[Federal Register Volume 59, Number 3 (Wednesday, January 5, 1994)]
[Rules and Regulations]
[Pages 511-514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 93-32115]
[[Page Unknown]]
[Federal Register: January 5, 1994]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-68-AD; Amendment 39-8786; AD 94-01-04]
Airworthiness Directives; Honeywell Traffic Alert and Collision
Avoidance System II Computer Units, as Installed on Various Transport
Category Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to all Honeywell Traffic Alert and Collision Avoidance
System II (TCAS II) computer units installed on various transport
category airplanes, that requires replacing certain TCAS II computer
units with new units that incorporate updated collision avoidance
system (CAS) logic, and modifying the computer surveillance logic. This
amendment is prompted by the development of candidate enhancements to
TCAS II logic that will improve its utility and increase its overall
operational acceptance. The actions specified by this AD are intended
to prevent collisions or near misses caused by incompatibility between
the TCAS II processors and the current air traffic control system.
DATES: Effective February 4, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of February 4, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Honeywell Inc., Commercial Flight Systems Group, Air
Transport Systems Division, P.O. Box 21111, Phoenix, Arizona 85036.
This information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue,
SW., Renton, Washington; at the FAA, Transport Airplane Directorate,
Los Angeles Aircraft Certification Office, 3229 East Spring Street,
Long Beach, California; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Abby Malmir, Aerospace Engineer,
Systems and Equipment Branch, ANM-132L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3229 East
Spring Street, Long Beach, California 90806-2425; telephone (310) 988-
5351; fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to all Honeywell Traffic Alert and Collision Avoidance
System II (TCAS II) computer units installed on various transport
category airplanes was published in the Federal Register on September
9, 1993 (58 FR 47407). That action proposed to require replacing
certain TCAS II computer units with new units that incorporate updated
collision avoidance system (CAS) logic, and modifying the computer
surveillance logic.
Since the issuance of the notice, an additional change to Version
6.04A collision avoidance system (CAS) logic was recommended at a
meeting held to discuss the progress made in implementing logic
modification 6.04A. Meeting attendees included representatives from the
FAA and European civil aviation authorities, U.S. and European aviation
industry, and U.S. operators. The logic change that was recommended
involves reducing unnecessary crossing resolution advisories (RA). That
change is included in a new enhanced software package (identified as
Version 6.04A), specified in Mitre letter F046-L-0069, dated September
21, 1993.
Subsequently, Honeywell Inc. has issued Service Bulletin 4066010-
34-SW16, dated December 20, 1993. The service bulletin describes
procedures for converting certain TCAS II computer units to new units
(Version 6.04A). The new units incorporate all of the logic changes
specified in the preamble to the notice, including updating CAS logic,
modifying the computer surveillance logic to ensure that these units
accommodate Mode C altitude input of 100-foot increments, and ensuring
that the system will be tracked and coordinated by intruding aircraft
when the Mode S transponder CA field is set at CA=7. The conversion is
onboard-loadable, or it may be accomplished at a field repair shop. The
first method involves data loading the TCAS II computer unit in the
aircraft equipment bay using an ARINC 615 or 603 data loader. The
second method entails performing a final test, and then programming the
TCAS II computer unit to convert it to the latest enhanced version at a
field repair shop.
The notice proposed that operators accomplish the modification
requirements of this AD in accordance with a method approved by the
FAA. However, the FAA has reviewed and approved the Honeywell service
bulletin discussed previously, and has determined that accomplishment
of this service bulletin is an appropriate method of compliance.
Consequently, the FAA has revised paragraph (a) of the final rule to
cite the Honeywell service bulletin as the appropriate source of
service information, and has removed the language referring to
accomplishing the actions ``in accordance with a method approved by the
FAA.'' Even though this language has been deleted from paragraph (a),
operators may still be permitted to accomplish the actions in
accordance with an FAA-approved method under the provisions of
paragraph (c) of the final rule.
In light of this new data and software developement, the FAA has
revised the final rule by changing the reference to Mitre letter F046-
L-0056, dated July 20, 1993, which appeared in paragraph (a)(1) of the
NPRM, to Mitre letter F046-L-0069, dated September 21, 1993, since the
latter identifies the enhanced software package. Since the original
Version 6.04A software was never issued, no operator could have
installed that version. Therefore, no redundant actions would be
required on the part of any operator as a result of this change.
Since the enhanced Version 6.04A software introduces a change in
the operation of the aircraft, the FAA also finds that a revision to
the Airplane Flight Manual (AFM) is necessary as a conforming change to
correspond with that new software configuration. The AFM revision is
advisory only, and will ensure that the flight crew is aware of the
changes associated with the new software installation. Consequently,
paragraph (b) has been added to the final rule to reflect this
informational AFM revision.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received in response to the notice:
One commenter, Honeywell, objects to the proposed compliance date
of December 30, 1993, and states that December 31, 1994, represents a
more realistic compliance timeframe. Honeywell indicates that operators
vary in their ability to load the updated software due to maintenance
and aircraft schedules and data-load/test resources. Honeywell states
that, although it has been working aggressively to implement the latest
change, that change has resulted in a delay in the date operators will
be able to implement the latest change.
