Document ID: FAA-2017-0164-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2017-04-14T04:00Z

[Federal Register Volume 82, Number 71 (Friday, April 14, 2017)]
[Proposed Rules]
[Pages 17945-17947]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-07477]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0164; Directorate Identifier 2017-NE-06-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain General Electric Company (GE) CF34-8 model turbofan engines. 
This proposed AD was prompted by analysis that resulted in the 
reduction of the life of the affected fan blades. This proposed AD 
would require inspections of the affected fan blades until their 
removal. We are proposing this AD to correct the unsafe condition on 
these products.

DATES: We must receive comments on this proposed AD by May 30, 2017.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact General 
Electric Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 
45215, phone: 513-552-3272; fax: 513-552-3329; email: geae.aoc@ge.com. 
You may view this service information at the FAA, Engine & Propeller 
Directorate, 1200 District Avenue, Burlington, MA. For information on 
the availability of this material at the FAA, call 781-238-7125.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-
0164; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Martin Adler, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 
District Avenue, Burlington, MA 01803; phone: 781-238-7157; fax: 781-
238-7199; email: martin.adler@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this NPRM. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2017-0164; 
Directorate Identifier 2017-NE-06-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. We will 
consider all comments received by the closing date and may amend this 
NPRM because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this NPRM.

Discussion

    We learned that GE has determined, based on analysis, that the 
stresses in the pinholes in the affected fan blade could result in 
crack initiation at pinhole surfaces beyond 19,000, 19,500, or 25,000 
cyles-since-new (CSN), depending on the engine model on which the blade 
is installed. GE, therefore, has initiated a program of initial and 
repetitive eddy current inspections (ECIs) and removal of this fan 
blade before it reaches 41,000 CSN. GE also provided an option to 
repair the blade which allows for an additional 28,000 cycles before it 
must be removed. This condition, if not corrected, could result in 
failure of the fan blade, uncontained blade release, damage to the 
engine, and damage to the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed GE Alert Service Bulletins (ASBs) CF34-8C SB 72-A0137 
R05, dated June 15, 2016; and CF34-8E SB 72-A0060 R05, dated June 15, 
2016. These ASBs provide the procedures necessary for calculating the 
adjusted CSN for the initial inspection. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

Other Related Service Information

    We reviewed GE ASB CF34-8E SB 72-A0115 R03, issued on December 9, 
2016, and GE ASB CF34-8C SB 72-A0225 R03, issued on December 9, 2016. 
The ASB's describe procedures for repairing fan blade, part number (P/
N) 4114T15P02, to P/N 4114T31G01 with the installation of a bushing in 
the pinholes.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require initial and repetitive ECIs of the 
affected fan blade. This proposed AD would also require removal or 
repair of the affected fan blade at a reduced life. A fan blade

[[Page 17946]]

that has been repaired is eligible for an additional 28,000 cycles in 
service before it must be removed.

Differences Between This Proposed AD and the Service Information

    The determination in this proposed AD of CSN, when CSN is not 
known, is simpler and clearer than the method indicated in the service 
information. The service information has several options that may lead 
to confusion among operators in making this determination.

Costs of Compliance

    We estimate that this proposed AD affects 1,986 engines installed 
on airplanes of U.S. registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Initial ECI Inspection................  4 work-hours x $85 per                $0            $340        $675,240
                                         hour = $340.
Replacement of fan blade (prorated      0 work-hours x $85 per             5,460           5,460      10,843,560
 annual cost).                           hour = $0.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify 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),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, and
    (4) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

General Electric Company: Docket No. FAA-2017-0164; Directorate 
Identifier 2017-NE-06-AD.

(a) Comments Due Date

    We must receive comments by May 30, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) CF34-8C1, CF34-
8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-
8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6 and CF34-8E6A1 
engines, including engines marked on the engine data plate as CF34-
8C5B1/B, CF34-8C5/B, CF34-8C5A1/B, CF34-8C5A2/B, CF34-8C5/M, CF34-
8C5A1/M, CF34-8C5A2/M, CF34-8C5A3/B, or CF34-8C5B1/M, with a fan 
blade, part number (P/N) 4114T15P02 or P/N 4114T31G01, installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by analysis that resulted in the reduction 
of the life of the affected fan blades. We are issuing this AD to 
prevent failure of the fan blade, uncontained blade release, damage 
to the engine, and damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Eddy Current Inspections (ECIs)

