[Federal Register Volume 72, Number 22 (Friday, February 2, 2007)]
[Proposed Rules]
[Pages 4964-4966]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-1707]


 ========================================================================
 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. 72, No. 22 / Friday, February 2, 2007 / 
Proposed Rules  

[[Page 4964]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23742; Directorate Identifier 2005-NE-53-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney (PW) JT9D-7R4 Series 
Turbofan Engines

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

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: This supplemental NPRM revises an earlier proposed 
airworthiness directive (AD) for PW JT9D-7R4G2 series turbofan engines. 
That proposed AD would have required replacing the old configuration 
2nd stage high pressure turbine (HPT) air seal assembly with a new 
design 2nd stage HPT air seal assembly that increases cooling air flow. 
That proposed AD resulted from a report of an uncontained failure of 
the 2nd stage HPT air seal assembly, caused by the air seal assembly 
brace disengaging from the air seal, due to insufficient cooling air 
flow. This supplemental NPRM revises the proposed AD by proposing to 
include additional models of the PW JT9D-7R4 turbofan engines in the 
applicability, requiring a visual and a fluorescent penetrant 
inspection of the air seal assembly, replacing the 2nd stage HPT vane 
assemblies, and reopening the comment period. This NPRM results from 
comments to the proposed AD. We are proposing this AD to prevent 
uncontained failure of the 2nd stage HPT air seal assembly, leading to 
engine in-flight shutdown and damage to the airplane.

DATES: We must receive any comments on this proposed AD by April 3, 
2007.

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.
     Government-wide 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: 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:

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-2006-23742; 
Directorate Identifier 2005-NE-53-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, including 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 Offices 
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

    On April 19, 2006, we issued a proposal to amend part 39 of the 
Code of Federal Regulations (14 CFR part 39) to add an AD, applicable 
to PW JT9D-7R4G2 turbofan engines. The proposed AD published as an NPRM 
in the Federal Register on April 26, 2006 (71 FR 24613). That NPRM 
would have required at the next HPT module overhaul, replacing the 2nd 
stage HPT air seal assembly, P/N 815097, with a new configuration 2nd 
stage HPT air seal assembly that increases cooling air flow, either by 
installing a new 2nd stage air seal assembly or modifying the old 
configuration 2nd stage seal assembly. That NPRM resulted from two 
reports of failure of the 2nd stage HPT air seal assembly, part number 
(P/N) 815097, installed in JT9D-7R4G2 turbofan engines. That condition, 
if not corrected, could result in uncontained failure of the 2nd stage 
HPT air seal assembly, leading to engine in-flight shutdown and damage 
to the airplane.
    Since we issued that NPRM, we received comments to add additional 
models of the PW JT9D-7R4 series turbofan engines to the applicability 
for this proposed AD. Also, even though we added new engine models, our 
changes to the required actions reduced the number of engines that are 
affected and

[[Page 4965]]

the total cost of this proposed AD to the U.S. registered fleet.
    Since this change expands the scope of the originally proposed 
rule, we determined that it is necessary to reopen the comment period 
to provide additional opportunity for public comment.

Comments

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

Request to Expand the Applicability

    Two commenters, Pratt & Whitney and FedEx, ask us to expand the 
applicability to include the JT9D-7R4E1, -7R4E4, and -7R4H1. The 
commenters point out that the additional engine models are specified in 
PW Alert Service Bulletin (ASB) JT9D-7R4-A72-596, dated September 15, 
2005. We agree. We added the JT9D-7R4E1, -7R4E4, and -7R4H4 engine 
models to the applicability for this proposed AD.

Requests for Changes to the Costs of Compliance

    One commenter, FedEx, ask us to revise the Costs of Compliance to 
include the expanded number of engines from adding the additional JT9D-
7R4 engine models. The commenter states that the existing Economic 
impact analysis for the proposed AD considered only the JT9D-7R4G2 
engine model.
    We agree. We revised the Costs of Compliance section to include all 
affected JT9D-7R4 engine models. However, updated information from the 
engine manufacturer confirmed that the number of engines affected 
actually decreased, which results in reduced cost to the operators.
    The same commenter asks us to include the cost of material required 
to incorporate. The commenter estimates that material cost as $18,000 
per engine.
    We do not agree. We provide an estimated material cost of $5,400 
per engine in the Costs of Compliance in the proposed AD. Parts include 
new 2nd stage HPT vane covers, P/N 822734, and rivets, P/N ST1219-213, 
that are required to modify the 2nd stage HPT vane cluster assemblies 
as specified in ASB JT9D-7R4-A72-596.
    One commenter, Northwest Airlines, states the Cost of Compliance in 
the proposed AD is understated. The commenter states that the Costs of 
Compliance should include the cost to repair the honeycomb air seal 
land that is riveted to the 2nd stage vane clusters, which typically 
require restoring to maintain rotating knife edge-to-seal land 
clearances. The commenter states the FAA should include the maintenance 
and repair costs incurred when exposing the parts.
    We don't agree. The Costs of Compliance in the proposed AD doesn't 
include costs associated with parts that require replacement or repair 
due to typical wear or damage.

