Pilot/Controller Glossary 

4/20/23 

TRACK OF INTEREST (TOI)

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 Displayed data representing an airborne object that threatens or has the potential 

to threaten North America or National Security. Indicators may include, but are not limited to: noncompliance 

with air traffic control instructions or aviation regulations; extended loss of communications; unusual 

transmissions or unusual flight behavior; unauthorized intrusion into controlled airspace or an ADIZ; 

noncompliance with issued flight restrictions/security procedures; or unlawful interference with airborne flight 

crews, up to and including hijack. In certain circumstances, an object may become a TOI based on specific and 

credible intelligence pertaining to that particular aircraft/object, its passengers, or its cargo. 
TRACK OF INTEREST RESOLUTION

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 A TOI will normally be considered resolved when: the aircraft/object 

is no longer airborne; the aircraft complies with air traffic control instructions, aviation regulations, and/or issued 

flight restrictions/security procedures; radio contact is re

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established and authorized control of the aircraft is 

verified; the aircraft is intercepted and intent is verified to be nonthreatening/nonhostile; TOI was identified 

based on specific and credible intelligence that was later determined to be invalid or unreliable; or displayed data 

is identified and characterized as invalid

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TRAFFIC

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a. 

A term used by a controller to transfer radar identification of an aircraft to another controller for the purpose 

of coordinating separation action. Traffic is normally issued: 

1. 

In response to a handoff or point out, 

2. 

In anticipation of a handoff or point out, or 

3. 

In conjunction with a request for control of an aircraft. 

b. 

A term used by ATC to refer to one or more aircraft. 

TRAFFIC ADVISORIES

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 Advisories issued to alert pilots to other known or observed air traffic which may 

be in such proximity to the position or intended route of flight of their aircraft to warrant their attention. Such 

advisories may be based on: 

a. 

Visual observation. 

b. 

Observation of radar identified and nonidentified aircraft targets on an ATC radar display, or 

c. 

Verbal reports from pilots or other facilities. 

Note 1: The word “traffic” followed by additional information, if known, is used to provide such advisories; e.g., 

“Traffic, 2 o’clock, one zero miles, southbound, eight thousand.” 

Note 2: Traffic advisory service will be provided to the extent possible depending on higher priority duties of 

the controller or other limitations; e.g., radar limitations, volume of traffic, frequency congestion, or controller 

workload. Radar/ nonradar traffic advisories do not relieve the pilot of his/her responsibility to see and avoid 

other aircraft. Pilots are cautioned that there are many times when the controller is not able to give traffic 

advisories concerning all traffic in the aircraft’s proximity; in other words, when a pilot requests or is receiving 

traffic advisories, he/she should not assume that all traffic will be issued. 

(Refer to AIM.) 

TRAFFIC ALERT (aircraft call sign), TURN (left/right) IMMEDIATELY, (climb/descend) AND 

MAINTAIN (altitude). 

(See SAFETY ALERT.) 

TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS)

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 An airborne collision avoidance 

system based on radar beacon signals which operates independent of ground-based equipment. TCAS-I 

generates traffic advisories only. TCAS-II generates traffic advisories, and resolution (collision avoidance) 

advisories in the vertical plane. 
TRAFFIC INFORMATION

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(See TRAFFIC ADVISORIES.) 

TRAFFIC INFORMATION SERVICE

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BROADCAST (TIS

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B)

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 The broadcast of ATC derived traffic 

information to ADS

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B equipped (1090ES or UAT) aircraft. The source of this traffic information is derived from 

PCG T

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