    (1) For CF34-8C1, CF34-8C5B1, CF34-8C5B1/B and CF34-8E2 engines 
with fan blade, P/N 4114T15P02, installed:
    (i) Perform an initial ECI of the fan blade pinhole prior to the 
fan blade accumulating 25,000 cycles-since-new (CSN); and
    (ii) Repeat this inspection within every 3,000 cycles 
thereafter.
    (2) For CF34-8C5, CF34-8C5/B, CF34-8C5A1, CF34-8C5A1/B, CF34-
8C5A2, CF34-8C5A2/B, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E6 and 
CF34-8E6A1 engines with fan blade, P/N 4114T15P02, installed:
    (i) Perform an initial ECI of the fan blade pinhole prior to the 
fan blade accumulating 19,500 CSN; and
    (ii) Repeat this inspection within every 3,000 cycles 
thereafter, until the fan blade has accumulated 25,000 CSN, then 
repeat the inspection every 1,500 cycles thereafter.
    (3) For CF34-8C5/M, CF34-8C5A1/M, CF34-8C5A2/M, CF34-8C5A3, 
CF34-8C5A3/B, CF34-8C5B1/M, and CF34-8E5A2 engines with fan blade, 
P/N 4114T15P02, installed:
    (i) Perform an initial ECI of the fan blade pinhole prior to the 
fan blade accumulating 19,000 CSN; and
    (ii) Repeat this inspection within every 3,000 cycles 
thereafter, until the fan blade has accumulated 25,000 CSN, then 
repeat the inspection every 1,500 cycles thereafter.
    (4) For any affected engine with a fan blade, P/N 4114T15P02, 
installed where the CSN of the fan blade is unknown on the effective 
date of this AD:

[[Page 17947]]

    (i) Assume the blade has accumulated 25,000 CSN on the effective 
date of this AD; and
    (ii) Inspect the blade prior to installation or within 500 
cycles after the effective date of this AD, whichever is earlier.
    (5) If a fan blade is moved from one affected engine model to 
another affected model after the initial ECI:
    (i) Perform an additional ECI of the blade prior to installation 
in the new model; and
    (ii) Repeat this inspection based on the intervals of the new 
engine installation, as specified in paragraph (g) of this AD.
    (6) If a fan blade, P/N 4114T15P02, has been used on more than 
one engine model prior to the initial ECI, use Appendix A of GE 
Alert Service Bulletin (ASB) CF34-8C SB 72-A0137 R05, dated June 15, 
2016, or Appendix A of GE ASB CF34-8E SB 72-A0060 R05, dated June 
15, 2016, to calculate the new cycle limit for the initial 
inspection of that fan blade.

(h) Fan Blade Removal

    (1) For any affected engine with a fan blade, P/N 4114T15P02, 
installed, remove the blade from service or repair to P/N 4114T31G01 
prior to the blade accumulating 41,000 CSN.
    (2) For any affected engine with a fan blade, P/N 4114T31G01, 
installed, remove the blade from service prior to the blade 
accumulating 28,000 cycles since installation of the pinhole 
bushing.

(i) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures found in 14 CFR 39.19 to make your 
request. You may email your request to: ANE-AD-AMOC@faa.gov.

(j) Related Information

    (1) For more information about this AD, contact Martin Adler, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA 01803; 
phone: 781-238-7157; fax: 781-238-7199; email: martin.adler@faa.gov.
    (2) GE ASBs: CF34-8C SB 72-A0137 R05, dated June 15, 2016; CF34-
8E SB 72-A0060 R05, dated June 15, 2016; CF34-8E SB 72A0115 R03, 
issued December 9, 2016; and CF34-8C ASB 72-A0225 R03, issued 
December 9, 2016; can be obtained from GE using the contact 
information in paragraph (j)(3) of this AD.
    (3) For service information identified in this proposed AD, 
contact General Electric Company, GE-Aviation, Room 285, 1 Neumann 
Way, Cincinnati, OH 45215, phone: 513-552-3272; fax: 513-552-3329; 
email: geae.aoc@ge.com.
    (4) You may view this service information at the FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 
781-238-7125.

    Issued in Burlington, Massachusetts, on April 5, 2017.
Carlos A. Pestana,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2017-07477 Filed 4-13-17; 8:45 am]
 BILLING CODE 4910-13-P