{"id":"F2006B08452","name":"AD/CF34/4 Amdt 1 - Main Fuel Control","slug":"ad-cf34-4-amdt-1-main-fuel-control","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51077,"registerId":"commonwealth-F2006B08452-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF34/4 Amdt 1 - Main Fuel Control","content":"![](image.001.png)  \n![](image.002.png)  \nGeneral Electric Turbine Engines \\- CF34 Series\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/CF34/4 and issues the following AD under subregulation 39.1 (1) of CAR 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\nAD/CF34/4\n\nAmdt 1\n\n  \nMain Fuel Control 7/2000\n\nApplicability: General Electric CF34-1A, \\-3A, \\-3A1, \\-3A2, \\-3B and \\-3B1 series engines installed on but not limited to Bombardier, Inc. Canadair model CL-600-2A12, \\-2B16 and \\- 2B19 aircraft.\n\nRequirement: 1. If a Main Fuel Control (MFC) part numbers (P/N’s) 6078T55P02 thru P10 inclusive is installed, and the MFC has Buna-N preformed packings (O-rings), P/N’s R1307P020 and R1307P141 incorporated, do one of the following:\n\n    (a) Replace Buna-N O-rings with Viton O-rings, P/N’s M83485-1-020 (M83485/1-020) and 37B201714P130, in accordance with the Accomplishment Instructions, paragraph 3.A., of alert service bulletin (ASB) CF34AL 73-A0025, dated July 7, 1999 or ASB CF34BJ 73-A0040, dated July 7, 1999, OR\n\n    (b) For all CF34-3A1 engines with serial numbers (SN’s) 807001 and up, CF34- 3B engines with SN’s 872001 and up, and CF34-3B1 engines with SN’s 872001 and up, with MFC P/Ns 6078T55P02 thru P10 inclusive installed, install a MFC with a flange vent groove that conforms to the requirements of CF34 ASB CF34AL S/B 73-0026 dated August 12, 1999, or CF34BJ S/B 73- 0041, dated August 12, 1999 or Revision 1, dated November 1, 1999.\n\n    2. For all CF34-1A, -3A, and -3A2 series engines with SN’s 350003 thru 350525, install an MFC with a flange groove that conforms to the requirements of CF34 ASB CF34BJ S/B 73-0041 dated August 12, 1999 or Revision 1 dated November 1, 1999.\n\n    3. Install a serviceable MFC with improved overspeed protection as follows:\n\n    (a) For all CF34-1A, -3A, and -3A2 series engines, install a serviceable MFC in accordance with step 2A thru step 2G of the Accomplishment Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or Revision 1, dated May 29, 1998 or Revision 2, dated March 9, 1999, or in accordance with step 3A(1) thru step 3A(7) of the Accomplishment Instructions of CF34 ASB No. CF34BJ 73-A0033, Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n    (b) For CF34-3A1, and -3B series engines installed on Canadair aircraft models CL 601 or CL 604 (Challenger aircraft), install a serviceable MFC in accordance with step 2A thru step 2G of the Accomplishment Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or Revision 1, dated May 29, 1998, or Revision 2, dated March 9, 1999 or in accordance with step 3A(1) thru step 3A(7) of the Accomplishment Instructions of CF34 ASB No. CF34BJ 73-A0033, Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 1999.\n\n    (c) For CF34-3A1 and -3B1 series engines installed on Canadair aircraft model CL 601RJ (Regional Jet aircraft), install a serviceable MFC in accordance with step 2A thru step 2G of the Accomplishment Instructions of CF34 ASB No. A73-19, Revision 1, dated February 20, 1998, or Revision 2, dated March 9, 1999 or in accordance with step 3A(1) thru step 3A(7) of the Accomplishment Instructions of CF34 ASB CF34AL 73-A0019, Revision 3, dated September 9,1999.\n\nReplacing an MFC with a serviceable MFC, constitutes terminating action for the requirements of this AD. For the purposes of this AD, a serviceable MFC is defined as any MFC that incorporates the improved overspeed protection modifications, or an MFC that has been reworked to provide the improved overspeed protection as provided by the applicable GE ASB and is not one of the following P/Ns; 6078T55P02 thru P10 inclusive, or 6047T74P07, 6047T74P09, or 6091T07P01,\n\nNote: FAA AD 99-23-26R1 refers.\n\nCompliance: 1. Unless accomplished previously, before 6 January 2000.\n\n    2. Unless accomplished previously, at the next time the engine is removed or the next time the MFC is removed.\n\n    3. Unless accomplished previously;\n\n    (a) at the next hot section inspection, or within 53 months after the effective date of this AD, whichever occurs first;\n\n    (b) at the next hot section inspection, or within 53 months after the effective date of this AD, whichever occurs first;\n\n    (c) within 4000 hours time in service (TIS) after the effective date of this AD, or within 17 months after the effective date of this AD, whichever occurs first.\n\nThis Amendment becomes effective on 13 July 2000.\n\nBackground: This AD is issued to prevent uncommanded engine accelerations, which could result in an engine overspeed, uncontained engine failure, and damage to the aircraft. The requirements of this AD supersede the requirements of AD/CF34/3 which has been cancelled. Engines in compliance with AD/CF34/3 may be affected by the requirements of this AD.\n\nThis Amendment reflects corrections to the FAA AD as detailed in FAA AD 99-23- 26R1.