[Federal Register Volume 63, Number 219 (Friday, November 13, 1998)]
[Rules and Regulations]
[Pages 63391-63393]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30320]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-53-AD; Amendment 39-10873; AD 98-23-08]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Pratt & Whitney (PW) PW4000 series turbofan
engines not incorporating modifications described in certain PW service
bulletins listed in the applicability section, that requires high
pressure compressor (HPC) blade tip grinding of the rotor assembly,
installation of aluminum oxide coated HPC blade tips in stages 9
through 12, modification of HPC 8th through 14th stage stators,
incorporation of 1st stage high pressure turbine (HPT) vanes with
increased airflow area which also requires additional HPT hardware
modifications, and incorporation of HPC 13th-15th stage zirconium oxide
blade tips. This amendment is prompted by reports of HPC surge caused
by excessive HPC rear stage rotor-to-case clearance. The actions
specified by this AD are intended to prevent HPC surge, which can
result in engine power loss at a critical phase of flight such as
takeoff or climb.
DATES: Effective January 12, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 12, 1999.
ADDRESSES: 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 Federal Aviation Administration (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: Chris Gavriel, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA
[[Page 63392]]
01803-5299; telephone (781) 238-7147, fax (781) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Pratt & Whitney (PW)
PW4000 series turbofan engines not incorporating modifications
described in certain PW service bulletins listed in the applicability
section was published in the Federal Register on June 18, 1998 (63 FR
33295). That action proposed to require high pressure compressor (HPC)
blade tip grinding of the rotor assembly, installation of aluminum
oxide coated HPC blade tips in stages 9 through 12, modification of HPC
8th through 14th stage stators, incorporation of 1st stage high
pressure turbine (HPT) vanes with increased airflow area which also
requires additional HPT hardware modifications, and incorporation of
HPC 13th-15th stage zirconium oxide blade tips.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter requests a change to the Compliance Section to allow
the accomplishment of either PW Service Bulletins (SBs) No. PW4ENG-72-
514, or the appropriate nozzle guide vane and TOBI duct section of SB
PW4ENG-72-504. The commenter wants to have a choice to incorporate the
pertinent sections of SB PW4ENG-72-504 after the effective date of this
AD and still comply with the AD. The FAA concurs, provided that all of
the requirements of that SB are incorporated, since incorporation of
only the pertinent sections will not produce a certified engine
configuration. Engines that have incorporated the modifications in SB
PW4ENG-72-504 already are exempted from the AD based upon the
applicability. If an operator wants to exercise this choice after the
effective date of this AD, instead of incorporating the modifications
in SB PW4ENG-72-514, that choice will produce an airworthy engine to an
equivalent level of the modifications in SB PW4ENG-72-514. There are
two other SBs listed in the applicability section: SB PW4ENG-72-490 and
PW4ENG-72-572 that accomplish equivalent actions to SB PW4ENG-72-504.
Therefore, a paragraph has been added to the compliance section
clarifying that if the modifications contained in certain SBs listed in
the applicability paragraph are incorporated after the effective date
of this AD, no further action is required.
One commenter states that it has already complied with the
requirements of this AD and that those requirements are effective in
preventing surges from occurring in service.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 187 engines of the affected design in the
worldwide fleet. The FAA estimates that there are currently 61 engines
installed on aircraft of U.S. registry that would be affected by this
AD. Required parts would cost approximately $20,000 per engine. Based
on these figures, the total cost impact of the AD, including labor
costs, is estimated to be $1,220,000.
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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it 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 adding the following new
airworthiness directive:
98-23-08 Pratt & Whitney: Amendment 39-10873. Docket 97-ANE-53-AD.
