Document ID: FAA-2009-0776-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Dowty Propellers R408/6-123-F/17 Model Propellers
Posted Date: 2009-09-25T04:00Z

[Federal Register: September 25, 2009 (Volume 74, Number 185)]
[Proposed Rules]               
[Page 48870-48872]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25se09-21]                         

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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]
RIN 2120-AA64

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

[[Page 48871]]

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 (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.

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.

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.

List of Subjects in 14 CFR Part 39

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

[[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:

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 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.

    Issued in Burlington, MA, on September 21, 2009.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E9-23209 Filed 9-24-09; 8:45 am]

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