[Federal Register Volume 72, Number 15 (Wednesday, January 24, 2007)]
[Rules and Regulations]
[Pages 3052-3055]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-686]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24452; Directorate Identifier 2006-NE-11-AD; 
Amendment 39-14893; AD 2007-02-06]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney PW2000 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
Pratt & Whitney PW2000 series turbofan engines. This AD requires a 
onetime focused visual and fluorescent penetrant inspection (FPI) of 21 
suspect PW2000 8th stage high pressure compressor (HPC) drum rotor disk 
assemblies. This AD results from a PW2037 8th stage HPC drum rotor disk 
assembly failure event caused by tooling damage that occurred during 
disk assembly manufacture. We are issuing this AD to prevent 8th stage 
HPC drum rotor disk assembly failure that could result in an 
uncontained engine failure and damage to the airplane.

DATES: This AD becomes effective February 28, 2007. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in the regulations as of February 28, 2007.

ADDRESSES: You can get the service information identified in this AD 
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-8770; fax (860) 565-4503.
    You may examine the AD docket on the Internet at http://dms.dot.gov 
or in Room PL-401 on the plaza level of the Nassif Building, 400 
Seventh Street, SW., Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mark Riley, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; telephone (781) 238-7758; 
fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to Pratt & Whitney PW2000 
series turbofan engines. We published the proposed AD in the Federal 
Register on August 3, 2006 (71 FR 43997). That action proposed to 
require a onetime focused visual and FPI of 21 suspect PW2000 8th stage 
HPC drum rotor disk assemblies.

[[Page 3053]]

Examining the AD Docket

    You may examine the docket that contains the AD, any comments 
received, and any final disposition in person at the Docket Management 
Facility Docket Office 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 DMS receives them.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Claim That AD Action Is Redundant

    Northwest Airlines and Air Transport Association claim that the 
proposed AD is redundant to existing requirements in the engine manual, 
and would only put an additional administrative burden on the 
operators. They further state that existing AD 2005-18-03 (enhanced 
inspection of critical rotating parts) already requires a focused FPI 
of the drum rotor disk and includes the area of question on the 8th 
stage disk. The commenters point out that the visual inspection 
referenced in Pratt & Whitney Alert Service Bulletin (ASB) No. PW2000 
A72-706, dated February 17, 2006 requires that any disk damage be 
within the limits in the engine manual visual inspection.
    We do not agree. The intent of this AD is to require inspection of 
the HPC 8th stage disk when the HPC rotor assembly is exposed but with 
compressor blades installed. The requirements in this AD are more 
restrictive than the requirements of AD 2005-18-03, which only requires 
inspection when the HPC rotor is removed from the HPC module and 
disassembled to the piece-part level with compressor blades removed.
    For clarification, we revised the AD compliance section to state 
that the 8th stage HPC drum rotor disk assembly is a rotor with 
compressor blades installed.

Proposed AD Not Clear if the Nondestructive Inspection Procedures 
(NDIPs) Are Mandatory

    Northwest Airlines and Air Transport Association state that the 
proposed AD is not clear if the NDIPs referenced in the Pratt & Whitney 
ASB No. PW2000 A72-706, dated February 17, 2006, are mandatory.
    We agree. We clarified the AD by splitting up the information 
needed in paragraph (f), into subparagraphs. We also clarified the AD 
by specifying to use paragraphs 3., 3.A., and 3.B., of the 
Accomplishment Instructions of Pratt & Whitney ASB No. PW2000 A72-706, 
dated February 17, 2006, to use NDIP 1096, dated January 19, 2006, and 
to use NDIP 1095, dated January 12, 2006.

Claim That AD Is Not Required

    Northwest Airlines states that the AD is not required, since all 
affected parts will be scrapped at exposure. The commenter states that 
since most of the affected parts in the field are likely to have very 
few cycles remaining, the parts will be retired upon their next 
disassembly.
    We do not agree. The estimated number of cycles on the affected 8th 
stage disks currently in service ranges from about 13,500 cycles to 
19,000 cycles. The current life limit of the 8th stage disk is 20,000 
cycles. Therefore, some of the affected 8th stage disks probably will 
be returned to service after a shop visit. Affected parts with very few 
cycles remaining and voluntarily removed from service, will not require 
inspection or incur any inspection cost.

Recommend Compliance Time Be Reduced

    The National Transportation Safety Board (NTSB) supports the need 
for a onetime focused visual and FPI inspection of the HPC 8th stage 
disk. However, the NTSB recommends that the compliance time be reduced 
due to unknown factors from the disk failure investigation (failure 
location striation count) and the disk's demonstrated lack of damage 
tolerance.
    We do not agree. The finite element structural analysis performed 
by Pratt & Whitney for the 8th stage disk failure (PW2037 engine 
uncontained 8th stage HPC drum rotor disk assembly failure event, March 
10, 2005,) correlate well with results from the Materials & Processes 
Engineering Lab measurements. The Lab measurements were of the fatigue 
striation counts from the failed disk. Based on the failure analysis 
and the manufacturing records review of the 8th stage disk, a risk 
analysis determined that an acceptable level of safety will be 
maintained for the compliance described in the AD.

