So I was flying for the dozen or so time and everything was working fine until I went under a bridge, went to turn around and it crashed into the river.  Total loss
If ya'll want to see the flight, take a look and let me know if anyone has any insight.  I didn't think I was all that low and perhaps I didn't have all the protections on.  I'm trying to figure out exactly what happened so I can avoid it with the next one.


http://app.airdata.com/main?share=tMpBVi

These are the reason your accident happen :
H 10m 09s 3.3 ft 634 ft Warning Weak signal. Adjust antenna and avoid signal block.
           SPLASH down Happen here between H and I  <---- just my opinion, you need DJI to look at it .
I 10m 12s -165.4 ft 0 ft Data Loss Downlink data connection lost for 2.3 seconds
J 10m 12s -165.4 ft 0 ft Mode Mode changed to Atti
K 10m 12s -165.4 ft 0 ft Warning Warning:Satellite Positioning Off. Fly with caution

There was a recent discussion about flying under bridges that's probably relevant to this situation, especially since in this case it appeared to be a larger bridge.

Probably the aircraft lost GPS signal under the bridge.
I'd suggest you to sync your flight records from the DJI Go app and send an email to support.us@dji.com with your DJI account email and the date this occurred.
Our engineers will analyze the flight records and let you know what could have caused the issue.

I'm not an expert.. i saw your log:
the main problem is lost of signal and that happened  cause you went under the bridge (from the log you can see the as you start going under it it lose gps) the best would have been once passed the bridge to get higher but you decided to turn back ..
there if the aircraft started ascending to RTH could hit the bridge .. or just sink in the water :-(

You crashed because you lost signal gps, you were flying in an unsuitable area, it also looks from those logs that you were flying below the height of your RC , and it's signal was weak, bridges are difficult for these aircraft loosing gps, and they are built with a lot of steel and rebar concrete, which is likely to have a serious effect on radio signal and compass.
You are not the first to make these mistakes, but if you think the signals that help you fly the aircraft are gps and radio , if you block these of then the chances of you loosing control are great.
If you use VLOS when your flying where you can both see the aircraft and radio signal has clear los with the aircraft then this will much reduce your chances of loosing signal.

Thank you all for your help.  I agree that it appears it is because of the signal loss.  For some reason, I was under the impression that once it enters ATTI mode, it will just hover.  Right before it crashed into the river, I saw a maximum rotor RPM reached as well, which I thought was odd.  The only thing I can think of is that I had it too low and the air current above the river actually sucked it down?  

sarguy Posted at 2017-4-19 12:08
Thank you all for your help.  I agree that it appears it is because of the signal loss.  For some reason, I was under the impression that once it enters ATTI mode, it will just hover.  Right before it crashed into the river, I saw a maximum rotor RPM reached as well, which I thought was odd.  The only thing I can think of is that I had it too low and the air current above the river actually sucked it down?

Correct - that can happen - you have a tunnel along the river and you should consider this in relation to wind velocity and direction. You were most likely just too low to be able to recover. Had you however gone up as opposed to just turning it could have saved the day. Turning without GPS and vision systems will cause the craft to go down - natural for these things - and in this case it was just too low.

Sorry for your loss. Hope you have a better luck with new aircraft.