Document ID: FAA-2011-1176-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Pratt and Whitney Turbofan Engines
Posted Date: 2011-11-23T05:00Z

[Federal Register Volume 76, Number 226 (Wednesday, November 23, 2011)]
[Proposed Rules]
[Pages 72348-72350]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-30137]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1176; Directorate Identifier 2011-NE-35-AD]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Turbofan Engines

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 
Pratt & Whitney JT9D-7R4D, -7R4D1, -7R4E, -7R4E1, -7R4G2, -7R4H1, and -
7R4E4 turbofan engines. This proposed AD would establish a new lower 
life limit for high-pressure turbine (HPT) 1st stage air seals, part 
number (P/N) 735907, and would require removing them from service using 
a drawdown schedule. This proposed AD was prompted by the determination 
that a new lower life limit for the HPT 1st stage air seals, P/N 
735907, is necessary. We are proposing this AD to prevent critical 
life-limited rotating engine part failure and damage to the airplane.

DATES: We must receive comments on this proposed AD by January 23, 
2012.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
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 Office (phone: (800) 647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Stephen Sheely, Aerospace Engineer, 
Engine & Propeller Directorate, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: (781) 238-7750; fax: (781) 238-7199; 
email: stephen.k.sheely@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-1176; 
Directorate Identifier 2011-NE-35-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 because of those comments.
    We will post all comments we receive, without change, to http://

[[Page 72349]]

www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We received two reports of HPT 1st stage air seals, P/N 735907, 
found cracked by fluorescent penetrant inspection during engine 
overhaul. The cracks were located on the flat section of the seal, 
between the bolted flange and the knife edge seals. One of the air 
seals had accumulated 11,150 cycles-since-new (CSN), and the other air 
seal had accumulated 13,340 CSN. The current published life limit for 
these seals is 15,000 CSN. Pratt & Whitney has informed us that they 
are preparing to issue service information which will require reducing 
the published life limit from 15,000 CSN to 9,000 CSN. This condition, 
if not corrected, could result in critical life-limited rotating engine 
part failure and damage to the airplane.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require establishing a new lower life limit 
for HPT 1st stage air seals, P/N 735907, from 15,000 CSN, to 9,000 CSN, 
and would require removing them from service using a drawdown schedule.

Costs of Compliance

    We estimate that this proposed AD would affect 257 Pratt & Whitney 
JT9D-7R4D, -7R4D1, -7R4E, -7R4E1, -7R4G2, -7R4H1, and -7R4E4 turbofan 
engines installed on airplanes of U.S. registry. We also estimate that 
it would take about 28.8 work-hours per engine to perform the actions 
required by this AD, and that the average labor rate is $85 per work-
hour. Required parts will cost about $37,200 per engine. Based on these 
figures, we estimate the total cost of the AD to U.S. operators to be 
$10,189,536.

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),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

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: Docket No. FAA-2011-1176; Directorate Identifier 
2011-NE-35-AD.

(a) Comments Due Date

    We must receive comments by January 23, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Pratt & Whitney JT9D-7R4D, -7R4D1, -7R4E, -
7R4E1, -7R4G2, -7R4H1, and -7R4E4 turbofan engines.

(d) Unsafe Condition

    This AD was prompted by the determination that a new lower life 
limit of 9,000 cycles-since-new (CSN) for high-pressure turbine 
(HPT) 1st stage air seals, part number (P/N) 735907, is necessary. 
We are issuing this AD to prevent critical life-limited rotating 
engine part failure, and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(f) Removal of HPT 1st Stage Air Seals, P/N 735907

    Remove HPT 1st stage air seals, P/N 735907, from service as 
follows:
    (1) For air seals that have fewer than 6,500 CSN on the 
effective date of this AD, remove from service before exceeding 
9,000 CSN.
    (2) For air seals that have 6,500 CSN or more on the effective 
date of this AD, do the following:
    (i) If the engine has a shop visit before the air seal exceeds 
9,000 CSN, remove the air seal from service before exceeding 9,000 
CSN.
    (ii) If the engine does not have a shop visit before the air 
seal exceeds 9,000 CSN, remove the air seal from service at the next 
shop visit, not to exceed 2,500 cycles from the effective date of 
this AD or 15,000 CSN, whichever occurs first.
    (3) Remove from service any HPT 1st stage air seal, P/N 735907, 
that is installed or re-installed after the effective date of this 
AD, before the air seal exceeds the new life limit of 9,000 CSN.

(g) Installation Prohibition

    After the effective date of this AD, do not install or reinstall 
into any engine any HPT 1st stage air seal, P/N 735907, that exceeds 
the new life limit of 9,000 CSN.

(h) Engine Shop Visit Definition

    For the purposes of this AD, an engine shop visit is the 
induction of an engine into the shop after the effective date of 
this AD, where the separation of a major engine flange occurs, 
except that the following maintenance actions, or any combination, 
are not considered engine shop visits:
    (1) Introduction of an engine into a shop solely for removal of 
the compressor top or bottom case for airfoil maintenance or 
variable stator vane bushing replacement.
    (2) Introduction of an engine into a shop solely for removal or 
replacement of the stage 1 fan disk.
    (3) Introduction of an engine into a shop solely for replacement 
of the turbine rear frame.

[[Page 72350]]

    (4) Introduction of an engine into a shop solely for replacement 
of the accessory gearbox or transfer gearbox, or both.
    (5) Introduction of an engine into a shop solely for replacement 
of the fan forward case.

(i) Alternative Methods of Compliance (AMOCs)

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

(j) Related Information

    For more information about this AD, contact Stephen Sheely, 
Aerospace Engineer, Engine & Propeller Directorate, FAA, 12 New 
England Executive Park, Burlington, MA 01803; phone: (781) 238-7750; 
fax: (781) 238-7199; email: stephen.k.sheely@faa.gov.

    Issued in Burlington, Massachusetts, on November 15, 2011.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-30137 Filed 11-22-11; 8:45 am]
BILLING CODE 4910-13-P