Applicability: Pratt & Whitney (PW) Model PW4152, PW4056,
PW4156, PW4256, PW4052, PW4158, PW4060, PW4160, PW4460, PW4050,
PW4060A, PW4156A, PW4062, PW4462, PW4060C, and PW4650 turbofan
engines, not incorporating at least one of the modifications
described in the PW service bulletins (SBs) and listed in items (1)
through (6), excluding those engines having a (-3) identifier next
to the engine model number on the engine data plate. These engines
are installed on but not limited to Boeing 767 and 747 series
aircraft, McDonnell Douglas MD-11 series aircraft, and Airbus A310
and A300-600 series aircraft.
(1) PW4ENG 72-484, Revision 3, dated July 1, 1997, or earlier
revisions, PW4ENG 72-486, Revision 1, dated November 23, 1994, or
original issue.
(2) PW4ENG 72-484, Revision 3, dated July 1, 1997, or earlier
revisions, PW4ENG 72-575, Revision 1, dated June 30, 1997, or
original issue, PW4ENG 72-486, Revision 1, dated November 23, 1994,
or original issue.
(3) PW4ENG 72-514, Revision 1, dated August 2, 1996, or original
issue.
(4) PW4ENG 72-490, Revision 1, dated August 2, 1994, or original
issue.
(5) PW4ENG 72-504, Revision 1, dated May 9, 1995, or original
issue.
(6) PW4ENG 72-572, dated June 16, 1995.
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 (b) 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 high pressure compressor (HPC) surge, which can
result in engine power loss at a critical phase of flight such as
takeoff, accomplish the following:
(a) Within 1,400 cycles in service (CIS) after the effective
date of this AD, or prior to June 30, 1999, whichever occurs first,
perform the following modifications:
(1) Incorporate stage 9 through 12 aluminum oxide blade tips and
grind HPC
[[Page 63393]]
blade tips at the rotor assembly in accordance with the
Accomplishment Instructions of PW SB No. PW4ENG-72-484, Revision 3,
dated July 1, 1997, concurrently with the requirements of paragraph
(a)(4) of this AD.
(2) Modify HPC 8th-14th stage stators in accordance with the
Accomplishment Instructions of PW SB No. PW4ENG-72-486, Revision 1,
dated November 23, 1994.
(3) Modify the 1st stage high pressure turbine (HPT) cooling
duct (TOBI Duct), install a metering plug in the Number 2 bearing
thrust balance vent tube, and incorporate 1st stage HPT vanes with
increased airflow area in accordance with the Accomplishment
Instructions of PW SB No. PW4ENG-72-514, Revision 1, dated August 2,
1996.
(4) Incorporate HPC 13th-15th stage zirconium oxide blade tips
in accordance with the Accomplishment Instructions of PW SB No.
PW4ENG-72-575, Revision 1, dated June 30, 1997.
(5) If at any time prior to the compliance time of this AD
incorporation of the requirements of any one of the SBs, identified
in items (4), (5), and (6) in the applicability section of this AD
is accomplished on any engine, then such an engine will not be
subject to the requirements of this AD and no further action is
required.
(b) 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 request 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.
(c) 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.
(d) The actions required by this AD shall be done in accordance
with the following PW SBs:
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Document No. Pages Revision Date
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PW4ENG-72-484.................. 1-16................... 3...................... July 1, 1997.
17-78.................. 1...................... November 8, 1994.
79..................... 2...................... March 10, 1995.
80, 81................. 3...................... July 1, 1997.
Total Pages: 81.
PW4ENG-72-486.................. 1-31................... 1...................... November 23, 1994.
Total Pages: 31.
PW4ENG-72-514.................. 1-6.................... 1...................... August 2, 1996.
7...................... Original............... June 23, 1994.
8-35................... 1...................... August 2, 1996.
Total Pages: 35.
PW4ENG-72-575.................. 1-43................... 1...................... June 30, 1997.
Total Pages: 43.
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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.
(e) This amendment becomes effective on January 12, 1999.
Issued in Burlington, Massachusetts, on November 5, 1998.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 98-30320 Filed 11-12-98; 8:45 am]
BILLING CODE 4910-13-P
