[Federal Register Volume 64, Number 60 (Tuesday, March 30, 1999)]
[Proposed Rules]
[Pages 15137-15139]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-7688]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-69]


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 to revise an existing airworthiness 
directive (AD), applicable to Pratt & Whitney JT9D series turbofan 
engines, that currently requires initial and repetitive eddy current 
inspections (ECI) of 14th and 15th stage high pressure compressor (HPC) 
disks for cracks, and removal of cracked disks and replacement with 
serviceable parts. This action would revise the definition of a shop 
visit to make compliance less restrictive, and add references to a 
Nondestructive Inspection Procedure attached to applicable service 
bulletins. This proposal is prompted by feedback from operators saying 
that the shop visit definition in the current AD made AD compliance 
unnecessarily restrictive. The actions specified by the proposed AD are 
intended to prevent 14th and 15th stage HPC disk rupture, which

[[Page 15138]]

could result in an uncontained engine failure and damage to the 
aircraft.

DATES: Comments must be received by April 29, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 95-ANE-69, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[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, Publications Department, Supervisor 
Technical Publications Distribution, M/S 132-30, 400 Main St., East 
Hartford, CT 06108; telephone (860) 565-7700. 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 Executive 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 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 95-ANE-69.'' 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. 95-ANE-69, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On October 5, 1998, the Federal Aviation Administration (FAA) 
issued airworthiness directive (AD) 98-21-22, Amendment 39-10830 (63 FR 
55500, October 16, 1998), applicable to Pratt & Whitney (PW) Model 
JT9D-59A, -70A, -7Q, -7Q3, and JT9D-7R4 series turbofan engines, to 
require initial and repetitive eddy current inspections (ECI) of 14th 
and 15th high pressure compressor (HPC) disks for cracks. That action 
was prompted by reports of disk bore cracks found during shop 
inspections on both the 14th and 15th stage HPC disks. That condition, 
if not corrected, could result in 14th and 15th stage HPC disk rupture, 
which could result in an uncontained engine failure and damage to the 
aircraft.
    Since the issuance of that AD, the FAA has received feedback that 
requests changing the definition of shop visit as published in the 
final rule, published October 16, 1998, to the wording used in the 
supplemental NPRM (SNPRM), published January 5, 1998. In writing the 
final rule, the FAA changed the definition of shop visit for 
clarification from the version published in the SNPRM, January 5, 1998. 
This change, in effect, made the definition of shop visit more 
restrictive. The final rule states in paragraph (e) ``For the purpose 
of this AD, a shop visit is defined as the induction of an engine into 
the shop for scheduled maintenance.'' The SNPRM stated in paragraph (e) 
``For the purpose of this AD, a shop visit is defined as a low pressure 
turbine module removal from an uninstalled engine.''
    In order to conduct the repetitive inspections of 14th and 15th 
stage HPC disks for cracks when the opportunity presents itself when 
the low pressure turbine module is removed, typically when the engine 
is in the shop and maintenance work is being performed, and to be 
consistent with the risk analysis, the definition of shop visit is 
proposed to be changed to ``For the purpose of this AD, a shop visit is 
defined as a low pressure turbine module removal''.
    In addition, this final rule adds references to the Nondestructive 
Inspection Procedure No. 858 (NDIP-858), dated November 7, 1995, 
attached to the various versions of the referenced service bulletins, 
which was inadvertently omitted from the current AD.
    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 revise AD 98-21-22 to revise the shop visit 
definition and add reference to NDIP-858.
    Since this revised proposed rule would only change the definition 
of the shop visit and add reference to the NDIP, there is no effect on 
the economic analysis.
    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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:

[[Page 15139]]

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 removing 39-10830 (63 FR 55500, 
October 16, 1998), and by adding a new airworthiness directive, to read 
as follows:

Pratt & Whitney: Docket No. 95-ANE-69. Revises AD 98-2122, Amendment 
39-10830.

