[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