Help me understand what went wrong here

[happydays]

Lost my V+ in a reservoir today. I'm trying to understand what went wrong.

Firstly, I am an experienced pilot, hundreds of flights with no issues. The Phantom (this one was my third) is a P2V+ from last June, with the original motors and ESCs, no upgrades done. The only addition was a new Tx with the shoulder wheel which I got months ago and have been using with no issues.

The phantom has never been crashed, is always hand caught so has never had a hard landing. I used it last Friday and it flew perfectly normally.

This morning I drove up to a local reservoir to make a clip of it. I fired up in the usual order, TX, repeater, phantom, linked in the pc (to use reflector for screen recording) almost immediately I got 8 sats, so I took off.

The normal procedure that I use is to hover about 10' up, check everything is ok and then go about filming. So I did this, but the aircraft started drifting around, and would not respond to the controls at all. I was using maximum sticks to keep it airborne. It flew off at about a 45 degree angle towards the ground but I managed to get it going up and it crossed a road and crash landed in a field. Thankfully, this being good old Ireland, it was a bog, and it got a soft landing.

When it all started going wrong, I wasn't looking at the phone screen, using direct line of sight. When the phantom came down, I noticed that the screen said 'battery communication error' and so I believed that a dodgy battery might have been the cause. However, upon reviewing the reflector recording, I can see that this message only popped up on the screen upon impact, and the battery was partially ejected.

Thinking about this a bit more logically here at home, the battery message wouldn't really have much relevance to lack of control, but in the field...

So I changed battery (both are the larger, square pin type) and thought I'd have a second go, believing incorrectly that the battery error message was the issue. I got a gimbal warning message on screen, but this cleared and I took off again. Exactly the same thing happened again, the phantom took off at all sorts of angles, but this time it crash landed in the reservoir and is now lost for good.

Why would this have happened? There can't be any interference coming from anywhere, it's in a mountain range in the middle of nowhere, there are no electricity pylons or anything else close by. I'm at a loss to understand what happened.

Here are the two screen recordings; you can see I had loads of sats. Anyone able to help?

 

[clayton4115]

looking at those videos and the angle it was flying, it most certainly looks like a faulty esc.

 

[IrishSights]

So sorry to hear of your loss Connor.

 

[smokiespliff]

sorry to hear that

I'm terrified that will happen someday and land on someone's face

 

[PhantomOfTheSky]

Man that's bad luck & as for what caused it I have no clue but I can't understand why you would of taken off near water on the second flight when u knew u had issues? That's like havin no safety on your car then driven through the desert & why didn't u get in after it I'd have been swimming

 

[cougar]

Very sorry for what happened. Not sure if it has any relevance since it is wifi related but noted the absent battery indicator for your range extender in the videos?

 

[happydays]

Very sorry for what happened. Not sure if it has any relevance since it is wifi related but noted the absent battery indicator for your range extender in the videos?

I'm using an RE500 extender as the RE700 went faulty.

 

[happydays]

Man that's bad luck & as for what caused it I have no clue but I can't understand why you would of taken off near water on the second flight when u knew u had issues? That's like havin no safety on your car then driven through the desert & why didn't u get in after it I'd have been swimming

I thought it was a battery issue. I didn't get in after it because it's about 100' deep.

 

[Mako79]

Using an RE500 vs RE700 is irrelevant as that only affects visual..

If you are able to take off second time, this means your ESC is still functional.

Can you tell us if you are flying north of where you are standing after launch.
I'm asking as I think the compass on the phantom is skitzing out. The video looks forward but the phantom triangle in the radar is doing erratic 360s etc. The compass may be sending conflicting info. This explains why you cannot control the phantom.

 

[GSSP]

Wow, to bad, that is a hard one to figure out

 

[BlackTracer]

Wow so sorry about that. What a bummer. I am sure in hindsight you wish you wouldn't have taken off the second time. After all hindsight is 20-20. With your experience level and those videos, we can say with near 100% certainty that it wasn't pilot error during the flight. I wonder if there was some compass interference from that take off spot. It looks like some kind of aggregate that may have some iron reinforcement inside? We know that can wreak havoc on your compass. Although my experience with that sort of thing is the Phantom warns you if you set it near some metal. We don't see that. Now I do notice in the first video that the orientation pointer spins some without your device or the Phantom changing orientation, right before takeoff. Don't know if that is any kind of clue, although that may mean compass related.

Did you do a compass cal before the second try? Sucks that it is gone now and we will never know too much without being able to look at the bird. Once again sorry for the loss.

EDIT: I see some others have mentioned the compass also. I was in the middle of my post when the others were put up.

 

[happydays]

Using an RE500 vs RE700 is irrelevant as that only affects visual..

If you are able to take off second time, this means your ESC is still functional.

Can you tell us if you are flying north of where you are standing after launch.
I'm asking as I think the compass on the phantom is skitzing out. The video looks forward but the phantom triangle in the radar is doing erratic 360s etc. The compass may be sending conflicting info. This explains why you cannot control the phantom.

Just checked on Google Earth. In standing facing West all the time The hill and small club of trees are due west of where I'm standing. To be honest, I never paid much attention to the compass on the app. Maybe I should have!

