[Federal Register Volume 65, Number 239 (Tuesday, December 12, 2000)]
[Proposed Rules]
[Pages 77530-77532]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-31614]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-71-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT8D series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Pratt

[[Page 77531]]

& Whitney (PW) JT8D series turbofan engines. This proposal would 
require removing certain 2nd stage compressor disks, specified by 
serial number, from service. This proposal is prompted by a report from 
PW of a number of JT8D engine 2nd stage compressor disks that were 
delivered to the field with potential machining damage to the tie rod, 
counterweight, and pin holes. The actions specified by the proposed AD 
are intended to prevent rupture of the 2nd stage compressor disk caused 
by machining damage, which could result in an uncontained engine 
failure and damage to the airplane.

DATES: Comments must be received by February 12, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-71-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) 565-6600, 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: Christopher Spinney, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (781) 238-7175; 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 98-ANE-71-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. 98-ANE-71-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    Pratt & Whitney (PW) notified the Federal Aviation Administration 
(FAA) of the possibility of machining damage in the holes of five 
hundred twenty-three 2nd stage compressor disks, part number (P/N) 
745902, P/N 790832, and P/N 807502. Machining damage may have resulted 
in distorted microstructure in the tie rod, counterweight, and pin 
holes. Increased stress due to the distorted microstructure could cause 
cracks that propagate through the disk. This condition, if not 
corrected, could result in rupture of the 2nd stage compressor disk 
caused by machining damage, which could result in an uncontained engine 
failure and damage to the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved the technical content of JT8D 
Alert Service Bulletin (ASB) JT8D A6336, Revision 1, dated June 29, 
1999, that lists the serial numbers (SN's) of certain 2nd stage 
compressor disks, P/N 745902, P/N 790832, and P/N 807502, and describes 
procedures replacing the disk if it is listed by SN in the ASB.

Explanation of Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, this AD is 
being proposed to prevent rupture of the 2nd stage compressor disk 
caused by machining damage, which could result in an uncontained engine 
failure and damage to the airplane. This proposed AD would require 
removal of 2nd stage compressor disks, P/N 745902, P/N 790832, and P/N 
807502, before accumulating 2,000 cycles-since-new if the SN is listed 
in the ASB. The compliance time was established based on the safety 
concerns and the life management analysis. The actions would be 
required to be accomplished in accordance with the ASB described 
previously.

Cost Impact

    There are approximately 110 engines of the affected design in the 
worldwide fleet. The FAA estimates that 60 engines, installed on 
airplanes of U.S. registry, would be affected by this proposed AD, that 
it would take approximately 48 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $60 per work 
hour. The prorated cost of the unusable life of a 2nd stage disk is 
$30,000. The manufacturer has informed the FAA that it may pay the cost 
of the disk, which may lower the cost to operators. Based on these 
figures, the FAA estimates the total cost impact of the proposed AD on 
U.S. operators to be $1,972,800.

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.

[[Page 77532]]

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. 98-ANE-71-AD.

    Applicability: JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A,-11, -15, 
-15A, -17, -17A, -17R, and -17AR series turbofan engines with 2nd 
stage compressor disks, part number (P/N) 745902, P/N 790832, and P/
N 807502, installed. These engines are installed on, but not limited 
to Boeing 727 series airplanes, Boeing 737-100 and -200 series 
airplanes and McDonnell Douglas DC-9 series airplanes.

    Note 1: This airworthiness directive (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 (b) 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: Required as indicated, unless accomplished 
previously.
    To prevent a rupture of the 2nd stage compressor disk, caused by 
machining damage, which could result in an uncontained engine 
failure and damage to the airplane, accomplish the following:

Removal of Disk

    (a) Remove from service 2nd stage compressor disks, P/N 745902, 
P/N 790832, and P/N 807502, identified by serial number in the 
Accomplishment Instructions of JT8D Alert Service Bulletin (ASB) 
JT8D A6336, Revision 1, dated June 29, 1999, prior to accumulating 
2,000 cycles since new.

Alternative Methods of Compliance

    (b) 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 shall submit their requests 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.

Special Flight Permits

    (c) Special flight permits may be issued in accordance with 
21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 
and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on December 5, 2000.
Diane S. Romanosky,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-31614 Filed 12-11-00; 8:45 am]
BILLING CODE 4910-13-U