Several other commenters also request that the FAA extend the
proposed compliance date from 3 to 18 months after the date specified
in the proposal in order to accommodate implementation, verification,
certification, and incorporation of the proposed software change into
existing installations. One commenter, the Air Transport Association
(ATA) of America, supports implementation of the latest enhanced
Version 6.04A, and requests that the FAA issue a supplemental notice of
proposed rulemaking (NPRM) to propose that this revised software be
retrofitted by June 30, 1995. ATA contends that significant differences
exist between Version 6.04A and the latest enhanced version. Another
commenter requests that the FAA solicit comments from foreign agencies
participating in TCAS evaluation and simulations to help ensure that
the proposed Version 6.04A revision will be compatible and acceptable.
The FAA concurs partially with these requests to extend the
compliance time. The FAA has considered the safety implications, the
time necessary for approval of the enhanced Version 6.04A software, the
size of the fleet, and normal maintenance schedules for timely
accomplishment of implementation of the modification. In light of these
considerations, the FAA has determined that a compliance date of
December 31, 1994, is appropriate. Paragraph (a) of the final rule has
been revised to specify the revised compliance date.
However, in response to the requests that a supplemental NPRM be
issued and that further public comments be solicited, the FAA submits
the following. Comments received in response to the proposal reflect
unanimous support for implementation of the latest enhanced Version
6.04A software. The FAA considers the logic change (reduction of
unnecessary crossing RA's) incorporated in the enhanced software to be
a minor change. The intent of this AD is to require that the addressed
unsafe condition be corrected by installing modified TCAS II computer
units that incorporate updated CAS logic. The FAA has determined that a
requirement to implement Version 6.04A software, including the latest
enhancement, will meet that intent, will not alter the substance of the
rule, and will impose no additional burden on any member of the public.
Additionally, issuance of a supplemental NPRM would necessitate (under
the provisions of the Administrative Procedure Act) reissuing the
notice, reopening the period for public comment, considering additional
comments received, and eventually issuing a final rule; the time
required for that procedure may be as long as four additional months.
In light of this, and in consideration of the amount of time that has
already elapsed since issuance of the original NPRM, the FAA concludes
that solicitation of further public comment is not necessary and that
further delay of this final rule action is not appropriate.
One commenter requests that the FAA require Honeywell TCAS II
processors that are already installed be operated in the ``traffic
advisory (TA) only'' mode until the updated software package is
installed. The commenter indicates that ``possible hidden problems''
could exist between the different versions of logic that are installed
currently in the TCAS II processors.
The FAA does not concur with the commenter's request. Operation of
currently installed TCAS II processors in the ``TA only'' mode would
impair the capability of those processors to alert the flight crew of
appropriate aircraft maneuvers that must be taken to prevent mid-air
collisions. Further, the FAA is unaware of any ``possible hidden
problems'' between the different versions of logic installed currently
in the TCAS II processors, as suggested by the commenter. Therefore,
the FAA concludes that currently installed TCAS II processors should
not be operated in the ``TA only'' mode until the updated software
packaged is installed.
One commenter requests clarification of the unsafe condition
specified in the proposed rule. This commenter points out differences
in the wording of the unsafe condition between this proposed rule and
two existing proposals that address the same CAS logic change for
Rockwell International/Collins Air Transport Division (Collins), and
Allied Signal Aerospace Company/Air Transport Avionics (Allied Signal),
TCAS II processors. From this comment, the FAA infers that the
commenter requests that the proposed statement of unsafe condition more
closely parallels the statement of unsafe condition in the other two
proposals addressing the same subject.
The FAA concurs. The FAA has revised the unsafe condition specified
in this final rule to coincide with the proposals that address Collins
and Allied Signal TCAS II processors to more explicitly reference
safety considerations, as follows: ``* * * to prevent collisions or
near misses caused by incompatibility between the TCAS II processors
and the current air traffic control system.''
One commenter, Falcon Jet Corporation, indicates that Honeywell
TCAS II processors are installed on Mystere-Falcon Model 50 and 900
series airplanes, and requests that these airplanes be included in the
portion of the applicability of the AD that lists airplanes on which
this TCAS II processor may be installed. The FAA concurs with the
commenter's request and has revised the final rule accordingly. In
addition, the FAA has become aware of other airplane models affected by
this AD and has included those models in that portion of the
applicability statement of the final rule. The FAA clarifies that, as
stated in the preamble and the applicability of the proposal, the
affected Honeywell TCAS II processors are installed on various
transport category airplanes and are not limited only to those
airplanes listed in the applicability of this AD.
Several commenters request that the FAA revise the economic impact
information specified in the proposal to reflect costs borne by
suppliers, installers, and airline operators associated with
development, testing, and certification of the modified processor.
The FAA does not concur with the commenters' request to revise the
economic impact information contained in this AD. The appropriate
number of hours required to accomplish the required actions, specified
as 3 in the economic impact information, below, was provided to the FAA
by the processor manufacturer based on the best data available to date.
