[Federal Register Volume 73, Number 221 (Friday, November 14, 2008)]
[Proposed Rules]
[Pages 67427-67429]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-26909]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1131; Directorate Identifier 2008-NE-37-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney (PW) Models PW2037, 
PW2037(M), and PW2040 Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for PW models PW2037, PW2037(M), and PW2040 turbofan engines. This 
proposed AD would require inspecting all high-pressure turbine (HPT) 
2nd stage hubs at the next HPT overhaul after the effective date of the 
proposed AD. The inspections of the hubs include fluorescent penetrant 
inspection (FPI) for cracks and an optical comparator inspection (OCI) 
of the blade retention slots to confirm the hubs are within dimensional 
tolerances before returning them to service. This proposed AD results 
from an uncontained release of HPT 2nd stage blades and blade retention 
lugs. We are proposing this AD to detect cracks and remove 
nonconforming HPT 2nd stage hubs, which could result in an uncontained 
release of turbine blades and blade retention lugs, and damage to the 
airplane.

DATES: We must receive any comments on this proposed AD by January 13, 
2009.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal Rulemaking 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 Pratt & Whitney, 400 Main Street, East Hartford, CT 06108 
for the service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Mark Riley, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7758, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2008-1131; Directorate 
Identifier 2008-NE-37-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light of 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).

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

[[Page 67428]]

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.

Discussion

    On August 6, 2008, a PW2037 turbofan engine experienced an 
uncontained failure of multiple HPT 2nd stage blades. Although the root 
cause is still under investigation, we have determined that cracks in 
the blade retention lugs of the HPT 2nd stage hub resulted in fracture 
of multiple lugs, and release of 2nd stage blades. Optical comparator 
inspections (OCIs) performed on the blade retention slots of the HPT 
2nd stage hub confirmed the slots were out of dimensional tolerances. 
HPT 2nd stage hubs with blade retention slots that are out of tolerance 
can cause cracks and fracture of multiple blade retention lugs and 
release of 2nd stage blades from the hub. This condition, if not 
corrected, could result in an uncontained release of turbine blades and 
blade retention lugs, and damage to the airplane.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
performing an FPI of the hub for cracks and an OCI of the blade 
retention slots on the forward and aft sides of the HPT 2nd stage hub 
for conformance to dimensional tolerances at the next HPT overhaul 
after the effective date of this AD.

Interim Action

    These actions are interim actions and we are requiring reporting 
inspection data, including negative findings, to determine if we need 
to take further rulemaking actions in the future.

Costs of Compliance

    We estimate that this proposed AD would affect 762 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 6 work-hours per engine to perform the proposed actions, and 
that the average labor rate is $80 per work-hour. No parts are 
required. Based on these figures, we estimate the total cost of the 
proposed AD to U.S. operators to be $365,760.

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 have 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 that the proposed 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. Would 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. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration 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:

Pratt & Whitney: Docket No. FAA-2008-1131; Directorate Identifier 
2008-NE-37-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by January 13, 
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney models PW2037, PW2037(M), 
and PW2040 turbofan engines. These engines are installed on, but not 
limited to, Boeing 757-200 and 757-300 airplanes.

Unsafe Condition

    (d) This AD results from an uncontained release of high-pressure 
turbine (HPT) 2nd stage blades and blade retention lugs. We are 
issuing this AD to detect cracks and remove nonconforming HPT 2nd 
stage hubs, which could result in an uncontained release of turbine 
blades and blade retention lugs, and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next HPT overhaul, unless the actions have 
already been done.

Performing Inspections on HPT 2nd Stage Hubs

    (f) Perform a fluorescent penetrant inspection (FPI) of the hub 
for cracks. Pratt & Whitney Engine Manual part number 1A6231 
(Chapter 72-52-00, Inspection/Check-02, (Subtask 72-52-16-230-007)) 
contains information on performing the FPI.
    (g) Remove from service any cracked hubs.
    (h) Any HPT 2nd stage hubs inspected as specified in paragraphs 
(f) of this AD, must pass an optical comparator inspection before 
the hubs are eligible for return to service. Pratt & Whitney Alert 
Service Bulletin, PW2000 A72-734, contains information about the 
inspection.

Reporting Requirements

    (i) For 6 months from the effective date of the AD, and within 
72 hours of completing the inspections required by this AD, report 
the following to the Engine Certification Office, ATTN: Mark Riley, 
Engine & Propeller Directorate, 12 New England Executive Park, 
Burlington, MA 01803:
    (1) Inspection Date.
    (2) Disk part number and serial number.
    (3) Hours since new.
    (4) Cycles since new.
    (5) Hours since overhaul.
    (6) Cycles since overhaul.
    (7) Fluorescent penetrant inspection findings.
    (8) Optical comparator inspection findings.
    (j) Under the provisions of the Paperwork Reduction Act, the 
Office of Management and

[[Page 67429]]

Budget (OMB) have approved the information collection requirements 
and has assigned OMB Control Number 2120-0056.

Definitions

    (k) This AD defines an HPT overhaul as when the HPT is at its 
piece-part level.

Alternative Methods of Compliance

    (l) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (m) Contact Mark Riley, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: [email protected]; 
telephone (781) 238-7758, fax (781) 238-7199, for more information 
about this AD.
    (n) Pratt & Whitney Alert Service Bulletin, PW2000 A72-734, 
contains information about the optical comparator inspection.

    Issued in Burlington, Massachusetts, on November 6, 2008.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. E8-26909 Filed 11-13-08; 8:45 am]
BILLING CODE 4910-13-P