This video is a mostly boring practice session where I'm trying out the hand gesture modes. At about 1:30 in, I start trying to land the Air, and failed. I had to go to the controller to land. Can you tell from the video why the Air would not land in response to my hand gesture?

It looks like your hand was not level, finger tips were to high up.  And you have to pause your hand at bottom of downward gesture for 2 to 3 seconds.

To land the drone, use the same open hand sign used to start the drone, and then slowly lower the arm. After the arm reaches to about hip level, keep the arm locked for two to three seconds until the drone automatically lands itself. Exit out of Smart Capture mode once it lands to stop the tracking.

HedgeTrimmer Posted at 2018-4-20 20:49
It looks like your hand was not level, finger tips were to high up.  And you have to pause your hand at bottom of downward gesture for 2 to 3 seconds.

To land the drone, use the same open hand sign used to start the drone, and then slowly lower the arm. After the arm reaches to about hip level, keep the arm locked for two to three seconds until the drone automatically lands itself. Exit out of Smart Capture mode once it lands to stop the tracking.

Nice video, useful information, thanks for sharing.

It could also be the surface you were landing on. I seem to recall reading somewhere that the downfacing sensors need a bit of contrast to function at their best.