DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0142; Product Identifier 2018-NE-04-AD; Amendment
39-19368; AD 2018-17-14]
RIN 2120-AA64

Airworthiness Directives; General Electric Company CF34-8E 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) CF34-8E turbofan engines. This AD was
prompted by a report from GE regarding a quality escape of
nonconforming thrust reverser fire seals. This AD requires a one-time
inspection of the gap between the core cowl seal and the pylon seal of
the thrust reverser for correct gap width, and replacement of the
seals, if needed. We are issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective November 7, 2018.

ADDRESSES: For service information identified in this final rule,
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215;
telephone 513-552-3272; email: aviation.fleetsupport@ge.com. You may
view this service information at the FAA, Engine and Propeller
Standards Branch, 1200 District Avenue, Burlington, MA 01803. For
information on the availability of this material at the FAA, call 781-
238-7759. It is also available on the internet at http://www.regulations.gov
by searching for and locating Docket No. FAA-2018-0142.

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-2018-
0142; or in person at Docket Operations 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 Docket Operations (phone: 800-647-
5527) is U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC, 20590.

FOR FURTHER INFORMATION CONTACT: David Bethka, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7129; fax: 781-238-7199; email: david.bethka@faa.gov.

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 CF34-8E turbofan
engines. The NPRM published in the Federal Register on April 17, 2018
(83 FR 16794). The NPRM was prompted by a report from the manufacturer
about a fire seal gap quality escape on GE CF34-8E turbofan engines.
Some thrust reverser fire seals, installed on thrust reverser part
numbers (P/Ns) 15G0002-013, 15G0002-014, 15G0003-013, and 15G0003-014,
were shipped from a supplier with nonconforming seal gaps. The NPRM
proposed to require a one-time inspection of the gap between the core
cowl seal and the pylon seal of the thrust reverser for correct gap
width, and replacement of the thrust reverser fire seals, if needed. We
are issuing this AD to address the unsafe condition on these products.

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.

Request To Change the Applicability

Two commenters, Horizon Air and Republic Airline, requested that we
limit the applicability of this AD to a specific group of GE CF34-8E
turbofan engine thrust reverser halves that are known to have a fire
seal gap nonconformance. A change of applicability from all GE CF34-8E
turbofan engines to only the known group of affected thrust reverser
halves would reduce the inspection burden on operators.
We agree. We changed the applicability of this AD to list only the
affected half thrust reverser P/Ns and serial numbers. We also updated
the number of affected thrust reverser assemblies and estimated costs.

Request To Change Required Actions

Horizon Air requested that we change the required actions of this
AD to replace ``all GE CF34-8E turbofan engines'' with ``all thrust
reversers listed in paragraph (c).''
We agree. We reworded the required actions of this AD to indicate
that these actions are only required for GE CF34-8E turbofan engines with
affected half thrust reversers installed.

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:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
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

We reviewed GE CF34-8E Service Bulletin (SB) 78-0066 R01, dated
June 20, 2018. The SB describes procedures for measuring the width of
the RTV filled gap between the thrust reverser fire seals at the 12
o'clock core cowl seal and pylon seal installed on thrust reverser P/Ns
15G0002-013, 15G0002-014, 15G0003-013, and 15G0003-014, and replacing
with parts eligible for installation, if needed.

Costs of Compliance

We estimate that this AD affects 194 thrust reverser assemblies
installed on airplanes of U.S. registry.
We estimate the following costs to comply with this AD:

Estimated Costs

We estimate the following costs to do any necessary replacements
that would be required based on the results of the proposed inspection.
We have no way of determining the number of aircraft that might need
these replacements:

On-Condition Costs

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, 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

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