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

[Federal Register Volume 75, Number 162 (Monday, August 23, 2010)]
[Rules and Regulations]
[Pages 51656-51657]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-20707]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0776; Directorate Identifier 2009-NE-32-AD; 
Amendment 39-16403; AD 2010-17-11]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. 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. 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 issuing this AD to prevent an in-flight double generator 
failure, which could result in reduced controllability of the airplane.

DATES: This AD becomes effective September 27, 2010. The Director of 
the Federal Register approved the incorporation by reference of certain 
publications listed in this AD as of September 27, 2010.

ADDRESSES: The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

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: [email protected]; telephone (781) 238-7761; fax (781) 238-
7170.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on September 25, 2009 
(74 FR 48870). That NPRM proposed to correct an unsafe condition for 
the specified products. The MCAI states that:

    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.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received.
    One commenter, a private citizen, requests that the AD allow 
propellers modified under earlier revisions of the service bulletin to 
meet the requirements of the AD, as the modification instructions are 
the same.
    We agree. We added a paragraph that allows for previous credit for 
initial sealant application done before the effective date of the AD 
using earlier versions of the service bulletin. We also reference using 
Dowty Propellers Alert Service Bulletin No. D8400-61-A66, Revision 5, 
dated June 16, 2010 in the compliance section, which is the latest 
version. Since Revision 5 of the ASB requires repetitive applications 
of sealant, we eliminated the AD differences that appeared in the 
proposed AD.

Conclusion

    We reviewed the available data, including the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously. We determined that these 
changes will not increase the economic burden on any operator or 
increase the scope of the AD.

Costs of Compliance

    Based on the service information, we estimate that this AD will 
affect about 104 propellers installed on airplanes of U.S. registry. We 
also estimate that it will take about 2 work-hours per propeller to 
comply with this AD. The average labor rate is $80 per work-hour. 
Required parts will cost about $20 per propeller. Based on these 
figures, we estimate the cost of the 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 AD will not have federalism implications 
under Executive Order 13132. This AD will 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 AD:
    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 AD and placed it in the AD docket.

[[Page 51657]]

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 AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (phone (800) 647-5527) is provided in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2010-17-11 Dowty Propellers (formerly Dowty Aerospace; Dowty Rotol 
Limited; and Dowty Rotol): Amendment 39-16403. Docket No. FAA-2009-
0776; Directorate Identifier 2009-NE-32-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective 
September 27, 2010.

Affected 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 serial numbers 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 Alert Service Bulletin No. D8400-61-A66, Revision 5, 
dated June 16, 2010, 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) None.

Previous Credit

    (g) Sealant application performed before the effective date of 
this AD using Dowty Propellers Service Bulletin No. D8400-61-66, 
dated February 9, 2007, Revision 1, dated May 4, 2007, Alert Service 
Bulletin No. D8400-61-A66, Revision 2, dated August 19, 2009, 
Revision 3, dated November 10, 2009, Revision 4, dated January 19, 
2010, or Revision 5, dated June 16, 2010, satisfies the initial 
sealant application requirement of this AD.

Alternative Methods of Compliance (AMOCs)

    (h) 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

    (i) Refer to EASA AD 2009-0114, dated May 28, 2009, for related 
information.
    (j) Contact Michael Schwetz, Aerospace Engineer, Boston Aircraft 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7761; fax (781) 238-
7170, for more information about this AD.

Material Incorporated by Reference

    (k) You must use Dowty Propellers Alert Service Bulletin No. 
D8400-61-A66, Revision 5, dated June 16, 2010, to do the actions 
required by this AD.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact Dowty 
Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL 
29QN, UK; telephone: 44 (0) 1452 716000; fax: 44 (0) 1452 716001.
    (3) You may review copies at the FAA, New England Region, 12 New 
England Executive Park, Burlington, MA; or at the National Archives 
and Records Administration (NARA). For information on the 
availability of this material at NARA, call (202) 741-6030, or go 
to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Burlington, Massachusetts, on August 5, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-20707 Filed 8-20-10; 8:45 am]
BILLING CODE 4910-13-P

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