[Federal Register Volume 66, Number 169 (Thursday, August 30, 2001)]
[Proposed Rules]
[Pages 45789-45791]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-21895]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-16-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a 
new airworthiness directive (AD) that is applicable to Pratt & Whitney 
(PW) JT9D-7R4 series turbofan engines. This proposal would require a 
one-time inspection of low pressure turbine (LPT) 5th stage disks for 
evidence of blend repairs and mechanical damage, and replacement based 
on the extent of those repairs and damage. This proposal is prompted by 
a report of a PW JT9D-7R4G2 turbofan engine that experienced an 
uncontained failure of the LPT 5th stage disk. The actions specified by 
the proposed AD are intended to prevent uncontained failure of the LPT 
5th stage disk, due to incomplete blend repairs, resulting in in-flight 
shutdown and damage to the airplane.

DATES: Comments must be received by October 29, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No.2001-NE-16-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``[email protected]''. Comments sent via the Internet must contain the 
docket number in the subject line. Comments may be inspected at this 
location between 8 a.m. and 4:30 p.m., Monday through Friday, except 
Federal holidays. The service information referenced in the proposed 
rule may be obtained from Pratt & Whitney, 400 Main St., East Hartford, 
CT 06108; telephone (860) 565-8770; fax (860) 565-4503. This 
information may be examined at the FAA, New England Region, Office of 
the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Tara Goodman, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Office Park, Burlington, MA 01803-5299; telephone (781) 
238-7130, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NE-16-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2001-NE-16-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    The FAA has received a report of an uncontained LPT 5th stage disk 
failure on a PW JT9D-7R4G2 turbofan engine that resulted in damage to 
the airplane and in-flight shutdown. The

[[Page 45790]]

investigation into the cause of that failure revealed that the disk 
failure resulted from an incomplete blending of damage, previously 
caused by an LPT stage 4-5 tiebolt fracture. High-energy damage to the 
disk caused by a tiebolt fracture, if not completely removed by 
blending, may lead to disk cracking and fracture. Also, a review of the 
Engine Manual and the Standard Practices Operating Procedures for 
blending repairs indicates that these blending procedures may not 
ensure complete removal of all damaged material from the disks. This 
condition, if not corrected, could result in uncontained failure of the 
LPT 5th stage disk, due to incomplete blend repairs, resulting in in-
flight shutdown and damage to the airplane.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of PW 
service bulletin (SB) JT9D-7R4-72-574, Revision 1, dated June 26, 2001. 
That SB describes procedures for a one-time visual inspection of all PW 
JT9D-7R4 series LPT 5th stage disks for evidence of blend repairs and 
damage from fractured tiebolts in the forward and aft web and bore 
area, and disk removal from service based on the extent of damage.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Pratt & Whitney JT9D-7R4 series turbofan 
engines of the same type design, the proposed AD would require a one-
time visual inspection of PW JT9D-7R4 series LPT 5th stage disks for 
evidence of blend repairs in the forward and aft web and bore area. If 
a disk has any amount of blended or unblended damage in the web and 
bore area that was caused by a fractured tiebolt, or if a disk has five 
or more blended or unblended areas of damage by any cause, the disk 
must be removed from service. The actions would be required to be 
accomplished at the next separation of the LPT module from the engine 
after the effective date of this AD, in accordance with the service 
bulletin described previously.

Economic Impact

    There are approximately 647 Pratt & Whitney (PW) JT9D-7R4 series 
turbofan engines of the affected design in the worldwide fleet. The FAA 
estimates that 151 engines installed on airplanes of U.S. registry 
would be affected by this proposed AD. The FAA also estimates that it 
would take approximately one work hour per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
A replacement disk would cost approximately $145,260 per engine. Based 
on these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $21,943,320.

Regulatory Impact

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. 2001-NE-16-AD.

Applicability

    This airworthiness directive (AD) is applicable to Pratt & 
Whitney (PW) JT9D-7R4D, -7R4D1, -7R4E, -7R4E1, -7R4E4, -7R4G2, and 
7R4H1 series turbofan engines with LPT 5th stage disks, part numbers 

(P/N's) 787905, 787905-001, and 798305 installed. These engines are 
installed on, but not limited to Airbus Industrie A300 and A310 
series, and Boeing 747 and 767 series airplanes.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

Compliance

    Compliance with this AD is required as indicated at the next 
separation of the LPT module from the engine, unless already done.
    To prevent uncontained failure of the low pressure turbine (LPT) 
5th stage disk due to incomplete blend repairs, resulting in in-
flight shutdown and damage to the airplane, do the following:
    (a) Perform a one-time visual inspection for evidence of blend 
repairs of LPT 5th stage disks, P/N's 787905, 787905-001, and 798305 
in accordance with the Accomplishment Instructions section of PW 
service bulletin (SB) JT9D-7R4-72-574, Revision 1, dated June 26, 
2001.
    (1) Remove from service those LPT 5th stage disks that were 
installed in engines that experienced a tiebolt fracture and are 
found with blended or unblended damage in the web and bore area, and 
replace with a serviceable part.
    (2) Remove from service disks that have five or more blended or 
unblended damage areas by any cause, and replace with a serviceable 
part.
    (b) After the effective date of this AD, do not install any LPT 
module that contains an LPT 5th stage disk, P/N 787905, 787905-001, 
or 798305 unless that disk has been inspected as specified in 
paragraph (a) of this AD.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office (ECO). 
Operators must submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.



[[Page 45791]]


    Issued in Burlington, Massachusetts, on August 22, 2001.
Donald Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-21895 Filed 8-29-01; 8:45 am]
BILLING CODE 4910-13-P