This number represents the time required to gain access, remove the
existing processor, install a diskette containing the revised software,
and close up. The cost analysis in AD rulemaking actions typically does
not include costs associated with development, testing, and
certification of a modified processor, as suggested by the commenter.
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 previously
described. 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 2,700 transport category airplanes in the
worldwide fleet on which the Honeywell TCAS II computer units may be
installed. The FAA estimates that 1,150 airplanes of U.S. registry will
be affected by this AD, that it will take approximately 3 work hours
per airplane to accomplish the required actions, and that the average
labor rate is $55 per work hour. Required parts will be supplied by the
manufacturer at no cost to operators. Based on these figures, the total
cost impact of the AD on U.S. operators is estimated to be $189,750, or
$165 per airplane. This total cost figure assumes that no operator has
yet accomplished the requirements of this AD.
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:
94-01-04 Honeywell: Amendment 39-8786. Docket 93-NM-68-AD.
Applicability: Traffic Alert and Collision Avoidance System
(TCAS) II computer units; part numbers 4066010-901, -902, and -903;
as installed on, but not limited to, the following airplanes,
certificated in any category:
Airbus Industrie Model A300-600, A310-200, A310-300, A320-200, and
A340 series airplanes;
Boeing Model 727-100 and -200; 737-100, -200, -300, and -400; 747-
100, -200, -300, -400 and 747SP; 757-200 and -500; and 767-200 and -
300 series airplanes;
Cessna Citation Model C550 and C560 series airplanes, and Cessna
Citation III and VII series airplanes;
Canadair Challenger Model CL-600-2B16 and -2A12 series airplanes;
British Aerospace Model 125-800A;
Gulfstream Model GII, GIIB, GIII, and GIV series airplanes;
Lockheed Model L-1011 series airplanes;
McDonnell Douglas Model DC-9-10, -20, -30-, -40, and -50; DC-10-10,
-15, -30, and -40; MD-11; and DC-9-80 series airplanes; and Model
MD-88 airplanes;
Dassault Aviation Model Mystere-Falcon 50 and 900 series airplanes;
Short Brothers Model SD3-60 series airplanes;
de Havilland Model DHC-8-100 and DHC-7 series airplanes;
Fokker Model F27 series airplanes; and
Corporate Jets Limited Model BAe 125-800A and BAe 125-1000A series
airplanes.
Compliance: Required as indicated, unless accomplished
previously.
To prevent collisions or near misses caused by incompatibility
between the TCAS II processors and the current air traffic control
system, accomplish the following:
(a) Before December 31, 1994, accomplish the requirements of
paragraphs (a)(1) and (a)(2) of this AD in accordance with Honeywell
Service Bulletin 4066010-34-SW16, dated December 20, 1993.
(1) Remove existing Honeywell TCAS II computer units, part
numbers 4066010-901, -902, and -903, and replace those units with
new units that incorporate updated collision avoidance system (CAS)
logic, identified as Version 6.04A in Mitre letter F046-L-0069,
dated September 21, 1993.
(2) Modify the computer surveillance logic on Honeywell TCAS II
computer units, part numbers 4066010-901, -902, and -903, to ensure
that these units accommodate Mode C altitude input of 100-foot
increments and that the system will be tracked and coordinated by
intruding aircraft when the Mode S transponder CA field is set at
CA=7.
(b) Prior to further flight after accomplishing the requirements
of paragraph (a) of this AD, revise the Airplane Flight Manual (AFM)
or AFM Supplement by accomplishing either paragraph (b)(1) or (b)(2)
of this AD.
(1) Revise the Normal Procedures Section of the AFM to include
the appropriate TCAS operating characteristic relative to the
modifications required by paragraph (a) of this AD, in accordance
with a method approved by the Manager, Los Angeles Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate; or
(2) Revise the Normal Procedures Section of the AFM to include
the following TCAS operating characteristic relative to the
modification required by paragraph (a) of this AD. This may be
accomplished by inserting a copy of this AD in the AFM or AFM
Supplement.
``All Resolution Advisory (RA) and Traffic Advisory (TA) aural
messages are inhibited at a radio altitude of less than 1,100 feet
above ground level (AGL) climbing, and less than 900 feel AGL
descending.''
(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, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal Avionics
Inspector, who may add comments and then send it to the Manager, Los
Angeles ACO.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(d) Special flight permits may be issued in accordance with FAR
21.197 and 21.199 to operate the airplane to a location where the
requirements of this AD can be accomplished.
(e) The replacement and modification shall be done in accordance
with Honeywell Service Bulletin 4066010-34-SW16, dated December 20,
1993. 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 Honeywell Inc., Commercial
Flight Systems Group, Air Transport Systems Division, P.O. Box
21111, Phoenix, Arizona 85036. Copies may be inspected at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; at the FAA, Transport Airplane Directorate, Los Angeles
Aircraft Certification Office, 3229 East Spring Street, Long Beach,
California; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on February 4, 1994.
Issued in Renton, Washington, on December 29, 1993.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 93-32115 Filed 12-30-93; 8:45 am]
BILLING CODE 4910-13-P