[Federal Register Volume 87, Number 183 (Thursday, September 22, 2022)]
[Rules and Regulations]
[Pages 57818-57820]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-20508]



Federal Aviation Administration

14 CFR Part 91

[Docket No.: FAA-2022-1212]

Changes to Surveillance and Broadcast Services

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notification of changes to Surveillance Services.


SUMMARY: This action announces termination of the Mode-S Traffic 
Information Service (TIS) at 104 terminal Mode-S radar sites. The FAA 
is replacing these legacy terminal Mode-S radars via the Mode-S Beacon 
Replacement System (MSBRS) program, or may remove legacy terminal Mode-
S radars as part of other ongoing activities. As each legacy terminal 
Mode-S Radar is replaced or removed, the FAA will no longer provide 
Mode-S TIS to capable transponders from that location. This change does 
not affect existing Traffic Information Service--Broadcast (TIS-B), 
Automatic Dependent Surveillance--Rebroadcast (ADS-R), or Automatic 
Dependent Surveillance--Same Link Rebroadcast (ADS-SLR) services 
currently provided to properly ADS-B equipped aircraft.

DATES: September 22, 2022.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this action, contact: Michael Freie, Technical Advisor, Surveillance 
Services, AJM-4, Air Traffic Organization, Federal Aviation 
Administration, 600 Independence Avenue SW, Washington, DC 20597; 
telephone: 202-528-2337; email: [email protected].


Executive Summary

    In 2018, the FAA commissioned a study to assess the safety and 
economic impacts on general aviation owners and operators (from here on 
referred to as ``the GA Community'') from the termination of Mode-S 
Traffic Information Service (TIS). The purpose of this study was to 
communicate information on the removal of Mode-S TIS from the National 
Airspace System (NAS) through user outreach and engaging with non-
governmental organizations (e.g., AEA, AOPA, EAA, and GAMA). The 
results of the study confirmed that removal of Mode-S TIS has no 
significant adverse safety or economic impacts on the GA Community. 
Therefore, beginning in

[[Page 57819]]

2024, Mode-S TIS will terminate at each radar location as current Mode-
S radars are replaced by the Mode-S Beacon Replacement System (MSBRS) 
program, or as legacy terminal Mode-S radars are removed as part of 
other ongoing activities. The GA Community should no longer rely on 
reception of TIS information from Mode-S capable radars.

I. Background

    In 2000, FAA implemented Mode-S Traffic Information System (TIS) 
via Mode-S radar data-link functionality. Mode-S TIS has also been 
referred to informally as TIS-A by some in industry. Mode-S TIS was 
implemented by FAA in response to an NTSB recommendation suggesting 
improvement of situational awareness information for the general 
aviation (GA) community not equipped with a traffic alert and collision 
avoidance system (TCAS).
    In May 2010, the FAA published 14 CFR 91.225 and 91.227, requiring 
aircraft to be equipped with Automatic Dependent Surveillance--
Broadcast (ADS-B) Out equipment by 1 January 2020 in order to operate 
in certain U.S. airspace. ADS-B was identified as the backbone for the 
future of the FAA's Next Generation (NextGen) programs. From 2010 
through 2020, the FAA funded deployment of approximately 700 ADS-B 
radio stations across the U.S. to provide improved surveillance 
coverage across the NAS. Along with improving surveillance coverage, 
the FAA implemented functionality into ADS-B radio stations geared at 
providing appropriately equipped GA aircraft with enhanced situational 
awareness through both Traffic Information Services--Broadcast (TIS-B) 
and Automatic Dependent Surveillance--Rebroadcast (ADS-R).\1\ In 2016, 
FAA funded the addition of Automatic Dependent Surveillance--Same Link 
Rebroadcast (ADS-SLR) service at the busiest U.S. airports with a 
surface surveillance system.\2\

    \1\ More information on TIS-B and ADS-R can be found at the 
FAA's NEXTGEN ADS-B website: https://www.faa.gov/nextgen/programs/adsb.
    \2\ FAA has two surface surveillance systems: ASSC (Airport 
Surface Surveillance Capability) and ASDE-X (Airport Surface 
Detection Equipment, Model X). See https://www.faa.gov/nextgen/programs/adsb/atc/assc and https://www.faa.gov/air_traffic/technology/asde-x.

Traffic Information Services

    In 2017, MITRE issued a report on Mid-Air Collision (MAC) rates 
from 1990 to 2006. Upon the implementation of Mode-S TIS functionality 
into FAA terminal radars, the data showed a decline of approximately 50 
percent in the GA MAC rate from 2000 to 2003--when Mode-S TIS avionics 
were first being installed in GA aircraft. This lower MAC rate 
stabilized after 2003 when Mode-S TIS installations were largely 
completed and stayed at the lower level until today. Reception of Mode-
S TIS information was not a functionality that was required for Mode-S 
transponders. To this day, a very limited set of transponders are known 
to be capable of receiving and processing Mode-S TIS information from 
FAA terminal radars.
    In the decades following the initial Mode-S TIS deployment, the FAA 
implemented improved systems for provisioning information on proximate 
aircraft to GA pilots through the use of TIS-B, ADS-R and ADS-SLR 
services. These new services expand beyond the currently provided Mode-
S TIS. Now that the ADS-B mandate is in effect, and low-cost avionics 
systems for receiving and displaying ADS-B, ADS-R, ADS-SLR and TIS-B 
information are readily available, the GA community is able to obtain a 
heightened situational awareness of the traffic around them. This is 
especially true when flying around the terminal areas where significant 
ADS-B coverage is available today.
    As of April 3, 2022, approximately 127,755 aircraft have been 
identified as being 1090ES, UAT, or Dual ADS-B In capable. The vast 
majority of these are General Aviation aircraft due to the number of 
portable ADS-B In devices or integrated ADS-B In/Out systems available 
to this market.

