[Federal Register Volume 77, Number 101 (Thursday, May 24, 2012)]
[Proposed Rules]
[Pages 30926-30928]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-12414]



[[Page 30926]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0217; Directorate Identifier 2009-NE-23-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 an existing airworthiness directive 
(AD) that applies to all Pratt & Whitney Division (Pratt & Whitney) 
PW4052, PW4056, PW4060, PW4062, PW4062A, PW4074, PW4077, PW4077D, 
PW4084D, PW4090, PW4090-3, PW4152, PW4156A, PW4158, PW4164, PW4168, 
PW4168A, PW4460, and PW4462 turbofan engines. The existing AD currently 
requires initial and repetitive fluorescent penetrant inspections (FPI) 
for cracks in the blade locking and loading slots of the high-pressure 
compressor (HPC) drum rotor disk assembly rear drum. Since we issued 
that AD, Pratt & Whitney has developed a redesigned HPC drum rotor disk 
assembly for certain affected engine models. This proposed AD would 
also require replacement of the 13th, 14th, and 15th stage HPC seals as 
an additional action and would add an optional terminating action to 
the repetitive inspection requirements by allowing replacement of the 
entire HPC drum rotor disk assembly. We are proposing this AD to 
prevent failure of the HPC drum rotor disk assembly, which could lead 
to an uncontained engine failure, and damage to the airplane.

DATES: We must receive comments on this proposed AD by July 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.
    For service information identified in this AD, contact Pratt & 
Whitney, 400 Main St., East Hartford, CT 06108; phone: 860-565-7700; 
fax: 860-565-1605. You may review copies of the referenced 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; 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: James Gray, Aerospace Engineer, Engine 
& Propeller Directorate, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: 781-238-7742; fax: 781-238-7199; email: 
[email protected].

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-2010-0217; 
Directorate Identifier 2009-NE-23-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 August 26, 2010, we issued AD 2010-18-13, Amendment 39-16427 (75 
FR 55459, September 13, 2010), for all Pratt & Whitney PW4052, PW4056, 
PW4060, PW4062, PW4062A, PW4074, PW4077, PW4077D, PW4084D, PW4090, 
PW4090-3, PW4152, PW4156A, PW4158, PW4164, PW4168, PW4168A, PW4460, and 
PW4462 turbofan engines. That AD requires initial and repetitive FPI 
for cracks in the blade locking and loading slots of the HPC rear drum. 
That AD resulted from reports of cracked locking and loading slots in 
the HPC rear drum. We issued that AD to prevent failure of the HPC drum 
rotor disk assembly, which could lead to an uncontained engine failure, 
and damage to the airplane.

Actions Since Existing AD Was Issued

    Since we issued AD 2010-18-13 (75 FR 55459, September 13, 2010), 
Pratt & Whitney has developed a redesigned HPC drum rotor disk assembly 
for PW4000-94'' and PW4000-100'' engine models. The redesign includes 
new 13th, 14th, and 15th stage HPC seals that lower the temperature in 
the loading and locking slots and decrease the likelihood of cracking. 
Based on the risk analysis, it was determined that installing the 
redesigned 13th, 14th, and 15th stage HPC seals on the original design 
HPC drum rotor disk assembly is an additional required action to 
maintain an acceptable level of safety and prevent cracking in the 
loading and locking slots while the redesigned HPC drum rotor disk 
assembly is being implemented. The option of installing a redesigned 
HPC drum rotor disk assembly is considered final corrective action to 
the repetitive inspections required by this AD.

