Airworthiness directives: General Electric Co.,

[Federal Register: September 8, 1999 (Volume 64, Number 173)]

[Proposed Rules]

[Page 48721-48723]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr08se99-11]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-24-AD]

RIN 2120-AA64

Airworthiness Directives; General Electric Company CF6-80C2 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6- 80C2 series turbofan engines. This proposal would require replacement of the fuel tube connecting the flowmeter to the Integrated Drive Generator (IDG) and the fuel tube(s) connecting the Main Engine Control (MEC) or Hydromechanical (HMU) to the flowmeter with improved fuel tubes. This proposal is prompted by reports of fuel leaking in the core cowl cavity under high pressure that can be ignited by the hot engine case temperatures. The actions specified by the proposed AD are intended to prevent high-pressure fuel leaks caused by improper seating of fuel tube flanges, which could result in an engine fire and damage to the airplane.

[[Page 48722]]

DATES: Comments must be received by November 8, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-24-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ane- adcomment@faa.gov''. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from General Electric Aircraft Engines, c/o Commercial Technical Publications, 1 Neumann Way, Room 230, Cincinnati, OH 45215- 1988; telephone (513) 552-2005, fax (513) 552-2816. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Ian Dargin, Aerospace Engineer, Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238- 7178, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NE-24-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-24-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Federal Aviation Administration (FAA) received reports of 21 incidents of fuel leaks on General Electric Company (GE) CF6-80C2 series engines at the fuel tube flanges at either the tube connecting the Main Engine Control (MEC) or Hydromechanical Unit (HMU) to the fuel flowmeter or the tube connecting the fuel flowmeter to the Integrated Drive Generator (IDG) cooler. Five of the incidents resulted in in- flight engine shutdowns, with the majority directly attributable to incorrect flange seating of one of the fuel tube flanges. One of these events resulted in an engine fire on a Boeing 747-400 aircraft. This engine fire was caused by fuel leaking due to improper fuel tube flange seating at the inlet mating flange end of the tube connecting with the IDG cooler. The improper fuel tube flange seating condition, if not corrected, could result in high-pressure fuel leaks, which could result in an engine fire and damage to the airplane.

The FAA has reviewed and approved the technical contents of GE Alert Service Bulletin (ASB) No. 73-A224, Revision 2, July 9, 1997, that describes procedures for replacing the fuel flowmeter to IDG cooler fuel tube with an improved tube; and ASB No. 73-A0231, Revision 1, May 3, 1999, that describes procedures for replacing the MEC or HMU to fuel flowmeter fuel tubes with improved tubes.

Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, the proposed AD would require replacement of the fuel flowmeter to IDG cooler fuel tubes and MEC or HMU to fuel flowmeter fuel tubes with improved tubes. The improved design fuel tube prevents hang-up of the flange on the tube, thus allowing proper flange seating. The replacement would be required at the next time the tubes are disconnected, or the next shop visit after the effective date of this AD, whichever occurs first. The actions are required to be accomplished in accordance with the ASBs described previously.

There are approximately 2,693 engines of the affected design in the worldwide fleet. The FAA estimates that 581 engines installed on airplanes of US registry would be affected by this proposed AD, that it would take approximately 0.5 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Of the 581 engines, some have already complied with the ASBs. Required parts for complying with ASB 73-A224 would cost approximately $659 per engine for the remaining 35 domestic engines. To comply with ASB 73- A0231, required parts would cost $2,858 per engine for the remaining 204 domestic Full Authority Digital Engine Control (FADEC) engines, and $1,229 per engine for the remaining 204 domestic Power Management Control (PMC) engines. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $856,813.

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed regulation (1) Is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

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

[[Page 48723]]

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.

   Sec. 39.13 [Amended]

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

   General Electric Company: Docket No. 99-NE-24-AD.

   Applicability: General Electric Company (GE) CF6-80C2 A1/ A2/ A3/ A5/ A8/ A5F/ B1/ B2/ B4/ B6/ B1F/ B2F/ B4F/ B6F/ B7F/ D1F turbofan engines, installed on but not limited to Airbus Industrie A300-600/ 600R series and A310-200Adv/ 300 series, and Boeing 747- 200/ 300/ 400 series and 767-200ER/ 300/ 300ER/ 400ER and McDonnell Douglas MD-11 series airplanes.

   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 (c) 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 improper fuel tube flange seating, resulting in high pressure fuel leaks, which could result in an engine fire and damage to the airplane, accomplish the following:

   (a) At the next time the tubes are disconnected for on-wing maintenance, or the next shop visit after the effective date of this AD, whichever occurs first, replace the old configuration fuel tubes with the improved tubes, as follows:

   (1) Replace the fuel flowmeter to Integrated Drive Generator (IDG) cooler fuel tube, part number (P/N) 1321M42G01, with a serviceable part in accordance with paragraph 2 of GE Alert Service Bulletin (ASB) No. 73-A224, Revision 2, July 9, 1997 and perform a leak check after accomplishing the replacement.

   (2) Replace Main Engine Control (MEC) to fuel flowmeter fuel tube, P/N 1334M88G01, and bolts, P/N MS9557-12, with serviceable parts, in accordance with paragraph 3A for engines with Power Management Controls, or Hydromechanical Unit (HMU) to fuel flowmeter fuel tubes, P/Ns 1383M12G01 and 1374M30G01 with serviceable parts, in accordance with paragraph 3B for engines with Full Authority Digital Electronic Controls, in accordance with GE ASB No. 73-A0231, Revision 1, May 3, 1999; and perform a leak check after accomplishing the replacement.

   Note 2: Information on performing the leak check can be found in the Aircraft Maintenance Manual, 71-00-00.

   (b) For the purpose of this AD, a shop visit is defined as any time an engine is removed from service and returned to the shop for any maintenance.

   (c) For the purpose of this AD, a serviceable part is defined as any part other than tube, P/N 1321M42G01, for the fuel flowmeter to IDG cooler; tube; P/N 1334M88G01, and bolt, P/N MS9557-12, for the MEC to fuel flowmeter tube; and tubes, P/Ns 1383M12G01 and 1374M30G01, for the HMU to fuel flowmeter fuel tubes.

   (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 request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.

   Note 3: 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 Secs. 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.

   Issued in Burlington, Massachusetts, on August 30, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 99-23254Filed9-7-99; 8:45 am]

   BILLING CODE 4910-13-U