As per the title I nearly had a flyaway today! Scared me sh88les.

It was the 2nd flight of the day at a log cabin in north yorkshire. first flight was fine. only a few mins but zero issues.

I decided a 2nd flight to look at a zip wire they had set up over the field and after about 20 seconds in the air the screen said compass error and it started drifting away. I raised the altitude up to circa 130ft? enough to be over any trees and happy I had a better line of sight for the signal but flight control was shot! It seemed to be doing the opposite of my commands and was really tough to get any directional control.

Thankfully I managed to navigate just using the tiny little map on the app screen and get it back to in front of the lodge so landed ASAP.

I relly thought I had lost it. I did not dare try the RTH function as for one I launched off the balcony and there was the roof 15ft above me it would likly hit but also the distance on the app I think was showing zero even though it was a good 500+ ft awat from me so I wa not sure if it had any clue where it was.

When it disapeered over the trees away from me the missis hid in cabin lol and I just tried to stay cool and work the problem. all the time looking at the signal strength thinking thats the one thing I really need to stay with me for a recovery.

Anyway ill flire it up tomorrow and recalibrate everything to make sure its happy and do some really low level manuvers to check it flys ok. Cant think what would have caused it though and so how to prevent it in the future?

David, always check your sensor values prior to takeoff. You're compass mod should be consistently around 1500. When magnetic interference impacts flight, immediately switch the P A F switch to A mode flight. Climb if possible, and turn the nose of the red triangle in the radar toward the center and fly home. If the interference stops, switch back to P-mode flight.  

Great info. Thanks for that.

I did wonder if there was something I could do like that. Maybe need to study the flight modes a bit more.

I remember the first time it happened to me, scared me to ( Might have peed a little  too ! )  Just remember as Terry stated be sure to switch out of GPS and get to ATTI mode, that way if the GPS is giving bad info you have a way to make it home.


Did you re-calibrate  the IMU, camera and of course compass after the latest  Updates.  That is mandatory my friend.
Good Luck- donnie  

I had this happen a few weeks ago because I hadn't re-calibrated the compass after travelling 200 miles.  I thought the last time I flew was in that spot, but quickly realised it wasn't.  Mine immediately switched to ATTI mode just as a big cloud engulfed it (I was on a mountain).  All of a sudden I couldn't see or hear it & it wasn't very far away either.  I did the same, raised it above any obstacles & flew back on the map.  Their was no image from the camera either, just lots of white.

It's a gut-wrenching feeling.  I didn't realise how sound absorbing clouds were!

Just shows how easy it is for problems to escalate.

Not enough data to tell anything for certain.
What can you say about where and when you last calibrated the compass?

Learn to fly atti when this happebs

Michael M Posted at 2016-4-22 22:46
Learn to fly atti when this happebs

It's a must.  Also, you have to stay calm & make rational thought-out decisions.  I think hitting RTH might have been the worst thing to do in the circumstances.

Remaining calm is one thing  I am well trained at flying Boeing's for a living. However its clear I know the systems of a 737 much better than my drone. I need to do some study so I KNOW my back ups when stuff happens next time.

As for re calibrations. yea I might have forgotten to do that since updating the firmware a few days ago. Opps.

Ill be checking and realigning everything very carefully tomorrow.

Thanks for the info guys.

davidathomas42 Posted at 2016-4-23 08:11
Remaining calm is one thing  I am well trained at flying Boeing's for a living. However its clear I  ...

"As for re calibrations. yea I might have forgotten to do that since updating the firmware a few days ago. Opps. "

Not necessarily.  You don't need to calibrate the compass every flight and the calibrate-every-time strategy can introduce additional risk when people calibrate their compass in a (magnetically) bad location.

Getting a compass error in flight is unusual and the most common cause is a bad compass calibration and then flying away from the magnetic influence where the compass was calibrated.
Like this:  

davidathomas42 Posted at 2016-4-22 23:11

Remaining calm is one thing  I am well trained at flying Boeing's for a living. However its clear I know the systems of a 737 much better than my drone.

It's good to hear that

nigelw Posted at 2016-4-22 18:48
It's a must.  Also, you have to stay calm & make rational thought-out decisions.  I think hitting  ...

it happened to me before. Manually switch to atti and throttle up above everything. Then take control.

davidathomas42 Posted at 2016-4-23 08:11
Remaining calm is one thing  I am well trained at flying Boeing's for a living. However its clear I  ...

'I am well trained at flying Boeing's for a living.'

Then that makes at least one commercial pilot who could tell the difference between a drone and a plastic bag on approach to Heathrow....

Didn't happen to me yet, hope it wont, but it's great to see what you guys say what to do when it does! Thank you!
So I have read about compass issues really goofing up GPS.. what's up with that? If compass fails, why would GPS be also goofed up?  These 2 do seem to always go hand in hand.. is that because the aircraft loses it's ability to tell direction? But if that is the case, how can you use the arrow on the app to figure out direction? Can the arrow direction still be trusted?
Thx!

GT

Suggestions above are very useful. And David, don't forget to do IMU and compass calibration before next flight. What's more, you can also refer to the safety tips via : https://www.youtube.com/playlist?list=PL8-vxWY64sBOmkQQJ2KWNL-uRBZsP43-r .

nigelw Posted at 2016-4-22 17:40
I had this happen a few weeks ago because I hadn't re-calibrated the compass after travelling 200 mi ...

