwork:** Compliance is demonstrated by completing the work in accordance with the referenced service bulletin(s), and maintenance records must show that the required modification was accomplished. No alternative compliance route is specified in the text; only later RLD-approved revisions of the same service bulletin are allowed.\n\n**Other notes drawn from the amendment text**\n\n- The amendment corrects a typographical error in the serial-number range from the original directive and explicitly permits compliance using later revisions of the Fokker service bulletin if those revisions are approved by the RLD (see \"Background\").\n\n- Related documents referenced: Fokker Service Bulletin F50-73-013 (6 July 1992), Fokker Component Service Bulletin F7941-006-73-03, and RLD BLA 92-086.\n\n(References: Applicability, Requirement, Compliance and Background sections of the directive.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system","history":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system/history","analysis":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system/analysis","conflicts":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system/conflicts","importantCases":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system/important-cases","documents":"/api/acts/ad-f50-59-amdt-1-engine-electronic-control-system/documents"}}