First flyaway experience, hopefully the last

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Let me start by saying that I'm not new to flying and that I've been doing this for some time now and am quite familiar with how to operate this aircraft. I'm posting this more to share my experience then to be told what I did wrong. Every flight I do is preceded with proper pre-flight checks and I keep my phantom up to date and calibrated. This particular flight and its erratic behavior is puzzling but I'm fairly certain the bridge itself is some how to blame as it is the only structure in the area and no power lines or high power electrical devices near by. I'll also say that when I did my compass calibration, I did it a couple hundred feet from the bridge so that I could be fairly sure that the bridge its self would not interfere with the calibration process.

With all that in mind, the point or lesson here is that flyaways happen and you need to know what to do when it does. For this particular incident, flipping the S1 switch into ATTI mode allowed me to regain control so that I could land. After landing I packed up and left. No need to try again and risk losing it. For those out there new to flying, learn what the switches do and practice flying without GPS in case the situation were to arise. Sometimes there is nothing you can do but let's hope that never happens. I like to think that there is always something that can be done whether its flipping out of GPS mode or turning off the control and then turning it on again. Best thing to do is not panic and to stay calm, if you freak out you may not be able to find a solution before your copter fly's out of range.

Another point I'd like to make, something that I do that helped in the situation that might help others in the future is to keep your Phantom close. I try not to fly more that 500ft from myself unless its an area that I know very well. Part of the reason I was able to recover from this is because I could see everything that was going on and it didn't have time to fly out of my line of sight
 
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Wow that was close. I see no reason why a bridge like that would affect anything. The only other thing I can think of is maybe solar storm activity that day? I know a lot of owners laugh that off and claim no proof, yet things like this happen and people wonder why. GPS instruments can get affected by solar activity, and these "toys" don't exactly have the most sophisticated GPS system around and may be susceptible to it. Nice job staying cool under pressure.
 
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It certainly looked as though the GPS thought it was in one place, then all of a sudden thought it was elsewhere and started trying to compensate by flying very quickly. Then, another jump as it thinks it's in a completely different place again and starts flying the other way to compensate.

You'd think that the FC would be able to detect "infeasible" changes in GPS position readings but the above would explain the "flyaway", and why when you switched back to ATTI you had total control again.
 
Well as far as the bridge... it's possible there's ample enough steel to create a [magnetic] problem both on take-off and flying near it.
Do you know there is no electrical distribution or transmission co-located within the bridge itself?
 
I calibrated the compass far away from the bridge and off the concrete path that leads to it. As far as the solar k level, from what I saw after looking it up, it was at normal levels. As far are electrical interference goes, I can't rule that out entirely either because the bridge does have lights on it but I'd think that flying in a city would cause more issues than out on a remote bridge. This bridge is miles out of any town and I had to hike 1/2 just to get to it. I didn't see any nearby transformers, cell towers or high tension lines that would give me reason to pause.
 
Before the P3 came along there were quite a few posts on here with P2s doing something like that.
The cause isn't really clear, but it seems likely that there is a firmware issue causing erratic behaviour from time to time with the P2.Possibly related to compass or gps.
You did the right thing to put it Atti and bring it home.


BTW, splitting hairs, the right hand switch is called S1 (the chinese read their characters from right to left)
 
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Sometimes, bridges have large power trunk lines running under them as an easy method for engineers to run power without having to encase them for a water run. If there aren't any big power lines in the area, that would lead me to suspect this even more so.

Have you flown your drone in a known, good location to make sure it isn't having an internal issue?
 
Before the P3 came along there were quite a few posts on here with P2s doing something like that.
The cause isn't really clear, but it seems likely that there is a firmware issue causing erratic behaviour from time to time with the P2.Possibly related to compass or gps.
You did the right thing to put it Atti and bring it home.


BTW, splitting hairs, the right hand switch is called S1 (the chinese read their characters from right to left)
Yeah I realized my mistake on the S1/S2 after I put the video together. Kind of kicking myself a bit but I did mention going into ATTI mode so figured people would know what I meant.
 
