Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 82, Number 169 (Friday, September 1, 2017)]
[Rules and Regulations]
[Pages 41508-41511]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-18570]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0164; Product Identifier 2017-NE-06-AD; Amendment 
39-19008; AD 2017-17-18]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

DATES: This AD is effective October 6, 2017.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of October 6, 
2017.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, GE--Aviation, Room 285, 1 Neumann 
Way, Cincinnati, OH 45215, phone: 513-552-3272; fax: 513-552-3329; 
email: [email protected]. You may view this service information at the 
FAA, Engine and Propeller Standards Branch, Policy and Innovation 
Division, 1200 District Avenue, Burlington, MA. For information on the 
availability of this material at the FAA, call 781-238-7125. It is also 
available on the internet at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2017-0164.

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 final rule, the regulatory evaluation, any comments 
received, and other information. The address for the Docket Office 
(phone: 800-647-5527) is Document Management Facility, U.S. Department 
of Transportation, Docket Operations, M-30, West Building

[[Page 41509]]

Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 
20590.

FOR FURTHER INFORMATION CONTACT: John Frost, Aerospace Engineer, FAA, 
ECO Branch, Compliance and Airworthiness Division, 1200 District 
Avenue, Burlington, MA 01803; phone: 781-238-7756; fax: 781-238-7199; 
email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain GE CF34-8 model 
turbofan engines. The NPRM published in the Federal Register on April 
14, 2017 (82 FR 17945). The NPRM was prompted by analysis that showed 
that the stresses in the pinholes, in the affected fan blades, could 
result in crack initiation at pinhole surfaces beyond 19,000, 19,500, 
or 25,000 cycles-since-new (CSN), depending on the engine model on 
which the blade is installed. The NPRM proposed to require initial and 
repetitive eddy current inspections (ECIs) and removal of affected fan 
blades before reaching 41,000 CSN. The NPRM also provided an option to 
repair affected blades, which allows for an additional 28,000 cycles 
before removal. 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.

Comments

    We gave the public the opportunity to participate in developing 
this final rule. The following presents the comments received on the 
NPRM and the FAA's response to each comment.
    The Air Line Pilots Association expressed support for the NPRM.

Request To Rescind the AD

    Republic Airlines requested that we rescind the AD action. Republic 
Airlines does not feel that the failure of the blade is an 
airworthiness issue that should be addressed by this AD. Republic 
Airlines feels that in the event of a failed blade, the aircraft could 
continue to a safe flight and landing. The failure would be evident 
operationally and the crews would take the appropriate steps to return 
the aircraft and its occupants safely to the closest airport.
    We disagree. Based on the analysis that resulted in the reduction 
of the life of the affected fan blades, the FAA determined an unsafe 
condition exists based on the extremely high number of forecasted 
events. We did not change this AD.

Request To Change Related Service Information

    J-Air & Horizon Air requested that we mandate the use of specific 
service bulletins in paragraph (g) of this AD. Paragraph (g) of this AD 
does not specify an ECI procedure.
    We partially agree. We disagree with mandating the use of specific 
service bulletins in paragraph (g) of this AD because that would 
preclude the use of other procedures that may be acceptable.
    However, we added a statement to compliance paragraph (g) in this 
AD indicating the GE service documents in which guidance can be found 
for performing the ECI.

Request To Add Repetitive Inspections Intervals

    Horizon Air requested that we provide instructions with regard to 
the repetitive inspection interval requirements for fan blades that 
have accumulated an unknown number of CSN.
    We agree. We added paragraph (g)(4)(iii) of this AD to mandate a 
repetitive inspection.

Request To Add Terminating Action

    Horizon Air requested that we provide a designated paragraph for 
terminating action. Although paragraph (h) of this AD provides fan 
blade, part number (P/N) 4114T31G01, as a repair option, the repair is 
not specifically given as a means to terminate the repetitive 
inspections required for fan blade, P/N 4114T15P02.
    We disagree. This AD requires repetitive inspections only for fan 
blade, P/N 4114T15P02. Therefore, once a fan blade is repaired to P/N 
4114T31G01, a repetitive inspection is not required. We did not change 
this AD.

