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[Federal Register: July 14, 2010 (Volume 75, Number 134)]
[Proposed Rules]               
[Page 40757-40759]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14jy10-14]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0596; Directorate Identifier 2010-NE-22-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Pratt & Whitney PW4000 series turbofan engines. This 
proposed AD would require initial and repetitive borescope inspections 
(BSI) or fluorescent penetrant inspections (FPI) for cracks in the 
anti-vortex tube (AVT) shelf slots on the 10th stage disk of the high-
pressure compressor (HPC) drum rotor disk assembly. This proposed AD 
results from 47 reports received since 2007 of HPC 10th stage disks 
found cracked in the AVT shelf slots during shop visit inspections. We 
are proposing this AD to prevent failure of the HPC 10th stage disk, 
uncontained engine failure, and damage to the airplane.

DATES: We must receive any comments on this proposed AD by September 
13, 2010.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     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 Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-8770; fax (860) 565-4503, for a copy of the service 
information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: James Gray, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
james.e.gray@faa.gov; telephone (781) 238-7742; 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-2010-0596; Directorate 
Identifier 2010-NE-22-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 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

    Since 2007, we have received 47 reports of HPC 10th stage disks 
found cracked in the AVT shelf slots during shop visit inspections. 
Investigation has revealed the root cause of the cracks to be the slot 
configuration in the 9th stage compressor stator inner shroud. The 
number of slots matches the number of anti-vortex tubes and causes an 
aerodynamic interaction during engine operation. This interaction 
results in high-cycle-fatigue cracks in the AVT shelf slots on the 10th 
stage disk of the HPC drum rotor disk assembly. This condition, if not 
corrected, could result in failure of the HPC 10th stage disk, 
uncontained engine failure, and damage to the airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of Pratt & 
Whitney Service Bulletin (SB) No. PW4ENG 72-799, dated January 22, 
2010, and SB No. PW4G-100-72-226, dated April 22, 2010, that describe 
procedures for inspecting for cracks in the AVT shelf slots on the 10th 
stage disk of the HPC drum rotor disk assembly.

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 
initial and repetitive BSI or FPI for cracks in the AVT shelf on the 
10th stage disk of the HPC drum rotor disk assembly. The proposed AD 
would require you to use the service information described previously 
to perform these actions.

Interim Actions

    These actions are interim actions and we may take further 
rulemaking actions in the future.

[[Page 40758]]

Costs of Compliance

    We estimate that this proposed AD would affect 869 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about one work-hour per engine to perform a proposed inspection, 
and that the average labor rate is $85 per work-hour. Required parts 
would cost about $303,010 per HPC drum rotor disk assembly. About 61 
HPC drum rotor disk assemblies would need replacement due to cracks. 
Based on these figures, we estimate the cost of the AD on U.S. 
operators to be $18,557,475.

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, Incorporation by 
reference, 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-2010-0596; Directorate Identifier 
2010-NE-22-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by September 
13, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the following Pratt & Whitney turbofan 
engines with a ring case configuration rear high-pressure compressor 
(HPC) installed. These engines are installed on, but not limited to, 
Boeing 747-200, 767-200/-300, and MD-11 airplanes, and Airbus A300-
600, A310-300, A330-300, and A330-200 airplanes.

PW4000-94'' Engines

    (1) PW4000-94'' series engine models PW4050, PW4052, PW4056, 
PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, 
PW4158, PW4160, PW4460, PW4462, and PW4650, including all models 
with a dash number suffix.

PW4000-100'' Engines

    (2) PW4000-100'' series engine models PW4168A-1D and PW4170 with 
serial numbers P735001 through P735039; and
    (3) All engines converted to PW4164-1D, PW4168-1D, PW4168A-1D, 
or PW4170 model engines.

Unsafe Condition

    (d) This AD results from 47 reports received since 2007 of HPC 
10th stage disks found cracked in the AVT shelf slots during shop 
visit inspections. We are issuing this AD to prevent failure of the 
HPC 10th stage disk, uncontained engine failure, and damage to the 
airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Initial Inspection of the AVT Shelf Slots

    (f) For engines listed in paragraphs (c)(1) and (c)(3) of this 
AD, do the following:
    (1) Remove the low-pressure turbine (LPT) shaft and borescope-
inspect (BSI) for cracks in the AVT shelf slots on the 10th stage 
disk of the HPC drum rotor disk assembly; or
    (2) Remove the HPC drum rotor disk assembly and fluorescent-
penetrant inspect (FPI) for cracks in the AVT shelf slots on the 
10th stage disk of the HPC drum rotor disk assembly.
    (3) Perform the inspection:
    (i) Within 7,200 cycles-in-service (CIS) since incorporation of 
any of the following Pratt & Whitney Service Bulletins: (SB) No. 
PW4ENG 72-755, SB No. PW4ENG 72-756, SB No. PW4ENG 72-757, SB No. 
PW4ENG 72-759, or SB No. PW4G-100-72-220; or
    (ii) Within 1,000 CIS after the effective date of this AD, 
whichever occurs later.
    (4) If a crack is found, remove the HPC drum rotor disk assembly 
from service.
    (g) For engines listed in paragraph (c)(2) of this AD, do the 
following:
    (1) Remove the LPT shaft and BSI for cracks in the AVT shelf 
slots on the 10th stage disk of the HPC drum rotor disk assembly; or
    (2) Remove the HPC drum rotor disk assembly and FPI for cracks 
in the AVT shelf slots on the 10th stage disk of the HPC drum rotor 
disk assembly.
    (3) Perform the inspection:
    (i) Within 7,200 cycles-since-new; or
    (ii) Within 1,000 CIS after the effective date of this AD, 
whichever occurs later.
    (4) If a crack is found, remove the HPC drum rotor disk assembly 
from service.

Repetitive Inspections of the AVT Shelf Slots

    (h) Thereafter, perform a BSI or FPI for cracks in the AVT shelf 
slots on the 10th stage HPC disk of the HPC drum rotor disk assembly 
within every 7,200 cycles-since-last-inspection.
    (i) If a crack is found, remove the HPC drum rotor disk assembly 
from service.

Relevant Service Bulletins

    (j) Use paragraphs 3.A through 3.H of the Accomplishment 
Instructions of Pratt & Whitney SB No. PW4ENG 72-799, dated January 
22, 2010, to perform the BSIs for engines listed in paragraph (c)(1) 
of this AD.
    (k) Use paragraphs 3.A through 3.H of the Accomplishment 
Instructions of Pratt & Whitney SB No. PW4G-100-72-226, dated April 
22, 2010, to perform the BSIs for engines listed in paragraphs 
(c)(2) and (c)(3) of this AD.

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.

Interim Actions

    (m) These actions are interim actions and we may take further 
rulemaking actions in the future.

[[Page 40759]]

Related Information

    (n) Contact James Gray, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: james.e.gray@faa.gov; 
telephone (781) 238-7742; fax (781) 238-7199, for more information 
about this AD.
    (o) Pratt & Whitney SB No. PW4ENG 72-799, dated January 22, 
2010, and SB No. PW4G-100-72-226, dated April 22, 2010, pertain to 
the subject of this AD. Contact Pratt & Whitney, 400 Main St., East 
Hartford, CT 06108; telephone (860) 565-8770; fax (860) 565-4503, 
for a copy of this service information.

    Issued in Burlington, Massachusetts, on July 8, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-17145 Filed 7-13-10; 8:45 am]
BILLING CODE 4910-13-P
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