[Federal Register Volume 59, Number 77 (Thursday, April 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-7785]


[[Page Unknown]]

[Federal Register: April 21, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 91-ANE-45; Amendment 39-8862; AD 94-07-04]

 

Airworthiness Directives; General Electric Company CF6 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to General Electric Company (GE) CF6-80A series turbofan 
engines, that requires an inspection for cracks in the stage 1 high 
pressure turbine (HPT) disk rim bolt holes. This amendment is prompted 
by a report of an uncontained stage 1 HPT disk failure, which resulted 
in an aborted takeoff. The actions specified by this AD are intended to 
prevent an uncontained stage 1 HPT disk failure, which could result in 
an inflight engine shutdown, aborted takeoff, or damage to the 
aircraft.

DATES: Effective May 23, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 23, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from General Electric Aircraft Engines, CF6 Distribution 
Clerk, room 132, 111 Merchant Street, Cincinnati, OH 45246. This 
information may be examined at the Federal Aviation Administration 
(FAA), New England Region, Office of the Assistant Chief 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.

FOR FURTHER INFORMATION CONTACT: Robert J. Ganley, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7138; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to General Electric Company (GE) CF6-80A series turbofan 
engines was published as a notice of proposed rulemaking (NPRM) in the 
Federal Register on January 9, 1992 (57 FR 857). That action proposed 
to require a one-time inspection for cracks in the stage 1 high 
pressure turbine (HPT) disk rim bolt holes in accordance with GE 
Commercial Engine Service Memorandum (CESM) No. 27, dated September 27, 
1991.
    Since the issuance of that NPRM, GE issued CF6-80A Service Bulletin 
(SB) No. 72-604, Revision 3, dated April 8, 1993, which revised the 
inspection program based on additional investigation findings on the 
reported disk failure. A Supplemental NPRM was published in the Federal 
Register on November 3, 1993 (58 FR 58667), which proposed to require 
an inspection for cracks in the stage 1 HPT disk rim bolt holes in 
accordance with the revised inspection program described in GE CF6-80A 
SB No. 72-604, Revision 3, dated April 8, 1993.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the rule as proposed.
    One commenter states that previous revision levels of GE CF6-80A SB 
No. 72-604, Revision 3, dated April 8, 1993, should be incorporated by 
reference. The FAA does not concur. Compliance paragraph (d) of the 
proposed rule already addresses inspections performed in accordance 
with these previous revision levels.
    One commenter states that the AD should not refer to a specific 
revision of the GE SB, but instead, use the phrase ``latest revision'' 
when citing the SB. The FAA does not concur. When incorporating a 
manufacturer's SB into an AD, the actual revision level and issue date 
of the SB must be specified. The FAA can not review and approve the 
technical contents of a document that has not yet been issued. Future 
revisions to a SB incorporated into an AD that do not substantively 
change the compliance requirements or times, may carry FAA approval as 
alternate methods of compliance to allow operators the greatest 
flexibility in performing the requirements of an AD.
    One commenter states that the inspection thresholds should be based 
on cycles since new on the issuance of GE CF6-80A SB No. 72-604, 
Revision 2, dated July 2, 1992, rather than the effective date of the 
AD to be consistent with their current inspection program. The FAA does 
not concur. This recommendation might cause an undue burden to another 
operator based on the anticipated publication date of this amendment.
    The FAA has determined that the compliance end date of December 31, 
1993, noted in compliance paragraph (a)(3) of the NPRM, is inconsistent 
with the anticipated publication date of this amendment, and as such 
may place undue burden on operators. The NPRM proposed a compliance 
period of 60 days to accomplish the required actions based on the 
anticipated publication date of the AD at the time the NPRM was 
published. Therefore, the compliance end date in compliance paragraph 
(a)(3) of this final rule has been revised to 90 days after date of 
publication in the Federal Register. This time period is comprised of 
the 30 day period after publication and prior to the effective date 
plus 60 days.
    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 change described 
previously. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    There are approximately 154 GE CF6-80A series engines of the 
affected design in the worldwide fleet. The FAA estimates that 48 
engines installed on aircraft of U.S. registry will be affected by this 
AD, that it will take approximately 232 work hours per engine to 
accomplish the required actions, and that the average labor rate is $55 
per work hour. Required parts will cost approximately $172,800 per 
engine. Based on these figures, and assuming all inspected disks 
require replacement, the total cost impact of the AD on U.S. operators 
is estimated to be $8,906,880.
    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 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 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

94-07-04 General Electric Company: Amendment 39-8862. Docket 91-ANE-
45.

