Definition
A graphical indicator on an electronic airspeed display that shows the predicted airspeed value six seconds into the future, based on the current rate of acceleration or deceleration. It appears as a magenta or cyan arrow extending up or down the airspeed tape from the present airspeed reading.
Plain English
A small arrow next to the airspeed reading on a glass cockpit display that shows what your airspeed will be in about six seconds if you keep doing what you're doing right now.
Context Anchor
Seen on glass cockpit airspeed displays during instrument flying, especially while adjusting pitch or power to hold level flight.
Derivation
Trend' comes from the Old English 'trendan,' meaning to turn or roll, and now means the direction something is moving. 'Vector' comes from the Latin 'vector,' meaning 'carrier' or 'one who conveys,' and in aviation it indicates direction and magnitude. Together: an indicator that shows the direction airspeed is heading and how fast it's getting there.
Why Pilots Care
It lets the pilot see an airspeed change coming and make a small pitch correction before the speed actually deviates from the target.
Intuition Check
Do not read the airspeed trend vector as the airplane’s actual airspeed. It is a short-term prediction based on how fast the airspeed is changing right now.
Example Sentence 1
As she reduced power for the descent, the airspeed trend vector shrank toward the target approach speed, telling her she had set the right power.
Example Sentence 2
While leveling off after descent, the pilot watched the airspeed trend vector to set the final pitch attitude.