[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               
----------------------------------------------------------------------------------------------------------------
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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