Airworthiness Directives; General Electric Aircraft Engines CF34 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment revises an existing airworthiness directive (AD), that is applicable to General Electric Aircraft Engines (GE) CF34 series turbofan engines. That AD currently requires:

(1) Replacement of Buna-N O-rings with Viton O-rings; or

(2) A new location of the vent groove on the MFC mounting flange; or

(3) Installation of an MFC with improved overspeed protection.

This amendment requires the installation of an MFC with improved overspeed protection. If this action can not be completed within 30 days of the effective date of this AD, then either:

(1) Replace Buna-N O-rings with Viton O-rings, followed by replacement with an MFC with improved overspeed protection within a specified time; or

(2) Replace with an MFC with a relocated vent groove on the MFC mounting flange and improved overspeed protection.

This amendment is prompted by nonsubstantive revisions to the manufacturer's service bulletins and comments from the manufacturer regarding various typographical errors in the AD. 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.

DATES:

Effective February 17, 2000.

The incorporation by reference of GE Alert Service Bulletins (ASB's) No. A73-33, dated November 21, 1997; A73-33, Revision 1, dated May 29, 1998; and A73-19, Revision 1, dated February 20, 1998, was approved by the Director of the Federal Register as of July 27, 1999.

The incorporation by reference of GE ASB's No. CF34AL 73-A0025, dated July 7, 1999; CF34BJ 73-A0040, dated July 7, 1999; GE service bulletin (SB) CF34AL S/B 73-0026, dated August 12, 1999; and GE SB CF34BJ S/B 73-0041, dated August 12, 1999, was approved by the Director of the Federal Register as of December 6, 1999.

The incorporation by reference of GE ASB No. A73-19, Revision 2, dated March 9, 1999; CF34-AL 73 A0019, Revision 3, dated September 9, 1999; A73-33, Revision 2, dated March 9, 1999; CF34-BJ 73-A0033, Revision 3, dated September 9, 1999; CF34-BJ 73-A0033, Revision 4, dated November 1, 1999; and CF34-BJ 73-0041, Revision 1, dated November 1, 1999 is approved by the Director of the Federal Register as of March 20, 2000.

ADDRESSES:

The service information referenced in this AD may be obtained from GEAE Technical Publications, Attention: H. Decker MZ340M2, 1000 Western Avenue, Lynn, MA 01910; telephone (781) 594-6323, fax (781) 594-0600. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Norman Brown, Controls Specialist, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7181, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Events Leading to Original AD; AD No. 99-11-08

On May 17, 1999, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 99-11-08, Amendment 39-11179 (64 FR 28905, May 28, 1999), to require, within 800 hours time in service (TIS) or 120 days after the effective date of that AD, whichever occurs first, installation of an MFC incorporating a flange vent groove. In addition, that AD required 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 that AD, or 24 months after the effective date of that AD, whichever occurred 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 months after the effective date of that AD, whichever occurred first. That action was prompted by reports of rapid uncommanded engine acceleration events. That condition, if not corrected, could have resulted in uncommanded engine accelerations, which could have resulted in an engine overspeed, uncontained engine failure, and damage to the airplane.

Events Leading to Current AD; AD No. 99-23-26

After the FAA issued AD 99-11-08, the engine manufacturer informed the FAA that GE CF34 Alert Service Bulletin (ASB) No. A73-18, Revision 1, dated September 24, 1997, and CF34 ASB No. A73-32, Revision 1, dated September 24, 1997, that describe procedures for reworking MFC's by adding a flange vent groove were in error and had incorrectly located the flange vent groove. Also, the manufacturer has determined that replacement of the Buna-N preformed packings (O-rings) with Viton O-rings would achieve a similar level of safety as the installation of an MFC with a correctly located flange vent groove. On the basis of that information, the FAA issued AD 99-23-26 on November 5, 1999 (64 FR 63171, November 19, 1999) to supersede AD 99-11-08.

Events Leading to This AD Revision

AD 99-23-26 was issued as a Final Rule; request for comments, and interested persons were given an opportunity to comment. Due consideration has been given to the comments received.

Request To Remove Certain MFC P/N's From Paragraphs (a) and (a)(2)

One commenter, the manufacturer, states that paragraphs (a) and (a)(2) incorrectly require that MFC part numbers (P/N's) 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 be replaced with MFC's with the relocated vent groove. The manufacturer points out that those MFC's incorporate overspeed protection and are not subject to the requirements of this AD. The Federal Aviation Administration (FAA) agrees. Paragraphs (a) and (a)(2) have been changed to delete MFC P/N's 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 from this AD.

