Definition
A feature on an electronic primary flight display that shows where the aircraft's indicated airspeed will be in approximately six seconds if the current rate of acceleration or deceleration continues. It typically appears as a magenta or green arrow alongside the airspeed tape, extending upward when accelerating and downward when decelerating.
Plain English
A small arrow next to the airspeed display that predicts what your speed will be a few seconds from now if nothing changes. It points up if you're speeding up and down if you're slowing down.
Context Anchor
Seen on electronic flight displays, especially on the vertical airspeed scale during takeoff, climb, descent, and approach.
Derivation
Trend simply means a direction of change over time. The indicator shows the trend of airspeed — where it's heading — rather than just where it is right now.
Why Pilots Care
It lets the pilot make smooth, timely power or pitch corrections instead of reacting after the speed has already drifted too far.
Analogy
It is like a short weather forecast for your airspeed: it does not say what must happen, but it shows where the speed is headed if nothing changes.
Intuition Check
Do not read the trend indicator as a second airspeed reading. It is a prediction based on the present rate of change, not a guaranteed future speed.
Example Sentence 1
As she lowered the nose for the descent, the airspeed trend indicator stretched upward, warning her she'd exceed the flap limit if she didn't reduce power.
Example Sentence 2
After extending flaps, the pilot watched the airspeed trend indicator to capture the new target speed smoothly.