[Federal Register Volume 63, Number 2 (Monday, January 5, 1998)]
[Proposed Rules]
[Pages 167-169]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-69]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 63, No. 2 / Monday, January 5, 1998 /
Proposed Rules
[[Page 167]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-ANE-69]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
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SUMMARY: This notice revises an earlier proposed airworthiness
directive (AD), applicable to Pratt & Whitney JT9D series turbofan
engines, that would have required 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. That proposal was prompted by reports of disk bore
cracks found during shop inspections on both the 14th and 15th stage
HPC disks. This action revises the proposed rule by extending the
repetitive inspection interval and changing the definition of a shop
visit. The actions specified by this proposed AD are intended to
prevent 14th and 15th stage HPC disk rupture, which could result in an
uncontained engine failure and damage to the aircraft.
DATES: Comments must be received by March 6, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
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.dot.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 Assistant Chief
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 NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, New England Region, Office of the Assistant Chief Counsel,
Attention: Rules Docket No. 95-ANE-69, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to
Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, -7Q3, and JT9D-7R4
series turbofan engines, was published as a notice of proposed
rulemaking (NPRM) in the Federal Register on May 6, 1996 (61 FR 20192).
That NPRM would have required initial and repetitive eddy current
inspections (ECI) of 14th and 15th high pressure compressor (HPC) disks
for cracks in accordance with Non-Destructive Inspection Procedure No.
858 (NDIP-858), dated November 7, 1995, attached to PW Alert Service
Bulletin (ASB) No. JT9D-7R4-A72-524, dated December 13, 1995, and ASB
No. A6232, Revision 1, dated January 11, 1996. That action also
proposed to require the removal of cracked disks and replacement with
serviceable parts. That NPRM 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 NPRM, the FAA received several comments
that required changing the compliance section.
Several commenters state that the proposed rule's definition for
shop visit (separation of ``N'' flange) would cause hardship, since
operators have no records for tracking ``N'' flange separation. The
commenters propose to change the definition of shop visit to occur when
the low pressure turbine (LPT) is inspected as a module. One of the
commenters further states that this inspection is done whenever the LPT
module is separated from the engine at the ``N'' flange. The FAA
concurs with this change, since the proposed definition facilitates the
FAA's intent. Therefore, the ``Shop Visit'' definition
[[Page 168]]
in this final rule has been changed accordingly.
Another commenter disagrees with the FAA's statement that the
required action would take place during regularly scheduled
maintenance. The FAA agrees with the commenter that this inspection may
not always coincide with scheduled maintenance activity, since the shop
visit rates can vary between operators. However, the FAA's intent is to
facilitate this required inspection during a shop visit to the extent
possible, while maintaining the required level of safety.
The same commenter proposes that the inspections be required at
next shop visit, instead of using cycles since last shop visit. The FAA
disagrees. Shop visit intervals vary among different operators and may
exceed the inspection intervals established to maintain an acceptable
level of safety.
Another commenter states that the cyclic drawdown should be
extended from 1,000 cycles to 1,500 cycles in order to prevent possible
premature engine removals. The commenter does not provide any
additional data/actions that would assure an equivalent level of
safety. The FAA disagrees, since the proposed additional cycles of
operation without inspections would result in a reduced level of
safety. Therefore, the 1,000 cycle in service (CIS) inspection interval
remains as proposed.
The FAA conducted an additional review of the proposed inspection
intervals and concluded that the inspection requirements of paragraph
(c)(1)(iv) as published are unnecessarily restrictive. Therefore, the
inspection interval of 3,000 cycles since new is extended to 5,000
cycles since new, in order to make it consistent with the inspection
requirement of the preceding paragraph.
Since this change expands the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
There are approximately 1,100 engines of the affected design in the
worldwide fleet. The FAA estimates that 170 engines would be affected
by this proposed AD. The FAA anticipates that the majority of the
required initial and repetitive eddy current inspections would take
place during regularly scheduled maintenance visits, but it would take
3 work hours per engine per inspection, and the average labor rate is
$60 per work hour. Based on these figures, the total cost impact of the
proposed AD per engine is estimated to be $30,600. Based on these
estimates, the total cost of the proposed AD would be $5,202,000.
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:
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. 95-ANE-69.
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/N's) 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 Non-Destructive Inspection Procedure No. 858 (NDIP-858), dated
November 7, 1995, attached to PW Alert Service Bulletin (ASB) No.
JT9D-7R4-A72-524, dated December 13, 1995, 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 PW ASB No. A6232, Revision 1, dated
January 11, 1996, 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.
[[Page 169]]
(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, Revision 1, dated January 11, 1996, 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.
(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 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, dated December 13, 1995. 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 from an uninstalled engine.
(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 December 23, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 98-69 Filed 1-2-98; 8:45 am]
BILLING CODE 4910-13-U
