[Federal Register Volume 72, Number 97 (Monday, May 21, 2007)]
[Proposed Rules]
[Pages 28459-28461]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-9697]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27230; Directorate Identifier 2007-NE-04-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney (PW) PW4164, PW4168, 
and PW4168A 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 PW4164, PW4168, and PW4168A turbofan engines with certain low 
pressure turbine (LPT) stage 4 disks, part number (P/N) 51N404, 
installed. This proposed AD would require removing certain LPT stage 4 
disks, listed by serial number at the next piece-part exposure or 
within 7,500 cycles-since-new (CSN), whichever occurs first. This 
proposed AD results from a report of improperly manufactured LPT stage 
4 disks. We are proposing this AD to prevent an uncontained engine 
failure due to low-cycle fatigue (LCF), which could result in damage to 
the airplane.

DATES: We must receive any comments on this proposed AD by July 20, 
2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: V. Rose Len, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; telephone (781) 238-
7772; 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-2007-27230; 
Directorate Identifier 2007-NE-04-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy

[[Page 28460]]

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://dms.dot.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 
DOT Web site, anyone can find and read the comments in any of our 
dockets, including 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) or you 
may visit http://dms.dot.gov.

Examining the AD Docket

    You may examine the docket that contains the proposal, any comments 
received and, any final disposition in person at the Docket Management 
Facility between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays. The Docket Office (telephone (800) 647-5227) is 
located on the plaza level of the Department of Transportation Nassif 
Building at the street address stated in ADDRESSES. Comments will be 
available in the AD docket shortly after the Docket Management Facility 
receives them.

Discussion

    On September 29, 2006, we received a report of 16 LPT stage 4 
disks, P/N 51N404, manufactured with an improper material process. The 
disks were not properly heat treated during the manufacturing process. 
The manufacturer solution-heat treated the disks for one hour instead 
of the four hours required. We believe this manufacturing discrepancy 
will result in reduced LCF properties for the disks. Operating the 
affected disks to the certified life limit could result in uncontained 
failure of the disk due to LCF. Although we have received no reports of 
disk separations, this condition, if not corrected, could result in the 
disk separating from the engine due to LCF, which could result in 
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 
removing certain LPT stage 4 disks, P/N 51N404, listed by serial number 
in the proposed AD, at the next piece-part exposure, or within 7,500 
CSN, whichever occurs first.

Costs of Compliance

    We estimate that this proposed AD would affect 11 engines installed 
on airplanes of U.S. registry. We also estimate that it would take 
about 250 work-hours per engine to perform the proposed action, if not 
done at piece-part exposure, and that the average labor rate is $80 per 
work-hour. Required parts would cost about $186,288 per engine. Based 
on these figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $2,269,168.

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-2007-27230; Directorate Identifier 
2007-NE-04-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by July 20, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney PW4164, PW4168, and 
PW4168A turbofan engines with certain low pressure turbine (LPT) 
stage 4 disks, part number (P/N) 51N404, that have a serial number 
listed in the following Table 1 of this AD installed. These engines 
are installed on, but not limited to, Airbus A330-200 and A330-300 
series airplanes.

          Table 1.--Affected LPT Stage 4 Disks by Serial Number
 
                     LPT stage 4 disk serial numbers
 
CLDLC01142
CLDLC01143
CLDLC01144
CLDLC01145
CLDLC01146
CLDLC01148
CLDLC01149
CLDLC01150
CLDLC01151
CLDLC01152
CLDLC01181
CLDLC01182
CLDLC01183
CLDLC01185
CLDLC01186
CLDLC01187
 


[[Page 28461]]

Unsafe Condition

    (d) This AD results from a report of improperly manufactured LPT 
stage 4 disks. We are issuing this AD to prevent an uncontained 
engine failure due to low-cycle fatigue, which could result in 
damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next piece-part exposure after the effective 
date of this AD or within 7,500 cycles-since-new, unless the actions 
have already been done.

Removing the LPT Stage 4 Disk

    (f) Remove from service any LPT stage 4 disk that has a serial 
number listed in Table 1 of this AD.

Prohibition Against Installing an Affected Disk

    (g) After the effective date of this AD, do not install any 
disk, P/N 51N404, that has a serial number listed in Table 1 of this 
AD or any disk removed as specified in paragraph (f) of this AD 
except as allowed by paragraph (h) of this AD.

Alternative Methods of Compliance

    (h) 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.

Special Flight Permits

    (i) Under 14 CFR part 39.23, we are prohibiting the special 
flight permits for this AD.

Related Information

    (j) None.

    Issued in Burlington, Massachusetts, on May 11, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-9697 Filed 5-18-07; 8:45 am]
BILLING CODE 4910-13-P