DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-9451; Product Identifier 2016-NE-24-AD; Amendment
39-19058; AD 2017-20-01]
RIN 2120-AA64

Airworthiness Directives; Honeywell International Inc. 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 all
Honeywell International Inc. (Honeywell) TFE731-20 and TFE731-40
turbofan engines. This AD was prompted by two fan disks found with a
manufacturing-caused flaw. This AD requires removing affected fan disks
and replacing fan disks with a part eligible for installation. We are
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective November 2, 2017.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of November 2,
2017.

ADDRESSES: For service information identified in this final rule,
contact Honeywell International Inc., 111 S. 34th Street, Phoenix, AZ
85034-2802; phone: 800-601-3099; Internet: https://myaerospace.honeywell.
com/wps/portal. 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) 238-7125.
It is also available on the internet at http://www.regulations.gov by
searching for and locating Docket No. FAA-2016-9451.

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-2016-
9451; 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 Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer, Los
Angeles ACO Branch, FAA, 3960 Paramount Blvd., Lakewood, CA 90712-4137;
phone: 562-627-5246; fax: 562-627-5210; email: joseph.costa@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 all Honeywell TFE731-20 and
TFE731-40 turbofan engines. The NPRM published in the Federal Register
on March 7, 2017 (82 FR 12755). The NPRM was prompted by two fan disks
found with a manufacturing-caused flaw. The NPRM proposed to require
removing the affected fan disks, performing a one-time inspection, and
replacing fan disks that fail inspection. We are issuing this AD to
prevent uncontained failure of the fan disks, damage to the engine, and
damage to the airplane.

Comments

We gave the public the opportunity to participate in developing
this final rule. We have considered the comment received.

Miscellaneous Comment

We received a comment regarding Honeywell as a company that was not
relevant to this AD. No further discussion is required.

Changes to This AD

Based on further review, we made the following changes to this AD.
We corrected the cost per product estimate under ``On-condition
costs'' in the Costs of Compliance section of the NPRM from $300,510 to
$50,085 in this AD. The cost per product in the NPRM incorrectly
estimated the cost for six engines rather than for one engine. On
further review, we also redefined the work hours needed to install the
new or reworked fan disk. The 8 work hours to inspect the fan disk were
listed as a separate item in the NPRM but, in this final rule, we added
these work hours to the estimated cost of installing the reworked or
new fan disk. The overall estimated cost of this work per engine
remains the same.
We corrected the product identification from ``Honeywell
International Inc. (Type Certificate previously held by AlliedSignal
Inc., Garrett Engine Division; Garrett Turbine Engine Company; and
AiResearch Manufacturing Company of Arizona)'' to ``Honeywell
International Inc. (Type Certificate previously held by AlliedSignal
Inc.).''
We removed paragraph (g)(4) of the NPRM which required inspection
of the removed fan disks in accordance with paragraph 3.D.(2) in the
Accomplishment Instructions of Honeywell SB TFE731-72-5256, Revision 0,
dated October 7, 2016. Although fan disks may be returned to Honeywell
for inspection and rework to become eligible for installation, that is
not a requirement of this AD.
We revised the definition of ``parts eligible for installation'' in
paragraph (g) of this AD to read: ``For the purposes of this AD, parts
eligible for installation are: (i) Fan disks not listed in the
Accomplishment Instructions, Table 9, in Honeywell SB TFE731-72-5256,
Revision 0, dated October 7, 2016; or (ii) fan disks listed in Table 9
that have been inspected, reworked, and marked with ``T43374'' adjacent
to the P/N or S/N. Guidance on returning affected parts to Honeywell
for inspection and rework is found in the Accomplishment Instructions,
paragraph 3.D., of Honeywell SB TFE731-72-5256.'' This definition
clarifies that fan disks with a P/N not affected by this AD, as well as
parts that have been reworked and remarked, are eligible for
installation.

Conclusion

We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting this
final rule as proposed for minor editorial changes and the additional changes
explained above. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

We reviewed Honeywell Service Bulletin (SB) TFE731-72-5256,
Revision 0, dated October 7, 2016. The SB identifies affected fan disks
by serial number and describes procedures for removing, inspecting, and
replacing the fan disks. This service information is available by the
means identified in the ADDRESSES section.

Costs of Compliance

We estimate that this AD affects 61 engines 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 disk
replacements that would be required based on the results of the
required inspection. We estimate that 6 engines will need this
replacement:

On-Condition Costs

According to the manufacturer, some of the costs of this AD may be
covered under warranty, thereby reducing the cost impact on affected
individuals. We do not control warranty coverage for affected
individuals. As a result, we have included all costs in our cost
estimate.

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
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

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):