
[Federal Register Volume 79, Number 107 (Wednesday, June 4, 2014)]
[Proposed Rules]
[Pages 32197-32199]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-12973]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0072; Directorate Identifier 2013-NE-04-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Division Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede airworthiness directive (AD) 2013-15-
09, which applies to all Pratt & Whitney Division (PW) PW4074, PW4074D, 
PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engine models 
with certain second-stage high-pressure turbine (HPT) air seals, 
installed. AD 2013-15-09 currently requires initial and repetitive 
inspections for cracks in second-stage HPT air seals. Since we issued 
AD 2013-15-09, we received reports of cracking in the original location 
on two additional part numbers (P/Ns) as well as reports of through-
cracks in a new location in the second-stage HPT air seal. PW has 
developed a redesigned second-stage HPT air seal that addresses the 
cracking condition in both locations. This proposed AD would expand the 
applicability of AD 2013-15-09 to include additional P/Ns, require 
replacement of the mating hardware if the second-stage HPT air seal is 
found with a through-crack, and add mandatory terminating action to the 
repetitive inspections. We are proposing this AD to prevent failure of 
the second-stage HPT air seal, which could lead to uncontained engine 
failure and damage to the airplane.

DATES: We must receive comments on this proposed AD by August 4, 2014.

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.
    For service information identified in this proposed AD, contact 
Pratt & Whitney Division, 400 Main St., East Hartford, CT 06108; phone: 
(860) 565-8770; fax: (860) 565-4503. You may view this 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.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2013-
0072; 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.

[[Page 32198]]


FOR FURTHER INFORMATION CONTACT: James Gray, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; phone: (781) 238-7742; 
fax: (781) 238-7199; email: james.e.gray@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-2013-0072; 
Directorate Identifier 2013-NE-04-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://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

    On July 19, 2013, we issued AD 2013-15-09, Amendment 39-17525 (78 
FR 49111, August 13, 2013), (``AD 2013-15-09''), for all PW PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engine 
models with second-stage HPT air seal, P/N 54L041, installed. AD 2013-
15-09 requires initial and repetitive inspections for cracks in second-
stage HPT air seals and replacement of air seals that fail inspection. 
AD 2013-15-09 resulted from the discovery of cracks in second-stage HPT 
air seals. We issued AD 2013-15-09 to prevent failure of the second-
stage HPT air seal, which could lead to uncontained engine failure and 
damage to the airplane.

Actions Since AD 2013-15-09 Was Issued

    Since we issued AD 2013-15-09, we received multiple reports of 
through-cracks in a different location on second-stage HPT air seal, P/
N 50L041, and reports of cracking in the original location in two 
additional second-stage HPT air seal P/Ns, 50L960 and 50L976. The 
cracking in the two additional P/Ns requires that they be added to the 
applicability of this proposed AD. PW has developed a redesigned 
second-stage HPT air seal that corrects the cracking condition in both 
locations.
    The new cracking location in the second-stage HPT air seal, P/N 
50L041, is in the front forward fillet radius. PW determined that 
through-cracks in the front forward fillet radius increase the stresses 
in the mating hardware in the HPT rotor and that increased stress 
reduces the life of the first-stage HPT hub, second-stage HPT hub, and 
second-stage HPT blade retaining plate. Therefore, the first-stage HPT 
hub, second-stage HPT hub, and second-stage HPT blade retaining plate 
must be removed from service if the second-stage HPT air seal, P/N 
50L041, is found with a through-crack.

Relevant Service Information

    We reviewed PW Alert Service Bulletin (ASB) No. PW4G-112-A72-330, 
Revision 2, dated July 11, 2013, which describes procedures for 
inspecting the second-stage HPT air seal for cracks and PW Service 
Bulletin (SB) No. PW4G-112-72-332, Revision 2, dated April 9, 2014, 
which describes procedures for replacing the second-stage HPT air seal.

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 expand the population of affected P/Ns, 
require removal from service of two newly identified P/Ns, require 
replacement of the mating hardware if the second-stage HPT air seal is 
found with a through-crack, and add mandatory terminating action to the 
repetitive inspection requirements.

Costs of Compliance

    We estimate that this proposed AD would affect 116 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 5 hours to perform the inspection required by this proposed 
AD. The average labor rate is $85 per hour. We estimate that two 
engines will also require replacement of the first-stage HPT hub, 
second-stage HPT hub, and second-stage HPT blade retaining plate. We 
estimate that parts would cost about $698,920 per engine. Based on 
these figures, we estimate the total cost of this proposed AD to U.S. 
operators to be $23,420,020.

