[Federal Register Volume 63, Number 134 (Tuesday, July 14, 1998)]
[Rules and Regulations]
[Pages 37765-37767]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18649]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-04; Amendment 39-10652; AD 97-25-10 R1]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment revises an existing airworthiness directive
(AD), applicable to certain Pratt & Whitney (PW) JT9D series turbofan
engines, that currently requires initial and repetitive fluorescent
penetrant inspections (FPI) for cracks in cooling air holes of first
stage high pressure turbine (HPT) disks, and replacement of cracked
disks with serviceable parts. In addition, the current AD requires
initial and repetitive FPI for cracks in tie bolt holes of certain
other affected second stage HPT disks installed in PW JT9D series
turbofan engines. This amendment calls out the second stage HPT hub
assembly by part number (P/N) in addition to the hub P/N for
clarification of affected parts, and references a service bulletin that
does not change any of the requirements in the AD, but better explains
the inspection procedures that are referenced in the current AD. This
amendment also increases the repetitive inspection interval of first
stage HPT disks. This amendment is prompted by the need to clarify the
inspection procedures and the parts affected by this AD and by a re-
evaluation of the risk analysis, based on new data from service, to
establish a new repetitive inspection interval for the first stage HPT
disk. The actions specified by this AD are intended to prevent turbine
disk failure due to cooling air hole or tie bolt hole cracking, which
could result in an uncontained engine failure and damage to the
aircraft.
DATES: Effective July 29, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 29, 1998.
Comments for inclusion in the Rules Docket must be received on or
before September 14, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Regional
Counsel, Attention: Rules Docket No. 97-ANE-04, 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.
The service information referenced in this AD 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; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
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: On November 28, 1997, the Federal Aviation
Administration (FAA) issued AD 97-25-10, Amendment 39-10234 (62 FR
64514, December 8, 1997), applicable to certain Pratt & Whitney (PW)
JT9D series turbofan engines, to require initial and repetitive
fluorescent penetrant inspections (FPI) for cracks in cooling air holes
of affected first stage high pressure turbine (HPT) disks, and, if
necessary, replacement with serviceable parts. In addition, that
airworthiness directive (AD) requires initial and repetitive FPI for
cracks in tie bolt holes of all affected second stage HPT disks.
Finally, that action requires reporting findings of cracked turbine
disks. That action was prompted by reports of a cracked cooling air
hole on one first stage HPT disk, and a cracked tie bolt hole on one
second stage HPT disk. That condition, if not corrected, could result
in turbine disk failure due to cooling air hole or tie bolt hole
cracking, which could result in an uncontained engine failure and
damage to the aircraft.
Since the issuance of that AD, the FAA received questions regarding
clarifying the inspection procedures for second stage HPT disk tie bolt
holes. In addition, one commenter requested that the 48 hour time
requirement to notify the FAA that a cracked disk is found be changed
to 10 working days. The commenter explained that 48 hours is not
practical if a cracked disk is found over a holiday weekend. The FAA
concurs, and has changed this revision to the final rule AD to include
a 10 working day reporting requirement.
[[Page 37766]]
Also, based on new data and subsequent re-evaluation of the risk
analysis since publication of the existing AD, the FAA has determined
that the repetitive inspection interval for first stage HPT disks may
be extended. This revision to the final rule AD includes the extended
inspection interval.
The FAA has reviewed and approved the technical contents of PW
Service Bulletin (SB) No. JT9D-7R4-72-536, Revision 2, dated April 30,
1998, that describes procedures for FPI for cracks in tie bolt holes of
all affected second stage HPT disks.
Since an unsafe condition has been identified that is likely to
exist or develop on other engines of this same type design, this AD
revises AD 97-25-10 to call out the second stage HPT hub assembly by
part number (P/N) in addition to the hub P/N for clarification of
affected parts, and reference a SB that does not change any of the
requirements in the AD, but better explains the inspection procedures
that are referenced in the current AD. The actions are required to be
accomplished in accordance with PW SB No. JT9D-7R4-72-536, Revision 2,
dated April 30, 1998.
Since the issuance of that AD, the FAA received a request to
increase the inspection interval for first stage HPT disks. The FAA has
determined, by review of risk analysis, that extending the inspection
interval provides an adequate margin of safety.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption Addresses. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD 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 97-NE-04.'' The postcard will be date stamped and
returned to the commenter.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and is not a ``significant regulatory action''
under Executive Order 12866. It has been determined further that this
action involves an emergency regulation under DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979). If it is determined
that this emergency regulation otherwise would be significant under DOT
Regulatory Policies and Procedures, a final regulatory evaluation will
be prepared and placed in the Rules Docket. A copy of it, if filed, may
be obtained from the Rules Docket at the location provided under the
caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 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 removing Amendment 39-10234 (62 FR
64514, December 8, 1997) and by adding a new airworthiness directive,
Amendment 39-10652, to read as follows:
97-25-10 R1 Pratt & Whitney: Amendment 39-10652. Docket 97-ANE-04.
Revises AD 97-25-10, Amendment 39-10234.
