The flare began, and where the plane ended up

What ArduPilot says:

• Distance from LAND point=N.Nm
• Flare N.Nm sink=N.N speed=N.N dist=N.N

The flare is the last moment of an automatic landing: the motor is stopped, the heading is locked and the nose is held up so that the plane settles at TECS_LAND_SINK. It begins LAND_FLARE_ALT (3 m by default) above the landing point, or LAND_FLARE_SEC (2 s by default) before touchdown at the present sink rate. The line gives the height (m), the sink rate (m/s), the GPS ground speed (m/s) and the distance still to go to the landing point (m). “Distance from LAND point” comes once the plane has disarmed: how far from the planned point it stopped.

What to do, most likely first

1. The flare came too high (the plane stalled and dropped) or too low (it flew into the ground).

   CheckCompare the height in the “Flare” line with what you saw.

   FixWithout a rangefinder the height comes from the barometer, which can drift by metres during a flight; a downward rangefinder with RNGFND_LANDING 1 makes the flare height true. Otherwise change LAND_FLARE_ALT and LAND_FLARE_SEC in small steps.

2. The plane landed long or short: the distance from the landing point is large.

   FixLand into the wind, and set the approach speed with TECS_LAND_ARSPD: a slower approach floats less. A high speed in the “Flare” line means it arrived too fast.

Parameters to look at