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Proposed Rule

Airworthiness Directives; Dowty Propellers R408/6-123-F/17 Model Propellers

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Start Preamble

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: Friction or contact between a propeller de-ice bus bar and the backplate assembly can cause failure of the bus bar and a consequent intermittent short circuit. Such a short circuit can cause a dual AC generator shutdown that, particularly in conjunction with an engine failure in icing conditions, could result in reduced controllability of the airplane.

We are proposing this AD to prevent an in-flight double generator failure, which could result in reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by October 26, 2009.

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, Anson Business Park, Cheltenham Road East, Gloucester GL 29QN, UK; telephone: 44 (0) 1452 716000; fax: 44 (0) 1452 716001, for the service information identified in this proposed AD.

Examining the AD Docket

You may examine the AD docket on the Internet at http://Start Printed Page 48871www.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 (telephone (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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Terry Fahr, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: terry.fahr@faa.gov; telephone (781) 238-7155; fax (781) 238-7170.

End Further Info End Preamble Start Supplemental Information

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-2009-0776; Directorate Identifier 2009-NE-32-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 AD 2009-0114, dated May 28, 2009 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

Friction or contact between a propeller de-ice bus bar and the backplate assembly can cause failure of the bus bar and a consequent intermittent short circuit. Such a short circuit can cause a dual AC generator shutdown that, particularly in conjunction with an engine failure in icing conditions, could result in reduced controllability of the airplane.

For the reason described above, this AD requires initial and repetitive application of sealant between the propeller bus bar assemblies and the backplate assembly.

You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Dowty Propellers has issued Service Bulletin No. D8400-61-66, Revision 1, dated May 4, 2007. 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 propeller 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, they have 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 on other propellers of the same type design. This proposed AD would require initial applications of sealant between the bus bar assembly and the backplate assembly of line-replaceable units (LRU) serial numbers (SNs) below DAP0347, and repetitive applications of sealant on all R408/6-123-F/17 model propellers.

Differences Between This AD and the Service Information

We have reviewed the related service information and, in general, agree with its substance, which gives instructions on performing a one-time application of sealant for R408/6-123-F/17 model propellers with a hub, actuator, and backplate assembly LRU SNs below DAP0347. However, we have found it necessary to also require repetitive applications of sealant for all R408/6-123-F/17 model propellers, the same as the MCAI. This difference is described in a separate paragraph of the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 104 propellers installed on airplanes of U.S. registry. We also estimate that it would take about 2 work-hours per propeller to comply with this proposed AD. The average labor rate is $80 per work-hour. Required parts would cost about $20 per propeller. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $18,720.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects Start Printed Page 48872

The Proposed Amendment

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

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[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-2009-0776; Directorate Identifier 2009-NE-32-AD.

Comments Due Date

(a) We must receive comments by October 26, 2009.

Affected Airworthiness Directives (ADs)

(b) None.

Applicability

(c) This AD applies to Dowty Propellers R408/6-123-F/17 model propellers. These propellers are installed on, but not limited to, Bombardier, Inc. (formerly de Havilland Canada) models DHC-8-400, DHC-8-401, and DHC-8-402 series airplanes.

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 an in-flight double generator failure, which could result in reduced controllability of the airplane.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) For R408/6-123-F/17 model propellers with a hub, actuator, and backplate assembly line-replaceable unit (LRU) SNs below DAP0347, do the following initial sealant application within 5,000 flight hours (FH) after the effective date of this AD:

(i) Apply sealant between the bus bar assemblies and the backplate assembly.

(ii) Use paragraph 3 of the Accomplishment Instructions of Dowty Propellers Service Bulletin No. D8400-61-66, Revision 1, dated May 4, 2007, to do the sealant application.

(2) Thereafter, for all R408/6-123-F/17 model propellers, re-apply sealant as specified in paragraphs (e)(1)(i) through (e)(1)(ii) within every additional 10,000 FH.

Installation Prohibition

(3) After modification of all propellers on an airplane as required by paragraph (e)(1) of this AD, do not install any Dowty R408/6-123-F/17 propeller on that airplane unless sealant has been applied between the bus bar assemblies and the backplate assembly of that propeller using the requirements of this AD.

FAA AD Differences

(f) Dowty Propellers Service Bulletin No. D8400-61-66, Revision 1, dated May 4, 2007, requires a one-time application of sealant for R408/6-123-F/17 model propellers with a hub, actuator, and backplate assembly LRU SNs below DAP0347. However, this AD and the MCAI require repetitive applications of sealant for all R408/6-123-F/17 model propellers.

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 EASA AD 2009-0114, dated May 28, 2009, and Dowty Propellers Service Bulletin No. D8400-61-66, Revision 1, dated May 4, 2007, for related information. Contact Dowty Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL 29QN, UK; telephone: 44 (0) 1452 716000; fax: 44 (0) 1452 716001, for a copy of this service information.

(i) Contact Terry Fahr, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: terry.fahr@faa.gov; telephone (781) 238-7155; fax (781) 238-7170, for more information about this AD.

Start Signature

Issued in Burlington, MA, on September 21, 2009.

Peter A. White,

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

End Signature End Part End Supplemental Information

[FR Doc. E9-23209 Filed 9-24-09; 8:45 am]

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