AD 2001-10-03

[Federal Register Volume 66, Number 95 (Wednesday, May 16, 2001)]
[Rules and Regulations]
[Pages 27017-27020]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-12006]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-42-AD; Amendment 39-12229; AD 2001-10-03]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF34 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to General Electric Company (GE) CF34-1A, -3A, -3A1, -
3A2, -3B, and -3B1 turbofan engines. This action requires a one-time 
inspection, and if necessary replacement of certain fan disks for 
electrical arc-out indications, and assigns a reduction in the life 
limit of certain fan disks. This amendment is prompted by a report of a 
crack that was found during a visual inspection as part of routine 
engine maintenance. The actions specified in this AD are intended to 
prevent rupture of the fan disk due to cracks that initiate at an 
electrical arc-out, which could result in an uncontained failure of the 
engine.

DATES: Effective May 31, 2001. The incorporation by reference of 
certain publications listed in the rule is approved by the Director of 
the Federal Register as of May 31, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before July 16, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-NE-42-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: <a href="/cdn-cgi/l/email-protection#8db4a0ece3e8a0ece9eee2e0e0e8e3f9cdebececa3eae2fb"><span class="__cf_email__" data-cfemail="f1c8dc909f94dc9095929e9c9c949f85b1979090df969e87">[email&#160;protected]</span></a>. 
Comments sent via the Internet must contain the docket number in the 
subject line.
    The service information referenced in this AD may be obtained from 
GE Aircraft Engines, 1000 Western Avenue, Lynn, MA 01910; Attention: 
CF34 Product Support Engineering, Mail Zone: 34017; telephone (781) 
594-6323; fax (781) 594-0600. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT: Eugene Triozzi, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone 781-
238-7148; fax 781-238-7199.

SUPPLEMENTARY INFORMATION: The FAA has received a report of a crack at 
one of the fan blade installation pin holes in a GE CF34-3A1 engine fan 
disk. The crack was found during a visual inspection that was being 
conducted as part of routine engine maintenance. Crack initiation 
sites, consisting of small zones of melted and resolidified metal,

[[Page 27018]]

have been discovered on fan disk surfaces. Three additional burned 
zones were observed adjacent to the crack site, but crack propagation 
at those sites did not occur because they were at lower stress 
locations. Metallurgical examination determined that these defects were 
a result of inadvertent contact by electrical probes used during an 
electrochemical etching procedure during manufacture. The defect is 
being referred to as electrical arc-out. These crack initiation sites 
may have occurred at fan disk surface locations accessible during part 
marking. Stress and life analyses conducted by the manufacturer show 
that if these sites occur at high-stress locations on disks, then crack 
propagation and rupture may occur before the part reaches its published 
low-cycle fatigue removal life. Also, some disks have manufacturing 
records that indicate blending, possibly of arc-outs, was performed at 
initial manufacture. This is referred to as a blended callout. Because 
arc-outs that may have occurred on these disks may have been blended 
away, these disks can not be reliably inspected for arc-out using the 
visual methods developed for other disks. Therefore, these disks must 
be removed from service. This condition, if not corrected, could result 
in rupture of the fan disk due to cracks that initiate at an electrical 
arc-out, which could result in an uncontained failure of the engine.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of GE 
Aircraft Engines (GEAE) Alert Service Bulletin (ASB) CF34-BJ 72-A0088, 
Revision 1, dated October 30, 2000; and ASB CF34-AL 72-A0103, dated 
August 4, 2000. These ASB's provide procedures for inspections of 
certain disks for electrical arc-out indications, and if necessary, 
replacement of the disk with a serviceable disk.

Requirements of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 
turbofan engines of the same type design, this AD is being issued to 
prevent rupture of the fan disk due to cracks that initiate at an 
electrical arc-out. This AD requires an inspection of fan disks P/N's 
5921T18G01, 5921T18G09, 5921T18G10, 5921T54G01, 5922T01G02, 5922T01G04, 
5922T01G05, 6020T62G04, 6020T62G05, 6078T00G01, 6078T57G01, 6078T57G02, 
6078T57G03, 6078T57G04, 6078T57G05, and 6078T57G06 for electrical arc-
out indications and, if necessary, replacement of the fan disk with a 
serviceable disk. This AD also requires replacement of certain fan 
disks with blended callouts that are listed by P/N and SN in this AD 
before achieving a new reduced life limit. The inspection and 
replacement must be done in accordance with the alert service bulletins 
described previously.

Differences Between the Manufacturer's Service Information and This 
AD

    Although fan disk P/N 5922T01G02 is not specified by ASB CF34-BJ 
72-A0088, Revision 1, dated October 30, 2000, fan disk P/N 5922T01G02 
is subject to the requirements specified in this AD.

Immediate Adoption of This AD

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 2000-NE-42-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    This final rule does not have federalism implications, as defined 
in Executive Order No. 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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

2001-10-03  General Electric Company: Amendment 39-12229. Docket 
2000-NE-42-AD.