Mode-S Radar Beacon Replacement System

    Many FAA Mode-S terminal radars are approaching the end of their 
useful lifecycle. Additionally, the FAA is facing an increased 
maintenance cost from the inability to purchase parts, due to parts 
obsolescence or part shortages, necessary to ensure continued 
operational availability. To mitigate this, the FAA has initiated a 
radar modernization effort called the Mode-S Beacon Replacement System 
(MSBRS) program. Under this program, the FAA will replace at least 
forty-six (46) aging Mode-S terminal radars starting in 2024. Starting 
in 2024 as the new MSBRS radars replace the existing terminal radars, 
the existing Mode-S TIS functionality will disappear at the location of 
each replaced terminal radar.
    During this timeframe, the FAA will continue to provide Mode-S TIS 
through the existing terminal radars until the existing radar is 
replaced with a new MSBRS radar. This document is intended to provide 
time for GA aircraft owners and operators who have not yet equipped 
with an ADS-B receiver to acquire and install, if appropriate, an ADS-B 
In capable system.

Other FAA Surveillance System Improvement Activities

    Independent of the MSBRS program, FAA is also engaged in multiple 
activities aimed at improving existing surveillance systems. These 
activities are aimed at reducing FAA operating costs and/or reducing 
congestion on surveillance system RF frequencies. As these activities 
proceed, FAA may remove one or more Mode-S terminal radars from 
operation, which would eliminate Mode-S TIS at that location.

II. Industry Discussion on Mode-S TIS Removal

    Using surveys and discussions with industry organizations, the FAA 
was able to obtain the necessary data required to understand the 
potential safety and economic impacts from removing Mode-S TIS 
functionality from the existing terminal radars. FAA conducted surveys, 
such as the General Aviation/Part 135 Air Taxi Activity Survey, to 
produce a set of comprehensive data on Part 91 and Part 135 aircraft 
and their operations. The FAA reviewed data from survey reports for 
2010, 2014, 2016, 2018, and 2019, and discussed these reports with 
industry association experts. The data from these reports were utilized 
to study the relevant surveillance equipage for all types of aircraft: 
Fixed Wing Piston, Fixed Wing turboprop single and multi-engine, 
turbojet, and rotorcraft.
    The FAA worked with the Aircraft Owners and Pilots Association 
(AOPA) to develop a special survey of AOPA's members about the impacts 
of eliminating Mode-S TIS. The survey was sent to 50,000 AOPA members 
with 2,567 responses received by March 2021. A follow up survey was 
conducted in an attempt to increase the percentage of AOPA members' 
responses. The final number of respondents by May 2021 was 5,752--over 
10% of the aircraft owners surveyed. After the final survey results 
were received, AOPA and FAA performed a joint review of the collected 
information. In addition to answering 31 specific questions about their 
aircraft, its relevant avionics, hours, operations, and locations, the 
GA community also submitted over 700 comments pertaining to the impact 
of terminating Mode-S TIS. More than 50% of the GA community stated 
that there would be no or little impact to their traffic

[[Page 57820]]

awareness capability and safety due to the removal of Mode-S TIS.
    Over the last 3 years, the FAA has conducted industry briefings and 
discussions with major avionics manufacturing companies on the MSBRS 
program and the associated planned removal of Mode-S TIS from terminal 
radars. These discussions assisted in gathering pertinent information 
on equipage and gaining insight into potential concerns.

III. Summary

    Based on data obtained from the aviation community and feedback 
received through industry engagement, FAA has determined that the 
overall safety and economic impacts due to the removal of Mode-S TIS 
functionality will have little to no impact on the GA community.
    Replacement of the existing terminal radars capable of providing 
Mode-S TIS under the MSBRS Program will provide an improvement in ATC 
capabilities, which will benefit military and civil aviation, including 
General Aviation. Installation of the new state-of-the-art Mode-S 
radars will improve system operational reliability and reduce system 
down time.
    Removal of legacy terminal Mode-S radars may occur as part of other 
ongoing FAA activities to divest radars or which are being replaced 
with other modern cooperative surveillance systems. These activities 
are being pursued to lower FAA operating costs and/or reduce congestion 
on surveillance system RF frequencies.
    Aircraft operating within ADS-B mandated airspace, specified under 
14 CFR 91.225, have transitioned their avionics equipment to be 
compliant with the performance requirements of the regulation. If the 
ADS-B Out equipment is performing and configured properly, aircraft 
equipped with ADS-B In are capable of receiving ADS-R, ADS-SLR, and 
TIS-B services from the FAA ADS-B ground stations across the NAS. These 
low-cost ADS-B In avionics systems are widely available, and provide 
the GA community with a heightened situational awareness of the traffic 
around them which was not previously available using solely Mode-S TIS 
information. These services expand coverage and more than replace the 
information currently provided by Mode-S TIS.

    Issued in Washington, DC, on September 16, 2022.
Mark DeNicuolo,
Vice President, Program Management Organization, Air Traffic 
[FR Doc. 2022-20508 Filed 9-21-22; 8:45 am]