First flight issue?

Tonygalo · Jun 26, 2017

Hi all, trying to get a take on what happened to me yesterday on my first flight. Everything seemed normal for the first 5 or so minutes of flight. Then I got a message on the screen "visual positioning" and the craft began to descend quickly form about 250'. I had no control as the decent did not slow until the Mavic hit the ground quite hard. No damage and I had to recalibrate the vision sensors. I have since flown and all seems well but I'm a bit concerned it will happen again. Now being a newbie, I was in a class E fly zone. There is a helicopter pad near by that the police use. But I don't think it would crash my craft?
Thanks T

msinger · Jun 26, 2017

Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like other people to review and comment on your flight log, then please post a link back here after you upload it.

Tonygalo · Jun 26, 2017

msinger said:
Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like other people to review and comment on your flight log, then please post a link back here after you upload it.

Thank you, I will do that tonight when I get home.
T

Tonygalo · Jun 27, 2017

UNCLE! Ok I cant figure out how to upload the flight log.

msinger · Jun 27, 2017

Tonygalo said:
I cant figure out how to upload the flight log.

You can find instructions here. If they are not clear, please let me know where you're stuck.

Tonygalo · Jun 27, 2017

Humm, ok thanks, I think I will try a different lap top tonight. It kept saying there was a problem with the drive. I'm thinking Its Norton messing with it... maybe. Thanks, Ill report back

Tonygalo · Jun 27, 2017

Airdata UAV - Flight Data Analysis for Drones

Think I got it

msinger · Jun 28, 2017

It looks like you found your TXT flight log. Please upload it here instead and post a link back here.

Tonygalo · Jun 28, 2017

ugg, ok. I'll have to do it tonight, had to use my wife's lap top. Saved it on hers cause it didn't like mine for some reason. Thanks.

Tonygalo · Jun 28, 2017

DJI Flight Log Viewer - PhantomHelp.com

msinger · Jun 28, 2017

Your flight log shows your Mavic auto switched to forced landing mode because you had the throttle in the full down position while the downward sensors were detecting the ground was near (even though it wasn't). That occurred here:

I noticed the downward sensors were detecting something for a majority of your flight. Do you have any 3rd party accessories installed near the bottom sensors? If so, that could explain what the sensors were seeing. If not, try calibrating the sensors like this:

Tonygalo · Jun 28, 2017

Yes, I had the extended landing gear with the shock absorb. I have since flown without them and also calibrated the vision sensors. But not before that flight. Makes sense. I wont use them again.

Qoncussion · Jun 28, 2017

I'd bet that you had the rear landing gear extension on backwards. The hard back of that extender should be facing backwards, towards the rear status light of the Mavic.

Tonygalo · Jun 28, 2017

Unfortunately the rear landing gear ejected when it hit the ground. I cant be sure how I had it. I probably did have it wrong, just makes sense. Thanks for all the help, Tony

Tonygalo · Jun 29, 2017

Just one more question. looking at my other flight records, I guess the VPS altitude should always be fairly close to the actual altitude unless you have the VPS turned off correct? I guess my issue could have been avoided if I was paying attention the telemetry. A lesson learned.

msinger · Jun 29, 2017

Tonygalo said:
I guess the VPS altitude should always be fairly close to the actual altitude unless you have the VPS turned off correct?

No.

The VPS altitude shows the distance between the Mavic and the ground at the Mavic's current location. The actual altitude shows the distance between the takeoff point (0 feet) and the height the Mavic has currently ascended over the takeoff point. When the Mavic descends below the takeoff point, the actual altitude will be a negative value.