Applicability: Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, -7Q3, -
7R4D, -7R4D1, -7R4E, and -7R4E1 (AI-500) series turbofan engines,
installed on but not limited to Airbus Industrie A300 and A310,
Boeing 747 and 767, 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 (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 turbine disk failure due to cooling hole or tie bolt
hole cracking, which could result in an uncontained engine failure
and damage to the aircraft, accomplish the following:
(a) For first stage high pressure turbine (HPT) disks, part
numbers (P/Ns) 768001, 792701, 812901, 819801, 840501, 840401,
840701, 840601, and 840301, installed in PW JT9D-59A, -70A, -7Q, and
-7Q3 engines, accomplish the following:
(1) Disks that have not been fluorescent penetrant inspected or
eddy current inspected since introduction into service, perform an
initial fluorescent penetrant inspection (FPI) for cracks in all 40
cooling air holes in accordance with PW Turbojet Engine Standard
Practices Manual, P/N 585005, Chapter/Section 70-33, Special Process
Operation Procedure (SPOP) 84, as follows:
(i) Disks with 3,500 cycles since new (CSN) or more on the
effective date of this AD, inspect prior to accumulating 5,000 CSN,
or within 1,500 cycles in service (CIS) after the effective date of
this AD, whichever occurs later.
[[Page 37767]]
(ii) Disks with less than 3,500 CSN on the effective date of
this AD, inspect prior to accumulating 5,000 CSN.
(2) Disks that have been reoperated in accordance with PW
Service Bulletin (SB) No. 5815, Revision 2, dated July 31, 1992, or
prior revisions, that have not been fluorescent penetrant inspected
or eddy current inspected since reoperation, perform an initial FPI
for cracks in all 40 cooling air holes in Chapter/Section 70-33,
SPOP 84, as follows:
(i) Disks with 3,500 CIS or more since reoperation on the
effective date of this AD, inspect prior to accumulating 5,000 CIS
since reoperation, or within 1,500 CIS after the effective date of
this AD, whichever occurs later.
(ii) Disks with less than 3,500 CIS since reoperation on the
effective date of this AD, inspect prior to accumulating 5,000 CIS
since reoperation.
(3) Disks that have been fluorescent penetrant inspected, or
eddy current inspected, since introduction into service or since
reoperation, in accordance with PW SB No. 5744, Revision 3, dated
March 31, 1993, or prior revisions, or PW JT9D-7Q, -7Q3 Engine
Manual, P/N 777210, 72-51-00, Inspection -03, or PW JT9D-59A, -70A
Engine Manual, P/N 754459, 72-51-00, Heavy Maintenance Check -03,
perform an FPI for cracks in all 40 cooling air holes, prior to
accumulating 5,000 CIS since last FPI or ECI, or within 250 CIS
after the effective date of this AD, whichever occurs later, in
accordance with PW Turbojet Engine Standard Practices Manual, P/N
585005, Chapter/Section 70-33, SPOP 84.
(4) Thereafter, perform FPI for cracks in all 40 cooling air
holes at intervals not to exceed 5,000 CIS since last FPI, in
accordance with PW Turbojet Engine Standard Practices Manual, P/N
585005, Chapter/Section 70-33, SPOP 84.
(5) Prior to further flight, remove from service cracked disks,
and replace with serviceable parts.
(b) For second stage HPT disks, P/N 5001802-01, or hub assembly,
P/N 808242, installed in PW JT9D-7R4D, -7R4D1, -7R4E, and -7R4E1
(AI-500) engines, accomplish the following:
(1) Disks that have not been fluorescent penetrant inspected
since introduction into service, perform an initial FPI for cracks
in all 30 tie bolt holes in accordance with PW SB No. JT9D-7R4-72-
536, Revision 2, dated April 30, 1998, as follows:
(i) Disks with 6,000 CSN or more on the effective date of this
AD, inspect within 2,000 CIS after the effective date of this AD.
(ii) Disks with less than 6,000 CSN on the effective date of
this AD, inspect prior to accumulating 8,000 CSN.
(2) Disks that have been fluorescent penetrant inspected since
introduction into service, perform an FPI for cracks in all 30 tie
bolt holes, prior to accumulating 8,000 CIS since last FPI, or
within 250 CIS after the effective date of this AD, whichever occurs
later, in accordance with PW SB No. JT9D-7R4-72-536, Revision 2,
dated April 30, 1998.
(3) Thereafter, perform FPI for cracks in all 30 tie bolt holes
at intervals not to exceed 8,000 CIS since last FPI, in accordance
with PW SB No. JT9D-7R4-72-536, Revision 2, dated April 30, 1998.
(4) Prior to further flight, remove from service cracked disks,
and replace with serviceable parts.
(c) Report findings of cracked turbine disks within 10 working
days after inspection to 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, Internet:
``Tara.G[email protected]''. Reporting requirements have been
approved by the Office of Management and Budget and assigned OMB
control number 2120-0056.
(d) 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 method of compliance with this AD, if any, may be
obtained from the Engine Certification Office.
(e) 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.
(f) The inspections shall be done in accordance with the
following PW SB:
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Document Number Pages Revision Date
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JT9D-7R4-72-536..................... 1 2...................... April 30, 1998.
2 Original............... February 28, 1997.
3, 4 2...................... April 30, 1998.
5, 6 Original............... February 28, 1997.
7 2...................... April 30, 1998.
8-10 1...................... October 13, 1997.
Total pages: 10.
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This incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from Pratt & Whitney, 400 Main St., East
Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-4503.
Copies may be inspected at the FAA, New England Region, Office of
the Regional Counsel, 12 New England Executive Park, Burlington, MA;
or at the Office of the Federal Register, 800 North Capitol Street,
NW., suite 700, Washington, DC.
(g) This amendment becomes effective on July 29, 1998.
Issued in Burlington, Massachusetts, on July 6, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 98-18649 Filed 7-10-98; 9:33 am]
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