I went out to fly yesterday and for the first time installed prop guards because it has been recommended by so many.  The flight went fine and I got good video, I think.  I brought the copter back towards me and decided to climb higher and turn around slowly to get a 360 shot before landing.  I got up maybe 150 feet or so and started the 360.  All of a sudden the Phantom started wobbling violently  right to left and back.

I could not regain control and the copter went right into the lake.  I was able to recover it but needless to say, it's a loss.

I never had a problem until I put on the prop guards and I have never heard of anyone else having a problem with the guards installed.

Any ideas on what may have caused this problem?

Thanks

Sounds like VRS (Vortex Ring State)

There have been many, many of reports of crashes due to this and it seems prop guards are adding to the likelihood of a crash.

Unfortunately it's too late now but keep your descent slow and when possible move in a direction while descending to keep the rotors in clean air.

Sorry for the loss. This can be caused because of overweight.Do you have any video of the accident to analyze?

When you retrieved the copter, were all prop guards still firmly attached? Did any of the screws holding them to the copter arms come undone? Is there any movement at any of the prop guards where they attach to the arms? All this is important, because a wobbly prop guard may throw the gyro system out of whack once the lot begins to oscillate out of control.

If all prop guards were found to be still firmly attached, yes, have a look at the video, because this will tell you whether your copter was crippled by VRS. Your recording is still good? Can you post it?

My god... sorry for the loss !!!  ...an unfortunate combination of circumstances?

This is what my dealer thinks about the phenomenon...  can cause a VRS. Wind direction and wind speed, certain movements, decrease rapidly and some other acts. An aerodynamic term, but simply we can say that a VRS resulting in a crash or loss of the device. Especially when you move over long distances or when you fly over water it, is to watch out.

That's why it is important that you as a pilot recognize the warning signs of a so-called VRS. As mentioned above, a VRS mainly caused by coming too fast. Into a straight line down What happens at that point, is that among the propellers is an unstable air layer begins to form. Once that unstable air has beaten around the propellers you hit it hard (read: no more) off. You propellers at that moment no longer standing. You would think, I just throttle up, but self that will not work anymore. Once VRS occurs, you can bet little to remedy and your device will crash.

Fortunately VRS go not immediately, so you can recognize some symptoms. Mainly you will make very unstable Phantom moves from left to right, strong vibrations are the result.

What you can do at that moment, your Phantom of the unstable air by his strong left, right, forward or backward (with the right stick so). You can thereby bring the stick all the way to the limit, to get out. Unstable layer of air as soon as possible.

Watch this video
Sorry for my bad translation

Thank you all for your help.  Unfortunately the video was corrupt.  There is an upside to this whole accident.  It looks as though my credit card company is going to replace the Phantom because they give extended coverage with purchases made on their card.  

This makes the whole incident a bit easier to accept.

I have learned from this incident and will move on.  I know now how to avoid VRS and get out of it should it happen.  

Happy flying to all

@canula:
You mentioned that the prop guards have been "recommended by so many"...
I've not seen that, and like you've discovered, they may do more harm than good.
There are posts out there saying to avoid them or remove them when not required.
Maybe you could tell us where they are being recommended, and we can be sure to post a precaution?

canula@verizon. Posted at 2014-10-11 03:12
Thank you all for your help.  Unfortunately the video was corrupt.  There is an upside to this whole ...

Hello! Theres a way you recoverd the corrupt videos. so many we can see what happen and send it to dji

Yes, I second PP's post. I'd love to see if we can glean a cause to the mishap. Canula, do you think you could give that a go?

Cheers.

Glad to hear the good news.Enjoy the weekend~

Hello Canula, you can not get Vortex Ring in the hover, only in a vertical descend (I.o.w., descending through your own downwash) Have you recently done a firmware update? V3.06? I have had prop guards on for some time, and have only seen advantages. The biggest disadvantage is that I will have to remove them once I by a case. I know there are cases available where you don't have to remove them, but the case is just to big and uncomfortable.

Happen to me twice, one was about 15 ft high and i managed to control it before hitting the ground, second was 70 ft high and totaly loss control, broke 2 of the prop guard and made some damage to the shell casing... At first i just thought i pulled both trottle down but im positive I just pulled left only.. I started reading and found out, its the vortex phenomenon...

HOPE THIS WILL HELP TO EXPLAIN WHY IT HAPPENED...

T J Gilbert Posted at 2014-10-11 04:02
@canula:
You mentioned that the prop guards have been "recommended by so many"...
I've not seen that ...

It's in the DJI manual Version 1.4, page 16:

"For beginner flyers, Phantom 2 Prop Guards are recommended. Contact your authorized dealer or DJI customer service to purchase if necessary."

Sorry to hear that you crashed your Phantom.  Also sorry to hear that you went with prop guards because many recommended them to you, I'm one of very many persons that would recommend against them unless while you do some training flights close to the ground. The Prop guards reduce lift and create additional turbulence which significantly diminishes flight stability that in combination with the high weight of the Vision+  is an accident waiting to happen.