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 
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 to the extent 
that it justifies making a regulatory distinction, 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

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

[[Page 32199]]

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by removing airworthiness directive (AD) 
2013-15-09, Amendment 39-17525 (78 FR 49111, August 13, 2013), and 
adding the following new AD:

Pratt & Whitney Division: Docket No. FAA-2013-0072; Directorate 
Identifier 2013-NE-04-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by August 4, 
2014.

(b) Affected ADs

    This AD supersedes AD 2013-15-09, Amendment 39-17525 (78 FR 
49111, August 13, 2013).

(c) Applicability

    This AD applies to all Pratt & Whitney Division (PW) PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan 
engine models with second-stage high-pressure turbine (HPT) air 
seal, part number (P/N) 54L041, 50L960, or 50L976, installed.

(d) Unsafe Condition

    This AD was prompted by additional reports of cracking in the 
second-stage HPT air seal. We are issuing this AD to prevent failure 
of the second-stage HPT air seal, which could lead to uncontained 
engine failure and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) At the next piece-part exposure after the effective date of 
this AD, do the following:
    (i) Remove from service second-stage HPT air seals, P/N 50L960, 
50L976, and 50L041.
    (ii) Fluorescent-penetrant inspect (FPI) second-stage HPT air 
seal, P/N 50L041, for a through-crack in the front forward fillet 
radius.
    (iii) If a through-crack in the front forward fillet radius is 
found, remove the first-stage HPT hub, second-stage HPT hub, and 
second-stage HPT blade retaining plate from service. Do not 
reinstall the first-stage HPT hub, second-stage HPT hub, or second-
stage HPT blade retaining plate into any engine.
    (2) For engines with second-stage HPT air seals, P/N 50L041, 
installed, perform initial and repetitive inspections for cracks on-
wing until the part is removed from the engine as follows:
    (i) Perform an initial eddy current inspection (ECI) for cracks 
prior to reaching 2,200 cycles-since-new or within 100 cycles-in-
service after the effective date of this AD, whichever occurs later.
    (ii) Thereafter, repeat the ECI every 1,200 cycles since last 
inspection, or fewer, depending on the results of the inspection.
    (iii) Use section 4.0 of the appendix of PW Alert Service 
Bulletin (ASB) No. PW4G-112-A72-330, Revision 2, dated July 11, 
2013, to perform the inspection and use paragraph 8 of the 
Accomplishment Instructions of PW ASB No. PW4G-112-A72-330, Revision 
2, dated July 11, 2013, to disposition the results of the 
inspection.

(f) Installation Prohibition

    After the effective date of this AD, do not install any second-
stage HPT air seal P/N 50L041, P/N 50L960, or P/N 50L976 into any 
engine.

(g) Definitions

    (1) For the purpose of this AD, piece-part exposure is when the 
second-stage HPT air seal is removed from the engine and fully 
disassembled.
    (2) For the purpose of this AD, a through-crack is a crack that 
has propagated through the thickness of the part and can be seen on 
both the inner diameter and outer diameter of the front forward 
fillet radius.

(h) Credit for Previous Actions

    (1) If you performed an ECI of the second-stage HPT air seal 
before the effective date of this AD, using PW ASB No. PW4G-112-A72-
330, Revision 1, dated February 14, 2013, or earlier version, you 
have met the requirements of paragraph (e)(2)(i) of this AD.
    (2) If you performed an in-shop FPI of the second-stage HPT air 
seal before the effective date of this AD, you have met the 
requirements of paragraph (e)(2)(i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

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

(j) Related Information

    (1) For more information about this AD, contact James Gray, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, MA 
01803; phone: (781) 238-7742; fax: (781) 238-7199; email: 
james.e.gray@faa.gov.
    (2) For service information identified in this AD, contact Pratt 
& Whitney Division, 400 Main St., East Hartford, CT 06108; phone: 
(860) 565-8770; fax: (860) 565-4503.
    (3) You may view this 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 May 28, 2014.
Colleen M. D'Alessandro,
Assistant Directorate Manager, Engine & Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-12973 Filed 6-3-14; 8:45 am]
BILLING CODE 4910-13-P


