[Federal Register Volume 63, Number 175 (Thursday, September 10, 1998)]
[Rules and Regulations]
[Pages 48418-48421]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23997]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-02-AD; Amendment 39-10746; AD 98-19-03]
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
[[Page 48419]]
PW4000 series turbofan engines, that requires fluorescent penetrant and
eddy current inspections of 2nd stage high pressure turbine (HPT)
rotating airseals for cracks, removal from service of cracked parts,
incorporation of improved 2nd stage HPT rotating airseals, and
modification of 2nd stage ring segments and vane clusters to increase
cooling flow and reduce stress as terminating action to the inspection
requirements. This amendment is prompted by reports of 2nd stage HPT
rotating airseal cracking. The actions specified by this AD are
intended to prevent 2nd stage HPT rotating airseal cracking, which
could result in an uncontained engine failure and damage to the
aircraft.
DATES: Effective November 9, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 9, 1998.
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:
Peter White, Aerospace Engineer, Engine Certification Office, FAA,
Engine and Propeller Directorate, 12 New England Executive Park,
Burlington, MA 01803-5299; telephone (781) 238-7128, 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 (PW) Models
PW4052, PW4056, PW4060, PW4060A, PW4062, PW4152, PW4156A, PW4158,
PW4460, PW4462, PW4164, and PW4168 turbofan engines was published in
the Federal Register on March 24, 1998 (63 FR 14055). That action
proposed to require fluorescent penetrant and eddy current inspections
of 2nd stage high pressure turbine (HPT) rotating airseals for cracks,
removal from service of cracked parts, incorporation of improved 2nd
stage HPT rotating airseals, and modification of 2nd stage ring
segments and vane clusters to increase cooling flow and reduce stress
as terminating action to the inspection requirements.
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 they have had no uncontained engine
failures following HPT rotating airseal fracture events but makes no
comment to the text of the proposed rule.
One commenter notes two typographical errors in the applicability,
with the ``P'' deleted for models PW4060 and PW4462. This final rule
corrects those errors in the applicability.
The same commenter also notes that the proposed rule seems to use a
different compliance requirement than that pointed out in the
applicable Service Bulletin (SB). The proposed rule defines a hot
section visit as ``any time the HPT Module is disassembled'', which is
less restrictive than the requirement stated in the SB. The FAA
concurs. The FAA has determined that the compliance interval stated in
the proposed rule poses less of a burden on the operators, is
consistent with the risk assessment assumptions, and maintains the
safety level desired.
The same commenter states that the proposed rule does not address
fluorescent penetrant inspection (FPI) requirements for new parts with
the old P/Ns, and believes the intention is for no FPI inspection
requirement. The FAA concurs as there is no intention in the AD to
require fluorescent penetrant inspections of new parts.
The same commenter states that there is no applicability reference
for the SBs in the proposed rule, and that while it can be implicitly
assumed that the SBs required for the 94'' engine are only those
beginning with PW4ENG (and for the 100'' engine those beginning with
PW4G), there is currently nothing explicitly stating this. The FAA
concurs. The SB versus Engine Model applicability has been clarified in
the final rule.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and 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 1,720 engines of the affected design in the
worldwide fleet. The FAA estimates that 350 engines installed on
aircraft of U.S. registry will be affected by this AD, that it will
take additional time to accomplish the required actions. Required parts
will cost approximately $57,200 per engine. In addition, these parts
will have consumed some portion of their life limits at the time of
their removal, so this full cost burden will not be realized. Based on
these figures, assumed an average part removal time of 7,000 cycles,
the total cost impact of the AD on U.S. operators is estimated to be
$10,677,333. Pratt & Whitney has advised the FAA that it has an
Industry Support Program that will reimburse operators for unconsumed
life in parts that are retired early for cracking. This should
eliminate the majority of the financial burden to the operators.
