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Proposed Rule

Airworthiness Directives; Dowty Propellers Type R212/4-30-4/22 and R251/4-30-4/49 Propeller Assemblies

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Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Reports have been received from a small number of HS.748 operators of finding cracks in the propeller hub port buttress threads of R212 and R251 propellers. The affected hubs had accumulated in excess of 6,000 flight hours. This condition, if not detected and corrected, could lead to propeller blade separation, possibly resulting in damage to the aeroplane and/or injury to persons on the ground.

We are proposing this AD to prevent propeller hub failure due to cracks in the hub, which could result in damage to the airplane.

DATES:

We must receive comments on this proposed AD by June 27, 2011.

ADDRESSES:

You may send comments by any of the following methods:

  • Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • 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.

Contact Dowty Propellers, 114 Powers Court, Sterling, VA 20166, telephone (703) 421-4434; fax (703) 450-0087, for the service information identified in this proposed AD.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​ 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 regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (phone (800) 647-5527) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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FOR FURTHER INFORMATION CONTACT:

Michael Schwetz, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: michael.schwetz@faa.gov; telephone (781) 238-7761; fax (781) 238-7170.

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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-2011-0033; Directorate Identifier 2011-NE-01-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD 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 proposed AD. Using the search function of the Web site, anyone can find and read the comments in any of our dockets, including, if provided, the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78).

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2011-0012, dated January 20, 2011 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

Reports have been received from a small number of HS.748 operators of finding cracks in the propeller hub port buttress threads of R212 and R251 propellers. The affected hubs had accumulated in excess of 6,000 flight hours. This condition, if not detected and corrected, could lead to propeller blade separation, possibly resulting in damage to the aeroplane and/or injury to persons on the ground.

The cracks originating from the root of the buttress threads in the blade ports, are caused by high-cycle fatigue. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Dowty Propellers has issued Alert Service Bulletin (ASB) No. 61-1043, Revision 6, dated January 5, 2011. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

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 United Kingdom, EASA has notified us of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all information provided by EASA and determined the unsafe condition exists and is likely to exist or develop in other products of the same type design. This proposed AD would require initial and repetitive Start Printed Page 27282inspections of the buttress threads in the propeller hub ports for cracks.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 2 propellers installed on one airplane of U.S. registry. We also estimate that it would take about 1 work-hour per propeller to comply with this proposed AD. The average labor rate is $85 per work-hour. Required parts would cost about $20,000 per propeller. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $40,170.

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); and

3. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

Dowty Propellers (formerly Dowty Aerospace; Dowty Rotol Limited; and Dowty Rotol): Docket No. FAA-2011-0033; Directorate Identifier 2011-NE-01-AD.

Comments Due Date

(a) We must receive comments by June 27, 2011.

Affected Airworthiness Directives (ADs)

(b) None.

Applicability

(c) This AD applies to Dowty Propellers type R212/4-30-4/22 propeller assemblies with hub and driving center assembly part number (P/N) 601022105, 601022211, 601022294, 601021426, 601021858, or 601021859 installed, and type R251/4-30-4/49 propeller assemblies with hub and driving center assembly P/N 660207202 or P/N 660207203 installed.

Reason

(d) This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. We are issuing this AD to prevent propeller hub failure due to cracks in the hub, which could result in damage to the airplane.

Actions and Compliance

(e) Unless already done, do the following:

(1) Within 500 flight hours after the effective date of this AD, and thereafter at intervals not exceeding 500 flight hours, inspect the buttress threads in the propeller hub and driving center assembly, for cracks.

(2) Use paragraphs 2.A.(1) through 2.A.(4)(a) of Accomplishment Instructions of Dowty Propellers Alert Service Bulletin No. 61-1043, Revision 6, dated January 5, 2011, and NDT Technique NDT 175U (Appendix A of Dowty Propellers Alert Service Bulletin No. 61-1043, Revision 6, dated January 5, 2011), to do the inspection.

(3) If a crack is found, remove the propeller assembly from service before further flight.

(4) After the effective date of this AD, do not install this propeller on any airplane unless the propeller hub and driving center has passed the inspections required by this AD.

FAA AD Differences

(f) This AD differs from the service information as follows:

(1) Although the service bulletin tells you to return the affected parts to the manufacturer, this AD does not require that action.

(2) Although the service bulletin tells you to submit information to the manufacturer, this AD does not require that action.

Alternative Methods of Compliance (AMOCs)

(g) The Manager, Boston Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(h) Refer to MCAI European Aviation Safety Agency AD 2011-0012, dated January 20, 2011, and Dowty Propellers Alert Service Bulletin No. 61-1043, Revision 6, dated January 5, 2011, for related information. Contact Dowty Propellers, 114 Powers Court, Sterling, VA 20166, telephone (703) 421-4434; fax (703) 450-0087, for a copy of this service information.

(i) Contact Michael Schwetz, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: michael.schwetz@faa.gov; telephone (781) 238-7761; fax (781) 238-7170, for more information about this AD.

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Issued in Burlington, Massachusetts, on April 28, 2011.

Peter A. White,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. 2011-11480 Filed 5-10-11; 8:45 am]

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