[Federal Register Volume 64, Number 136 (Friday, July 16, 1999)]
[Rules and Regulations]
[Pages 38301-38302]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-17554]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-55-AD; Amendment 39-11220; AD 99-15-01]
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 PW4000 series turbofan engines,
that reduces life limits of certain 4th stage low pressure turbine
(LPT) disks. It also allows the original life limits of the disks to be
restored if reoperation is performed to incorporate the original
slotted cooling hole configuration. This amendment is prompted by
reports that a change of a cooling hole geometry, which was introduced
in the design of certain 4th stage LPT disks, inadvertently caused a
reduction on the cooling air flow to the disk and an increased level of
stress. The actions specified by this AD are intended to prevent an
uncontained disk failure and damage to the aircraft.
DATES: Effective September 14, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of September 14, 1999.
ADDRESSES: The service information referenced in this AD 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) 565-8770. 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 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 Pratt & Whitney Model PW4056,
PW4152, PW4156A, PW4164, PW4168, and PW4460 turbofan engines was
published in the Federal Register on March 9, 1998 (63 FR 11381). That
action proposed to reduce life limits of affected 4th stage low
pressure turbine (LPT) disks, identified by serial number (S/N). It
would also allow the original life limits to be restored, if
reoperation is performed to incorporate the slotted cooling air
configuration.
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 states that it does not own any of the disks affected
by this AD, and will therefore not be affected by it. The commenter,
however, states that the 4th stage LPT disk was subjected to a design
change but retained the same part number. The commenter states that for
tracking purposes it is desirable to change the part number. The FAA
agrees with the concept; however, this issue addresses practices at the
manufacturer and not this action, since both part number and serial
numbers are identified for tracking purposes. The FAA will communicate
this request to the manufacturer for future considerations.
One commenter states that the economic analysis should be revised
to note that the labor cost is accurate when the engine is torn down to
obtain access to the LPT. The FAA concurs and has added this language
to the economic analysis of this final rule.
Two commenters state that they do not own any of the affected disks
and that therefore would not be affected by the proposed rule.
One commenter supports the rule as proposed.
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 as proposed. The FAA has
determined that this change will neither increase the economic burden
on any operator nor increase the scope of the AD.
There are approximately 27 engines of the affected design in the
worldwide fleet. The FAA estimates that there are currently no engines
installed on aircraft of U.S. registry that will be affected by this
AD, but if one were installed, it would take approximately 4 work hours
per engine to accomplish the required actions when the engine is torn
down to obtain access to the LPT, and that the average labor rate is
$60 per work hour. Required parts will cost approximately $240 per
engine. Based on these figures, the total cost impact per engine is
estimated to be $480.
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.
[[Page 38302]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
99-15-01 Pratt & Whitney: Amendment 39-11220. Docket 97-ANE-55-AD.
Applicability: Pratt & Whitney Model PW4056, PW4152, PW4156A,
PW4164, PW4168, and PW4460 turbofan engines, with 4th stage low
pressure turbine (LPT) disks, part number (P/N) 50N924, serial
numbers (S/Ns) CLDL BX2061, CLDL BX6620, CLDL BX2054, CLDL BX2055,
CLDL BX6596, CLDL BX2059, CLDL BX2060, CLDL BX6600, CLDL BX6597,
CLDL BX6599, CLDL BX6601, CLDL BX6598, CLDL BX6604, CLDL BX6605,
CLDL BX6602, CLDL BX6609, CLDL BX6607, CLDL BX6612, CLDL BX6611,
CLDL BX6610, CLDL BX6608, CLDL BX6606, CLDL BX6615, CLDL BX6616,
CLDL BX6619, CLDL BX2058, and CLDL BX6603 installed. These engines
are installed on but not limited to Airbus Industrie A330, Boeing
747, and McDonnell Douglas MD-11 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 (c) 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 and uncontained disk failure and damage to the
aircraft, accomplish the following:
(a) Except as provided in paragraph (b) of this AD, prior to
accumulating 7,500 cycles in service (CIS), remove the affected 4th
stage LPT disks and replace them with new or serviceable parts.
Note 2: A list of the affected 4th stage LPT disks, identified
by P/N and S/N, appears in the ``Applicability'' paragraph for this
AD.
(b) Restoration of the original life limits on the affected
disks may be accomplished as follows:
(1) Reoperation performed on the LPT disks installed in PW4164
and PW4168 model engines, in accordance with Pratt & Whitney (PW)
Service Bulletin (SB) No. PW4G 100-72-105, dated November 12, 1997,
prior or 7,000 CIS to incorporate the slotted cooling air
configuration may restore the life limit to 15,000 CIS.
(2) Reoperation performed on the LPT disks installed in PW4156A
and PW4460 model engines in accordance with PW SB No. PW4ENG 72-657,
dated November 25, 1997, prior to 5,500 CIS to incorporate the
slotted cooling air configuration may restore the life limit to
15,000 CIS.
(3) Reoperation performed on the LPT disks installed in PW4056
and PW4152 model engines in accordance with PW SB No. PW4ENG 72-657,
dated November 25, 1997, prior to 4,500 CIS to incorporate the
slotted cooling air configuration may restore the life limit to
20,000 CIS.
(c) 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 3: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(d) Special flight permits may be issued in accordance with
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR
21.197 and 21.199) to operate the airplane to a location where the
requirements of this AD can be accomplished.
(e) The actions required by this AD shall be done in accordance
with the following PW SBs:
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Document No. Pages Dates
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PW4G=100-72-105........................... 1-19....................... November 12, 1997.
Total Pages: 19
PW4ENG 72-657............................. 1-22....................... November 25, 1997.
Total Pages: 22
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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, Publications
Department, Supervisor Technical Publications Distribution, M/S 132-
30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770.
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.
(f) This amendment becomes effective on September 14, 1999.
Issued in Burlington, Massachusetts, on July 6, 1999.
David A. Downey,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 99-17554 Filed 7-15-99; 8:45 am]
BILLING CODE 4910-13-M