Service Documents Should Be Incorporated by Reference

    Modification and Replacement Parts Association (MARPA) states that 
the Pratt & Whitney service information referenced in the proposed AD 
should be incorporated by reference for the AD to be considered legal.
    We agree. Paragraph (i) of this AD incorporates by reference the 
necessary service information. The proposed AD did not contain the 
incorporation by reference paragraph (i), because it is only a notice 
of proposed rulemaking.

Service Documents Should Be Published in the Docket Management System 
(DMS)

    MARPA states that the Pratt & Whitney service information to be 
incorporated by reference in the AD, should be published in the DMS, as 
it is part of the AD.
    We partially agree. We are currently reviewing issues surrounding 
the posting of service information on the DMS as part of an AD Docket. 
Once we thoroughly examine all aspects of this issue and make a final 
determination, we will consider if our current practice needs revising.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 15 engines installed on 
airplanes of U.S. registry. We also estimate that it will take about 70 
work-hours per engine to perform the actions, and that the average 
labor rate is $80 per work-hour. We do not expect that parts will be 
required. Based on these figures, we estimate the total cost of the AD 
to U.S. operators to be $84,000 for the inspection.

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

[[Page 3054]]

that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. 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.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 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.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2007-02-06 Pratt & Whitney: Amendment 39-14893. Docket No. FAA-2006-
24452; Directorate Identifier 2006-NE-11-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective February 
28, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney PW2037, PW2040, and 
PW2037M turbofan engines. These engines are installed on, but not 
limited to Boeing 757 airplanes.

Unsafe Condition

    (d) This AD results from a Pratt & Whitney PW2037 8th stage 
high-pressure compressor (HPC) drum rotor disk assembly failure 
event caused by tooling damage that occurred during disk assembly 
manufacture. We are issuing this AD to prevent 8th stage HPC drum 
rotor disk assembly failure that could result in an uncontained 
engine failure and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next shop visit, not to exceed an additional 
6,000 engine cycles, after the effective date of this AD, when the 
8th stage HPC drum rotor disk assembly (compressor blades installed) 
is exposed and removed from the HPC module, unless the actions have 
already been done.

Inspect the 8th Stage Drum Rotor Disk

    (f) Inspect the 8th stage drum rotor disks listed by part 
numbers and serial numbers in Table 1 of the Accomplishment 
Instructions of Pratt & Whitney Alert Service Bulletin No. PW2000 
A72-706, dated February 17, 2006, as follows:
    (1) Do a onetime focused visual and fluorescent penetrant 
inspection (FPI) of suspect 8th stage HPC drum rotor disk assemblies 
that may have been damaged during manufacture.
    (2) Use paragraphs 3., 3.A., and 3.B. of the Accomplishment 
Instructions of Pratt & Whitney Alert Service Bulletin No. PW2000 
A72-706, dated February 17, 2006, Nondestructive Inspection 
Procedure (NDIP) 1096, dated January 19, 2006, and NDIP 1095, dated 
January 12, 2006, to do the inspections.
    (3) Any 8th stage disk damage that exceeds the serviceable 
limits specified in Pratt & Whitney PW2000 Engine Manual, Part 
Number 1A6231, Chapter/Section 72-35-03, Inspection/Check-01/-04, 
can not be returned to service.
    (g) After the effective date of this AD, do not install any 
uninspected 8th stage drum rotor disk assemblies listed in Table 1 
of the Accomplishment Instructions of Pratt & Whitney Alert Service 
Bulletin No. PW2000 A72-706, dated February 17, 2006, in any engine.

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.

Material Incorporated by Reference

    (i) You must use the Pratt & Whitney service information 
specified in Table 1 to perform the actions required by this AD. The 
Director of the Federal Register approved the incorporation by 
reference of the documents listed in Table 1 of this AD in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 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. 
You may review copies at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

                                      Table 1.--Incorporation by Reference
----------------------------------------------------------------------------------------------------------------
      Pratt & Whitney service
            information                     Page              Revision                       Date
----------------------------------------------------------------------------------------------------------------
Alert Service Bulletin No. PW2000   All................  Original..........  February 17, 2006.
 A72-706.
Total Pages: 11...................
Nondestructive Inspection           All................  Original..........  January 12, 2006.
 Procedure 1095.
Total Pages: 18...................
Nondestructive Inspection           All................  Original..........  January 19, 2006.
 Procedure 1096.
Total Pages: 18...................
----------------------------------------------------------------------------------------------------------------


[[Page 3055]]

Relate Information

    (j) Contact Mark Riley, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; telephone (781) 238-7758; fax 
(781) 238-7199, e-mail: [email protected] for more information 
about this AD.

    Issued in Burlington, Massachusetts, on January 12, 2007.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. E7-686 Filed 1-23-07; 8:45 am]
BILLING CODE 4910-13-P