[Federal Register Volume 62, Number 238 (Thursday, December 11, 1997)]
[Notices]
[Pages 65305-65306]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-32451]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
Traffic Advisory System (TAS) Airborne Equipment
AGENCY: Federal Aviation Administration.
ACTION: Notice of availability for public comment.
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SUMMARY: This notice announces the availability of and requests
comments on a proposed Technical Standard Order (TSO) pertaining to
traffic advisory system (TAS) airborne equipment. The proposed TSO
prescribes the minimum operational performance standards that traffic
advisory system (TAS) airborne equipment must meet to be identified
with the marking ``TSO-C147.''
DATES: Comment must identify the TSO file number and be received on or
before February 20, 1998.
ADDRESSES: Send all comments on the proposed technical standard order
to: Technical Programs and Continued Airworthiness Branch, AIR-120,
Aircraft Engineering Division, Aircraft Certification Service, Federal
Aviation Administration, 800 Independence Avenue, SW., Washington, DC
20591. Or deliver comments to: Federal Aviation Administration, Room
815, 800 Independence Avenue, SW., Washington, DC 20591. Comment must
identify the TSO file number.
FOR FURTHER INFORMATION CONTACT: Ms. Bobbie J. Smith, Technical
Programs and Continued Airworthiness Branch, AIR-120, Aircraft
Engineering Division, Aircraft Certification Service, Federal Aviation
Administration, 800 Independence Avenue, SW., Washington, DC 20591, FAX
No. (202) 267-5340.
Comments Invited
Interested persons are invited to comment on the proposed TSO
listed in this notice by submitting such written data, views, or
arguments as they desire
[[Page 65306]]
to the above specified address. Comments received on the proposed
technical standard order may be examined, before and after the comment
closing date, in Room 815, FAA Headquarters Building (FOB-10A), 800
Independence Avenue, SW., Washington, DC 20591, weekdays except Federal
holidays, between 8:30 a.m. and 4:30 p.m. All communications received
on or before the closing date for comments specified above will be
considered by the Director of the Aircraft Certification Service before
issuing the final TSO.
Background
This TSO is proposed for a new system of airborne equipment
designated TAS. TAS is an airborne traffic advisory system that
interrogates ATC transponders in nearby aircraft and uses computer
processing to identify and advise the crew of potential and predicted
collision threats. The system is designed to protect a volume of
airspace around the TAS equipped aircraft by assisting pilots in the
visual acquisition of intruder traffic. TAS is similar to TCAS I with
changes in the power output and display requirements that make it more
encomical, and therefore more appealing, to the General Aviation
community. There are two classes of TAS equipment:
Class A. Traffic Display and Aural Alerting
Class A systems provide a flight deck traffic display that
indicates the relative position and altitude of ATC transponder-
equipped aircraft. Class A systems will provide appropriate aural and
visual advisories to assist the flightcrew in visually acquiring the
threat aircraft when TAS predicts a penetration of the protected
airspace. TAS assist the flightcrew in visually acquiring the intruding
aircraft. Traffic advisories indicate the relative positions of
intruding aircraft that meet certain range and altitude criteria and
are approximately 30 seconds from the closest point of approach.
Traffic advisories can be generated for aircraft with operative Mode S,
Mode C or Mode A (non-altitude reporting) transponders. The aural alert
message ``Traffic-Traffic,'' spoken once, shall be used to inform the
crew of a Traffic Advisory (TA). The TAS equipment is viewed as a
supplement to the pilot who, with the aid of the ATC system, has the
primary responsibility for avoiding mid-air collisions. The TAS system
provides no indication of aircraft without operative transponders.
Class B. Aural Alerting and Annunciation Only
Class B systems do not include a cockpit traffic display. Class B
systems will provide appropriate aural advisories and visual
annunciations to assist the flightcrew in visually acquiring the threat
aircraft when TAS predicts a penetration of the protected airspace.
Traffic advisories indicate the relative positions of intruding
aircraft that meet certain range and altitude criteria and are
approximately 30 seconds from the closest point of approach. They
assist the flightcrew in visually acquiring the intruding aircraft. The
aural alert message ``Traffic-Traffic,'' spoken once, shall be used to
inform the crew of a Traffic Advisory (TA). This aural alert message
will be accompanied by a discrete visual annunciation indicating that a
TA is currently active. This annunciation will remain as long as the TA
is active and will extinguish when no TAs are active. TAs will, upon
crew command, generate an aural message defining the relative position
of ATC transponder-equipped aircraft. Traffic advisories can be
generated for aircraft with operative Mode S, Mode C, or Mode A (non-
altitude reporting) transponders. The TAS equipment is viewed as a
supplement to the pilot who, with the aid of the ATC system, has the
primary responsibility for avoiding mid-air collisions. The TAS system
provides no indication of aircraft without operative transponders. RTCA
Document No. DO-160C sets forth the environmental standards for the
Traffic Advisory System. RTCA Document DO-178B sets forth the minimum
performance requirements for software for the Traffic Advisory System
and requires that each article be marked with the appropriate software
level. Because the proposed TSO calls for 2 classes of equipment, the
TSO also requires that each article be marked as equipment Class A or
Class B, as applicable.
The minimum performance standards for this Traffic Advisory System
TSO differ slightly from those standards in RTCA DO-197 (TCAS 1). This
TSO was developed specifically, but not exclusively for the general
aviation market. The Traffic Advisory System has a lower radiated power
output than TCAS 1 and gives an alert as to the presence of intruder
aircraft. However, TCAS 1 has resolution alert that gives the pilot
directional commands when intruder aircraft are present. These
differences make the Traffic Advisory System more economical for the
general aviation community. The exceptions to RTCA DO-197A are detailed
in the Appendix 1 of this TSO. In order to comply with TSA-C147, the
applicant must also meet the performance standards set forth in RTCA
Document No. DO-197A, with the stated exceptions in Appendix 1.
How To Obtain Copies
A copy of the proposed TSO-C147 may be obtained via Internet
(http://www.faa.gov/avr/air/100home.htm) or on request from the office
listed under ``For Further Information Contact.'' Copies of RTCA, Inc.
Document No. DO-197A, ``Minimum Operational Performance Standards for
An Active Traffic Alert and Collision Avoidance System I (ACTIVE TCAS
1),'' dated September 12, 1994. RTCA Document No. 160D, ``Environmental
Conditions and Test Procedures for Airborne Equipment,'' dated July 29,
1997; and RTCA Document No. DO-178B, ``Software Considerations in
Airborne Systems and Equipment Certification,'' dated 1, 1992, may be
purchased from the RTCA Inc., 1140 Connecticut Avenue, NW., Suite 1020,
Washington, DC 20036.
Issued in Washington, DC, on December 5, 1997.
Henri P. Branting,
Acting Manager, Aircraft Engineering Division, Aircraft Certification
Service.
[FR Doc. 97-32451 Filed 12-10-97; 8:45 am]
BILLING CODE 4910-13-M
