[Federal Register Volume 59, Number 220 (Wednesday, November 16, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-28109]


[[Page Unknown]]

[Federal Register: November 16, 1994]

BILLING CODE 4910-13-M
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-01; Amendment 39-9067; AD 94-23-05]

 

Airworthiness Directives; AlliedSignal Inc. TFE731-3A and -3AR 
Model Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to AlliedSignal Inc. (formerly Garrett Engine Division) 
TFE731-3A-200G and -3AR-200G model turbofan engines. This action 
requires removing from service certain low-pressure turbine (LPT) 
disks, imposing an hourly life limit on the first stage and second 
stage LPT disks, performing a dimensional inspection of second stage 
LPT disks at repetitive intervals, and incorporating honeycomb material 
in the second stage LPT nozzle air seal. This amendment is prompted by 
reports of LPT disk web separations. The actions specified in this AD 
are intended to prevent LPT disk web separations, which can result in 
an uncontained engine failure and damage to the aircraft.

DATES: Effective December 1, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 1, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before January 17, 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. 94-ANE-01, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
AlliedSignal Inc., Aviation Services Division, Data Distribution, Dept. 
64-3/2102-1M, P.O. Box 29003, Phoenix, AZ 85038-9003; telephone (602) 
365-2548. This information may be examined at the FAA, New England 
Region, Office of the Assistant Chief 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: Joseph Costa, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3229 East Spring Street, Long Beach, CA 90806-2425; 
telephone (310) 988-5246; fax (310) 988-5210.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received reports of two low pressure turbine (LPT) disks that 
failed in the disk web area due to creep fatigue on AlliedSignal Inc. 
(formerly Garrett Engine Division) Model TFE731-3A-200G turbofan 
engines. Both disk failures were uncontained. A metallurgical 
examination of first and second stage LPT disks found that two heat 
treatment production processes created a microstructure more 
susceptible to creep fatigue cracking. Both production processes 
affected AlliedSignal Inc. TFE731-3 series engines' first and second 
stage LPT disks.
    In addition, a field inspection of LPT disks on AlliedSignal Inc. 
TFE731-3 series turbofan engines revealed that excessive disk growth 
occurred on AlliedSignal Inc. Model TFE731-3A-200G and TFE731-3AR-200G 
engines, which are installed on Israel Aircraft Industries, Ltd. (IAI) 
1125 Westwind Astra series aircraft. The FAA has determined that the 
IAI Astra flight profile subjects the first and second stage LPT disks 
to prolonged flight time at or near the maximum continuous inner 
turbine temperatures limit. Repeated prolonged exposure to high 
temperatures can cause a more rapid deterioration of the nickel-
graphite abradable material on the LPT second stage nozzle air seal 
than originally anticipated during the certification process of the 
engine. This deterioration results in increased seal clearance, which 
contributes to disk growth. This disk growth, also known as creep, 
resulting either from certain heat treatment production processes, 
excessive LPT second stage nozzle air seal clearance, or the LPT 
disk(s) prolonged exposure to elevated operating temperatures, if not 
corrected, could result in LPT disk web separations, which can result 
in an uncontained engine failure and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of 
AlliedSignal Aerospace Alert Service Bulletin (ASB) No. TFE731-A72-
3519, Revision 3, dated May 6, 1994, that imposes an hourly life limit 
on first and second stage LPT disks and describes procedures for 
removal and replacement of these LPT disks; SB No. TFE731-72-3530, 
Revision 1, dated October 8, 1993, that describes procedures for 
installing a second stage LPT turbine nozzle that incorporates a 
honeycomb air seal; and ASB No. TFE731-A72-3544, dated October 8, 1993, 
and ASB No. TFE731-A72-3557, dated May 12, 1994, that describe 
procedures for removal and replacement of specific serial numbered 
first and second stage LPT disks. Certain requirements of this AD may 
be accomplished using an earlier version of a service bulletin (SB) or 
ASB than the one cited in the AD. The original version of AlliedSignal 
Aerospace SB No. TFE731-72-3530 differs only by minor changes that do 
not impact the technical content of the procedures, and is an 
acceptable method of compliance to paragraph (c)(1) of this AD. Prior 
to the effective date of this AD, replacement of LPT disks in 
accordance with previous revisions of SB No. TFE731-A72-3519 is an 
acceptable method of compliance to paragraph (b) or (c)(2) of this AD.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other AlliedSignal Inc. TFE731-3A-200G series 
turbofan engines of the same type design, this AD is being issued to 
prevent LPT disk web separations, which can result in an uncontained 
engine failure and damage to the aircraft. This AD requires removing 
from service certain LPT disks, imposing an hourly life limit on first 
and second stage LPT disks, performing a dimensional inspection of 
second stage LPT disks at repetitive intervals, and incorporating 
honeycomb material in the second stage LPT nozzle air seal. The actions 
are required to be accomplished in accordance with the service 
bulletins described previously.
    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 94-ANE-01.'' 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

94-23-05 AlliedSignal Inc.: Amendment 39-9067. Docket 94-ANE-01.