    Applicability: Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, -
7Q3, and JT9D-7R4 series turbofan engines, with the following 14th 
and 15th stage high pressure compressor (HPC) disks installed: Part 
Numbers (P/Ns) 5000814-01, 790014, 789914, 790114, 5000815-01, 
5000815-021, 704315, 704315-001, 786215, 786215-001, 704314, 789814, 
and 790214. These engines are installed on but not limited to Airbus 
A300 and A310 series aircraft, Boeing 747 and 767 series aircraft, 
and McDonnell Douglas DC-10 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 (f) 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 14th and 15th stage HPC disk rupture, which could 
result in an uncontained engine failure and damage to the aircraft, 
accomplish the following:
    (a) Inspect 14th stage HPC disks, P/N 5000814-01, in accordance 
with Nondestructive Inspection Procedure No. 858 (NDIP-858), dated 
November 7, 1995, attached to PW Alert Service Bulletin (ASB) No. 
JT9D-7R4-524, original issue dated December 13, 1995, or Revision 1, 
dated June 26, 1997, as follows:
    (1) Perform an initial eddy current inspection (ECI) for cracks 
as follows:
    (i) For disks with 7,000 or more cycles since new (CSN), and 
3,000 or more cycles in service (CIS) since last shop visit, on the 
effective date of this AD, inspect within the next 1,000 CIS after 
the effective date of this AD, or at the next shop visit, whichever 
occurs first.
    (ii) For disks with 7,000 or more CSN, and less than 3,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 4,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with less than 7,000 CSN on the effective date 
of this AD, inspect at the next shop visit after the effective date 
of this AD, but before exceeding 4,000 CIS since last shop visit, or 
8,000 CSN, whichever occurs later.
    (iv) For uninstalled disks on or after the effective date of 
this AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 4,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (b) Inspect 14th stage HPC disks, P/N's 790014, 789914, 790114, 
and 15th stage HPC disks, P/N's 5000815-01, 5000815-021, 704315, 
704315-001, 786215, and 786215-001, in accordance with NDIP-858, 
dated November 7, 1995, attached to PW ASB No. JT9D-7R4-A72-524, 
dated December 13, 1995, or Revision 1, dated June 26, 1997, or PW 
ASB No. A6232, dated December 13, 1995, or Revision 1, dated January 
11, 1996, or Revision 2, June 26, 1997, as applicable, as follows:
    (1) Perform an initial ECI for cracks as follows:
    (i) For disks with 6,500 or more CSN, and 3,000 or more CIS 
since last shop visit, on the effective date of this AD, inspect 
within the next 1,000 CIS after the effective date of this AD, or at 
the next shop visit, whichever occurs first.
    (ii) For disks with 6,500 or more CSN, and less than 3,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 4,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with less than 6,500 CSN on the effective date 
of this AD, inspect at the next shop visit after the effective date 
of this AD, but before exceeding 4,000 CIS since last shop visit, or 
7,500 CSN, whichever occurs later.
    (iv) For uninstalled disks on or after the effective date of 
this AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 4,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (c) Inspect 14th stage HPC disks, P/N's 704314, 789814, and 
790214, in accordance with NDIP-858, dated November 7, 1995, 
attached to PW ASB No. A6232, original issue, dated December 13, 
1995, or Revision 1, dated January 11, 1996, or Revision 2, dated 
June 26, 1997, as follows:
    (1) Perform an initial ECI for cracks as follows:
    (i) For disks with 2,000 or more CSN, and 2,000 or more CIS 
since last shop visit, on the effective date of this AD, inspect 
within the next 1,000 CIS after the effective date of this AD, or at 
the next shop visit, whichever occurs first.
    (ii) For disks with 2,000 or more CSN, and less than 2,000 CIS 
since last shop visit, on the effective date of this AD, inspect 
within 3,000 CIS since the last shop visit, or at the next shop 
visit, whichever occurs first.
    (iii) For disks with 2,000 or more CSN, and no previous shop 
visits, inspect within 3,000 CIS after the effective date of this 
AD, or at the next shop visit, whichever occurs first.
    (iv) For disks with less than 2,000 CSN on the effective date of 
this AD, inspect at the next shop visit after the effective date of 
this AD, but before exceeding 5,000 CSN.
    (v) For uninstalled disks on or after the effective date of this 
AD, inspect prior to installation.
    (2) Thereafter, perform ECI for cracks at intervals not to 
exceed 3,000 CIS since last ECI.
    (3) Prior to further flight, remove cracked disks and replace 
with serviceable parts.
    (d) Within 30 days of inspection, report inspection results on 
the form labeled ``14th and 15th Stage HPC Disk Inspection Report,'' 
to Pratt & Whitney Customer Technical Support. The fax number is 
listed on that form which is attached to PW ASB No. JT9D-7R4-A72-
524, Revision 1, dated June 26, 1997, or PW ASB No. A6232, Revision 
2, June 26, 1997. Reporting requirements have been approved by the 
Office of Management and Budget and assigned OMB control number 
2120-0056.
    (e) For the purpose of this AD, a shop visit is defined as a low 
pressure turbine module removal.
    (f) 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. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

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

    (g) Special flight permits may be issued in accordance with 
sections 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 March 23, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-7688 Filed 3-29-99; 8:45 am]
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