{"id":"F2008L02659","name":"AD/F100/90 - Electrical Power - AC Contactors","slug":"ad-f100-90-electrical-power-ac-contactors","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74696,"registerId":"commonwealth-F2008L02659-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F100 (F28 Mk 100) Series Aeroplan","sectionType":"division","heading":"Fokker F100 (F28 Mk 100) Series Aeroplanes","content":"### Fokker F100 (F28 Mk 100) Series Aeroplanes\n\n| AD/F100/90 | Electrical Power - AC Contactors | 8/2008 |\n| ---------- | -------------------------------- | ------ |\n\n| Applicability: | F28 Mark 0100 aircraft, all serial numbers, unless modified in service in accordance with Fokker Service Bulletin SBF100-24-037 dated 2 October 2003 or later revision approved by the European Aviation Safety Agency (EASA). |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Remove the standard nuts and lock washers from electrical power contactors part number (P/N) SG02206, install new self-locking nuts and perform the applicable tests on the AC Bus Transfer System in accordance with the Accomplishment Instructions of Fokker Services SBF100-24-041 dated 29 January 2008 or later revision approved by the EASA. |\n| | Note 1: The replacement of contactors P/N SG02206 with improved versions in accordance with SBF100-24-037 or later revision approved by the EASA is acceptable as an alternate method of compliance for Requirement 1 provided that the replacement is accomplished within 36 months after the effective date of this Directive. |\n| | 2. Contactors P/N SG02206 may not be installed on any aircraft as a replacement part, unless it has been modified in accordance with Goodrich Power Systems SB SG02206-24-01 dated 4 March 2008 or later revision approved by the EASA. |\n| | Note 2: EASA AD 2008-0091 refers. |\n| Compliance: | For Requirement 1 - Within 36 calendar months after the effective date of this Directive. |\n| | For Requirement 2 - After 31 May 2011. |\n| | This Airworthiness Directive becomes effective on 31 July 2008. |\n| Background: | Several incidents have been reported where an electrical burning smell was noted in the cockpit, originating from the Electrical Power Centre.Troubleshooting revealed a partly molten terminal, which normally attaches a wire or bus bar to a stud of an Electrical Power Contactor, P/N SG02206. Furthermore, heat damage to the contactor stud itself was found. Material investigation revealed that the terminal, which was attached to the stud, was not properly torque tightened when the incident occurred. |\n\n| | Loss of torque is considered to have occurred during operation, for reasons not fully understood. Further loosening may have taken place in-service under influence of vibration. As a result, poor contact caused electrical arcing during which extremely high temperatures were developed, leading to partial melting of the terminal.Investigation of some other burned contactors revealed evidence (flat spring lock washer) of a fully torqued terminal/stud connection when the overheating occurred. The exact cause for the increase in temperature in the contactor and the terminal/stud could not be determined. However, it could not be excluded that an increase of the temperature inside the contactor could lead to reduction of the reliability of the contactor stud/terminal connection due to loss of lock washer tension. The affected Electrical Power Contactor is used on several locations in the electrical power system, i.e. Generator Line Contactor (GLC), Bus Tie Contactor (BTC), Auxiliary Power Contactor (APC) and External Power Contactor (EPC).This condition, if not corrected, could lead to further cases of overheating of terminals and studs of Electrical Power Contactors P/N SG02206, possibly resulting in the loss of electrical power systems, electrical arcing and fire/smoke in the cockpit. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n13 June 2008","sortOrder":0},{"sectionNumber":"AD/F100/90","sectionType":"part","heading":"AD/F100/90","content":"## AD/F100/90","sortOrder":1},{"sectionNumber":"Electrical Power - AC Contactors","sectionType":"part","heading":"Electrical Power - AC Contactors","content":"## Electrical Power - AC Contactors","sortOrder":2},{"sectionNumber":"8/2008","sectionType":"part","heading":"8/2008","content":"## 8/2008","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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Scope is limited to F28 Mark 0100 aircraft that still have contactors P/N SG02206 and to actions addressing those contactors (replacement of fasteners and testing; prohibition on installing unmodified SG02206). The Directive excludes aircraft already modified by the referenced Fokker service bulletin and permits an alternate compliance path via an approved replacement—so it narrows application where prior modification exists but does not expand beyond the fleet/part identified (Applicability; Note 1; Requirement 2)."},"complexity_factors":["Parts‑specific measures: targets a single part number (P/N SG02206) requiring physical hardware change","Two distinct obligations with separate deadlines (replace & test within 36 months; installation prohibition after 31 May 2011) (Requirement 1; Requirement 2; Compliance)","Alternate methods of compliance allowed via a different Fokker service bulletin if accomplished within 36 months (Note 1)","Reliance on external approvals: actions and revisions must be approved by the European Aviation Safety Agency (EASA) (Applicability; Requirement notes)","Operational testing requirement: AC Bus Transfer System tests per Fokker Services SBF100-24-041 introduce procedural labour and verification burden (Requirement 1)","Cross‑references to multiple service bulletins and a Goodrich service bulletin for modification of the part increase document tracking and approval complexity","Safety analysis background identifies uncertain failure mode (loss of torque/lock washer tension) which drives preventative hardware change and suppression of re‑installation (Background)","Applicability carve‑out for aircraft already modified in service requires fleet record checks and possible differential treatment of aircraft"],"plain_english_summary":"This Airworthiness Directive directs operators of Fokker F100 (F28 Mk 100) aeroplanes that retain electrical power contactors P/N SG02206 to fit self‑locking nuts (replacing standard nuts/lock washers), test the AC bus transfer system, and thereafter not install unmodified SG02206 contactors unless modified as specified. It applies to all serial numbers unless already modified by the cited Fokker service bulletin, and sets firm compliance deadlines for the hardware change, testing and the parts‑installation prohibition (Requirement 1–2; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific defective part (P/N SG02206) in a specific aircraft type. The alternative compliance method (replacing rather than modifying contactors) and the parts installation prohibition are natural extensions of the core safety purpose rather than scope creep."},"complexity_factors":["Single, specific aircraft type (Fokker F100) with clear serial number applicability","Only 2 main requirements with straightforward compliance timelines","References to external technical documents (Fokker and Goodrich service bulletins) but these are standard in aviation maintenance","One alternative method of compliance explicitly stated (Note 1)","Limited defined terms — only standard aviation abbreviations (P/N, EASA, GLC, BTC, APC, EPC)","No nested conditional logic or cross-referencing between multiple legislative instruments","Clear cause-and-effect background explanation"],"plain_english_summary":"This AD mandates corrective action on AC contactors (P/N SG02206) in Fokker F100 aircraft after reports of overheating, arcing and burning smells from loose connections that risk smoke, fire or total electrical failure. Owners/operators not previously modified must, within 36 months, either fit self‑locking nuts and test or replace the contactors with improved units; unmodified contactors are prohibited as spares after May 2011."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-90-electrical-power-ac-contactors","history":"/api/acts/ad-f100-90-electrical-power-ac-contactors/history","analysis":"/api/acts/ad-f100-90-electrical-power-ac-contactors/analysis","conflicts":"/api/acts/ad-f100-90-electrical-power-ac-contactors/conflicts","importantCases":"/api/acts/ad-f100-90-electrical-power-ac-contactors/important-cases","documents":"/api/acts/ad-f100-90-electrical-power-ac-contactors/documents"}}