During a flight yesterday I noticed that the drone was dropping altitude even though the H value at the go4 app stayd constant. It seemd as if the drone had no idea it was dropping in altitude. I was able to recover the height by manually sending the drone back up again but the H value still stayd the same. During landing the propellers wouldnt shut down as they used to, the drone was touching the ground and moving (scratching the legs) over the floor. I had to pick the drone up and flip it 90 degrees to make the props stop. After this flight 2 problems occur.

Problem 1: During take off the drone often does not reach a stable height and instead starts scratching/walking along the floor with props on.

Problem 2: The drone does not shut down the props after landing so it begins scratching/walking at the floor again.

I've recalibrated IMU and compass. I've did a factory reset. Ive tried different batteries. Any thoughts why this is happening?

Also GPS is green, problem can easily be reproduced, happens almost all the times i take-off and land. How do I share the flight logs on the forum? Uploading the file doesnt seem to work.

http://www.phantomhelp.com/LogViewer/KFDJH8L5GQ69GX5W1NUO/

This log is made during indoor flight but the problem is exactly the same during outdoor flights. I only took off, fly a flew meters and (tried to) land, landing didnt work so i had to flip the drone 90 degrees to shut down props.

Hi. I am sorry for the trouble. Can you please sync the flight records of your DJI Mavic Air using your DJI Go 4 application. I will post a DJI Tutorial Video on how to export flight logs.

Thanks for the reply The flight data now has been synchronized. The last flight could be used as an example. I took off (which went OK this time), flew a flew rounds, changed to sports mode and flew some more rounds, then return to home. After landing the aicraft starts bumping/scratching around the floor again with the props still on. I canceled the landing sequence after 3 seconds of bumping and tried a manual forced landing, which did succeed this time. (but also manual forced landings sometimes show the described behavior).

Seems as if the drone doesnt reach 0 meter even though it s touching the floor exactly where it took off. Could this be the reason that it doesnt stop the props?

I synchronized another flight, the one at 10:17:51 30-07-2018. The landing during this flight was also very unpleasant. Also another described problem happend during this flight.

at 2:41 you can see the drone thinks it's at 6 m height, but actually it was almost crashing into the terain. 8 times i had to move the drone up manually (Right stick up) to prevent it from crashing, but the drone just kept falling towards the terain.If you could read the bottom sensors you probably see it gets really close the floor at this point while the drone believes its 4-9 meters above takeoff level. It's weird to see that every time i move the drone up, the height value also goes up. But when the drone automatically descends it doesnt detect is getting lower. at 2:45 the drone was not more than 2 meters above take-off height, while all the time it thinks it is 4-9 meters above it.

Oh and by the way where I live the surface is really flat, so I'm definately sure that the area where the problem occured is not 7 meters above takeoff level ^^

Looks like the barometer in MA not working properly. You better send it back to check further.

I also think it has a defect barometer.

Simplified visualisation of the problem.
In Red you can see the actual height of the MA.
In green you can see the height displayed by Go4 app
At the yellow circles the MA gets too close to the ground so I make a manual movement up.
At the blue circles i releaese the sticks to the 0 position.

https://forum.dji.com/thread-88074-1-1.html#post_725807 More guys seem to have this problem

Please don't get me wrong, but are you sure that the propellers are mounted correctly (white marked props on white marked motors and black on black)? I am only asking to exclude this not totally uncommon source of problems.

Thanks for double checking, yes the props are mounted correctly

First flight of the day always seems to be fine. It's only after a period of time that the error keeps happening.