Three RMS Crossing The situation that the state error is more than three times the Route Mean Square (RMS) value.
Three RMS Crossing Rate See also Crossing (Rate).
The probability of occurrence of a three Route Mean Square (RMS) Crossing per hour and per Track.
Three Sigma Crossing The situation that the state error is more than three times the standard deviation.
Three Sigma Crossing Rate See also Crossing (Rate).
The probability of occurrence of a three sigma crossing, per hour and per Track.
Threshold Crossing Way-point
A three-dimensional, high-precision way-point typically located 50 to 55 feet above the runway
threshold. This height may vary depending upon the specific airport configuration.
Timation
Satellite System. Developed in 1972 by the Naval Research Laboratory (NRL), Timation satellites were intended to provide time and frequency transfer. The original satellite flew with stable quartz crystal oscillators. Later models flew with the first space-borne atomic clocks. The third satellite acted as a GPS technology demonstrator.
Time Dilution of Precision
A numerical value expressing the confidence factor of the position solution based on current
satellite geometry. The lower the TDOP value, the greater the confidence factor.
Time Division Multiple Access
TDMA is a multiple-access method used to provide an efficient method for various users to transmit information on the same digitally modulated carrier. TDMA is a method of time-division multiplexing (TDM) digitally modulated carriers between participating terminals within a network. With TDMA, each terminal transmits a short burst of a digitally modulated carrier during a precise time slot (epoch) within a TDMA frame. Each terminal's burst is synchronised so that each uses the RF at a different time from the other users. Consequently, only one terminal is active at any given time, thus avoiding a collision with other transmissions.
Time Division Multiple-Access Channel
In the AMSS the T-channel is the air-to ground data communications channel used for the transmission of longer messages (unlike the R-channel which is used for short messages). The GES selects a T-channel and working on the basis of first come, first served, reserves time slots on it as soon as an AES makes a call attempt. The AES then transmits in its reserved time slots. This scheme allows several aircraft to use the same T-channel.
Time Division Multiplexing
A channel sharing strategy in which packets of information from multiple sources occur on the same facility but not at the same time. Transmissions from various sources are interleaved in the time domain.
Time Horizon
The time window in which workers anticipate and plan into the future, allowing them to stay ahead of a situation.
Time Leakage
Inexplicable or unaccountable loss of time from working shift time.

 
Time Navigation A function of RNAV equipment that provides the capability to arrive/depart at a waypoint at a specified time. When added to a 3D system, TNAV is called 4D. Time Sequence Diagram Showing the sequence of message exchanges within a data link service. Time Stamp The addition of the time information -in the relevant field- in the target report (plot or track). In the ASTERIX the time information is coded in two octets with Least Significant Bit (LSB) equal to 1/128 seconds. Time Stamp Error Time Stamp Error is the constant time difference between the time system used for plot detection time stamping and a common reference time. Time To Alert Time to alert is the maximum allowable time interval between system performance going outside of operational performance limits and the appropriate integrity monitoring sub-system providing an alert. Time-Restricted Learning See Restricted (Time-restricted Learning). Top-Down Approach A specific scientific approach to a problem or opportunity, starting with a holistic view and reducing each iteration toward the individual component contributors. Top-Down Process The process of governing behaviour by plans, MMs, intentions and rules. Used to describe behaviour which is derived from cognition. Topic Theme which presents a unity and which corresponds to one major training objective. Total Delay The delay (expressed in terms of time) calculated for a flight in the sequence using trajectory prediction from its present position up to touch down. Total Electron Content The number of free electrons in a 1-square meter column along the path from ground through the ionosphere. It is measured in TEC units, where 1 TEC unit = 1016 electrons/m2. Total Estimated Elapsed Time For IFR flights, the estimated time required from take-off to arrive over the designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or, if no navigation aid is associated with the destination aerodrome, to arrive over the destination aerodrome. For VFR flights, the estimated time required from take-off to arrive over the destination aerodrome. Total System In the context of aircraft navigation, Total System refers to the complete set of equipment and personnel involved in navigating and controlling the aircraft. Such equipment and personnel may be located on the aircraft, on the ground and in space.