DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0719; Product Identifier 2016-NE-24-AD]
RIN 2120-AA64

Airworthiness Directives; Honeywell International Inc. Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2017-20-
01, which applies to certain Honeywell International Inc. (Honeywell)
TFE731-20 and TFE731-40 turbofan engines. AD 2017-20-01 requires
removing the affected fan disk and replacing it with a fan disk
eligible for installation. Since we issued AD 2017-20-01, we determined
that some turbofan engine models were omitted from the applicability of
AD 2017-20-01. This proposed AD would add these turbofan engine models
to the applicability, remove the Honeywell TFE731-20 turbofan engine
from the applicability, and prohibit installation of affected fan
disks. We are proposing this AD to address the unsafe condition on
these products.

DATES: We must receive comments on this proposed AD by October 29, 2018.

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 Honeywell
International Inc., 111 S. 34th Street, Phoenix, AZ, 85034-2802; phone:
800-601-3099 (Toll Free U.S.A./Canada); 602-365-3099 (International
Direct); website: www.myaerospace.com; email:
engine.reliability@honeywell.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.

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-
0719; 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 NPRM, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations (phone: 800-647-
5527) is listed above. Comments will be available in the AD docket
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer, Los
Angeles ACO Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA, 90712-
4137; phone: 562-627-5246; fax: 562-627-5210; email:
joseph.costa@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2018-0719;
Product Identifier 2016-NE-24-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 proposed AD.

Discussion

We issued AD 2017-20-01, Amendment 39-19058 (82 FR 45173, September
28, 2017), ("AD 2017-20-01"), for certain Honeywell TFE731-20 and
TFE731-40 turbofan engines with fan disk part number, (P/N) 3060287-2,
and a serial number (S/N) listed in Table 9 of Honeywell Service
Bulletin (SB) TFE731-72-5256, Revision 0, dated October 7, 2016. AD
2017-20-01 requires removing the affected fan disk and replacing it
with a part eligible for installation. AD 2017-20-01 resulted from two
fan disks found with surface rollovers in the dovetail slot area. We
issued AD 2017-20-01 to address the unsafe condition on these products.

Actions Since AD 2017-20-01 Was Issued

Since we issued AD 2017-20-01, we determined that Honeywell TFE731-
20R, -20AR, -20BR, and TFE731-40R, -40AR, and -40BR turbofan engine
models listed in Honeywell SB TFE731-72-5256, Revision 0, dated October
7, 2016, were omitted from the applicability of AD 2017-20-01. We also
determined that the Honeywell TFE731-20 turbofan engine model was never
produced and should be removed from the applicability; and that
affected fan disks, P/N 3060267-2, should be prohibited from
installation unless they have "T43374" marked adjacent to the engine
P/N or S/N. This proposed AD would add Honeywell TFE731-20R, -20AR, -
20BR, and TFE731-40R, -40AR, and -40BR turbofan engine models to the
applicability, remove the Honeywell TFE731-20 turbofan engine from the
applicability, and prohibit installation of affected fan disks.

Related Service Information Under 1 CFR Part 51

We reviewed Honeywell SB TFE731-72-5256, Revision 0, dated October
7, 2016. The SB identifies affected fan disks by S/N and describes
procedures for removing, inspecting, and replacing the affected fan
disks. 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.

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 retain certain requirements of AD 2017-20-
01. This proposed AD would add Honeywell TFE731-20R, -20AR, -20BR, and
TFE731-40AR, -40BR, and -40R turbofan engines with fan disk, P/N
3060287-2, and a S/N listed in Table 9 of Honeywell SB TFE731-72-5256,
Revision 0, dated October 7, 2016. This proposed AD would also remove
the Honeywell TFE731-20 turbofan engine from the applicability and
prohibit installation of affected fan disks that do not have "T43374"
marked adjacent to the engine P/N or S/N.

Costs of Compliance

We estimate that this proposed AD affects 61 engines installed on
airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

The new requirements of this proposed AD add no additional economic
burden. We estimate the following costs to do any necessary fan disk
replacements that would be required based on the results of the
proposed inspection. We estimate that 6 engines will need this
replacement.

On-Condition Costs

According to the manufacturer, some of the costs of this proposed
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
associated appliances to the Manager, Engine and Propeller Standards
Branch, Policy and Innovation Division.

Regulatory Findings

We have 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 that the 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, 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

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 removing Airworthiness Directive (AD)
2017-20-01, Amendment 39-19058; (82 FR 45173, September 28, 2017), and
adding the following new AD: