[Federal Register Volume 59, Number 1 (Monday, January 3, 1994)]
[Rules and Regulations]
[Pages 4-6]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 93-31907]


[[Page Unknown]]

[Federal Register: January 3, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-ANE-71; Amendment 39-8780; AD 93-25-16]

 

Airworthiness Directives; Allied-Signal Aerospace Company, 
Garrett Engine Division, TFE731 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule, request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Allied-Signal Aerospace Company, Garrett Engine 
Division, TFE731 series turbofan engines, that currently requires an 
improved, more definitive eddy current inspection, and replacement, if 
necessary, of certain fan disks for cracks. This amendment requires an 
additional 30 fan disks to be inspected. This amendment is prompted by 
the examination of fan disk eddy current inspection tapes using more 
definitive inspection criteria. The actions specified by this AD are 
intended to prevent an uncontained fan disk failure.

DATES: Effective January 18, 1994.
    The incorporation by reference of Allied-Signal Propulsion Engines 
ASB No. TFE731-A72-3504, Revision 1, dated July 2, 1993, is approved by 
the Director of the Federal Register as of January 18, 1994.
    The incorporation by reference of Allied-Signal Aerospace Company, 
Garrett Engine Division, ASB No. TFE731-A72-3504, dated November 25, 
1992, was approved previously by the Director of the Federal Register 
as of April 9, 1993 (58 FR 16113, March 25, 1993).
    Comments for inclusion in the Rules Docket must be received on or 
before March 4, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 93-ANE-71, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
AlliedSignal Engines, 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, 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: On February 19, 1993, the Federal Aviation 
Administration (FAA) issued AD 92-26-09, Amendment 39-8503 (58 FR 
16113, March 25, 1993), to require an improved, more definitive eddy 
current inspection of certain fan disks for cracks, and replacement, if 
necessary, of these fan disks. That action was prompted by reports of 
an uncontained failure of a fan disk on an Allied-Signal Aerospace 
Company, Garrett Engine Division, Model TFE731-3 turbofan engine. The 
FAA investigation determined that a fatigue crack originated in the aft 
acute corner of the dovetail slot. The fan disk had accumulated a total 
of 5291 cycles in service (CIS) at the time of the failure, and had 
been eddy current inspected in 1990 when the disk had accumulated 4055 
CIS. The fan disk displayed evidence of broaching grooves produced 
during the manufacture of the blade dovetail slots. These machining 
grooves may have contributed to the disk failure. From a metallurgical 
analysis, the FAA has determined that the failed fan disk had dovetail 
cracks which were not detected at the time of the eddy current 
inspection. A review of the eddy current inspection process used to 
inspect this disk and all disks inspected prior to May 1991 revealed 
that the process will not reliably detect this type of crack on these 
disks. Fan disk cracks, if not detected, could result in an uncontained 
fan disk failure.
    Since the issuance of that AD, the FAA has determined that an 
additional 30 fan disks will require inspection, or replacement, if 
necessary. In addition, the Applicability Section of AD 92-26-09 
identified the Learjet 55 series as one aircraft that might have an 
affected engine installed. The FAA has since learned that no Learjet 55 
series aircraft has an affected engine, and therefore, deletes the 
Learjet 55 series from that list of aircraft. Finally, AlliedSignal 
Propulsion Engines has issued Revision 1 to AlliedSignal Propulsion 
Engines Alert Service Bulletin (ASB) No. TFE731-A72-3504. This AD 
incorporates this revision.
    The FAA has reviewed and approved the technical contents of Allied-
Signal Aerospace Company, Garrett Engine Division, ASB No. TFE731-A72-
3504, dated November 25, 1992, and AlliedSignal Propulsion Engines ASB 
No. TFE731-A72-3504, Revision 1, dated July 2, 1993, that describe 
procedures for an improved, more definitive eddy current inspection of 
these fan disks for cracks.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, this AD 
supersedes AD 92-26-09 to require inspection of an additional 30 fan 
disks. Fan disks inspected in accordance with the existing AD, 92-26-
09, need not be inspected again. The inspection schedule for fan disks 
not yet inspected in accordance with the existing AD, however, remains 
the same, using April 9, 1993, the effective date of AD 92-26-09 as the 
starting point. 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 93-ANE-71.'' 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 14 CFR part 
39 of the Federal Aviation Regulations 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 removing Amendment 39-8503, (58 FR 
16113, March 25, 1993), and by adding a new airworthiness directive, 
Amendment 39-8780, to read as follows:

93-25-16 Allied-Signal Aerospace Company, Garrett Engine Division: 
Amendment 39-8780. Docket 93-ANE-71. Supersedes AD 92-26-09, 
Amendment 39-8503.