Relevant Service Information

    Prior to publishing AD 2010-18-13 (75 FR 55459, September 13, 
2010), we reviewed the technical contents of Pratt & Whitney Service 
Bulletin (SB) No. PW4ENG 72-796, dated June 11, 2009, SB No. PW4G-100-
72-186, Revision 1, dated September 2, 2004, and SB No. PW4G-112-72-
264, Revision 2, dated February 23, 2010. Those three SBs describe 
procedures for performing a local FPI of the HPC rear drum blade 
locking and loading slots for cracks.
    During the development of this proposed AD, we reviewed Pratt & 
Whitney SB No. PW4ENG 72-816, dated December 2, 2011, and SB No. PW4G-
100-72-240, dated November 15, 2011. Those two SBs describe procedures 
for replacing the 13th, 14th, and 15th stage HPC seals in PW4000-94'' 
and PW4000-100'' engine models, with redesigned seals. We also reviewed 
Pratt & Whitney SB No. PW4ENG 72-817, dated December 7, 2011, and SB 
No. PW4G-100-72-241, dated November 15, 2011. Those two SBs describe 
procedures for replacing the HPC drum rotor disk assemblies in PW4000-
94'' and PW4000-100'' engine models, with redesigned HPC drum rotor 
disk assemblies.

[[Page 30927]]

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 retain all of the requirements of AD 2010-
18-13 (75 FR 55459, September 13, 2010). This proposed AD would also 
require replacement of the 13th, 14th, and 15th stage HPC seals with 
redesigned seals, and would add an optional terminating action to the 
repetitive inspection requirements by allowing replacement of the HPC 
drum rotor disk assembly with a redesigned HPC drum rotor disk 
assembly.

Costs of Compliance

    We estimate that this proposed AD would affect 911 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 1 work-hour per engine to perform an inspection using an 
average labor rate of $85 per work-hour. We estimate that there are 770 
PW4000-94'' and PW4000-100'' engines that would require replacement of 
13th, 14th, and 15th stage HPC seals, at a parts cost of $3,000 per 
engine. No additional labor is assumed when the replacement is done at 
piece-part exposure of the HPC drum rotor disk assembly. The 
replacement parts cost of the redesigned HPC drum rotor disk assembly 
is $630,000. Based on these figures, we estimate that the total cost of 
the proposed AD to U.S. operators will be $2,387,435.

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, 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 removing airworthiness directive 
(AD) 2010-18-13, Amendment 39-16427 (75 FR 55459, September 13, 2010), 
and adding the following new AD:

Pratt & Whitney Division: Docket No. FAA-2010-0217; Directorate 
Identifier 2009-NE-23-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by July 23, 
2012.

(b) Affected ADs

    This AD supersedes AD 2010-18-13, Amendment 39-16427 (75 FR 
55459, September 13, 2010).

(c) Applicability

    This AD applies to the following Pratt & Whitney Division (Pratt 
& Whitney) turbofan engines:
    (1) PW4000-94'' engine models PW4052, PW4056, PW4060, PW4062, 
PW4062A, PW4152, PW4156A, PW4158, PW4460, and PW4462, including 
those models with any dash number suffix, with a high-pressure 
compressor (HPC) drum rotor disk assembly listed in Table 1 of this 
AD.
    (2) PW4000-100'' engine models PW4164, PW4168, and PW4168A, with 
a HPC drum rotor disk assembly listed in Table 1 of this AD.
    (3) PW4000-112'' engine models PW4074, PW4077, PW4077D, PW4084D, 
PW4090, and PW4090-3, with a HPC drum rotor disk assembly listed in 
Table 1 of this AD.

            Table 1--Affected HPC Drum Rotor Disk Assemblies
------------------------------------------------------------------------
                                 Affected HPC drum rotor disk assembly
        Engine models                         part numbers
------------------------------------------------------------------------
PW4000-94''..................  50H936; 50H936-002; 53H923-01; 53H923-
                                001; 53H973-01; 53H973-001; 54H803-01;
                                54H803-001; 54H803-002; 56H013-01;
                                56H013-001; 58H236-01.
PW4000-100''.................  53H973-01; 53H973-001; 54H803-01; 54H803-
                                001; 54H803-002; 56H013-01; 56H013-001;
                                58H236-01.
PW4000-112''.................  55H722-01; 55H410-01; 57H010-01; 57H210-
                                01; 57H610-01; 57H910-01.
------------------------------------------------------------------------

(d) Unsafe Condition

    This AD was prompted by Pratt & Whitney developing a redesigned 
HPC drum rotor disk assembly for certain affected engine models. We 
are issuing this AD to prevent failure of the HPC drum rotor disk 
assembly, which could lead to an uncontained engine failure, and 
damage to the airplane.

