AD 99-11-08

This amendment adopts a new airworthiness directive (AD), applicable to General Electric Aircraft Engines (GE) CF34 series turbofan engines, that requires installation of a main fuel control (MFC) that incorporates a flange vent groove and installation of an MFC with improved overspeed protection. This amendment is prompted by reports of rapid uncommanded engine acceleration events. The actions specified by this AD are intended to prevent uncommanded engine accelerations, which could result in an engine overspeed, uncontained engine failure, and damage to the airplane.

Final rule.

99-11-08 General Electric Aircraft Engines: Amendment 39-11179. Docket 98-ANE-19-AD.

Applicability: 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.

Compliance: 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 4,000hours 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 Sections 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

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.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to General Electric Aircraft Engines (GE) CF34 series turbofan engines was published in the Federal Register on September 18, 1998 (63 FR 49877). That action proposed to require, within 800 hours time in service (TIS), or 120 days after the effective date of this AD, whichever occurs first, installation of an MFC incorporating a flange vent groove. In addition, the action proposed to require installation of an MFC with improved overspeed protection: for CF34-3A1 and -3B1 series engines, installed on Canadair Regional Jet airplanes, within 4,000 hours TIS after the effective date of this AD, or 24 months after the effective date of this AD, whichever occurs first; and for CF34-1A, -3A, -3A1, -3A2, and -3B series engines, installed on Canadair Challenger airplanes, at the next hot section inspection, or within 60 monthsafter the effective date of this AD, whichever occurs first. The actions are required to be accomplished in accordance with GE CF34 Alert Service Bulletin (ASB) No. A73-18, Revision 1, dated September 24, 1997; CF34 ASB No. A73-32, Revision 2, dated May 29, 1998; CF34 ASB No. A73-33, Revision 1, dated May 29, 1998; and CF34 ASB No. A73-19, Revision 1, dated February 20, 1998.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public.

Since the publication of the notice of proposed rule making (NPRM), GE has issued Revision 2, dated May 29, 1998, to ASB A73-32 that added effectivity information to the Planning Information section of ASB A73-32. GE has also issued Revision 1, dated May 29, 1998 to ASB 73-33 that added effectivity information to the Planning Information section of ASB A73-33. The ASB revisions have not affected the technical or economic content of this proposed AD. We have added the updated ASB revisions to paragraphs (a), (b)(1), and (b)(2) of the compliance section of this AD. GE has implemented the vent groove and improved overspeed protection design changes in new MFC's. In addition, we have made editorial changes to the compliance section of this AD to improve readability and to remove ambiguity. We changed the requirement "with a flange vent groove reworked in accordance with" in paragraph (a) to "with a flange vent groove modified in accordance with." We made the change so that you are not restricted to installing only reworked MFC's, and to allow you to install a new MFC with the design improvements. We added the base part number 6078T55 of the MFC to each of the P0X numbers to remove any ambiguity over the MFC's that must be replaced. We changed the requirement "Install a reworked MFC with improved overspeed protection" in paragraph (b) to "Install a serviceable MFC with improved overspeed protection." We made the change to allow you to install a new MFC that incorporates the improved overspeed protection design change, and so you are not restricted to installing only reworked MFC's. We added the word "within" to the requirements of paragraphs (b)(1). (b)(2), and (b)(3) to allow you to perform the actions before reaching the specified calendar times after the effective date of the AD. We removed the new MFC P/N's from paragraphs (b)(1), (b)(2), and (b)(3) and changed "install MFC" to "install a serviceable MFC." We removed the P/N's so that you will not have to request an alternate method of compliance in accordance with paragraph (d) of this AD if a new MFC P/N is certificated for use on the applicable engines. We also added a new paragraph (c) that defines a serviceable MFC.

After careful review of the available data, including the changes noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the RegulatoryFlexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive: