[Federal Register Volume 65, Number 45 (Tuesday, March 7, 2000)]
[Proposed Rules]
[Pages 11940-11942]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-5011]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-ANE-56-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D 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 certain Pratt & Whitney JT9D 
series turbofan engines. This proposal would require initial and 
repetitive detailed eddy current inspections for cracks in 1st stage 
high pressure turbine (HPT) disks, and, if necessary, replacement with 
serviceable parts. This proposal is prompted by the finding of a crack 
in the web of one cooling air hole on a 1st stage HPT disk. The actions 
specified by the proposed AD are intended to prevent 1st stage HPT disk 
cracking, which could result in an uncontained engine failure and 
damage to the aircraft.

DATES: Comments must be received by May 8, 2000.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 99-ANE-56-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 8:00 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 0610; 
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: Wego Wang, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone 781-238-
7134, 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 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 notice 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-ANE-56-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    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. 99-ANE-56-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received a report of 
a cracked 1st stage high pressure turbine (HPT) disk installed on a 
Pratt & Whitney (PW) Model JT9D-7R4E turbofan engine. The crack was 
found during a routine maintenance inspection. The investigation 
revealed a 4-inch radial crack on the HPT 1st stage disk progressing 
through the web of one cooling air hole. The subject disk was returned 
to PW for investigation. Eddy current inspection (ECI) and fluorescent 
penetrant inspection (FPI) of the disk revealed axial indications on 
the surface of one 0.313-0.323 inch diameter cooling air hole surface 
that progressed completely through the web. Further examination 
revealed a severely worked layer extending to a maximum depth of 0.006 
inch from the surface of the hole. No other cooling air hole exhibited 
cracks. This condition, if not corrected, could result in 1st stage HPT 
disk cracking, which could result in an uncontained engine failure and 
damage to the aircraft.

Service Information

    The FAA has reviewed and approved the technical contents of PW 
Alert Service Bulletin (ASB) JT9D-7R4-A72-563, and ASB JT9D A6367, both 
dated July 28, 1999, that describe procedures for detailed ECI of 1st 
stage HPT disks for cracks.

[[Page 11941]]

Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require initial and repetitive detailed ECI for 
cracks in 1st stage HPT disks, and, if necessary, replacement with 
serviceable parts. The actions would be required to be accomplished in 
accordance with the ASB described previously.

Economic Analysis

    There are approximately 330 engines of the affected design in the 
worldwide fleet. The FAA estimates that 220 engines installed on 
aircraft of US registry would be affected by this proposed AD, that it 
would take approximately 4.5 work hours per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $165,000 per engine. Based on 
these figures, the total cost impact of the proposed AD on US operators 
is estimated to be $36,359,400.

Regulatory Impact

    This proposal does not have federalism implications, as defined in 
Executive Order No. 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 proposal.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order No. 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. 99-ANE-56-AD.

    Applicability: Pratt & Whitney (PW) JT9D-7R4D, -7R4D1, -7R4E, -
7R4E1 (AI-500), -7, -7A, -7AH, -7H, -7F, and -20 series turbofan 
engines, installed on but not limited to Boeing 747 and 767 series, 
McDonnell Douglas DC-10 series, and Airbus Industrie A300 series 
aircraft.

    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 (d) 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 1st stage high pressure turbine (HPT) disk cracking, 
which could result in an uncontained engine failure and damage to 
the aircraft, accomplish the following:

JT9D Series

    (a) For PW JT9D-7, -7A, -7AH, -7H, -7F, and -20 series turbofan 
engines, with 1st stage HPT disks, part numbers (P/Ns) 761401, 
811401, 823401, 825601, 826001, and 826301:

Initial Inspection

    (1) Perform the initial detailed eddy current inspection (ECI) 
for cracks in accordance with the Accomplishment Instructions of PW 
Alert Service Bulletin (ASB) No. JT9D A6367, dated July 28, 1999.
    (2) Inspect at the following compliance times, depending on 
whether parts have had prior fluorescent penetrant inspections (FPI) 
or not.

Initial Compliance Times

No Prior FPI

    (3) The following are the initial compliance times for parts 
that have had no prior FPI:
    (i) For disks with more than 8,000 total part cycles-since-new 
(CSN) on the effective date of this AD, inspect within 250 cycles-
in-service (CIS) after the effective date of this AD.
    (ii) For disks with at least 6,000 CSN though no more than 8,000 
total part CSN on the effective date of this AD, inspect within 
1,000 CIS after the effective date of this AD.
    (iii) For disks with at least 4,000 CSN though no more than 
5,999 total part CSN on the effective date of this AD, inspect 
within 2,000 CIS after the effective date of this AD.
    (iv) For disks with less than 4,000 total part CSN on the 
effective date of this AD, inspect prior to accumulating 6,000 total 
part CSN.

Prior FPI Accomplished

    (4) The following are the initial compliance times for parts 
that have had a previous FPI:
    (i) For disks with more than 8,000 CIS since last FPI on the 
effective date of this AD, inspect within 250 CIS after the 
effective date of this AD.
    (ii) For disks with at least 6,000 CSN though no more than 8,000 
CIS since last FPI on the effective date of this AD, inspect within 
1,000 CIS after the effective date of this AD.
    (iii) For disks with at least 4,000 CSN though no more than 
5,999 CIS since last FPI on the effective date of this AD, inspect 
within 2,000 CIS after the effective date of this AD.
    (iv) For disks with less than 4,000 CIS since last FPI on the 
effective date of this AD, inspect prior to accumulating 6,000 CIS 
since last FPI on the effective date of this AD.

Repetitive Inspections

    (5) Thereafter, perform detailed ECI for cracks:
    (i) At intervals not to exceed 6,000 CIS since last ECI.
    (ii) Inspect in accordance with the Accomplishment Instructions 
of PW ASB No. JT9D A6367, dated July 28, 1999.

Cracked Disks

    (6) Prior to further flight, replace cracked disks with 
serviceable parts.

JT9D-7R4 Series

    (b) For PW JT9D-7R4D, -7R4D1, -7R4E, and -7R4E1 (AI-500) series 
turbofan engines, with 1st stage HPT disks, P/N 825601:

Initial Inspection

    (1) Perform the initial detailed ECI for cracks in accordance 
with the Accomplishment Instructions of PW ASB No. JT9D-7R4-A72-563, 
dated July 28, 1999.
    (2) Inspect at the following compliance times, depending on 
whether parts have had prior FPI or not.

Initial Compliance Times

No Prior FPI

    (3) The following are the initial compliance times for parts 
that have had no prior FPI:
    (i) For disks with more than 10,000 total part CSN on the 
effective date of this AD, inspect within 250 CIS after the 
effective date of this AD.
    (ii) For disks with at least 8,000 CSN though no more than 
10,000 total part CSN on the effective date of this AD, inspect 
within 1,000 CIS after the effective date of this AD.

[[Page 11942]]

    (iii) For disks with at least 6,000 CSN though no more than 
7,999 total part CSN on the effective date of this AD, inspect 
within 2,000 CIS after the effective date of this AD.
    (iv) For disks with less than 6,000 total part CSN on the 
effective date of this AD, inspect prior to accumulating 8,000 total 
part CSN.

Prior FPI Accomplished

    (4) The following are the initial compliance times for parts 
that have had a previous FPI:
    (i) For disks with more than 10,000 CIS since last FPI on the 
effective date of this AD, inspect within 250 CIS after the 
effective date of this AD.
    (ii) For disks with at least 8,000 CSN though no more than 
10,000 CIS since last FPI on the effective date of this AD, inspect 
within 1,000 CIS after the effective date of this AD.
    (iii) For disks with at least 6,000 CSN though no more than 
7,999 CIS since last FPI on the effective date of this AD, inspect 
within 2,000 CIS after the effective date of this AD.
    (iv) For disks with less than 6,000 CIS since last FPI on the 
effective date of this AD, inspect prior to accumulating 8,000 CIS 
since last FPI on the effective date of this AD.

Repetitive Inspections

    (5) Thereafter, perform detailed ECI for cracks:
    (i) At intervals not to exceed 8,000 CIS since last ECI.
    (ii) Inspect in accordance with the Accomplishment Instructions 
of PW ASB No. JT9D-7R4-A72-563, dated July 28, 1999.

Cracked Disks

    (6) Prior to further flight, replace cracked disks with 
serviceable parts.

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 shall 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.

Ferry Flights

    (d) Special flight permits may be issued in accordance with 
Secs. 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 
inspection requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on February 23, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate Aircraft 
Certification Service.
[FR Doc. 00-5011 Filed 3-6-00; 8:45 am]
BILLING CODE 4910-13-U