[Federal Register Volume 59, Number 76 (Wednesday, April 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-9468]


[[Page Unknown]]

[Federal Register: April 20, 1994]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-ANE-49; Amendment 39-8861; AD 94-07-03]

 

Airworthiness Directives; AlliedSignal, Inc. TFE731-3 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes an existing priority letter 
airworthiness directive (AD), applicable to certain AlliedSignal, Inc. 
TFE731-3 series turbofan engines, that currently requires a revision to 
the Limitations Section of the Airplane Flight Manual (AFM) to provide 
procedures for monitoring engine performance in order to detect A5 seal 
cracking and opening before first stage low pressure (LP) turbine disk 
failure. Additionally, the revision to the AFM requires a procedure for 
verification of LP rotor (N1) rotation during engine start to detect 
rotor lockup due to first stage LP turbine rotor creep. This amendment 
maintains those requirements for engine and flight data monitoring, 
adds a more stringent procedure for verifying rotor lockup during 
engine start and for detection of rubbing noises, and requires 
replacement of A5 seals with a redesigned seal. Replacement of A5 seals 
with a redesigned seal constitutes terminating action to the monitoring 
requirements. This amendment is prompted by reports of an additional 
first stage LP turbine disk failure due to A5 seal cracking. The 
actions specified by this AD are intended to prevent uncontained 
failure of the first stage LP turbine disk.

DATES: Effective June 6, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 6, 1994.

ADDRESSES: 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. This information may be examined at the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, 12 New England Executive Park, Burlington, MA 01803-5299; 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: A proposal to amend part 39 of the Federal 
Aviation Regulations by superseding priority letter airworthiness 
directive (AD) 92-12-09, issued June 8, 1992, which is applicable to 
certain Allied-Signal Aerospace Company, Garrett Engine Division, 
TFE731-3 series turbofan engines, was published in the Federal Register 
on October 4, 1993 (58 FR 51587). That action proposed to continue the 
engine and flight data monitoring requirements of priority letter AD 
92-12-09 by revising the Limitations Section of the Airplane Flight 
Manual (AFM) to provide for procedures to trend monitor engine 
performance in order to detect A5 seal cracking and opening before 
first stage low pressure (LP) turbine disk failure. In addition, that 
action proposed to require a more stringent procedure for verifying N1 
rotation during engine start to detect rotor lockup and for detecting 
rubbing noises due to first stage LP turbine rotor creep. Also, that 
action proposed to add the Allied-Signal Aerospace Company, Garrett 
Engine Division, Model TFE731-2A engine to the AD applicability. 
Finally, that action proposed to require replacement of current A5 
seals with a redesigned A5 seal within 150 hours time in service after 
the effective date of the proposed AD. Installation of the redesigned 
A5 seal would constitute terminating action to the engine and flight 
data monitoring requirements.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter states that paragraph (a)(1) in the proposed rule 
requires that the engine and flight data monitoring must be 
accomplished for any engine that has more than 500 hours time in 
service since new (TSN). The commenter further states that the greater 
than 500 hours TSN qualification should be added to the applicability 
paragraph, as this qualification is applicable to all succeeding 
paragraphs. The FAA concurs in part. The FAA has added for clarity a 
compliance table in paragraph (d) that instructs operators on the 
replacement schedule for the A5 seal installed on engines with less or 
more than 500 hours TSN.
    One commenter states that paragraph (a)(4) of the proposed rule 
requires checking for rubbing noises and free rotation of the N1 spool 
following each engine shutdown. Paragraphs (a)(4) and (c) go on to 
state that if any rubbing noises are detected, the operator must 
discontinue further flight. The commenter suggests requiring 
discontinuation of further flight if the N1 spool locks up, or engine 
rubbing noises are detected during this check. The FAA concurs and the 
final rule has been changed accordingly.
    The Type Certification Data Sheet for the Allied-Signal Aerospace 
Company, Garrett Engine Division, TFE731-3 series turbofan engines was 
officially changed by the FAA during November 1993 to show the current 
corporate name of the manufacturer, AlliedSignal, Inc. All references 
to the corporate name have been changed accordingly in this final rule.
    In addition, AlliedSignal, Inc. has issued service bulletin (SB) 
No. TFE731-72-3509, dated January 4, 1994, that describes installation 
of a redesigned A5 seal and air cooled HP turbine blades and associated 
parts for TFE731-3B and -3BR models. Installation of a redesigned A5 
seal and air cooled HP turbine blades and associated parts in 
accordance with this SB constitutes an additional method of compliance 
to paragraph (d) of this AD.
    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.
    There are approximately 3,300 engines of the affected design in the 
worldwide fleet. The FAA estimates that 2,000 engines installed on 
aircraft of U.S. registry are affected by this AD, that it will take 
approximately 55 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $55 per work hour. Required 
parts will cost approximately $7,500 per engine. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $21,050,000.
    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.
    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 DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 
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 adding the following new 
airworthiness directive:

