[Federal Register Volume 71, Number 111 (Friday, June 9, 2006)]
[Proposed Rules]
[Pages 33412-33413]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-5242]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 71, No. 111 / Friday, June 9, 2006 / Proposed 
Rules  

[[Page 33412]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24487; Directorate Identifier 2006-NE-13-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney PW4074, PW4074D, 
PW4077, PW4077D, PW4084D, PW4090, PW4090-3, and PW4098 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 Pratt & Whitney PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, 
PW4090-3, and PW4098 turbofan engines, with certain front turbine hub 
part numbers installed. This proposed AD would require a onetime visual 
inspection of the anti-rotation slots in the front turbine hub, for a 
machining nonconformance, and its replacement if the inspection failed. 
This proposed AD results from a report of a crack found in an anti-
rotation slot of a front turbine hub, during overhaul shop inspection. 
The anti-rotation slot geometry was not machined in conformance with 
the design drawing. We are proposing this AD to prevent uncontained 
engine failure, damage to the airplane, and injury to passengers.

DATES: We must receive any comments on this proposed AD by August 8, 
2006.

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.
     Governmentwide 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 can get the service information identified in this proposed AD 
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-8770; fax (860) 565-4503.
    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: Antonio Cancelliere, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803; 
telephone (781) 238-7751; 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-2006-24487; 
Directorate Identifier 2006-NE-13-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy 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. This includes 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 DOT 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 Docket Management Facility receives 
them.

Discussion

    We received a report that during the overhaul shop inspection of a 
front turbine hub, a crack was found in an anti-rotation slot. Analysis 
by Pratt & Whitney revealed that the anti-rotation slot geometry was 
not machined in conformance with the design drawing. This 
nonconformance consisted of extra fillet radii in the anti-rotation 
slots. Extra fillet radii can cause local stress concentrations in the 
anti-rotation slots that lead to thermal mechanical fatigue and 
cracking. This condition, if not corrected, could result in uncontained 
engine failure, damage to the airplane, and injury to passengers.

Relevant Service Information

    We have reviewed and approved the technical contents of Pratt & 
Whitney Service Bulletin No. PW4G-112-72-282, Revision 1, dated March 
3, 2006. That Service Bulletin identifies the suspect population of 
front turbine hubs that might be affected by extra fillet radii by part 
number and serial number, describes procedures for visually inspecting 
the anti-rotation slots, and illustrates a machining nonconformance.

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 
at the next exposure of the rear side of the front turbine hub, a 
onetime visual inspection for extra fillet radii in the anti-rotation

[[Page 33413]]

slots, and its replacement if the inspection is failed. The proposed AD 
would require you to use the service information described previously 
to perform these actions.

Costs of Compliance

    We estimate that this proposed AD would affect 117 Pratt & Whitney 
PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3, and PW4098 
turbofan engines installed on airplanes of U.S. registry. We also 
estimate that it would take one workhour per engine to perform the 
proposed actions, and that the average labor rate is $80 per workhour. 
A replacement front turbine hub would cost about $253,000 for a PW4074, 
PW4074D, PW4077, PW4077D, or PW4084D engine, and about $283,000 for a 
PW4090, PW4090-3, or PW4098 engine. To date, the failure rate of 
inspected front turbine hubs is at ten percent. Assuming the failed 
front turbine hubs had 100 percent available life at the time of the 
inspection, the total cost of the proposed AD for the U.S. operators 
would be about $3,144,960.

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); 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. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

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-2006-24487; Directorate Identifier 
2006-NE-13-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by August 8, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney PW4074, PW4074D, PW4077, 
PW4077D, PW4084D, PW4090, PW4090-3, and PW4098 turbofan engines, 
with front turbine hub part numbers 50L761, 52L701, 55L221, 52L901, 
53L121, 55L521, and 53L021, installed. These engines are installed 
on, but not limited to, Boeing 777 airplanes.

Unsafe Condition

    (d) This AD results from a report of a crack found in an anti-
rotation slot of a front turbine hub, during overhaul shop 
inspection. The anti-rotation slot geometry was not machined in 
conformance with the design drawing. We are issuing this AD to 
prevent uncontained engine failure, damage to the airplane, and 
injury to passengers.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next exposure of the rear side of the front 
turbine hub after the effective date of this AD, unless the actions 
have already been done.

Onetime Visual Inspection

    (f) For front turbine hubs listed by part number and serial 
number in Table 1, Table 2, and Table 3 of Pratt & Whitney Service 
Bulletin (SB) No. PW4G-112-72-282, Revision 1, dated March 3, 2006, 
do the following:
    (1) Perform a onetime visual inspection for extra fillet radii 
in the anti-rotation slots.
    (2) Use paragraphs 1.A. through 1.C.(2) of the Accomplishment 
Instructions of Pratt & Whitney SB No. PW4G-112-72-282, Revision 1, 
dated March 3, 2006, to do the inspection.
    (3) Remove from service any front turbine hub that has extra 
fillet radii in the anti-rotation slots and install a serviceable 
front turbine hub.

Prohibition of Front Turbine Hubs That Have Extra Fillet Radii in the 
Anti-Rotation Slots

    (g) After the effective date of this AD, do not install any 
front turbine hub that has extra fillet radii in the anti-rotation 
slots, onto any engine.

Previous Credit

    (h) Previous credit is allowed for front turbine hubs inspected 
using Pratt & Whitney SB No. PW4G-112-72-282, dated February 27, 
2006, or Revision 1, dated March 3, 2006, before the effective date 
of this AD.

Alternative Methods of Compliance

    (i) 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.

    Issued in Burlington, Massachusetts, on June 5, 2006.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 06-5242 Filed 6-8-06; 8:45 am]
BILLING CODE 4910-13-P