So you guys are able to see your maps? I am caching my maps for offline use before I fly, but when my home point is updated, my map is an entire picture of the USA with a spot on the state i'm in. Ever since the last FW upgrade, my Android tablet will not use the offline maps correctly, so flying home using just the map would not be possible for me. It also makes it impossible to see if I'm next to (or in) a no fly zone on my map, which I used to use religiously before the FW upgrade killed it to make sure I was NOT in a NFZ (or right next to one) before trying to launch. What tablet are you using? Has anybody else experienced this issue since the last FW upgrade?

Curious, which Phantom were you flying?

DJI-Paladin Posted at 2016-4-23 15:01
Suggestions above are very useful. And David, don't forget to do IMU and compass calibration before  ...

Why not hit RTH and cancel it when it gets back to you and then manually control it back on to balcony.

gtokarsk Posted at 2016-4-23 15:30
Didn't happen to me yet, hope it wont, but it's great to see what you guys say what to do when it do ...

"If compass fails, why would GPS be also goofed up? "

In a situation where there is a conflict between compass data and GPS data the Phantom can't resolve navigation data, it ignores the GPS data and defaults to atti mode so you are able to fly it back.
This should be a very rare occurrence if you aren't calibrating your compass in bad locations.

jyurkyandsons Posted at 2016-4-23 20:49
Why not hit RTH and cancel it when it gets back to you and then manually control it back on to bal ...

If the phantom is having issues and drifting away because of a compass error, it doesn't really know where it is and may fly in some direction other than home if you initiate RTH. Definitely best to switch to Atti and fly it back after your heart starts beating again.

I did an IMU calibration this morning but I was unable to do a compass calibration. It seems I am in a bad area for it. We're at a log cabin retreat in the middle of a forest so I thought it would be great. But there are steel or tin roofs on all the cabins. They all have wifi and there are a couple of electricity lines running 30ft above the outdoor area in front of where I took off from so I guess it's not as good an area as I thought. Still at least I have learnt a few bits and its still safe in the travel case for next location :-)

Same thing happened to my friend.  We were flying in an area that used to be an old landing strip.  Little did we know that half go the strip has metal mesh buried under the old runway.  Anytime he got close to it, it would give a compass error.  The worst time he had to put it into atti mode to bring it back.

labroides@yahoo Posted at 2016-4-23 22:08
"If compass fails, why would GPS be also goofed up? "

In a situation where there is a conflict be ...

Will it go into atti.mode if you have it shutoff on app.

davidathomas42 Posted at 2016-4-24 00:23
I did an IMU calibration this morning but I was unable to do a compass calibration. It seems I am in ...

Indoors is never a good location to calibrate your compass.

But all the recalibration of the compass is almsot certainly unnecessary anyway.
You don't have to recalibrate the compass every flight and it's safe to stick with  a good calibration and use that for months.

jyurkyandsons Posted at 2016-4-24 01:45
Will it go into atti.mode if you have it shutoff on app.

Sorry ... I'm not sure what you mean there.
I'm not sure what you could shut off in the app that would do anything like that.
But if the compass and GPS are telling your Phantom two different stories and the numbers are too different for the Phantom to make sense of, it will ignore the GPS data (go into atti mode).

This is an unusual situation that doesn't happen often and it should never happen if you avoid giving your compass a bad calibration.

DJI-Paladin Posted at 2016-4-23 01:01
Suggestions above are very useful. And David, don't forget to do IMU and compass calibration before  ...

I have read "bad things" about IMU calibration.. causing some seriously long delays on future bootups... have you heard of these?

labroides@yahoo Posted at 2016-4-23 08:08
"If compass fails, why would GPS be also goofed up? "

In a situation where there is a conflict be ...

So ATTI mode can or cannot do return home? The manual says it can, but I sort of fail to understand how, and not sure if I'd trust it in such a situation. At least it would climb to my 30m altitude, then I could abort I guess...

gtokarsk Posted at 2016-4-24 15:27
So ATTI mode can or cannot do return home? The manual says it can, but I sort of fail to understan ...

If your Phantom is able to receive GPS satellite signals, whether it is in atti mode or not, your Phantom can RTH properly .. just as it says in the manual.

gtokarsk Posted at 2016-4-24 15:25
I have read "bad things" about IMU calibration.. causing some seriously long delays on future boot ...

No ...  sounds like you are confused.
Not everything you read is correct.
If your Phantom needs to have its IMU recalibrated, recalibration is a good thing.
If you do it when the Phantom is cool you will have quick warm up times.

labroides@yahoo Posted at 2016-4-24 00:27
Indoors is never a good location to calibrate your compass.

But all the recalibration of the comp ...

Just for info I never calibrate the compass inside, I was just making reference to all the metal around me when outdoors this time is probably whats caused it to throw a wobbly.

Ill be back home today so going to give it a try from my usual flight area to make sure everything is happy again.

davidathomas42 Posted at 2016-4-24 17:56
Just for info I never calibrate the compass inside, I was just making reference to all the metal a ...

There's always metal in buildings.
But at normal distances that should have no effect on a Phantom in flight.

labroides@yahoo Posted at 2016-4-24 01:02
No ...  sounds like you are confused.
Not everything you read is correct.
If your Phantom needs to ...

Agreed, but people said a lot about dealing with doing it after putting the quad in the fridge, and then AFTER calibration having a long warmup time sometimes.. Weird.. I guess the people who have no problems simply do not say it, so I read only 1 side of the story...  I will look through the tutorial for IMU calibration and readup a bit more about it.
The "beauty" of the internet, so much info available and not much validation.... Data overload!

Omg I'm glad you got control and was able to save your drone. I'm putting my P4 on EBay today. Thanks for this video as it made me realize the issues everyone has been having. And I'm not about to lose $1,400!