Definition
A short line or notch displayed on an electronic flight display (such as the airspeed tape, altitude tape, or heading indicator) that shows the predicted value of a parameter at a set time in the future, based on the current rate of change. Tick marks function as trend indicators, allowing the pilot to anticipate where airspeed, altitude, or heading will be in the next several seconds if conditions remain unchanged.
Plain English
A small mark on the glass cockpit display that shows where a value, like airspeed or altitude, is heading in the next few seconds if the trend continues.
Context Anchor
Seen on electronic flight displays when reading airspeed, altitude, or vertical speed trend cues.
Derivation
From the everyday sense of a 'tick' as a small mark or check. The display draws a tiny line out ahead of the current reading to 'tick off' where the value is going.
Why Pilots Care
Allows quick visual assessment of rate and direction of change without reading exact numbers on the tape.
Analogy
It works like the small lines on a ruler. The line itself is not the measurement; it shows exactly where to read the measurement.
Intuition Check
Do not read “tick” as a clock sound or a check mark on a list. Here, a tick mark is a small reference line on an instrument scale.
Example Sentence 1
As the airplane entered the climb, the airspeed tick mark stretched downward, warning the pilot that airspeed was about to drop.
Example Sentence 2
The pilot used the tick marks on the altitude trend indicator to judge the climb rate without looking away from the horizon line.