
[Federal Register Volume 77, Number 38 (Monday, February 27, 2012)]
[Proposed Rules]
[Pages 11421-11423]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-4448]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0071; Directorate Identifier 2012-NE-05-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada, Auxiliary Power 
Units

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 
certain serial numbers of Pratt & Whitney Canada (P&WC) PW901A 
auxiliary power units (APUs) approved under Technical Standard Order 
TSO-C77A and installed on, but not limited to, Boeing 747-400 series 
airplanes. This proposed AD was prompted by several events of high-
pressure turbine blade fracture leading to separation of the rear gas 
generator case and release of high energy debris. This proposed AD 
would require modifications of the rear gas generator case, exhaust 
duct support, and turbine exhaust duct flanges. We are proposing this 
AD to prevent separation of the rear gas generator case and release of 
high energy debris, which could result in injury and damage to the 
airplane.

DATES: We must receive comments on this proposed AD by April 27, 2012.

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.
    For service information identified in this proposed AD, contact 
Pratt & Whitney Canada Corp., 1000 Marie-Victorin, Longueuil, Quebec, 
Canada J4G 1A1; phone: 450-677-9411. You may review copies of the 
referenced 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.

[[Page 11422]]

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.

FOR FURTHER INFORMATION CONTACT: Mazdak Hobbi, Aerospace Engineer, New 
York Aircraft Certification Office, FAA, Engine & Propeller 
Directorate, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 
516-228-7330; fax: 516-794-5531; email: mazdak.hobbi@faa.gov.

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-2012-0071; 
Directorate Identifier 2012-NE-05-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

    Transport Canada, which is the aviation authority for Canada, has 
issued Canada AD CF-2011-40, dated October 26, 2011 (referred to after 
this as ``the MCAI''), to correct an unsafe condition for the specified 
products. The MCAI states:

    The PW901A Auxiliary Power Units have experienced several events 
of High Pressure Turbine (HPT) blade fracture, some of which have 
resulted in the separation of the rear gas generator case, exhaust 
duct support, the turbine exhaust duct flanges and the release of 
high energy debris. Subsequent investigation revealed the turbine 
exhaust duct can separate under excessive load conditions resulting 
from extreme engine distress such as HPT blade fractures.

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

Relevant Service Information

    P&WC has issued Service Bulletin No. A16255R2, dated March 1, 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

    These APUs have been approved by Canada, and are approved for 
operation in the United States. Pursuant to our bilateral agreement 
with Canada, 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 Canada, and 
determined the unsafe condition exists and is likely to exist or 
develop on other APUs of the same type design. This proposed AD would 
require modification of the APU rear gas generator case, exhaust duct 
support, and turbine exhaust duct flanges.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 135 APUs installed on airplanes of U.S. registry. 
The average labor rate is $85 per work-hour. Required parts would cost 
about $39,899 per APU. Based on these figures, we estimate the cost of 
the proposed AD on U.S. operators to be $5,386,365.

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.

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 
airworthiness directive (AD):

Pratt & Whitney Canada: Docket No. FAA-2012-0071; Directorate 
Identifier 2012-NE-05-AD.

(a) Comments Due Date

    We must receive comments by April 27, 2012.

(b) Affected ADs

    None.

[[Page 11423]]

(c) Applicability

    This AD applies to Pratt & Whitney Canada (P&WC) PW901A 
auxiliary power units (APUs) approved under Technical Standard Order 
TSO-C77A and installed on, but not limited to, Boeing 747-400 series 
airplanes. The affected APU serial numbers are PCE 900001 through 
PCE 900776 inclusive.

(d) Reason

    This AD was prompted by several events of high-pressure turbine 
blade fracture leading to separation of the rear gas generator case 
and release of high energy debris. We are issuing this AD to prevent 
separation of the rear gas generator case and release of high energy 
debris, which could result in injury and damage to the airplane.

(e) Actions and Compliance

    Unless already done, do the following actions.
    (1) Within 42 months after the effective date of this AD or the 
first time any maintenance is done other than preventative 
maintenance, whichever occurs first, modify the rear gas generator 
case, exhaust duct support, and turbine exhaust duct flanges.
    (2) Use paragraphs 3.A. through 3.B(3)(f) of Accomplishment 
Instructions, and paragraph 4.A. of Appendix, of P&WC Service 
Bulletin (SB) No. A16255R2, dated March 1, 2011, to do the 
modifications.

(f) Credit for Previous Action

    APUs modified previously using P&WC SB No. A16255R1, dated 
September 12, 2008, or P&WC SB No. A16255, dated December 12, 2007, 
meet the modification requirements of this AD.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, New York Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 
to make your request.

(h) Related Information

    (1) For more information about this AD, contact Mazdak Hobbi, 
Aerospace Engineer, New York Aircraft Certification Office, FAA, 
Engine & Propeller Directorate, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: 516-228-7330; fax: 516-794-5531; email: 
mazdak.hobbi@faa.gov.
    (2) Refer to Transport Canada AD CF-2011-40, dated October 26, 
2011, and P&WC SB No. A16255R2, dated March 1, 2011, for related 
information.
    (3) For service information identified in this AD, contact Pratt 
& Whitney Canada Corp., 1000 Marie-Victorin, Longueuil, Quebec, 
Canada J4G 1A1; phone: 450-677-9411. You may review copies of the 
referenced 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 February 17, 2012.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-4448 Filed 2-24-12; 8:45 am]
BILLING CODE 4910-13-P


