Airworthiness Directives; General Electric Company (GE) CF6-45 and CF6-50 Series Turbofan Engines

[Federal Register Volume 67, Number 27 (Friday, February 8, 2002)]
[Rules and Regulations]
[Pages 5937-5938]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-3064]



[[Page 5937]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-33-AD; Amendment 39-12637; AD 2002-02-09]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE) CF6-45 
and CF6-50 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to GE CF6-45 and CF6-50 series turbofan engines. This AD 
requires a reduction of the cyclic life limit for certain low pressure 
turbine rotor (LPTR) stage 2 disks, and requires removing certain LPTR 
stage 2 disks from service before exceeding the new, lower cyclic life 
limit. In addition, this amendment requires removing from service 
certain LPTR stage 2 disks that currently exceed, or will exceed, the 
new, lower cyclic life limit according to the compliance schedule 
described in this action. This amendment is prompted by a report of a 
cracked LPTR stage 2 disk found initially by flourescent penetrant 
inspection and later confirmed by a visual inspection. The actions 
specified by this AD are intended to prevent an uncontained engine 
failure and damage to the airplane, resulting from cracks in the LPTR 
stage 2 disk.

DATES: Effective date: March 15, 2002.

FOR FURTHER INFORMATION CONTACT: Ann Mollica, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7740; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that is 
applicable to GE CF6-45 and CF6-50 series turbofan engines, was 
published in the Federal Register on October 30, 2001 (66 FR 54731). 
That action proposed to require a reduction of the cyclic life limit 
for certain low pressure turbine rotor (LPTR) stage 2 disks, and would 
require removing certain LPTR stage 2 disks from service before 
exceeding the new, lower cyclic life limit. In addition, the proposal 
would require removing from service certain LPTR stage 2 disks that 
currently exceed, or will exceed, the new lower cyclic life limit 
according to the compliance schedule described in this proposal.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

No Objection

    One commenter states that he has no technical objections to the 
proposal.

Number of Affected Disks

    GEAE states that the number of disks noted in the NPRM that will be 
effected by the proposal is incorrect. According to GEAE records, 
currently there are a total of 747 disks installed world-wide that 
would be affected by this AD, of which 201 disks are installed on 
airplanes of U.S. registry. The FAA agrees. The economic analysis 
provided in the proposed rule reflects the FAA's best estimates of 
fielded engines at that time. This estimate was based on historic data. 
The FAA, however, recognizes that the manufacturer's records are more 
up-to-date and accurate based on the active service reporting program 
they have established with the operators of their engines. Therefore, 
the economic analysis has been adjusted to reflect the decrease in 
impacted disks.

Cracked Disk Discovery

    GEAE further states that the cracked LPTR stage 2 disk was 
initially discovered by fluorescent penetrant inpsection rather than 
visually, and was later confirmed by visual inspection. The FAA agrees.
    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 as proposed.

Economic Analysis

    There are approximately 747 GE CF6-45 and CF6-50 series turbofan 
engines of the affected design in the worldwide fleet. The FAA 
estimates that 201 engines installed on airplanes of U.S. registry 
would be affected by this AD. The rule does not impose any additional 
labor costs. A new disk would cost approximately $72,870 per engine. 
Based on these figures, and on the prorating for the usage of the 
disks, the cost effect of the proposed AD on U.S. operators is 
estimated to be $3,133,775.

Regulatory Analysis

    This final rule does not have federalism implications, as defined 
in Executive Order 13132, because it would 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this final rule.
    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 the DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
will not have a significant economic effect, 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 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.

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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

2002-02-09  General Electric Company: Amendment 39-12637. Docket No. 
2001-NE-33-AD.

Applicability

    This airworthiness directive (AD) is applicable to General 
Electric Company (GE) CF6-45 and CF6-50 series turbofan engines. 
These engines are installed on, but not limited to Airbus Industrie 
A300 series, Boeing 747 series, and McDonnell Douglas DC-10 series 
airplanes.

    Note 1: This 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

[[Page 5938]]

owner/operator must request approval for an alternative method of 
compliance in accordance with paragraph (e) 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

    Compliance with this AD is required as indicated, unless already 
done.
    To prevent an uncontained engine failure and damage to the 
airplane, resulting from cracks in the low pressure turbine rotor 
(LPTR) stage 2 disk, do the following:
    (a) Remove from service LPTR stage 2 disks, part numbers (P/N's) 
9061M22P08 and 9061M22P10 in accordance with Table 1 as follows:

              Table 1.--LPTR Stage 2 Disk Removal Schedule
------------------------------------------------------------------------
   If disk cycles-since-new (CSN) on the
       effective date of this AD are              Then remove disk
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(1) Fewer than 5,300 CSN..................  Before exceeding 10,400 CSN.
(2) 5,300 CSN or more, but fewer than       Within 5,100 additional
 10,400 CSN.                                 cycles-in-service from the
                                             effective date of this AD.
(3) 10,400 CSN or more....................  At next LPTR stage 2 disk
                                             exposure, or by 15,500 CSN,
                                             whichever occurs earlier.
------------------------------------------------------------------------

    (b) After the effective date of this AD, do not install any LPTR 
stage 2 disk, P/N 9061M22P08 or 9061M22P10, that has 10,400 or more 
CSN into an engine.
    (c) Except for as provided in paragraph (a) of this AD, this 
action establishes a new, cyclic life limit of 10,400 CSN for LPTR 
stage 2 disk, P/N 9061M22P08 and 9061M22P10, which is published in 
Chapter 05-10-00 of CF6-45 and CF6-50 Engine Shop Manual, GEK 50481.

Definition

    (d) For the purpose of this AD, LPTR stage 2 disk exposure is 
defined as disassembly and removal of the LPTR stage 2 disk from the 
LPTR structure, regardless of whether any blades, bolts, nuts, bolt 
retainers, blade retainers, blade inserts, balance weights, wear 
strips, or seals remain assembled to the disk.

Alternative Methods of Compliance

    (e) 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 must submit their request 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

    (f) Special flight permits may be issued in accordance 
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 done.

Effective Date

    (g) This amendment becomes effective on March 15, 2002.


    Issued in Burlington, Massachusetts, on January 31, 2002.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 02-3064 Filed 2-7-02; 8:45 am]
BILLING CODE 4910-13-U

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