Request To Remove Certain MFC P/N's Paragraph (e)

The same commenter asks that MFC P/N's 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 be deleted from paragraph (e) where they are listed as MFC P/N's that are not serviceable. The commenter also asks that MFC P/N's 6047T74P07, 6047T74P09, and 6091T07P01 be added to the listing of MFC P/N's that are not serviceable. The commenter points out that those MFC P/N's 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 incorporate overspeed protection and are serviceable parts. The Federal Aviation Administration (FAA) agrees. Paragraph (e) has been changed to delete MFC P/N's 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 from this AD. MFC P/N's 6047T74P07, 6047T74P09, and 6091T07P01 have been added to the listing of unserviceable MFC P/N's.

Request for a Correction to an SB Reference

The same commenter states that the reference to SB CF34AL S/B 73-0026, dated August 12, 1999, in paragraph (b) is incorrect and should be SB CF34-BJ 73-0041, dated August 12, 1999. The commenter asks that Revision 1, dated November 1, 1999, to SB CF34-BJ 73-0041 be listed in paragraph (b). Revision 1, dated November 1, 1999, was issued by the manufacturer after AD 99-23-26 was issued. The FAA agrees. The reference to “SB CF34AL S/B 73-0026” in paragraph (b) has been changed to “SB CF34-BJ 73-0041” and “or Revision 1, dated November 1, 1999,” has been added to paragraph (b).

Request To Add Certain Later SB Revisions to This AD

The same commenter also asks that references to following SB's be added to the applicable paragraphs in the compliance section of this AD:

• A73-19, Revision 2, dated March 9, 1999; and
• CF34-AL 73-A0019, Revision 3, dated September 9, 1999; and
• 73-33, Revision 2, dated March 9, 1999; and
• CF34-BJ 73-A0033, Revision 3, dated September 9, 1999; and
• CF34-BJ 73-A0033, Revision 4, dated November 1, 1999; and
• CF34-BJ 73-0041, Revision 1, dated November 1, 1999.

The issuance of the SB revisions was not communicated to the FAA. The FAA agrees. References to the above SB's have been added to the applicable paragraphs in the compliance section of this AD.

Request To Allow Future Revisions of the SB's To Be Referenced

The same commenter asks that the AD refer to the “latest revisions” of the SB's rather than specific revisions to the manufacturer's SB's. The FAA does not agree. The Administrative Procedures Act requires that all SB's incorporated by reference in AD's be approved and a copy retained by the Office of the Federal Register. A reference to the “latest revision”of a SB necessarily implies a reference to a document that does not yet exist, and, therefore, to a document for which the FAA cannot obtain the approval for incorporation by reference. The FAA may approve later revisions to the referenced SB's as alternate methods of compliance under the provisions of paragraph (f) of the AD.

Manufacturer Service Information

The FAA has reviewed and approved the technical contents of GE CF34 Alert Service Bulletins (ASB's) No. CF34AL 73-A0025, dated July 7, 1999, and CF34BJ 73-A0040, dated July 7, 1999, that describe procedures for replacement of the Buna-N preformed packings; CF34AL S/B 73-0026, dated August 12, 1999, CF34BJ S/B 73-0041, dated August 12,1999, and CF34BJ S/B 73-0041, Revision 1, dated November 1, 1999, that describe procedures for installation of a reworked MFC with a relocated pressure relief groove; and CF34 ASB No. A73-19, Revision 1, dated February 20, 1998, A73-19, Revision 2, dated March 9, 1999; or CF34 ASB No. CF34-AL 73-A0019, Revision 3, dated September 9, 1999, and CF34 ASB No. A73-33, dated November 21, 1997; A73-33, Revision 1, dated May 29, 1998; A73-33, Revision 2, dated March 9, 1999; or CF34 ASB No. CF34-BJ 73-A0033, Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 1999, that describe procedures for installation of a reworked MFC with improved overspeed protection.

When an MFC is returned to the manufacturer for drilling a relocated vent groove, the overspeed protection upgrades will be accomplished at the same time.

Differences Between the SB's and This AD

The GE SB's allow the MFC on CF34-1A, -3A, and -3A2 engines to be used until the MFC is removed for cause and then replaced with an MFC with a relocated vent groove. Because of the possibility that an unsafe condition may develop, this AD requires that the MFC be replaced with a serviceable MFC when the MFC is removed for any reason.

