[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). 

SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Dowty 

Propellers R352/6-123-Fil, 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 [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

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 Wl2-140, Washington, DC 

20590-0001. 
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-andoverhaul. 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. F AA-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. F AA-2015-3661; Directorate Identifier 20 15-NE-24-AD" at the 

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We vvill post all comments we receive, vvithout 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 

smcenew. 

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. 

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identifying 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 M 1 OM34, 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 identifying 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. 

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authority. 

We are issuing this rulemaking under tl1e 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 munber of small entities under the criteria of the Regulatory Flexibility Act. 

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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. 

§ 39.13 [Amended] 

2. The FAA amends§ 39.13 by adding the following new airworthiness directive 

(AD): 

Dowty Propellers: Docket No. FAA-2015-3661; Directorate Identifier 2015-NE-24-AD. 

(a) Comments Due Date 

We must receive comments by [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Dowty Propellers R352/6-123-F/l, R352/6-123-F/2, and 

R410/6-123-F/35 model propellers, part numbers (PINs) 660715001,660715004, and 

660715005 with hub PINs 660715201, 660715255, 660720217, 660720241, 660720252, 

660720260, and 660720288, installed. 

(d) Reason 

This AD was prompted by reports of dowel hole cracks in the face of the rear hub 

half. We are issuing 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. 

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(i) Review propeller maintenance records to determine if the affected propeller 

hub has been repaired in accordance with Dowty Propellers Alert Service Bulletin (ASB) 

No. F50-61-A165 Revision 2, dated July 28, 2015. 

(ii) If, during the maintenance records review required by paragraph (e)(l )(i) of 

this AD, an affected hub is found not repaired then, before next' flight, install liners into 

the hub location dowel holes and mark the hub. Use Dowty Propellers ASB No. F50-61-

A165 Revision 2, dated July 28,2015 to install the liners and mark the hub. 

(iii) If, during the maintenance records review required by paragraph (e)(1)(i) of 

this AD, an affected hub is found repaired then, before next flight, mark the hub using 

Dowty Propellers ASB No. F50-61-Al65 Revision 2, dated July 28, 2015. 

(f) Credit for Previous Actions 

(1) You may take credit for maintenance records reviews and installations that are 

required by paragraph (e) of this AD if you performed these actions before the effective 

date of this AD using Dowty Propellers ASB No. F50-61-Al65 Revision I, dated May 

12,2015 or initial issue dated November 19,2012. 

(2) You may take credit for any maintenance records reviews or corrective actions 

that are required by paragraph (e) of this AD if you performed these actions before the 

effective date of this AD using Component Maintenance Manual (CMM) 61-10-34, 

Repair No. 53, dated August 11, 2008, which relates to repair scheme 650510057. 

(g) Alternative Methods of Compliance (AMOCs) 

The Manager, Boston Aircraft Certification Office, FAA, may approve AMOCs 

for this AD. Use the procedures found in 14 CFR 39.19 to make your request. 

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michael.schwetz@faa.gov. 

(2) Refer to MCAI European Aviation Safety Agency AD 2015-0158, dated July 

30, 2015, for more information. You may examine the MCAI in the AD docket on the 

Internet at http://www.regulations.gov by searching for and locating it in Docket No. 

FAA-2015-3661. 

(3) Dowty Propellers ASB No. F50-61-Al65 Revision 2, dated July 28,2015 and 

CMM 61-10-34, Repair No. 53, dated August II, 2008 can be obtained from Dowty 

Propellers, using the contact information in paragraph (h)( 4) of this proposed AD. 

( 4) 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. 

( 5) 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. 

Issued in Burlington, Massachusetts, on September xx, 2015. 

Colleen M. D' Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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