[Federal Register Volume 64, Number 22 (Wednesday, February 3, 1999)]
[Notices]
[Pages 5337-5338]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-2503]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Stand-Alone Airborne Navigation Equipment Using the Global 
Positioning System Augmented by the Wide Area Augmentation System

AGENCY: Federal Aviation Administration, DOT.

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 
stand-alone airborne navigation equipment using the Global Positioning 
System (GPS) Augmented by the Wide Area Augmentation System (WAAS). The 
proposed TSO prescribes the minimum operational performance standards 
that stand-alone airborne navigation equipment must meet to be 
identified with the marking ``TSO-C146.''


[[Page 5338]]


DATES: Comments must be received on or before April 16, 1999.

ADDRESSES: Send all comments on the proposed technical standard order 
to: Avionics Systems Branch, AIR-130, Aircraft Engineering Division, 
Aircraft Certification Service, Federal Aviation Administration, 800 
Independence Avenue, SW., Washington, DC 20591. Or deliver comments to: 
Federal Aviation Administration (FAA), Room 815, 800 Independence 
Avenue, SW., Washington, DC 20591. Comments must identify the TSO file 
number.

FOR FURTHER INFORMATION CONTACT:
Ms. Michelle Swearingen, Avionics Systems Branch, AIR-130, Aircraft 
Engineering Division, Aircraft Certification Service, Federal Aviation 
Administration, 800 Independence Avenue, SW., Washington, D.C. 20591, 
(202) 267-3817, FAX No. (202) 493-5173.

SUPPLEMENTARY INFORMATION: 

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 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, D.C. 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, 
Aircraft Certification Service before issuing the final TSO.

Background

    The Wide Area Augmentation System (WAAS) is an augmentation to GPS 
that calculates GPS integrity and correction data on the ground and 
uses geostationary satellites to broadcast GPS integrity and correction 
data to GPS/WAAS users and to provide ranging signals. It is a safety 
critical system consisting of a ground network of reference and 
integrity monitor data processing sites to assess current GPS 
performance, as well as a space segment which broadcasts that 
assessment to Global Navigation Satellite System users to support 
enroute through precision approach navigation. Users of the system 
include all aircraft applying the WAAS data and ranging signal.
    Wide area reference stations and integrity monitors are widely 
dispersed data collection sites that contain GPS/WAAS ranging receivers 
which monitor all signals from the GPS, as well as the WAAS 
geostationary satellites. The reference stations collect measurements 
from the GPS and WAAS satellites so that differential corrections, 
ionospheric delay information, GPS/WAAS accuracy, WAAS network time, 
GPS time, and UTC can be determined. The standards of this TSO apply to 
equipment designed to accept a desired flight path and provide 
deviation commands referenced to that path. These deviations will be 
used by the pilot or autopilot to guide the aircraft.

How To Obtain Copies

    A copy of the proposed TSO-C146 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. RTCA Document No. 229A, 
``Minimum Operational Performance Standards for Global Positioning 
System/Wide Area Augmentation System Equipment,'' dated June 8, 1998, 
RTCA Document No. DO-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 December 1, 1992, RTCA Documents No. 
DO-200A, ``Standards for Processing Aeronautical Data,'' may be 
purchased from the RTCA Inc., 1140 Connecticut Avenue, NW., Suite 1020, 
Washington, D.C. 22036.
    Copies of the RTCA documents may be inspected at the FAA at the 
location listed under ADDRESSES. However, RTCA documents are 
copyrighted and may not be copied without the written consent of RTCA, 
Inc.

    Issued in Washington, DC, on January 28, 1999.
James C. Jones,
Manager, Aircraft Engineering Division, Aircraft Certification Service.
[FR Doc. 99-2503 Filed 2-2-99; 8:45 am]
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