What are the consequences of compass errors?

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Hey all, I knew to be cautious because of what I have researched online......but I shot some really close video (flying through it) of an old historic bridge today. Once I was in the middle of it I started getting compass errors. I immediately noticed that I had to correct drift. What are the consequences of compass errors like this? Is it what I experienced or much worse? Does it have the potential of flying away or only if it was on some kind of automated flight?

Thanks!


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Compass and GPS errors can cause the AC to automatically switch to ATTI mode, where you have to know how to manually control it. This is a safety feature. Sounds like you successfully manually navigated the bridge, so great job. In ATTi mode it will drift with the wind and only has barometer altitude hold. Always best to practice in ATTI mode so you know how to control things when needed.....especially if the AC is pointed toward you, or a windy day.

I believe the vast majority of Flyaways are the pilot's inability to control a drifting AC once in Atti mode, although I'm sure there are more rare situations where hardware fails and the AC seems to have a mind of its own.
 
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Is it possible that metal in the bridge was affecting the compass? Also if it was a covered bridge you would also lose gps!
 
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From what I know about the bridge it is made of iron. This was the reason for it and the bridge was not fully covered.....just beams across it. I can handle manually controlling it but I was wondering if it would do something like cause a fly away.


Sent from my iPad using PhantomPilots
 
Hey all, I knew to be cautious because of what I have researched online......but I shot some really close video (flying through it) of an old historic bridge today. Once I was in the middle of it I started getting compass errors. I immediately noticed that I had to correct drift. What are the consequences of compass errors like this? Is it what I experienced or much worse? Does it have the potential of flying away or only if it was on some kind of automated flight?
The consequences of compass error depend on how bad the error is.
You can generate a temporary low-level compass error by descending toward a steel roof and when you are about 6 feet above your Phantom will slowly spiral (toilet bowl effect).
You can escape this at any time by climbing out of the magnetic field of the steel roof.

Here is video of a larger and different kind of compass error caused by unnecessarily recalibrating the compass close to a lot of steel;
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And a different kind again would kick your compass into atti mode because the Phantom's flight controller can't deal with conflicting data from compass and GPS.
This leaves the Phantom vulnerable to drifting with the wind in atti mode as well ad directional instability.

All of these are easy to avoid.
The first type - don't fly very close to large steel objects - or if you do, be prepared to exit the distorted magnetic field.
The others - don't recalibrate your compass close to a lot of iron and steel (particularly reinforced concrete) or electric cables
 

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