    Applicability: General Electric Company (GE) CF6-80A series 
turbofan engines installed on but not limited to, Boeing 767 series 
and Airbus A310 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained stage 1 high pressure turbine (HPT) 
disk failure, which could result in an inflight engine shutdown, 
rejected takeoff, or damage to the aircraft, accomplish the 
following:
    (a) Eddy current inspect (ECI) for cracks stage 1 HPT disks, 
Part Numbers (P/N) 9234M67G12, 9234M67G13, 9234M67G14, 9234M67G15, 
9234M67G16, 9234M67G22, 9234M67G24, 9367M45G01, 9367M45G02, 
9367M45G03, and 9367M45G04, regardless of serial number; and stage 1 
HPT disks, P/N 9362M58G02, with serial numbers listed in paragraph 
1.A. of GE CF6-80A Service Bulletin (SB) No. 72-604, Revision 3, 
dated April 8, 1993; in accordance with the accomplishment 
instructions of GE CF6-80A SB No. 72-604, Revision 3, dated April 8, 
1993, as follows:
    (1) For disks that have accumulated less than 3,000 cycles since 
new (CSN) on the effective date of this AD, ECI the rim bolt holes 
at the next engine shop visit after accumulating 3,000 CSN, but not 
to exceed 4,500 CSN.
    (2) For disks that have accumulated 3,000 CSN or more, but less 
than 4,000 CSN on the effective date of this AD, ECI the rim bolt 
holes at the next engine shop visit, but not to exceed 4,500 CSN.
    (3) For disks that have accumulated 4,000 CSN or more, but less 
than 9,500 CSN on the effective date of this AD, ECI the rim bolt 
holes at the next engine shop visit, or prior to July 20, 1994, 
whichever occurs earlier.
    (4) For disks that have accumulated 9,500 CSN or more on the 
effective date of this AD, ECI the rim bolt holes at the next engine 
shop visit.
    (b) ECI stage 1 HPT disks, P/N 9362M58G02, with serial numbers 
not listed in paragraph 1.A. of GE CF6-80A SB No. 72-604, Revision 
3, dated April 8, 1993, in accordance with the accomplishment 
instructions of GE CF6-80A SB No. 72-604, Revision 3, dated April 8, 
1993, at the next exposure of the stage 1 HPT disk at the piece part 
level.
    (c) Remove from service disks found cracked, and replace with 
serviceable parts. Inspect replacement disks in accordance with 
paragraph (a) or (b) of this AD, if applicable.
    (d) Disks referenced in paragraph (a) or (b) of this AD that 
have been inspected in accordance with Commercial Engine Service 
Memorandum No. 27, dated September 27, 1991, or any revision level 
of GE CF6-80A SB No. 72-604, prior to the effective date of this AD, 
and whose CSN at the time of inspection was 3,000 or more, meet the 
inspection requirements of paragraph (a) and (b) of this AD.
    (e) For the purpose of this AD, an engine shop visit is defined 
as the induction of an engine into a shop for maintenance involving 
the separation of any major flange.
    (f) An alternative method of compliance or adjustment of the 
initial compliance time that provides an acceptable level of safety 
may be used if approved by the Manager, Engine Certification Office. 
The request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office. NOTE: Information concerning 
the existence of approved alternative methods of compliance with 
this airworthiness directive, if any, may be obtained from the 
Engine Certification Office.
    (g) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (h) The inspection, and replacement, if necessary, shall be done 
in accordance with the following service bulletin:

------------------------------------------------------------------------
      Document No.           Pages      Revision            Date        
------------------------------------------------------------------------
GE CF6-80A SB No. 72-604            1            3  Apr. 8, 1993.       
                                    2            2  July 2, 1992.       
                                    3            3  Apr. 8, 1993.       
                                 4-12            2  July 2, 1992.       
    Total Pages: 12.....                                                
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    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 General Electric Aircraft 
Engines, CF6 Distribution Clerk, room 132, 111 Merchant Street, 
Cincinnati, OH 45246. Copies may be inspected at the FAA, New 
England Region, Office of the Assistant Chief 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.
    (i) This amendment becomes effective on May 23, 1994.

    Issued in Burlington, Massachusetts, on March 23, 1994.
Marc Bouthillier,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 94-7785 Filed 4-20-94; 8:45 am]
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