[Federal Register Volume 64, Number 206 (Tuesday, October 26, 1999)]
[Proposed Rules]
[Pages 57608-57609]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-27937]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-79-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).

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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 removal from 
service of affected fan mid shafts prior to reaching a new, lower 
cyclic life limit, and replacement with serviceable parts. This 
proposal is prompted by recent component test data. The actions 
specified by the proposed AD are intended to prevent fan mid shaft 
failure, which could result in an uncontained engine failure and damage 
to the aircraft.

DATES: Comments must be received by December 27, 1999.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-ANE-79-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299. Comments may also be sent via the Internet 
using the following address: ``[email protected]''. Comments sent 
via the Internet must contain the docket number in the subject line. 
Comments may be inspected at this location between 8:00 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 Company via Lockheed Martin Technology 
Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, 
telephone (513) 672-8400, fax (513) 672-8422. 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: William S. Ricci, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7742, 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 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 filed in 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 98-ANE-79-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. 98-ANE-79-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    General Electric Company (GE), the manufacturer of CF6-80C2 series 
turbofan engines, recently conducted component tests and analysis of 
low pressure rotor shafts that resulted in the need to reduce the 
cyclic life limit of fan mid shafts, part number (P/Ns) 9326M74P04 and 
P/N 9326M74P05. The analysis revealed high stress in the fan mid shaft 
spline teeth, which results in reduced component cyclic life. This 
condition, if not corrected, could result in fan mid shaft failure, 
which could result in an uncontained engine failure and damage to the 
aircraft.

Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, the 
proposed AD would require removal from service of affected fan mid 
shafts prior to reaching a new, lower cyclic life limit, and 
replacement with serviceable parts.

Economic Analysis

    There are approximately 1,796 engines of the affected design in the 
worldwide fleet. The FAA estimates that 230 engines installed on 
aircraft of US registry would be affected by this proposed AD and that 
required parts would cost approximately $90,085 per engine. Based on 
these figures, the total cost impact of the proposed AD on US operators 
is estimated to be $20,719,600.

Regulatory Impact

    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

[[Page 57609]]

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:

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. 98-ANE-79-AD.

    Applicability: General Electric Company (GE) CF6-80C2 series 
turbofan engines, with fan mid shafts, part number (P/N) 9326M74P04 
or P/N 9326M74P05, installed. These engines are installed on but not 
limited to Airbus Industrie A300 and A310 series, Boeing 747 and 767 
series, and McDonnell Douglas MD-11 series aircraft.

    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 fan mid shaft failure, which could result in an 
uncontained engine failure and damage to the aircraft, accomplish 
the following:

Removal From Service

    (a) Remove from service affected fan mid shafts and replace with 
a serviceable part, as follows:

    Note 2: GE CF6-80C2 Service Bulletin (SB) No. 72-958, dated 
December 10, 1998, contains information on this subject.

    (1) For fan mid shafts that have accumulated 9,000 or more 
cycles-since-new (CSN) on the effective date of this AD, remove from 
service within 3,500 cycles-in-service (CIS) after the effective 
date of this AD, or prior to accumulating 15,000 CSN, whichever 
occurs first.
    (2) For fan mid shafts that have accumulated 1,800 CSN or more, 
but less than 9,000 CSN on the effective date of this AD, remove 
from service within 5,000 CIS, or prior to accumulating to 12,500 
CSN, whichever occurs first.
    (3) For fan mid shafts that have accumulated less than 1,800 CSN 
on the effective date of this AD, remove from service prior to 
accumulating 6,800 CSN.

    Note 3: GE CF6-80C2 SB 72-750, Revision 2, dated September 4, 
1998, contains information on reworking fan mid shafts that results 
in changing the part number. After that rework, this AD would not 
apply to engines containing the reworked fan mid shaft.

New Life Limits

    (b) Except for the provisions of paragraph (a) of this AD, no 
fan mid shafts, P/N 9326M74P04 or 9326M74P05, may remain in service 
beyond 6,800 CSN.

Alternate Method of Compliance

    (c) 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 request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Ferry Flights

    (d) 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 aircraft to a location where 
the requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on October 20, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-27937 Filed 10-25-99; 8:45 am]
BILLING CODE 4910-13-P