Request to Use a Shorter Rivet in the 2nd Stage Scaling Ring Assembly

    One commenter, Japan Air Lines, asks that we allow using a shorter 
rivet, part number (P/N) ST1219-212, instead of rivet, P/N ST12199-213, 
for the 2nd stage turbine air sealing ring segment assembly, P/N 
795187, when incorporating SB JT9D-7R4-A72-596. Japan Air Lines states 
that PW has approved using the shorter rivet with air sealing ring 
segment assembly 795187.
    We partially agree. Because we are now proposing only to require 
removing the reduced air flow 2nd stage HPT vane assemblies, P/Ns 
797282, 796972, 800082, 800072, 803182, 803282, and 822582, and we 
don't propose to require modifying the vane assemblies, the commenter 
can use the shorter rivet approved by PW. We don't need to approve it 
as an alternative method of compliance.

Request to Change the Compliance Time

    One commenter, Northwest Airlines, asks us to change the compliance 
time from the next exposure of the HPT module to next exposure of the 
2nd stage HPT vanes. The commenter states that changing the definition 
would align the compliance time with the definition of next exposure.
    We don't agree. The intent of the proposed AD is to require 
inspecting the HPT 2nd stage HPT air seal and removing the reduced 
cooling flow 2nd stage HPT vane assemblies when the HPT module is 
exposed. The HPT module is exposed when the 1st or 2nd stage HPT rotors 
are removed from the HPT module assembly, not when the 2nd stage HPT 
vane assemblies are removed from the HPT case.

Request to Remove or Change Paragraph (d) of the Proposed AD

    One commenter, Northwest Airlines, asks that we remove or change 
paragraph (d) of the proposed AD. The commenter states that as written, 
the paragraph requires reidentifying the next higher assembly, HPT case 
assembly, based on P/Ns installed in the module. The commenter states 
that including the P/N configuration of the top level assembly is not 
necessary.
    We agree. We removed the requirement to use PW ASB JT9D-7R4-A72-596 
to replace the vane assembly.

Relevant Service Information

    We have reviewed and approved the technical contents of PW Alert 
Service Bulletin JT9D-7R4-A72-596, dated September 15, 2005. That Alert 
Service Bulletin describes procedures for replacing 2nd stage HPT air 
seal assembly, P/N 815097, with a new configuration 2nd stage HPT air 
seal assembly that increases cooling air flow, either by installing a 
new 2nd stage air seal assembly or modifying the old configuration 2nd 
stage HPT seal assembly.

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 HPT module exposure:
     Visual and fluorescent penetrant inspections of the 2nd 
stage HPT air seal assembly, P/N 815097, and
     Removing the reduced cooling flow 2nd stage HPT vane 
assemblies.

Costs of Compliance

    We estimate that this proposed AD would affect 85 PW JT9D-7R4 
series turbofan engines installed on airplanes U.S. registry. We also 
estimate that it would take about 65.5 work-hours per engine to perform 
the proposed actions, and that the average labor rate is $80 per work-
hour. Required parts would cost about $5,400 per engine. Based on these 
figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $904,400.

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 4966]]

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-2006-23742; Directorate Identifier 
2006-NE-39-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by April 3, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney (PW) JT9D-74R4E1, -
74R4E4, -74R4G2, and -74R4H1 turbofan engines. These engines are 
installed on, but not limited to, Boeing 747-200B, -200C, -200F, and 
-300 airplanes.

Unsafe Condition

    (d) This AD results from a report of an uncontained failure of 
the 2nd stage high pressure turbine (HPT) air seal assembly, caused 
by the air seal assembly brace disengaging from the air seal, due to 
insufficient cooling air flow. We are issuing this AD to prevent 
uncontained failure of the 2nd stage HPT air seal assembly, leading 
to engine in-flight shutdown and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next HPT module exposure after the effective 
date of this AD, unless the actions have already been done.
    (f) At the next HPT module exposure, perform a visual inspection 
and a fluorescent penetrant inspection of the 2nd stage HPT air seal 
assembly part number (P/N) 815097. Use the engine maintenance manual 
to perform the inspections.
    (g) At the next HPT module exposure, remove reduced cooling flow 
2nd stage HPT vane assemblies P/Ns 797282, 796972, 800082, 800072, 
803182, 803182, 803282, and 822582. Pratt & Whitney Alert Service 
Bulletin JT9D-7R4-A72-596, dated September 15, 2005, contains 
information for modifying the reduced cooling flow 2nd stage HPT 
vane assemblies.

Definition

    (h) The manufacturer defines an HPT module exposure as removing 
the 1st stage HPT rotor and 2nd stage HPT rotor from the HPT case.

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.

Related Information

    (j) Pratt & Whitney Alert Service Bulletin JT9D-7R4-A72-596, 
dated September 15, 2005, contains information for modifying the 
reduced cooling flow 2nd stage HPT vane assemblies.

    Issued in Burlington, Massachusetts, on January 26, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E7-1707 Filed 2-1-07; 8:45 am]
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