AD 99-11-08 Airworthiness Directives; General Electric Aircraft Engines CF34 Series Turbofan Engines

General Electric Aircraft Engines (GE) CF34-1A, CF34-3A, -3A1, -3A2, and CF34-3B and -3B1 series turbofan engines, installed on but not limited to Bombardier, Inc. Canadair airplane models CL-600-2A12, -2B16, and -2B19. Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To prevent uncommanded engine accelerations, which could result in an engine overspeed, uncontained engine failure, and damage to the airplane, accomplish the following: (a) For all CF34-3A1 -3B, and -3B1 engines, with main fuel control (MFC) part numbers (P/N's) 6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 6078T55P06, 6078T55P07, 6078T55P08, 6078T55P09, or 6078T55P10 installed, within 800 hours time in service (TIS), or 120 days after the effective date of this AD, whichever occurs first, install an MFC with a flange vent groove modified in accordance with the Accomplishment Instructions of GE CF34 Alert Service Bulletin (ASB) No. A73-18, Revision 1, dated September 24, 1997, or CF34 ASB No. A73-32, Revision 1, dated September 24, 1997, or Revision 2, dated May 29, 1998, as applicable. (b) Install a serviceable MFC with improved overspeed protection as follows: (1) For all CF34-1A, -3A, and -3A2 series engines, install a serviceable MFC at the next hot section inspection, or within 60 months after the effective date of this AD, whichever occurs first, in accordance with step 2A through step 2G of the Accomplishment Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or Revision 1, dated May 29, 1998. (2) For CF34-3A1, and -3B series engines installed on Canadair aircraft models CL601 or CL604 (Challenger airplanes), install a serviceable MFC at the next hot section inspection, or within 60 months after the effective date of this AD, whichever occurs first, in accordance with step 2A through step 2G of the Accomplishment Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or Revision 1, dated May 29, 1998. (3) For CF34-3A1 and -3B1 series engines installed on Canadair aircraft model CL601RJ (Regional Jet airplanes), install a serviceable MFC within 4,000 hours TIS after the effective date of this AD, or within 24 months after the effective date of this AD, whichever occurs first, in accordance with step 2A through step 2G of the Accomplishment Instructions of CF34 ASB No. A73-19, Revision 1, dated February 20, 1998. (c) For the purposes of this AD, a serviceable MFC is defined as a new 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. (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (e) Special flight permits may be issued in accordance with Sec. Sec. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. (f) The MFC replacement must be done in accordance with the following General Electric Aircraft Engines alert service bulletins: ---------------------------------------------------------------------------------------------------------------- Document No. Pages Revision Date ---------------------------------------------------------------------------------------------------------------- A73-18......................... All.................... 1..................... September 24, 1997. A73-19......................... All.................... 1..................... February 20, 1998. A73-32......................... All.................... 1..................... September 24, 1997. A73-32......................... All.................... 2..................... May 29, 1998. A73-33......................... All.................... Original.............. November 21, 1997. A73-33......................... All.................... 1..................... May 29, 1998. ---------------------------------------------------------------------------------------------------------------- [[Page 28907]] This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from GEAE Technical Publications, Attention: N. Hanna MZ340M2, 1000 Western Avenue, Lynn, MA 01910; telephone (781) 594-2906, fax (781) 594-0600. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC. (g) This amendment becomes effective on July 27, 1999. Issued in Burlington, Massachusetts, on May 17, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 99-13484 Filed 5-27-99; 8:45 am] BILLING CODE 4910-13-P