DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-3661; Directorate Identifier 2015-NE-24-AD]
RIN 2120-AA64

Airworthiness Directives; Dowty Propellers Constant Speed
Propellers

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 Dowty Propellers R352/6-123-F/1, R352/6-123-F/2, and R410/6-
123-F/35 model propellers. This proposed AD was prompted by reports of
dowel hole cracks in the face of the rear hub half. This proposed AD
would require a records review to determine repair status and marking
the affected propeller hubs as required. This proposed AD would also
require installing dowel hole liners as necessary. We are proposing
this AD to prevent loss of structural integrity of the propeller hub,
which could result in damage to the propeller and damage to the
airplane.

DATES: We must receive comments on this proposed AD by December 14,
2015.

ADDRESSES: You may send comments by any of the following methods:

Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the
instructions for submitting comments.

Mail: Docket Management Facility, U.S. Department of
Transportation, 1200 New Jersey Avenue SE., West Building Ground Floor,
Room W12-140, Washington, DC 20590-0001.

Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Fax: 202-493-2251.

For service information identified in this proposed AD, contact
Dowty Propellers, 114 Powers Court, Sterling, VA 20166; phone: 703-421-
4434; fax: 703-450-0087; email: technicalsupport@dowty.com; Internet:
www.http://dowty.com/services/repair-and-overhaul. You may view this
service information at the FAA, Engine & Propeller Directorate, 12 New
England Executive Park, 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-2015-
3661; or in person at the Docket Operations office between 9 a.m. and 5
p.m., Monday through Friday, except Federal holidays. The AD docket
contains this proposed AD, the mandatory continuing airworthiness
information (MCAI), the regulatory evaluation, any comments received,
and other information. The 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: Michael Schwetz, Aerospace Engineer,
Boston Aircraft Certification Office, FAA, Engine & Propeller
Directorate, 12 New England Executive Park, Burlington, MA 01803;
phone: 781-238-7761; fax 781-238-7170; email: michael.schwetz@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-2015-3661;
Directorate Identifier 2015-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 based on 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
with FAA personnel concerning this NPRM.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical
Agent for the Member States of the European Community, has issued EASA
AD 2015-0158, dated July 30, 2015 (referred to hereinafter as "the
MCAI"), to correct an unsafe condition for the specified products. The
MCAI states:

Cracking around the hub location dowel holes in the face of the
rear hub half has occurred sporadically. Previous investigations
found no manufacturing defects in cracked hubs and concluded that
the hub cracking was caused by damage to the dowel holes during
propeller installation.

Since that original SB was issued, three hubs have been found to
show cracking around the location dowel holes. The hubs were all
found cracked within a short period of time and all had low time
since new.

This condition, if not detected, can adversely affect the
structural integrity of the propeller hub, with possible damage to
the propeller and to the aeroplane.

You may obtain further information by examining the MCAI in the AD
docket on the Internet at http://www.regulations.gov by searching for
and locating Docket No. FAA-2015-3661.

Related Service Information Under 1 CFR Part 51

Dowty Propellers has issued Alert Service Bulletin (ASB) No. F50-
61-A165, Revision 2, dated July 28, 2015. The service information
describes procedures for installing liners in the hub location dowel
holes in the face of the rear hub half and marking the hub with the
repair number. 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 of this
NPRM.

Other Related Service Information

Dowty Propellers has issued Component Maintenance Manual, 61-10-34,
Repair No. 53, dated May 15, 2013. The service information describes
procedures for installing liners in the hub location dowel holes and
marking the repair number on modified hubs.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of the
United Kingdom, and is approved for operation in the United States.
Pursuant to our bilateral agreement with the European Community, EASA
has notified us of the unsafe condition described in the MCAI and
service information referenced above. We are proposing this NPRM
because we evaluated all information provided by EASA and determined
the unsafe condition exists and is likely to exist or develop on other
products of the same type design. This NPRM would require marking and
inspecting the affected propeller hubs to determine repair status and
installing dowel hole liners as necessary.

Costs of Compliance

We estimate that this proposed AD would affect 4 propellers
installed on airplanes of U.S. registry. We also estimate that it would
take about 5 hours per propeller to comply with this proposed AD. The
average labor rate is $85 per hour. Required parts cost about $322 per
propeller. Based on these figures, we estimate the cost of this
proposed AD on U.S. operators to be $2,988.

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

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):