[Federal Register Volume 60, Number 163 (Wednesday, August 23, 1995)]
[Proposed Rules]
[Pages 43730-43732]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20851]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-ANE-38]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Pratt & Whitney (PW) JT9D-7R4 
series turbofan engines. This proposal would require removal of web 
material at ten bosses on the diffuser case assembly, inspections, 
shotpeening of the area, and remarking the diffuser case assemblies 
with a new part number. This proposal is prompted by reports of cracks 
in the aft corners of the bosses. The actions specified by the proposed 
AD are intended to prevent diffuser case assembly rupture, which could 
result in an uncontained engine failure, engine fire, and damage to the 
aircraft.

DATES: Comments must be received by October 23, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-ANE-38, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108. 
This information may be examined at the FAA, New England Region, Office 
of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA.

FOR FURTHER INFORMATION CONTACT: John Fisher, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7149, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal 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 95-ANE-38.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 95-ANE-38, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received reports of 
cracks at the aft corners of bosses on the diffuser case assembly on 
Pratt & Whitney (PW) JT9D-7R4 series turbofan engines. No engine 
failures have resulted from these cracks. The cracks occur in webs of 
material at ten bosses that were a result of a machining operation 
during original 

[[Page 43731]]
manufacture. The webs of material create stress concentrations that can 
cause a crack to start. Removal of this web material will provide local 
stress relief and prevent the initiation of cracks at the aft corners 
of the bosses. This condition, if not corrected, could result in 
diffuser case assembly rupture, which could result in an uncontained 
engine failure, engine fire, and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of PW 
Service Bulletin No. JT9D-7R4-72-469, Revision 2, dated April 25, 1994, 
that describes procedures for removing the web of material from ten 
bosses on the diffuser case assembly, performing a fluorescent 
penetrant inspection (FPI) and x-ray inspection of the reworked area, 
and shotpeening the reworked area. In addition, for diffuser case 
assemblies that have been previously weld-repaired but no records can 
be located to indicate that they have undergone furnace stress relief, 
or for diffuser case assemblies with weld repairs that have only been 
locally stress relieved, this SB describes procedures for performing 
furnace stress relief of these previously welded diffuser case 
assemblies to ensure that there is sufficient hardness.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, the 
proposed AD would require removing webs of material at ten bosses on 
the diffuser case assembly, performing an FPI and x-ray inspection of 
the reworked area, performing furnace stress relief if a local stress 
relief had been previously accomplished, shotpeening the reworked area, 
and remarking the diffuser case assemblies with a new part number. The 
actions would be required to be accomplished in accordance with the 
service bulletin described previously.
    The FAA estimates that 127 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 20 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $152,400.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (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 copy of the draft 
regulatory evaluation prepared for this action 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. 95-ANE-38.

    Applicability: Pratt & Whitney (PW) JT9D-7R4 series turbofan 
engines, installed on but not limited to Airbus A300 series and A310 
series, and Boeing 747 series and 767 series aircraft.

    Note: 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 use the 
authority provided in paragraph (c) to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition, or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any engine from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent diffuser case assembly rupture, which could result in 
an uncontained engine failure, engine fire, and damage to the 
aircraft, accomplish the following:
    (a) At the next engine shop visit, but not later than 6,000 
cycles in service after the effective date of this AD, whichever 
occurs first, inspect the diffuser case assembly, Part Numbers (P/N) 
790541, 798379, 789996, 5004770-01, or 5000366-02, for existence of 
web material at ten boss locations, in accordance with PW Service 
Bulletin (SB) No. JT9D-7R4-72-469, Revision 2, dated April 25, 1994.
    (1) For diffuser case assemblies that incorporate web material 
at any boss locations described in the above SB, accomplish the 
following:
    (i) Rework the diffuser case assembly in accordance with PW SB 
No. JT9D-7R4-72-469, Revision 2, dated April 25, 1994. This rework 
removes web material at ten boss locations.
    (ii) Perform a fluorescent penetrant inspection (FPI) of the 
reworked areas in accordance with PW SB No. JT9D-7R4-72-469, 
Revision 2, dated April 25, 1994, to ensure that there are no crack 
indications. If a crack indication is discovered, repair per Engine 
Manual Section 72-41-02, Repair 28, or remove the diffuser case from 
service and replace with a serviceable part.
    (iii) Perform an x-ray inspection of the reworked areas in 
accordance with PW SB No. JT9D-7R4-72-469, Revision 2, dated April 
25, 1994, to ensure that there are no crack indications. 
Additionally, the x-ray inspection is performed to assure that there 
are no cracks, incomplete fusion, incomplete penetration, voids, 
porosity, or inclusions from previous local weld repairs. If any of 
these defects are discovered, repair per PW JT9D-7R4 Engine Manual, 
Section 72-41-02, Repair 28, or remove the diffuser case from 
service and replace with a serviceable part.
    (iv) Determine if any previous weld repairs have been performed 
at any of the boss locations described in the above SB through 
reviewing maintenance records. If maintenance records cannot be 
located, or maintenance records indicate that a weld repair with no 
stress relief or with a local stress relief has been performed at 
any of the ten boss locations, perform furnace stress relief and FPI 
diffuser case assemblies in accordance with PW SB No. JT9D-7R4-72-
469, Revision 2, dated April 25, 1994.
    (v) Shotpeen the reworked areas in accordance with PW SB No. 
JT9D-7R4-72-469, Revision 2, dated April 25, 1994.
    (vi) Remark the diffuser case assembly with a new part number in 
accordance with PW SB No. JT9D-7R4-72-469, Revision 2, dated April 
25, 1994.
    (2) For diffuser case assemblies that have been previously 
reworked to remove web material at any boss locations prior to the 
effective date of this AD in accordance with the original issue of 
PW SB No. JT9D-7R4-72-469, dated October 2, 1992, accomplish the 
following:
    (i) Unless maintenance records indicate that x-ray inspections 
were performed at ten 

[[Page 43732]]
boss locations prior to the effective date of this AD in accordance 
with PW JT9D-7R4 Engine Manual, Section 72-41-02, Repair 28, perform 
an x-ray inspection of ten boss locations in accordance with the x-
ray requirements of PW JT9D-7R4 Engine Manual, Section 72-41-02, 
Repair 28.
    (ii) Determine if any previous weld repairs have been performed 
at any of the boss locations described in the above SB through 
reviewing maintenance records. If maintenance records cannot be 
located, or maintenance records indicate that a weld repair with a 
local stress relief has been performed at any of the boss locations, 
perform furnace stress relief, FPI, and shotpeen diffuser case 
assemblies in accordance with PW SB No. JT9D-7R4-72-469, Revision 2, 
dated April 25, 1994.
    (b) For the purpose of this AD, an engine shop visit is defined 
as when the ``K'' and ``M'' flanges are separated so that the 
diffuser case is removed.
    (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. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

    Note: 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 
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.

    Issued in Burlington, Massachusetts, on August 15, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-20851 Filed 8-22-95; 8:45 am]
BILLING CODE 4910-13-P