(e) Compliance

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

(f) Local Fluorescent Penetrant Inspection

    (1) Perform a local fluorescent penetrant inspection for cracks 
in the HPC drum rotor disk assembly rear drum blade locking and 
loading slots of the specific stages of the HPC drum rotor disk 
assemblies from which any

[[Page 30928]]

of the blades are removed as specified in Table 2 of this AD.

                         Table 2--Compliance Times and Service Bulletins by Engine Model
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           For engine model                   Inspect whenever--                    To inspect, use--
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PW4074, PW4077, PW4077D, PW4084D,       Any of the HPC 13thor           Paragraphs 1.A. through 1.B. of the
 PW4090, and PW4090-3.                   14thstage blades are removed    Accomplishment Instructions of PW4G-112-
                                         during a shop visit.            72-264, Revision 2, dated February 23,
                                                                         2010.
PW4164, PW4168, and PW4168A...........  Any of the HPC 13th, 14th, or   Paragraphs 1.A. through 1.C of the
                                         15th stage blades are removed   Accomplishment Instructions of PW4G-100-
                                         during a shop visit.            72-186, Revision 1, dated September 2,
                                                                         2004.
PW4052, PW4056, PW4060, PW4062,         Any of the HPC 13th, 14th, or   Paragraphs 1.A. through 1.C. of the
 PW4062A, PW4152, PW4156A, PW4158,       15th stage blades are removed   Accomplishment Instructions of PW4ENG
 PW4460, and PW4462.                     during a shop visit.            72-796, dated June 11, 2009.
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     (2) Remove from service any HPC drum rotor disk assembly rear 
drum found with a crack in any of the blade loading and locking 
slots.

(g) Replacement of 13th, 14th, and 15th HPC Seals

    At the next piece-part exposure of the HPC drum rotor disk 
assembly after the effective date of this AD:
    (1) Replace the 13th, 14th, and 15th stage HPC seals of engines 
listed in paragraph (c)(1) of this AD in accordance with the 
Accomplishment Instructions of Pratt & Whitney Service Bulletin (SB) 
No. PW4ENG 72-816, dated December 2, 2011.
    (2) Replace the 13th, 14th, and 15th stage HPC seals of engines 
listed in paragraph (c)(2) of this AD in accordance with the 
Accomplishment Instructions of Pratt & Whitney SB No. PW4G-100-72-
240, dated November 15, 2011.

(h) Optional Terminating Action

    As optional terminating action to the repetitive inspection 
requirements of this AD:
    (1) Replace the HPC drum rotor disk assembly of engines listed 
in paragraph (c)(1) of this AD with a redesigned HPC drum rotor disk 
assembly in accordance with the Accomplishment Instructions of Pratt 
& Whitney SB No. PW4ENG 72-817, dated December 7, 2011.
    (2) Replace the HPC drum rotor disk assembly of engines listed 
in paragraph (c)(2) of this AD with a redesigned HPC drum rotor disk 
assembly in accordance with the Accomplishment Instructions of Pratt 
& Whitney SB No. PW4G-100-72-241, dated November 15, 2011.

(i) Definition

    For the purpose of this AD, piece-part exposure means that the 
HPC drum rotor disk assembly is removed from the engine and 
completely disassembled.

(j) 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. AMOCs approved previously in accordance with AD 2010-18-13, 
Amendment 39-16427 (75 FR 55459, September 13, 2010) are approved as 
AMOCs for the corresponding requirements in paragraph (f) of this 
AD.

(k) Related Information

    (1) For more information about this AD, contact James Gray, 
Aerospace Engineer, Engine & Propeller Directorate, FAA, 12 New 
England Executive Park, Burlington, MA 01803; phone: 781-238-7742; 
fax: 781-238-7199; email: [email protected].
    (2) For service information identified in this AD, contact Pratt 
& Whitney, 400 Main St., East Hartford, CT 06108; phone: 860-565-
7700; fax: 860-565-1605. You may review copies of the referenced 
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 16, 2012.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-12414 Filed 5-23-12; 8:45 am]
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