{"id":"F2008L00786","name":"AD/CF34/15 - Fuel Metering Unit Wiring","slug":"ad-cf34-15-fuel-metering-unit-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":72866,"registerId":"commonwealth-F2008L00786-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"General Electric Turbine Engines - CF34 ","sectionType":"division","heading":"General Electric Turbine Engines - CF34 Series","content":"### General Electric Turbine Engines - CF34 Series\n\n| AD/CF34/15 | Fuel Metering Unit Wiring | 4/2008 |\n| ---------- | ------------------------- | ------ |\n\n| Applicability: | CF34 series engines as follows: |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | a. CF34-8C1/-8C5/-8C5B1/-8E5/- 8E5A1 turbofan engines, with General Electric (GE) fuel metering unit (FMU) part number (P/N) 4120T01P02, serial numbers (S/N) WYG89156 through WYGB4222, and Woodward Governor FMU Vendor Identification Number (VIN) 8061-926, S/Ns 11954378 through 15140071. |\n| | b. CF34-10E series turbofan engines, with GE FMU P/N 2043M10P05, S/Ns WYGA3251 through WYGB4085, and Woodward Governor FMU VIN 8063-884, S/Ns 13335695 through 15028283. |\n| | Note 1: These engines are know to be installed on, but not limited to, aeroplanes as follows: |\n| | a. CF34-8C1/-8C5/-8C5B1 turbofan engines - Bombardier Inc. Model CL-600-2C10 (CRJ-700 & -701) and CL-600-2D24/-2D15 (CRJ-900) model aeroplanes. |\n| | b. CF34-8E5/-8E5A1 turbofan engines - Embraer ERJ 170-100/-200 series aeroplanes. |\n| | c. CF34-10E series turbofan engines - Embraer ERJ 190-100/-200 series aeroplanes. |\n| Requirement: | 1. Unless previously accomplished , perform a onetime test of the FMU for a miswired (reversed polarity) condition of the input wires to the overspeed solenoid using paragraph 3A of the Accomplishment Instructions of following GE Service Bulletins (SB), as applicable: |\n| | a. SB CF34-8C-AL S/B 73-0030 Revision 3, dated 1 November 2007, |\n| | b. SB CF34-8E-AL S/B 73-0015, Revision 3, dated 1 November 2007, or |\n| | c. SB . CF34-10E S/B 72-0067, Revision 2, dated 28 August 2007. |\n| | 2. If the FMU fails the test, remove the FMU. |\n\n| | Actions accomplished prior to the effective date of this Directive in accordance with the following SBs are acceptable for compliance with this Directive. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | a. SB CF34-8C-AL S/B 73-0030, original issue dated 25 May 2007, Revision 1, dated 19 July 2007 or Revision 2, dated 28 August 2007; |\n| | b. SB CF34-8E-AL S/B 73-0015, original issue, dated 1 June 2007, Revision 1, dated 19 July 2007, or Revision 2, dated 28 August 2007; or |\n| | c. SB . CF34-10E S/B 72-0067, original issue dated 7 June 2007 or Revision 1, dated 26 July 2007. |\n| | Later revisions of the SBs listed in Requirement 1, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2008-05-01, are considered acceptable for compliance with the equivalent requirements of this Directive. |\n| | Note 2: FAA AD 2008-05-01 Amdt 39-15395 refers. |\n| Compliance: | For Requirement 1 - Within 2,200 hours time in service after the effective date of this Directive, but not to exceed 24 months after the effective date of this Directive. |\n| | For Requirement 2 - Before further operation of the engine. |\n| | This Airworthiness Directive becomes effective on 10 April 2008. |\n| Background: | The FAA has advised of the discovery of miswired FMU overspeed solenoids in the field which could prevent the engine from failing to shutdown during an overspeed and which may lead to uncontained engine failure. This Directive requires a one time test of the FMU for a miswired (reversed polarity) condition of the input wires to the overspeed solenoid. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n29 February 2008","sortOrder":0},{"sectionNumber":"AD/CF34/15","sectionType":"part","heading":"AD/CF34/15","content":"## AD/CF34/15","sortOrder":1},{"sectionNumber":"Fuel Metering Unit Wiring","sectionType":"part","heading":"Fuel Metering Unit Wiring","content":"## Fuel Metering Unit Wiring","sortOrder":2},{"sectionNumber":"4/2008","sectionType":"part","heading":"4/2008","content":"## 4/2008","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific manufacturing defect. The scope remains tightly focused on the identified wiring issue in specific FMU serial number ranges. No scope creep is evident; the directive does exactly what its title suggests — addresses fuel metering unit wiring defects."},"complexity_factors":["Highly specific applicability criteria requiring cross-referencing of multiple part numbers, serial number ranges, and vendor identification numbers","Three separate service bulletins referenced with specific revision dates and acceptable alternative revisions","Conditional compliance: different deadlines for testing versus removal actions","Cross-reference to US FAA AD 2008-05-01 and AMOC (Alternate Method of Compliance) provisions","Technical aviation terminology requiring domain knowledge (FMU, overspeed solenoid, turbofan, time in service)"],"plain_english_summary":"Australia’s CASA has issued a mandatory AD for certain General Electric CF34-8C/8E/10E engines used on regional jets (CRJ‑700/900, E‑Jet families) after some Fuel Metering Units (FMUs) were built with reversed overspeed‑solenoid wiring. Operators of affected engines must perform a one‑time polarity test within 2,200 flight hours or 24 months and remove/replace any FMU that fails before the next flight. The rule prevents engines that can’t be shut down during an overspeed event."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Scope is limited to the specified CF34 engine models and precise FMU part/serial ranges listed in the Applicability. The Directive accepts prior accomplishment under listed service bulletins and FAA‑approved later SB revisions as alternate compliance, but does not otherwise broaden or narrow the engine/part scope (Applicability; Actions accomplished; Note 2)."},"complexity_factors":["Technical specificity: test targets reversed‑polarity wiring to the FMU overspeed solenoid (Requirement 1).","Narrow applicability: detailed engine models, FMU part numbers and serial‑number ranges are listed, requiring careful part tracking (Applicability).","Operational constraint: two‑tier compliance timing — within 2,200 flight hours or 24 months for the test; immediate removal required if failure (Compliance; Requirement 2).","Multiple referenced documents: compliance depends on following particular GE Service Bulletins and allows only FAA‑approved later revisions as AMOC (Actions accomplished; Note 2).","Enforcement consequence: removal before further operation creates immediate operational disruption and potential replacement costs (Requirement 2; Compliance)."],"plain_english_summary":"Requires operators of specified GE CF34 turbofan engines to perform a one‑time test of the fuel metering unit (FMU) to detect reversed‑polarity wiring to the overspeed solenoid; FMUs that fail the test must be removed before further operation. Affects aircraft operators, maintenance organisations and FMU suppliers by imposing an inspection, possible part removal/replacement, and associated downtime and costs. The rule references GE service bulletins and FAA approval routes for acceptable compliance methods."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring","history":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring/history","analysis":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring/analysis","conflicts":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring/conflicts","importantCases":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring/important-cases","documents":"/api/acts/ad-cf34-15-fuel-metering-unit-wiring/documents"}}