    Applicability: AlliedSignal Inc. TFE731-3A-200G and -3AR-200G 
turbofan engines installed on but not limited to Israel Aircraft 
Industries, Ltd., 1125 Westwind Astra aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent low pressure turbine (LPT) disk web separations, 
which can result in an uncontained engine failure and damage to the 
aircraft, accomplish the following:
    (a) Remove from service first and second stage LPT disks, with 
Part Numbers (P/N) 3072351-(  ), 3072542-(  ), 3074103-1, and 
3074105-1, where (  ) denotes any dash number, identified by serial 
number in the Compliance Sections of AlliedSignal Aerospace Alert 
Service Bulletin (ASB) No. TFE731-A72-3544, dated October 8, 1993, 
and AlliedSignal Aerospace ASB No. TFE731-A72-3557, dated May 12, 
1994, within 100 hours time in service (TIS) after the effective 
date of this airworthiness directive (AD), in accordance with the 
Accomplishment Instructions of AlliedSignal Aerospace ASB No. 
TFE731-A72-3544, dated October 8, 1993, and AlliedSignal Aerospace 
ASB No. TFE731-A72-3557, dated May 12, 1994, and replace with 
serviceable disks.
    (b) Remove first stage LPT disk, P/N 3072351-(  ), where (  ) 
denotes any dash number, and install a serviceable first stage LPT 
disk in accordance with the Accomplishment Instructions of 
AlliedSignal Aerospace ASB No. TFE731-A72-3519, Revision 3, dated 
May 6, 1994, as follows:

------------------------------------------------------------------------
  Stage 1 LPT disk TIS since new                                        
              (TSN)                     Initial replacement schedule    
------------------------------------------------------------------------
More than 850 hours..............  Replace within the next 50 hours TIS 
                                    after the effective date of this AD,
                                    or at the next removal of the LPT   
                                    module, whichever occurs first.     
551 to 850 hours.................  Replace within the next 200 hours TIS
                                    after the effective date of this AD,
                                    900 hours TSN, or at the next       
                                    removal of the LPT module, whichever
                                    occurs first.                       
Less than 551 hours..............  Replace prior to 750 hours TSN.      
------------------------------------------------------------------------

    (c) Prior to 1,500 hours TIS after the effective date of this 
AD, or at the next removal of the LPT module, whichever occurs 
first, accomplish the following:
    (1) Replace the second stage LPT nozzle air seal, P/N 3071878-1, 
in accordance with the Accomplishment Instructions of AlliedSignal 
Aerospace SB No. TFE731-72-3530, Revision 1, dated October 8, 1993, 
with a serviceable nozzle air seal.
    (2) Replace or inspect the second stage LPT rotor assembly, P/N 
3072541-(  ), where (  ) denotes any dash number, and install a 
serviceable assembly in accordance with the Accomplishment 
Instructions of AlliedSignal Aerospace ASB No. TFE731-A72-3519, 
Revision 3, dated May 6, 1994.
    (d) Perform subsequent repetitive inspections and remove from 
service first and second stage LPT disks, and replace with a 
serviceable disk, as follows:
    (1) Remove first stage LPT disks, P/N 3074103-1, prior to 
accumulating 750 hours TSN, or 3,000 CSN.
    (2) Remove first stage LPT disks, P/N 3073733-1, prior to 
accumulating 1,500 hours TSN, or 3,000 CSN.
    (3) Remove second stage LPT disks, P/N 3074105-1 prior to 
accumulating 4,500 hours TSN, or 3,000 CSN.
    (4) Inspect the second stage LPT rotor assembly, P/N 3074106-1, 
by performing a balance rim dimensional inspection, wire gauge 
check, and fluorescent penetrant inspection, in accordance with the 
Engine Light Maintenance Manual, at intervals not to exceed 1,500 
hours TIS since last inspection.
    (e) 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, Los Angeles Aircraft 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, Los Angeles Aircraft Certification Office. NOTE: 
Information concerning the existence of approved alternative methods 
of compliance with this airworthiness directive, if any, may be 
obtained from the Los Angeles Aircraft Certification Office.
    (f) Accomplishment of the requirements of paragraph (c)(1) of 
this AD in accordance with the original version of AlliedSignal 
Aerospace SB No. TFE731-72-3530; or the requirements of paragraphs 
(b) or (c)(2) of this AD in accordance with the original version, 
Revision 1, or Revision 2 of AlliedSignal Aerospace ASB No. TFE731-
A72-3519 constitute acceptable alternative methods of compliance to 
the applicable requirements of this AD.
    (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.
    (h) The requirements of this AD shall be accomplished in 
accordance with the following applicable service documents:

----------------------------------------------------------------------------------------------------------------
                  Document No.                      Pages        Revision                     Date              
----------------------------------------------------------------------------------------------------------------
AlliedSignal Aerospace ASB No. TFE731-A72-3544.     1-10     Original........  Oct. 8, 1993.                    
Total pages: 10.                                                                                                
AlliedSignal Aerospace SB No. TFE731-72-3530...      1-2     1...............  Oct. 8, 1993.                    
                                                     3-4     Original........  July 2, 1993.                    
                                                       5     1...............  Oct. 8, 1993.                    
                                                     6-8     Original........  July 2, 1993.                    
Total pages: 8.                                                                                                 
AlliedSignal Aerospace ASB No. TFE731-A72-3519.      1-8     3...............  May 6, 1994.                     
Total pages: 8.                                                                                                 
AlliedSignal Aerospace ASB No. TFE731-A72-3557.     1-12     Original........  May 12, 1994.                    
Total pages: 12.                                                                                                
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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 AlliedSignal Inc., Aviation Services 
Division, Data Distribution, Dept. 64-3/2102-1M, P.O. Box 29003, 
Phoenix, AZ 85038-9003. Copies may be inspected at the FAA, New 
England Region, Office of the Assistant Chief 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.
    (i) This amendment becomes effective on December 1, 1994.

    Issued in Burlington, Massachusetts, on November 3, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-28109 Filed 11-15-94; 8:45 am]
BILLING CODE 4910-13-P