Requirements of This AD

Since an unsafe condition has been identified that is likely to exist or develop on other General Electric (GE) CF34 turbofan engines of the same type design, this AD supersedes AD 99-11-08 to require either replacement of Buna-N O-rings with Viton O-rings or replacement of the MFC with an MFC with a relocated vent groove within 30 days after the effective date of this AD. Replacement of the Buna-N O-rings is not required on CF34-1A, -3A, and -3A2 models. The actions are required to be accomplished in accordance with the service bulletin described previously.

After careful review of the available data, including the comments 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.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order (EO) 13132.

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 Regulatory Flexibility 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 USC 106(g), 40113, 44701.

2. Section 39.13 is amended by removing Amendment 39-11422 ( 64 FR 63171, November 19, 1999) and by adding a new airworthiness directive, Amendment 39-11566, to read as follows:

99-23-26 R1 General Electric Aircraft Engines (GE): Amendment 39-11566. Docket 98-ANE-19-AD. Revises AD 99-23-26, Amendment 39-11422.

Applicability: General Electric (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 (f) 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:

Replacement Requirements

(a) If the main fuel control (MFC) part numbers (P/N's) 6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 6078T55P06, 6078T55P07, 6078T55P08, 6078T55P09, or 6078T55P10 is installed, and if the MFC has Buna-N preformed packings (O-rings), P/N's R1307P020 and R1307P141, do one of the following:

(1) Replace Buna-N O-rings with Viton O-rings, P/N's M83485-1-020 (M83485/1-020) and 37B201714P130, within 30 days after the effective date of this AD, 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,

(2) 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 main fuel control (MFC) part numbers (P/N's) 6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 6078T55P06, 6078T55P07, 6078T55P08, 6078T55P09, or 6078T55P10 installed, within 30 days after the effective date of this AD, install an 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.

Replacement of the MFC

(b) For all CF34-1A, -3A, and -3A2 series engines with SN's 350003 through 350525, install an MFC with a flange groove that conforms to the requirements of CF34 SB CF34-BJ S/B 73-0041, dated August 12, 1999, or Revision 1, dated November 1, 1999, the next time the engine is removed or the next time the MFC is removed.

(c) 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 53 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; or Revision 2, dated March 9, 1999; or with step 3A(1) through step 3A(7) of the Accomplishment Instructions of CF34 ASB No. CF34-BJ 73-A0033, Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 1999.

(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 53 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; or Revision 2, dated March 9, 1999; or with step 3A(1) through step 3A(7) of the Accomplishment Instructions of CF34 ASB No. CF34-BJ 73-A0033, Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 1999.

(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 17 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; or Revision 2, dated March 9, 1999; or with step 3A(1) through step 3A(7) of the Accomplishment Instructions of CF34 ASB No. CF34-AL 73-A0019, Revision 3, dated September 9, 1999.

Terminating Action

(d) Replacing an MFC with a serviceable MFC, as defined in paragraph (e) of this AD, constitutes terminating action for the requirements of this AD.

Definition of a Serviceable MFC

(e) 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/N's 6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 6078T55P06, 6078T55P07, 6078T55P08, 6078T55P09, 6078T55P10, 6047T74P07, 6047T74P09, or 6091T07P01.

Alternative Method of Compliance

(f) 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 (ECO). Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(g) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished.

Manufacturer Service Bulletins

(h) The inspection shall be done in accordance with the following GE service bulletins:

(i) The incorporation by reference of GE ASB A73-19, dated February 20, 1998; ASB A73-33, dated November 21, 1997; and ASB A73-33, revision 1, dated May 29, 1998, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of July 27, 1999. The incorporation by reference of GE ASB's No. CF34AL 73-A0025, dated July 7, 1999; CF34BJ 73-A0040, dated July 7, 1999; GE service bulletin (SB) CF34AL S/B 73-0026, dated August 12, 1999; and GE SB CF34BJ S/B 73-0041, dated August 12, 1999, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of December 6, 1999.

Address for Obtaining Referenced Service Bulletins

(j) Copies may be obtained from GEAE Technical Publications, Attention: H. Decker MZ340M2, 1000 Western Avenue, Lynn, MA 01910; telephone (781) 594-6323, 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.

Effective Date of This AD

(k) This amendment becomes effective on the date of publication.