94-07-03: AlliedSignal, Inc. Amendment 39-8861. Docket 93-ANE-49.

    Applicability: AlliedSignal, Inc. Model TFE731-2A, -3, -3A, -3R, 
-3AR, -3B, and -3BR turbofan engines that have first stage low 
pressure (LP) turbine nozzles, Part Number (P/N) 3072842-1 or P/N's 
3072319-1 through -8, installed. These engines are installed on but 
not limited to Avions Marcel Dassault Falcon 50, AiResearch Aviation 
Company 731 Jetstar, Lockheed 1329-25 (Jetstar II), Israel Aircraft 
Industries Ltd. 1124 series (Westwind) and 1125, Westwind Astra, 
British Aerospace DH/HS/BH 125 series, Learjet 55 series, Cessna 650 
Citation III series, and Sabreliner NA265-65 (Sabreliner 65 and 65 
series) aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent uncontained failure of the first stage LP turbine 
disk, accomplish the following:
    (a) Prior to further flight revise the Limitations Section of 
the FAA-approved Airplane Flight Manual (AFM) to include the 
following paragraphs (1) through (4) relating to engine and flight 
data monitoring. This may be accomplished by inserting a copy of 
this AD in the AFM.

``Engine and Flight Data Monitoring

    (1) If any engine has more than 500 hours time in service since 
new (TSN), record the flight data set forth in paragraph (2) once 
every two flights while meeting the following conditions:
    a. Matched low pressure rotor (N1) speed;
    b. Turn engine anti-ice off (consistent with safe operation); 
and
    c. Attain a stabilized cruise speed for five minutes or longer.

    Note: If flight operations do not permit all of these conditions 
to be met, the engine to engine comparison data may be unreliable.

    (2) When the conditions specified in paragraph (1) are met, 
record the following flight data and retain this data for six 
months:

    a. Date of flight;
    b. Aircraft altitude or flight level;
    c. Outside static air temperature in degrees celsius ( deg.C);
    d. Mach number;
    e. Engine N1 speed for each engine;
    f. Engine high pressure rotor (N2) speed for each engine;
    g. Fuel flow for each engine; and
    h. Interstage turbine temperature (ITT) for each engine.
    (3) Verify N1 rotation during engine start by allowing N2 to 
increase to approximately 12 to 15 percent and confirm N1 rotation 
prior to fuel initiation. If no N1 rotation is observed, discontinue 
further attempts at engine start.
    (4) Check for rubbing noises and free rotation of the N1 spool 
following each engine shutdown. If any rubbing noises are detected, 
or if the N1 spool locks up, discontinue further flight.''
    (b) When engine and flight data monitoring is required by the 
AFM revision of paragraph (a) of this AD, accomplish the following:
    (1) After each flight, calculate the difference (i.e., No. 1 
minus No. 2, No. 1 minus No. 3, and No. 1 minus No. 4) between the 
engines' ITT, N2 speed, and fuel flow readings for each flight 
having recorded data. Compare these differences to the differences 
calculated from previous flights.
    (2) Discontinue further flight if a change of 20 deg.C or more 
occurs in the ITT difference between two engines, (on three and four 
engine airplanes compare No. 2, No. 3 and No. 4 engine parameters to 
the No. 1 engine) with the last ten flights having recorded data. 
Flight operation can be continued when the cause of the ITT 
temperature shift has been determined and appropriate corrective 
action has been accomplished. Engine and flight data monitoring must 
be continued upon return to flight operations.

