AD 2001-17-30

[Federal Register Volume 66, Number 169 (Thursday, August 30, 2001)]
[Rules and Regulations]
[Pages 45758-45760]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-21893]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-35-AD; Amendment 39-12421; AD 2001-17-30]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to Pratt & Whitney JT9D-7R4 series turbofan engines. This 
amendment requires initial and repetitive fluorescent penetrant 
inspection (FPI) of the high pressure turbine (HPT) 1st stage disk aft 
lugs, and if the aft lug(s) are cracked, replacement of the HPT 1st 
stage disk and HPT 1st stage airseals. Also, for certain configuration 
HPT disk assemblies, this amendment requires replacement of the HPT 1st 
stage airseals with newly designed airseals at the next accessibility. 
This amendment is prompted by reports of cracks in HPT 1st stage disk 
firtrees and failure of firtree lugs. The actions specified by this AD 
are intended to prevent 1st stage HPT disk firtree fracture, which 
could result in an uncontained engine failure, and damage to the 
airplane.

DATES: Effective date October 4, 2001.

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 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 AD that is 
applicable to Pratt & Whitney JT9D-7R4 series turbofan engines was 
published in the Federal Register on February 27, 2001 (66 FR 12440). 
That action proposed to require initial and repetitive fluorescent 
penetrant inspection (FPI) of the high pressure turbine (HPT) 1st stage 
disk aft lugs, and if the aft lug(s) are cracked, replacement of the 
HPT 1st stage disk and HPT 1st stage airseals. Also, for certain 
configuration HPT disk assemblies, this action proposed to require 
replacement of the HPT 1st stage airseals with newly designed airseals 
at the next accessibility.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Clarifications Requested

    One commenter addresses four issues:
    <bullet> First, the commenter states that there is confusion 
regarding the phrase ``before the latest of'' which the commenter 
interprets to mean ``whichever comes last.'' The commenter is correct. 
The phrase means whichever of the two cyclic limits occurs last.
    <bullet> Secondly, the commenter states that clarification is 
needed for ``initial F.P.I.'' because there is a difference between FPI 
as it is proposed in the NPRM and as it is described in applicable 
Pratt & Whitney service bulletins. The commenter wants to know if the 
standard SPOP84 full disk FPI inspection at HPT overhaul fulfills the 
requirements of the NPRM. It is the intent of this AD that the disk lug 
be inspected for cracks. The full disk FPI covers the requirement.
    <bullet> Thirdly, the commenter states that the NPRM requires that 
airseal P/N 820121 must be installed on HPT part number (P/N) 787521 
(powder metal disks) at the next hot section shop visit as described in 
Pratt & Whitney (PW) Service Bulletin (SB) JT9D-7R4-72-566. However, 
the commenter notes that the initial and repetitive inspection 
requirement of SB JT9D-7R4-72-567 remains unchanged. The commenter 
requests that the FAA delete the requirement to install the new 
airseals per SB JT9D-7R4-72-566. The FAA disagrees. The newer airseals 
offer a significant benefit in life over the older airseals. Though it 
is not stated explicitly in SB JT9D-7R4-72-567, there are no inspection 
limits for powder disks with the older sideplates, as it is assumed 
that they are all removed from service and replaced with the new 
sideplates per SB JT9D-7R4-72-566. Under this AD, there will be no 
requirement to inspect the older sideplates as they will be removed 
from service by paragraph (a) of this rule.

[[Page 45759]]

    <bullet> Finally, this commenter and two others note that the 
compliance for airseal P/N 820121 installation is specified as ``at the 
next hot section shop visit,'' which is further defined as ``any time 
the HPT rotor is disassembled.'' However, SB JT9D-7R4-72-566 specifies 
installation at piece-part opportunity. The FAA agrees and paragraph 
(e) will be changed to ``at disk piece-part opportunity.''
    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.

Cost Analysis

    There are approximately 324 engines of the affected design in the 
worldwide fleet. The FAA estimates that 47 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD. 
Although forced engine removals are not anticipated the first year as a 
result of this proposed action, a maximum of two removals will be 
assumed. It would take approximately 86 work hours per engine to 
accomplish the proposed actions, and the average labor rate is $60 per 
work hour. Based on these figures, the total labor cost impact of the 
proposed AD on U.S. operators the first year is estimated to be 
$24,520. Hardware costs the first year for HPT 1st stage airseals 
replaced by SB JT9D-7R4-72-566 are estimated to be $128,000, based on 
replacement costs of $147,110 per disk and $45,143 for sideplates, 
discounted for average \1/3\ life lost at removal. Total combined labor 
and hardware costs for the first year are therefore estimated to be 
$140,000.
    The following year, it is estimated that inspections will result in 
a maximum of three engines requiring forced replacement of the HPT 1st 
stage disk and HPT 1st stage airseals due to cracking. Due to these 
forced removals, approximately \1/3\ of the disk life will be lost. The 
total combined hardware and labor cost is estimated to be approximately 
$210,000. The total cost impact of this proposal on U.S. operators in 
the first two years is expected to be approximately $350,000.

