Third flight today went terribly wrong

[Fabio]

Hi everyone,

Still recovering from the shock of my Phantom 3 Professional falling down from the trees just an hour ago.

This is what happened:

Earlier today I had two perfectly fine experiences with my Phantom. We were having coffee near the river, and I took off and landed twice from a nearby parking. Did one 9 minute and one 6 minute flight without any problems. Calibrated the compass before the first of these two flight.

45 minutes later at home, I did the third flight of the day. Recalibrated the compass again on the Phantom, but this time something really weird happened....

I powered the engines and pushed my left stick up to get my Phantom in the air. But for some (to me) unknown reason the Phantom started to move to my left and I could still control it a bit, but it kept drifting until it hit a tree and fell out of there.

The result (as you can see in the pictures):

A bit of a damaged body, and a screw that fell out of somewhere (cannot tell from which part it is exactly, don't see any screws missing on the outside.

Any of you have an idea how this happened? And how I can prevent this in the future?

Your help will be much appreciated!

 

[Tbullseye]

Hi Fabio

Don't know if this YouTube video could help in you finding where the screw has came from. Ps I'm not suggesting you take your p3 apart.

 

[Bigfoot_Hunter]

I have gotten into the habit of using auto takeoff and as soon as I lift off I check for drift both vertical and horizontal. If there is any at all I land from 3 feet vs 40 or 50. Re calibrate and try again.

That white stuff on the threads of that screw helps screws from backing out. Does it look like it has ever been screwed in? If not, it could have been accidentally dropped into the bird at some point.

 

[msinger]

You were most like either flying in ATTI or you had a bad compass calibration. It's not a good idea to obsessively calibrate the compass before each flight. Here's a guide that explains when you need to recalibrate:

http://www.phantompilots.com/threads/compass-calibration-a-complete-primer.32829

 

[Fabio]

Thanks for all the responses! I was not flying in ATTI mode, and it is good to know that I shouldn't calibrate my compass too often (used to do it before every flight, because didn't think it could be bad).

Strange thing in my flight log is the following.

I took a couple of screenshots of my disaster flight which show that apparently GPS was really bad. On my iPad I saw the green status bar at the top center of my screen that GPS was good.

Do the following pictures shed a different light on the situation?

 

[Tbullseye]

How many satellites were you connected to?
You can check how many satellites are available at your house using GPS PLAN app for example.

 

[SiliconGeek]

I had an experience with some similarities to what you report. It was about my 15th flight, and I had not really gotten my "pre-flight" checklist in order. Was flying in a totally clear park, closest tree/building was >100' away. I got safe to takeoff sign, took off, and promptly lost GPS signal about 10 seconds in. Quad started flying in this slow loop.The quad auto-landed without me doing anything.

Went back and reviewed and the only thing that I did odd was to have the antennas "crossed". Not sure that caused the GPS drop.

I've changed a few things in my habits- the first is I'm not pretty methodic about getting the antennas in the proper configuration. The second is just counting the satellites that are locked- in my area seeing 14-17 as normal. Sometimes see a lot less than that, and in those cases just let the quad find the sats before starting props.

After takeoff, I'll take the quad up to 6-8' of altitude and just let it hang out, basically just observing the stability. For me, a GPS-stabilized quad that is wandering around is a sign to land it and figure out what is up.

 

[Mako79]

You were most like either flying in ATTI or you had a bad compass calibration. It's not a good idea to obsessively calibrate the compass before each flight. Here's a guide that explains when you need to recalibrate:

http://www.phantompilots.com/threads/compass-calibration-a-complete-primer.32829

+1

Think of calibration as in copying the compass file. If the copy you have is good (open field and free of magnetic interference) and you decide to copy it with a corrupt compass file (inside a metal hanger). If you use the corrupt compass file, the phantom will not function correctly. Think of this, lets say inside the hanger, there is a magnetic interference (anomaly) that throws the compass off by 90 degrees. When the phantom is near the anomaly, it behaves normally. The moment you fly away or get height from the compass anomaly, the phantom's compass will now adjust to the true earth's north and as a result, the phantoms heading are now altered and this is where "flyaways" occur.

You should just look in the DJI Pilot/GO > sensors and look at the compass values. If the values are 1300-1800, then I think you are safe to fly without needing a calibration. If you are taking off near roads/cars, you may get a compass calibration required. Just power down the phantom and walk to another location. If you keep getting the warning, then I suggest you find an open field and do the primer calibration.

 

[bbfpv]

I was not flying in ATTI mode,

You were if you didn't have a GPS signal

 

[Fabio]

ok, guys. thanks again!

Reading through all your comments and reading a bit more about ATTI, I think the switch from GPS to ATTI mode did happen and that was the reason why my phantom was blown into the tree. Not sure that the compass was also calibrated wrongly, but will definitely have a look into that as well.

@gsdogs: That screw is still in place, so still need to find out where that screw came from.

What would you all say in terms of flying with the drone with some damage to the body (photo in my original post).

Is it still good to go, or should i fix/replace some parts?