    Note: A suspect engine may indicate an increase in ITT 
temperature and an increase in N2 speed greater than 1% and an 
increase in fuel flow to a lesser degree with respect to the other 
normal engine(s).

    Additional guidance and information regarding flight data 
collection, trend monitoring, and corrective actions, may be 
obtained from Allied-Signal Aerospace Company, Garrett Engine 
Division, Operating Information Letter No. OI 731-13, Revision C, 
dated November 20, 1992.
    (c) Discontinue further flight if no N1 rotation is observed 
during engine start, or if engine rubbing noises are detected or the 
N1 spool locks up after engine shutdown. Flight operation can be 
continued when the cause of the N1 rotor lockup or engine rubbing 
noises has been determined and appropriate corrective action has 
been accomplished. Engine and flight data monitoring must be 
continued upon return to flight operations.
    (d) Replace the A5 seal assembled in affected first stage LP 
turbine nozzles and install a redesigned A5 seal in accordance with 
the Accomplishment Instructions of Allied-Signal Aerospace Company, 
Garrett Engine Division, Service Bulletin (SB) No. TFE731-72-3502, 
Revision 2, dated March 15, 1993, SB No. TFE731-72-3502, Revision 1, 
dated December 21, 1992, or SB No. TFE731-72-3502, Original, dated 
November 25, 1992; or SB No. TFE731-72-3503, Revision 1, dated 
December 21, 1992; or AlliedSignal, Inc. SB No. TFE731-72-3509, 
dated January 4, 1994, as applicable, as follows: 

------------------------------------------------------------------------
 Time in service since new (TSN) on                                     
   the effective date of this AD             Replacement schedule       
------------------------------------------------------------------------
500 hours TSN or more..............  Within 150 hours time in service   
                                      (TIS) after the effective date of 
                                      this AD.                          
Less than 500 hours TSN............  Prior to accumulating 650 hours    
                                      TSN.                              
------------------------------------------------------------------------

    Installation of the redesigned A5 seal constitutes terminating 
action to the engine and flight data monitoring and AFM revision 
required by this AD.
    (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 AD, if any, may be 
obtained from the Los Angeles Aircraft Certification Office.

    (f) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the aircraft to a location where 
the requirements of this AD can be accomplished.
    (g) The replacement of the A5 seal shall be done in accordance 
with the following service bulletins: 

------------------------------------------------------------------------
     Document No.          Pages       Revision             Date        
------------------------------------------------------------------------
Allied-Signal                  1-18  2............  Mar. 15, 1993.      
 Aerospace Company,                                                     
 Garrett Engine                                                         
 Division SB No.                                                        
 TFE731-72-3502.                                                        
Total pages: 18.                                                        
Allied-Signal                  1-16  1............  Dec. 21, 1992.      
 Aerospace Company,                                                     
 Garrett Engine                                                         
 Division SB No.                                                        
 TFE731-72-3502.                                                        
Total pages: 16.                                                        
Allied-Signal                  1-14  Original.....  Nov. 25, 1992.      
 Aerospace Company,                                                     
 Garrett Engine                                                         
 Division SB No.                                                        
 TFE731-72-3502.                                                        
Total pages: 14.                                                        
Allied-Signal                     1  1............  Dec. 21, 1992.      
 Aerospace Company,                                                     
 Garrett Engine                                                         
 Division SB No.                                                        
 TFE731-72-3503.                                                        
                                2-3  Original.....  Dec. 9, 1992.       
                                  4  1............  Dec. 21, 1992.      
                                  5  Original.....  Dec. 9, 1992.       
                                  6  1............  Dec. 21, 1992.      
                                7-9  Original.....  Dec. 9, 1992.       
                              10-16  1............  Dec. 21, 1992.      
Total pages: 16.                                                        
AlliedSignal, Inc. SB          1-10  Original.....  Jan. 4, 1994.       
 No. TFE731-72-3509.                                                    
Total pages: 10.                                                        
------------------------------------------------------------------------

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.
    (h) This amendment supersedes priority letter AD 92-12-09, 
issued June 8, 1992.
    (i) This amendment becomes effective on June 6, 1994.

    Issued in Burlington, Massachusetts, on April 11, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-9468 Filed 4-19-94; 8:45 am]
BILLING CODE 4910-13-P