Sometimes, bridges have large power trunk lines running under them as an easy method for engineers to run power without having to encase them for a water run. If there aren't any big power lines in the area, that would lead me to suspect this even more so.

Have you flown your drone in a known, good location to make sure it isn't having an internal issue?
Yeah, I took it out yesterday to a local baseball field and let it hover for 5mins and then did some close range flying for another 5mins to make sure it wasn't in fact an internal issue.
 
These are issues that happens also on p3 because are due to the compass
Happy that you were able to land it safely.

Anyway avoid to calibrate the compass if you are not 400-500km from the last point where you did it.
 
[Best thing to do is not panic and to stay calm, if you freak out you may not be able to find a solution before your copter fly's out of range.

This is the best advice!

And one should practice flying in ATTI regularly. Staying close is also a good idea as it might just be the FPV feed that gets you out of trouble.

GPS stability creates a false sense of security.

It certainly looked as though the GPS thought it was in one place, then all of a sudden thought it was elsewhere and started trying to compensate by flying very quickly. Then, another jump as it thinks it's in a completely different place again and starts flying the other way to compensate.

That's exactly what I was thinking. Pilots should practice an emergency scenario procedure & the first action should be a switch to ATTI followed by a yaw turn to point home using the direction indicator.
 
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I'm thinking the first thing I would do after switching to ATTI is hit the throttle to gain some altitude, giving me additional time to sort things out if needed. Then get it home.
 
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I'm thinking the first thing I would do after switching to ATTI is hit the throttle to gain some altitude, giving me additional time to sort things out if needed. Then get it home.
The first thing I tried was throttling up. I was worried about hitting the bridge and possibly the people on it. My go to solution when things get kinda crazy or I lose orientation is to throttle it up and clear the obstacles. The controls were unresponsive until I flipped the S1 switch though. It did seem like it had somewhere else to be though, it had somewhere else to be and in a hurry.
 
I'm thinking the first thing I would do after switching to ATTI is hit the throttle to gain some altitude, giving me additional time to sort things out if needed. Then get it home.
Yep grab a beer and let it sit on hoover top of you at 200 ft and then rth
 
I will say as a side note, after watching my own flyaway video and some others on YouTube, these things are very maneuverable when they want to be. Some of the maneuvers these things can do without crashing surprised me.
 
Even after the compass is correctly calibrated, I believe one should not take off very near steel structures because it gives the compass an initial bad reading, then tries to correct itself after takeoff. I'm sure the bridge concrete has rebars throughout its volume. That could contribute to your problems.
 
That's not related to solar storm activity. At worst it would make the GPS a little less precise .. just a couple of feet.
It's not a magnetic effect of the bridge - that would only make the Phantom not fly straight.
Why did you lose GPS? It looks like an open area with unobstructed sky.
 
That's not related to solar storm activity. At worst it would make the GPS a little less precise .. just a couple of feet.
It's not a magnetic effect of the bridge - that would only make the Phantom not fly straight.
Why did you lose GPS? It looks like an open area with unobstructed sky.
I wish I knew why it was dropping signal. I had 10 satellites while in the air and the suddenly they were gone. While that may not cause too many issues while flying around if you keep it close and know how to fly ATTI mode, something did cause it to think it was supposed to be somewhere other than where it was.
 
Obvious, I know, but haven't seen it mentioned here (unless I missed it)... Have you checked your GPS plug for a tight fit? Some say it is thought to have intermittent issues with connectivity because of the crappy plug and receptacle hardware that doesn't mate too well. That may explain the random behavior. I modified mine to get a snug fit because it seemed to just pop out with no resistance at all when I took off the upper shell.

Nice work to save your bird. You're right on the money with getting prepared for flying without GPS. It's just a matter of time for all of us to lose a GPS lock for one reason or another.
 

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