Request To Update Service Information

    Horizon Air requested that all references to GE Alert Service 
Bulletin (ASB) CF34-8E SB 72-A0115, R03 be revised to R04.
    We agree. We revised this AD to refer to the latest service 
information revision and date.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this final rule with the changes described previously and minor 
editorial changes. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for correcting the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    We reviewed GE ASB CF34-8C SB 72-A0137, Revision 5 (R05), dated 
June 15, 2016. This ASB identifies an approved inspection method and 
provides the procedures necessary for calculating the adjusted CSN for 
the initial inspection of CF34-8C fan blades.
    We also reviewed CF34-8E ASB 72-A0060, Revision 5 (R05), dated June 
15, 2016. This ASB identifies an approved inspection method and 
provides the procedures necessary for calculating the adjusted CSN for 
the initial inspection of CF34-8E fan blades.
    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 ASBs CF34-8E SB 72-A0115, R04, dated December 9, 
2016; and CF34-8C SB 72-A0225, R03, dated December 9, 2016. These ASBs 
describe procedures for repairing fan blade, part number (P/N) 
4114T15P02 to P/N 4114T31G01, with the installation of a bushing in the 
pinholes.

Costs of Compliance

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

[[Page 41510]]



                                                 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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to engines, propellers, and 
associated appliances to the Manager, Engine and Propeller Standards 
Branch, Policy and Innovation Division.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (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),
    (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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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):

2017-17-18 General Electric Company: Amendment 39-19008; Docket No. 
FAA-2017-0164; Product Identifier 2017-NE-06-AD.

(a) Effective Date

    This AD is effective October 6, 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-C8C5A2/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:
    (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.
    (iii) Repeat this inspection based on the intervals of the new 
engine installation, as specified in paragraph (g) of this AD.
    (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

[[Page 41511]]

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.
    (7) Guidance on performing the ECI can be found in GE Service 
Bulletins GE ASB CF34-8C SB 72-A0137, R05, dated June 15, 2016, or 
GE ASB CF34-8E SB 72-A0060, R05, dated June 15, 2016.

(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)

    (1) The Manager, FAA, ECO Branch, Compliance and Airworthiness 
Division, has the authority to approve AMOCs for this AD, if 
requested using the procedures found in 14 CFR 39.19. In accordance 
with 14 CFR 39.19, send your request to your principal inspector or 
local Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ECO Branch, send it to 
the attention of the person identified in paragraph (i)(1) of this 
AD. You may email your request to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    (1) For more information about this AD, contact John Frost, 
Aerospace Engineer, FAA, ECO Branch, Compliance and Airworthiness 
Division, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7756; fax: 781-238-7199; email: [email protected].
    (2) GE ASB CF34-8E SB 72-A0115, R04, dated December 9, 2016, and 
GE ASB CF34-8C SB 72-A0225, R03, dated December 9, 2016, can be 
obtained from GE using the contact information in paragraph (k)(3) 
of this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) General Electric Company (GE) Alert Service Bulletin (ASB) 
CF34-8C SB 72-A0137, Revision 5 (R05), dated June 15, 2016.
    (ii) GE ASB CF34-8E SB 72-A0060, Revision 5 (R05), dated June 
15, 2016.
    (3) For General Electric Company service information identified 
in this AD, contact General Electric Company, GE-Aviation, Room 285, 
1 Neumann Way, Cincinnati, OH 45215, phone: 513-552-3272; fax: 513-
552-3329; email: [email protected].
    (4) You may view this service information at FAA, Engine and 
Propeller Standards Branch, Policy and Innovation Division, 1200 
District Avenue, Burlington, MA. For information on the availability 
of this material at the FAA, call 781-238-7125.
    (5) You may view this service information at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call 202-741-6030, or go to: 
http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Burlington, Massachusetts, on August 29, 2017.
Robert J. Ganley,
Manager, Engine and Propeller Standards Branch, Aircraft Certification 
Service.
[FR Doc. 2017-18570 Filed 8-31-17; 8:45 am]
BILLING CODE 4910-13-P

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