[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: ``engineprop@faa.gov''. 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]
BILLING CODE 4910-13-P