Regulatory Impact

    This final rule does not have federalism implications, as defined 
in Executive Order 13132, because it would not have a substantial 
direct effect 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this final rule.
    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 the DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
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 by contacting the Rules Docket at the location provided 
under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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 adding a new airworthiness directive to 
read as follows:

2001-17-30  Pratt and Whitney: Amendment 39-12421. Docket 2000-NE-
35-AD.

    Applicability: This airworthiness directive (AD) is applicable 
to Pratt & Whitney (PW) JT9D-7R4 series turbofan engines. These 
engines are installed on, but not limited to, Boeing 747 and 767 
series and Airbus A300 and A310 series airplanes.

    Note 1: This 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 (f) 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: Compliance with this AD is required as indicated, 
unless accomplished previously.
    To prevent high pressure turbine (HPT) disk firtree fracture, 
which could result in an uncontained engine failure, and damage to 
the airplane, accomplish the following:

HPT 1st Stage Airseal Replacement

    (a) For engines that incorporate HPT 1st stage disk assembly 
part number (P/N) 787521, replace HPT 1st stage airseals with P/N 
820121 at the next disk piece-part opportunity. Information on 
replacement of the HPT 1st stage airseal is contained in PW service 
bulletin (SB) JT9D-7R4-72-566, dated May 26, 2000.

Fluorescent Penetrant Inspection (FPI)

    (b) Perform fluorescent penetrant inspection of the HPT 1st 
stage disk aft lug fillet radius for cracks according to the 
following Table 1 of this AD:

                                                     Table 1
----------------------------------------------------------------------------------------------------------------
   HPT 1st stage disk assembly      HPT 1st stage disk    Initial inspection    Repetitive inspection  interval
----------------------------------------------------------------------------------------------------------------
(1) P/N 787521...................  P/N 825701 or P/N     Before the latest of  Within 4,000 CSLI.
                                    827201.               4,000 CSN or 4,000
                                                          cycles since last
                                                          HPT disk lug FPI
                                                          (CSLI), or 500 CIS
                                                          after the effective
                                                          date of this AD.
(2) P/N 797621...................  (i) P/N 829401 with   Before the latest of  Within 4,000 CSLI.
                                    air seals P/N's       5,000 CSN or CSLI,
                                    797355, 796760,       or 500 CIS after
                                    803979, 797355-001    the effective date
                                    installed.            of this AD.
                                   (ii) P/N 829401 with  Before the latest of  Within 6,000 CSLI.
                                    air seals P/N         5,000 CSN or 5,000
                                    820121 installed.     CSLI, or 500 CIS
                                                          after the effective
                                                          date of this AD.
----------------------------------------------------------------------------------------------------------------


[[Page 45760]]

    Additional inspection information can be found in Paragraph 4 of 
the Accomplishment Instructions of PW SB JT9D-7R4-72-567, dated May 
26, 2000.
    (c) Replace any disks that have crack indications. Information 
on replacement of the disk is contained in PW SB JT9D-7R4-72-568, 
dated May 26, 2000.

Terminating Action

    (d) Installation of HPT disk P/N 820321 with redesigned HPT 1st 
stage airseal P/N 820121 is considered terminating action to the 
initial and repetitive inspection requirements of paragraph (b) this 
AD. Information on installation of the HPT disk is contained in PW 
SB JT9D-7R4-72-568, dated May 26, 2000.

Definition

    (e) For the purpose of this AD, at disk piece-part opportunity 
is defined as any time the 1st stage HPT rotor is disassembled.

Alternative Methods of Compliance

    (f) 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 (ECO). 
Operators must submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (g) 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.

Effective Date of this AD

    (h) This amendment becomes effective on October 4, 2001.

    Issued in Burlington, Massachusetts, on August 21, 2001.
Donald Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-21893 Filed 8-29-01; 8:45 am]
BILLING CODE 4910-13-P