[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]
BILLING CODE 4910-13-P