[[Page 27019]]

Applicability

    This airworthiness directive (AD) is applicable to General 
Electric Company (GE) CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 
turbofan engines with fan disk part numbers (P/N's) 5921T18G01, 
5921T18G09, 5921T18G10, 5921T54G01, 5922T01G02, 5922T01G04, 
5922T01G05, 6020T62G04, 6020T62G05, 6078T00G01, 6078T57G01, 
6078T57G02, 6078T57G03, 6078T57G04, 6078T57G05, and 6078T57G06 
installed. These engines are installed on but not limited to 
Bombardier, Inc. Canadair airplane models CL-600-2A12, -2B16, and -
2B19.

    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 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 rupture of the fan disk due to cracks that initiate 
at an electrical arc-out, which could result in an uncontained 
failure of the engine, do the following:

Removal of Certain Fan Disks from Service

    (a) On disk P/N's 5921T18G01, 5921T18G09, 5921T18G10, 
5921T54G01, 5922T01G02, 5922T01G04, 5922T01G05, 6020T62G04, 
6020T62G05, 6078T00G01, 6078T57G01, 6078T57G02, 6078T57G03, 
6078T57G04, 6078T57G05, and 6078T57G06, that are listed by P/N and 
serial number (SN) in the following Table 1 of this AD and that have 
less than 8,000 cycles-since-new (CSN) on the effective date of this 
AD, replace fan disk P/N's before accumulating 8,000 CSN:

    Table 1. Fan Disks That Require Removal Based on Blended Callouts
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             Disk part number                    Disk serial number
------------------------------------------------------------------------
 6078T57G04...............................  GEE09287
6078T00G01................................  GAT3860G
6078T57G02................................  GAT1924L
5922T01G04................................  GAT9599G
6078T57G04................................  GEE05831
6078T57G04................................  GEE06612
6078T57G04................................  GEE06618
6078T57G04................................  GEE06974
6078T57G04................................  GEE06980
6078T57G05................................  GEE143FY
6078T57G05................................  GEE1453G
6078T57G05................................  GEE14452
6078T57G05................................  GEE145NA
6078T57G04................................  GEE08086
6078T57G04................................  GEE09287
6078T57G04................................  GEE09337
6078T57G05................................  GEE12720
6078T57G05................................  GEE14214
6078T57G05................................  GEE142YT
6078T57G05................................  GEE146GT
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    (b) For disks with SN's listed in Table 1 of this AD that have 
8,000 CSN or greater on the effective date of this AD, replace the 
disk within 30 days after the effective date of this AD.

Inspection of All Other Fan Disks

    (c) Inspect all other fan disks, P/N's 5921T18G01, 5921T18G09, 
5921T18G10, 5921T54G01, 5922T01G02, 5922T01G04, 5922T01G05, 
6020T62G04, 6020T62G05, 6078T00G01, 6078T57G01, 6078T57G02, 
6078T57G03, 6078T57G04, 6078T57G05, and 6078T57G06 in accordance 
with paragraphs 3.A.(1) through 3.E.(2) of the Accomplishment 
Instructions of Alert Service Bulletin (ASB) CF34-BJ 72-A0088, 
Revision 1, dated October 30, 2000 or paragraphs 3.A.(1) through 
3.A.(2)(f) of the Accomplishment Instructions of ASB CF34-AL 72-
A0103, dated August 4, 2000. Use the compliance times specified in 
the following Table 2:

              Table 2. Fan Disk Inspection Compliance Times
------------------------------------------------------------------------
       Fan disk operating CSN                     Inspect by
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(1) Fewer than 8,000 CSN on the      Before accumulating 8,000 CSN or by
 effective date of this AD.           the next hot section inspection
                                      after the effective date of this
                                      AD, whichever occurs earlier.
(2) 8,000 CSN or greater on the      Within 120 days after the effective
 effective date of this AD.           date of this AD.
------------------------------------------------------------------------

Definitions

    (d) For the purposes of this AD, the following definitions 
apply:
    (1) A serviceable fan disk is defined as a fan disk that has 
been inspected as specified in paragraph (c) of this AD and is not 
listed in Table 1 of this AD.
    (2) Cycles-since-new for fan disk P/N's 5922T01G04 or 5922T01G05 
is defined as total cycles accrued since new as P/N 6078T57G02 or 
6078T57G03, added to total cycles accrued after modification from P/
N 6078T57G02 or 6078T57G03.

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 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

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

Documents That Have Been Incorporated by Reference

    (g) The actions specified in this AD must be done in accordance 
with the following GE alert service bulletins:

----------------------------------------------------------------------------------------------------------------
              Document No.                      Pages          Revision                    Date
----------------------------------------------------------------------------------------------------------------
ASB CF34-BJ 72-A0088...................  All................          1  October 30, 2000.
    Total pages: 15
ASB CF34-AL 72-A0103...................  All................   Original  August 4, 2000.
    Total pages: 78
----------------------------------------------------------------------------------------------------------------

    These incorporations by reference were 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 GE Aircraft Engines, 1000 
Western Avenue, Lynn, MA 01910; Attention: CF34 Product Support 
Engineering, Mail Zone: 34017; 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

[[Page 27020]]

Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

Effective Date of This AD

    (h) This amendment becomes effective on May 31, 2001.

    Issued in Burlington, Massachusetts, on May 7, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-12006 Filed 5-15-01; 8:45 am]
BILLING CODE 4910-13-U