I went to a scenic overlook yesterday afternoon, did a compass calibration, and armed the Phantom 4. Immediately upon takeoff the UAV started a clockwise yaw and was uncontrollable forward, backwards, right, and left. I did have vertical control so I climbed quickly to get it above the tree line. I continued to go through all my options for nearly a minute. Finally I gave it a full left yaw command and it went back to fairly normal flight. According to the flight record when I started the props, everything went back to center except the full right yaw input. It went from 100% to 85% just before I pushed the left stick full left and it went back to normal. I brought it back to land and it seemed "unsteady". A lot more lateral movement than normal. I landed, changed batteries, recalibrated the compass, and took off slowly but everything was completely normal this time. Completely steady, and flew that way for 20 minutes.
Nearly crashed yesterday, uncommanded full right yaw at takeoff.
- Thread starter jasondelane
- Start date
Interesting. There is an option to calibrate the sticks, but I have no idea what would put them out of calibration to start with.
Watching the thread...
Watching the thread...
I don't know how calibration would have helped. I don't understand how the stick could be sending a command of 100% right rudder for a full minute after takeoff.
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- Joined
- Sep 9, 2018
- Messages
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- Reaction score
- 6
- Age
- 74
- Joined
- Sep 9, 2018
- Messages
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- Reaction score
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- Age
- 74
My Flight began with a notice to Calibrate the Compass. Calibration failed twice and noted Magnetic interference. The third time it passed. I took off and at about 15 feet it Climbed almost out of sight. I tried down stick with No results. I hit the RTH button and it came down really fast. At least it hit in the neighbors yard about 100 feet away.
Where are you seeeing the hard right rudder input? It doesn’t seem to be depicted in the airdata replay.
A good start would be to forget about calibrating the compass before every flight. Get a good calibration and forget about it.
A good start would be to forget about calibrating the compass before every flight. Get a good calibration and forget about it.
What kind of surface were you taking off from?
Typically when you get a magnetic interference warning the problem is not with the compass but with some kind of outside influence such as metal structures or rebar in concrete. The best choice is to move your launch point, not to recalibrate the compass. In fact, if you recalibrate within a field of magnetic interference you will have serious problems when you fly out of that area.
As others stated above there is very rarely a need to recalibrate the compass and you certainly should not do it before every flight.
Meta4
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Your compass was warning you that it detected magnetic interference near your launch point.
If you have repeated failure of compass calibration that also confirms there's a problem with that spot.
Calibrating the compass doesn't fix what the compass was warning you about - moving away does.
The screen message advises Move aircraft or calibrate compass, but no-one ever seems to notice the first part.
That's unfortunate because the correct action is never to calibrate the compass.
It sounds like you've had a yaw error/compass error combination from launching right on top of some steel - reinforced concrete is the most common cause.
To confirm, go to DJI Flight Log Viewer - Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you.
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