\n\nThe original issue of this Airworthiness Directive became effective on 22 December 1999.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 31 May 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 14 June 2000.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":7,"scope_assessment":{"changed":false,"description":"This is an amendment to an existing Airworthiness Directive (AD/CF34/4), not an expansion beyond original scope. It reflects corrections to the FAA source directive (99-23-26R1) and maintains the same core purpose: preventing uncommanded engine acceleration. The amendment does not broaden applicability to new engine models or aircraft types beyond the original CF34 series and Bombardier installations."},"complexity_factors":["Multiple overlapping compliance paths (3 main requirements with sub-options a/b/c)","Extensive cross-referencing to external technical documents (7 different GE Alert Service Bulletins with specific revision dates)","Precise part number ranges (P/N 6078T55P02 thru P10) and serial number cutoffs (e.g., SN 807001 and up)","Nested conditional logic: applicability depends on engine model, serial number, aircraft type, AND specific part numbers installed","Multiple compliance deadlines varying by requirement (calendar date, flight hours, maintenance events, or time-in-service)","Technical terminology requiring aviation engineering knowledge (MFC, Buna-N, Viton, hot section inspection, TIS)","Definition of \"serviceable MFC\" requires negative exclusion (what it is NOT) plus positive modification requirements","Amendment structure revokes previous AD and incorporates corrections from FAA AD 99-23-26R1"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of certain GE CF34 engines (CF34‑1A, ‑3A/3A1/3A2/3B/3B1) installed on Bombardier Challenger and Regional Jet models to fix a fuel‑control defect that can cause uncommanded engine acceleration and possible overspeed/engine breakup.  \n\nAffected engines must receive corrective actions—O‑ring replacement, upgraded fuel controls, or serviceable MFCs with overspeed protection—to eliminate the safety hazard and prevent catastrophic failure."},"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":7,"scope_assessment":{"changed":true,"description":"This amendment revokes the earlier AD/CF34/4 and supersedes AD/CF34/3, incorporates corrections to the FAA AD and adds or clarifies applicability, part‑number detail, serial‑number ranges, and alternative compliance methods (see Background; Requirement). Those changes materially alter which engines/serials and which corrective actions are required, and set new deadlines and terminating action definitions compared with the prior AD."},"complexity_factors":["Detailed technical specificity of parts and exclusions (multiple P/N ranges listed: e.g. 6078T55P02 thru P10; excluded P/Ns) increasing identification and procurement complexity (Requirement).","Multiple engine models and specific serial‑number ranges with different obligations (CF34-1A, -3A, -3A1, -3A2, -3B, -3B1) raising applicability complexity (Applicability; Requirement).","Alternative compliance routes: replace O‑rings OR install redesigned MFCs OR install serviceable MFC with improved overspeed protection — operators must choose and document the route (Requirement).","Cross‑references to several GE Alert Service Bulletins and FAA AD (multiple ASB numbers and revisions cited) requiring access to and conformity with external technical instructions (Requirement).","Varied compliance triggers and deadlines (before a calendar date; next engine/MFC removal; next hot section inspection; within specified TIS or months), complicating scheduling and recordkeeping (Compliance).","A defined terminating action (installation of serviceable MFC) and a precise operational definition of 'serviceable MFC' that excludes specific P/Ns, affecting maintenance decisions and spare inventory (Requirement).","Regulatory amendment history and corrections (revocation/supersession of prior ADs and reflection of FAA corrections) requiring operators to reconcile earlier compliance steps with the revised AD (Background)."],"plain_english_summary":"Requires operators of aircraft fitted with specified General Electric CF34 engine models to modify or replace Main Fuel Controls (MFCs) — either by swapping listed Buna‑N O‑rings for Viton O‑rings or by installing MFCs with a revised flange/overspeed protection — to prevent uncommanded engine accelerations (Background). The Civil Aviation Safety Authority delegate sets compliance deadlines and serial‑number applicability; operators bear the cost of parts and maintenance and meet staged inspection/removal or hour/time limits to terminate the AD (Requirement; Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control","history":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control/history","analysis":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control/analysis","conflicts":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control/conflicts","importantCases":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control/important-cases","documents":"/api/acts/ad-cf34-4-amdt-1-main-fuel-control/documents"}}