    Applicability: Allied-Signal Aerospace Company, Garrett Engine 
Division, TFE731-2, -3, and -3R series turbofan engines installed on 
but not limited to Sabreliner NA-265-65 (Sabreliner 65); Israel 
Aircraft Industries 1124 series (Westwind); Avions Marcel Dassault 
Falcon 10, 50, 100 series; Learjet 35, 36, and 31 (M31) series; 
British Aerospace BAe HS125 series; and Lockheed 1329-23, -25 series 
(731 Jetstar, Jetstar II) aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained fan disk failure, accomplish the 
following:
    (a) For all disks previously eddy current inspected in 
accordance with the requirements of AD 92-26-09, no further action 
is required.
    (b) Remove prior to further flight fan disk Part Number (P/N) 
3073539-2 or 3072162-2 with Serial Number (S/N) 8-18040-6300, in 
accordance with Allied-Signal Aerospace Company, Garrett Engine 
Division, Alert Service Bulletin (ASB) No. TFE731-A72-3504, dated 
November 25, 1992, or AlliedSignal Propulsion Engines ASB No. 
TFE731-A72-3504, Revision 1, dated July 2, 1993, and replace with a 
serviceable disk.
    (c) Eddy current inspect fan disks, P/N 3072162-1 through -4, 
3073436-1 through -4, 3073539-2, and 3074529-2, in accordance with 
Allied-Signal Aerospace Company, Garrett Engine Division, ASB No. 
TFE731-A72-3504, dated November 25, 1992, or AlliedSignal Propulsion 
Engines ASB No. TFE731-A72-3504, Revision 1, dated July 2, 1993, and 
if necessary, replace with a serviceable disk, as follows:
    (1) For fan disks listed by S/N in Table 2 of Allied-Signal 
Aerospace Company, Garrett Engine Division, ASB No. TFE731-A72-3504, 
dated November 25, 1992, or AlliedSignal Propulsion Engines ASB No. 
TFE731-A72-3504, Revision 1, dated July 2, 1993, inspect, and if 
necessary, replace with a serviceable disk within 50 cycles in 
service (CIS) after April 9, 1993 (effective date of AD 92-26-09).
    (2) For the 10 added fan disks listed by S/N in Table 3 of 
AlliedSignal Propulsion Engines ASB No. TFE731-A72-3504, Revision 1, 
dated July 2, 1993, with 5000 or more CIS since new on the effective 
date of this AD, inspect, and if necessary, replace with a 
serviceable disk, within the next 50 CIS after the effective date of 
this AD.
    (3) For fan disks listed by S/N in Table 3 of AlliedSignal 
Propulsion Engines ASB No. TFE731-A72-3504, Revision 1, dated July 
2, 1993, other than the 10 added fan disks, with 5000 or more CIS 
since new on April 9, 1993, (effective date of AD 92-26-09), 
inspect, and if necessary, replace with a serviceable disk, within 
the next 50 CIS after April 9, 1993 (effective date of AD 92-26-09).
    (4) For the 10 added fan disks listed by S/N in Table 3 of 
Allied-Signal Propulsion Engines ASB No. TFE731-A72-3504, Revision 
1, dated July 2, 1993, with less than 5000 CIS since new on the 
effective date of this AD, inspect, and if necessary, replace with a 
serviceable disk within the next 100 CIS after the effective date of 
this AD, or prior to accumulating 5050 CIS since new, whichever 
occurs first.
    (5) For fan disks listed by S/N in Table 3 of AlliedSignal 
Propulsion Engines ASB No. TFE731-A72-3504, Revision 1, dated July 
2, 1993, other than the 10 added fan disks, with less than 5000 CIS 
since new on April 9, 1993, (effective date of AD 92-26-09), 
inspect, and if necessary, replace with a serviceable disk, within 
the next 100 CIS after April 9, 1993 (effective date of AD 92-26-
09), or prior to accumulating 5050 CIS since new, whichever occurs 
first.
    (6) For fan disks listed by S/N in Table 4 of Allied-Signal 
Propulsion Engines ASB No. TFE731-A72-3504, Revision 1, dated July 
2, 1993, inspect, and if necessary, replace with a serviceable disk, 
within the next 100 CIS after the effective date 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, Los Angeles Aircraft Certification 
Office. The request should be forwarded through an appropriate FAA 
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.
    (e) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (f) The inspection, and replacement, if necessary, shall be done 
in accordance with the following service documents: 

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        Document No.                    Pages                     Revision                       Date           
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Allied-Signal Propulsion      1-28....................  1...........................  July 2, 1993.             
 Engines ASB No. TFE731-A72-                                                                                    
 3504.                                                                                                          
    Total pages: 28.........                                                                                    
Allied-Signal Aerospace       1-24....................  Original....................  November 25, 1992.        
 Company, Garrett Engine                                                                                        
 Division, ASB No. TFE731-                                                                                      
 A72-3504.                                                                                                      
    Total pages: 24.........                                                                                    
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    The incorporation by reference of AlliedSignal Propulsion 
Engines ASB No. TFE731-A72-3504, Revision 1, dated July 2, 1993, is 
approved by the Director of the Federal Register in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. The incorporation by reference of 
Allied-Signal Aerospace Company, Garrett Engine Division, ASB No. 
TFE731-A72-3504, dated November 25, 1992, was approved previously by 
the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51 as of April 9, 1993 (58 FR 16113, March 25, 
1993). Copies may be obtained from AlliedSignal Engines, Aviation 
Services Division, Data Distribution, Dept. 64-3/2102-1M, P.O. Box 
29003, Phoenix, AZ 85038-9003; telephone (602) 365-2548. 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.
    (g) This amendment becomes effective on January 18, 1994.

    Issued in Burlington, Massachusetts, on December 21, 1993.
Jay J. Pardee,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 93-31907 Filed 12-30-93; 8:45 am]
BILLING CODE 4910-13-P