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 its 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 48420]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
98-19-03 Pratt & Whitney: Amendment 39-10746. Docket 98-ANE-02-AD.
Applicability: Pratt & Whitney Models PW4052, PW4056, PW4060,
PW4060A, PW4062, PW4152, PW4156A, PW4158, PW4460, PW4462, PW4164,
and PW4168 turbofan engines, with 2nd stage high pressure turbine
(HPT) rotating airseals, Part Numbers (P/N) 50L156 or 50L195,
installed. These engines are installed on but not limited to Boeing
747 and 767 series, McDonnell Douglas MD-11 series, and Airbus
Industrie A300, A310, and A330 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. This 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 eliminated, the request should include specific proposed
actions to address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent 2nd stage HPT rotating airseal cracking, which could
result in an uncontained engine failure and damage to the aircraft,
accomplish the following:
(a) At the next hot section shop visit after the effective date
of this AD, and at each subsequent hot section shop visit,
fluorescent penetrant inspect and eddy current inspect 2nd stage HPT
rotating airseals for cracks, remove from service cracked airseals,
and replace with serviceable parts, in accordance with Pratt &
Whitney Alert Service Bulletins (ASBs) No. PW4ENG A72-628, Revision
1, dated February 17, 1998, for models PW4052, PW4056, PW4060,
PW4060A, PW4062, PW4152, PW4156A, PW4158, PW4460 and PW4462, and
Pratt & Whitney ASB No. PW4G-100-A72-80, Revision 1, dated February
17, 1998, for models PW4164 and PW4168.
(b) For the purpose of this AD, a hot section shop visit is
defined as any time the HPT modules is disassembled.
(c) Within 6 years after the effective date of this AD, modify
2nd stage ring segments and vane clusters, and install improved 2nd
stage HPT rotating airseals in accordance with Pratt & Whitney
Service Bulletins (SBs) No. PW4ENG 72-636, dated May 16, 1997, and
No. PW4ENG 72-637, dated May 16, 1997, for models PW4052, PW4056,
PW4060, PW4060A, PW4062, PW4152, PW4156A, PW4158, PW4460 and PW4462,
and Pratt & Whitney ASB No. PW4G-100-72-93, dated May 22, 1997, and
No. PW4G-100-72-94, dated May 22, 1997 for the PW4164 and PW4168.
Performance of these modifications and installation of the improved
2nd stage HPT rotating airseal constitutes terminating action to the
inspection requirements of this AD.
(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 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.
(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 actions required by this AD shall be done in accordance
with the following Pratt & Whitney service documents:
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Document No Pages Revision Date
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ASB No. PW4ENG-A72-628........... 1, 2................ 1.................. February 17, 1998.
3................... Original........... November 21, 1996.
4-9................. 1.................. February 17, 1998.
10.................. Original........... November 21, 1996.
11-22............... 1.................. February 17, 1998.
NDIP-894......................... 1-25................ Original........... November 12, 1996.
NDIP-896......................... 1-10................ Original........... November 7, 1996.
Total Pages: 57.
ASB No. PW4G-100-A72-80.......... 1-16................ 1.................. February 17, 1998.
NDIP-894......................... 1-25................ Original........... November 12, 1996.
NDIP-896......................... 1-10................ Original........... November 7, 1996.
Total Pages: 51.
SB No. PW4ENG-72-636............. 1-30................ Original........... May 16, 1997.
Total Pages: 30.
SB No. PW4G-100-72-93............ 1-16................ Original........... May 22, 1997.
Total Pages: 16.
SB No. PW4ENG-72-637............. 1-15................ Original........... May 16, 1997.
Total Pages: 15.
SB No. PW4G-100-72-94............ 1-10................ Original........... May 22, 1997.
Total Pages: 10.
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[[Page 48421]]
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 November 9, 1998.
Issued in Burlington, Massachusetts on August 31, 1998.
Donald E. Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 98-23997 Filed 9-9-98; 8:45 am]
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