 

[edonovanl]

Just a thought....maybe there is a lot of iron in those nearby hills that could disrupt your compass? Was that your first time flying there?

 

[StevenQX]

Using an RE500 vs RE700 is irrelevant as that only affects visual..

If you are able to take off second time, this means your ESC is still functional.

Can you tell us if you are flying north of where you are standing after launch.
I'm asking as I think the compass on the phantom is skitzing out. The video looks forward but the phantom triangle in the radar is doing erratic 360s etc. The compass may be sending conflicting info. This explains why you cannot control the phantom.

I notice that too but often happen to me too, I don't know if is important that the red arrow point exactly toward the nose of the phantom, isn't it? And if is not pointing in the right direction what should be done to adjust it? Thanks mako

 

[robinb]

I think possibly your Naza controller or calibration of it are off. Its all over the place.

 

[Jtrjr]

Happy,

Really sorry to hear about the loss of your Phantom. I don't have the answer to your crash but felt I should share a similar incident. Although I have only been at this for a few months, I would consider myself fairly experienced. I am retired so I've had a lot of time to learn and fly. I've probably logged 150+ successful flights so far an 1 unsuccessful flight (P2V+V3, RE700). Looking at your videos, a similar event happened to me a couple of weeks ago. I don't have video because the data was corrupted from the crash. Anyway, normal GPS flight, as with you 9+ sats locked. Everything checked and recheck, home point locked. Takeoff and hover at about 10-15' maybe 15-20' in front of me. the bird dips slightly down and to the left, nothing big at all. I corrected it quickly. Hovering again (this is all within seconds), then it just took off on it's own like a rocket, ascending and fast. I pulled back on the stick to bring it back. Nothing. By now it's probably 50' high and about 20-25 yards out in front of me. I get my finger ready to switch S1 to ATTI (I'm in NAZA-M) to take over control. With no instruction, the bird make and immediate and hard right, heading at an angle towards the ground, again at full speed. I flipped S1 into ATTI. Nothing. Quickly attempted to flip back to GPS to see if it would stabilize but it was too late and it slammed into the ground. Fortunately the damage wasn't as bad as I first thought. I had and still have my (new) prop guards on and I'll leave them on especially after this event and I have both a gimbal saver and a carbon fiber camera guard installed. I went through a few long days of putting the bird back together and recalibrating everything and am back flying again. I have since flown through about a dozen battery cycles without any negative events.

I'm only sharing because to this day I have absolutely no idea what went wrong. I would be more than happy (although embarrassed) to admit to pilot error but I can't come up with it. I'd feel better knowing that I caused the crash than believing that there is some "unknown" problem with my bird/system. An "unknown" problem that could reoccur at anytime. I'm truly sorry that you lost your bird and would really like to hear of any stories from other members that may follow this same behavior or sequence of events.

Thanks,

Jerry

 

[MapMaker53]

Clearly, the crash wasn't due to any pilot error. (Second flight near the water was unfortunate, but guessing it was due to the battery problem is reasonable.) So it has to be due to either onboard mechanical failure or the bird receiving an incorrect compass, GPS, or RC signal. Rule out ESC failure because a second takeoff with same condition was possible. I assume all components including the RC battery were fully charged? Clearly, you had more than enough sats. I'm left feeling it was a major compass error or compass unit failure. I don't know how often they fail. Maybe the compass wire can loosen from where it connects into? You didn't mention if you did the compass dance before takeoff. Sorry for your loss, happydays. You are one of the more experienced fliers on this site and this type of event puts the fear in me. It was a P2V+v2?

 

[StevenQX]

Now that I remember a behavior like that happened to me once too but was my fault that I took off from a big metal plate on the ground...so I think that when the bird has that kind of behavior is due to compass mainly...

 

[Jeff48920]

Very sorry about the loss of the UAV. Loss of control is my worst nightmare when flying. (To be honest, any kind of loss of control is my worst nightmare...LOL). Has anyone else that has had a loss of control failure and was video logging at the same time seen the spinning "aircraft position icon" on the "radar" that is clearly shown in these vids? It seems to me that an ESC failure would cause a spinning or flipping Phantom that would be visible on the video contemporaneously with being transmitted to the "radar aircraft position icon". That coupled with the fact a second flight was even possible rules out ESC failure to me.

 

[RichWest]

Looking at the videos it does appear the control hardware went crazy, either the TX controller or Naza. The compass indicator and the angle of drift depicted in the video, the gimbal couldn't maintain horizon. Almost appears it went over angle (balance point) and the gimbal was out of room to stabilize. Normal flight angle would have been a non-issue for the gimbal to maintain.

Been strange, these fly-aways, over the last half year while I've been observing. I've never heard anyone condemn the Naza controller for the fault. Even the TX has never been suspect. For your failure, I'd place my money on it being the Naza controller based on the description you gave and the videos submitted.

FWIW, I don't think you could have anticipated/prevented this from happening. Sorry for your loss. Your event makes me realize my bird's days are numbered. Just need to keep mindful of that fact when flying around others or their property.