Flight over Powerline construction site

Northern Observer · May 29, 2016

These lines were not active at the time of flight, and of course at the point of maximum distance I received the usual compass error issue with total loss of GPS. I'm glad I had the video feed to put her back on track. Not shown on video.

What is the typical method to have DJI look at the compass problem, upload your flight history, email them and wait?

My old P2 would have flown this area with no
Issues.

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alokbhargava · May 29, 2016

What was the need to fly over power grid? Too risky operation for drone as well to the grid.

The way you lost compass and GPS clearly shows a presence of heavy electro magnetic field. There is no way for DJI to figure out the interference level but they will definitely look at the flight logs to analyze the cause.

Northern Observer · May 30, 2016

The line were not energized, I work in this field, no harm to the grid at all.

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Karanba · May 30, 2016

Guys hot to fly then over/under those power grids ? I have them on few my routes and I am scared to fly near them. So over them is no option ? Is it ok then to fly under them on 5m height ? Wires are on like 20-30m.

Meta4 · May 30, 2016

Northern Observer said:
These lines were not active at the time of flight, and of course at the point of maximum distance I received the usual compass error issue with total loss of GPS. I'm glad I had the video feed to put her back on track

A compass error usually doesn't mean that there is something wrong with your compass.
It indicates that the compass has detected an abnormality on the magnetic field.
There's nothing in the video to give a clue as to the cause of your compass error.
Can you give some information ... where was the Phantom at the time, what was close to it etc.
If it was just close to a large steel object, simply flying up or away from it should have returned things to normal.

Go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone might be able to analyse it and give you an understanding of the cause of the incident

Meta4 · May 30, 2016

Karanba said:
Guys hot to fly then over/under those power grids ? I have them on few my routes and I am scared to fly near them. So over them is no option ? Is it ok then to fly under them on 5m height ? Wires are on like 20-30m.

Flying close is not a good idea and flying under is no different from flying over.
If you are talking about high voltage transmission lined, 5 metres is probably too close for safe flying.

Karanba · May 30, 2016

Yes high voltage and I am talking about passing under the wires close to the floor. Like after that I have open field. So wires are on 20-30m and I fly 5m from the ground.

shockwave199 · May 30, 2016

When you say usual compass error, are you saying you've flown this spot before with the same issue? I think phantom 3's are much more sensitive to compass errors and I think in recent firmware they made it even more so. However, I don't particularly like how the error is handled in that it really puts the pilot in a challenging situation of instant atti mode and a loss of gps altogether makes for a real handicap. Dji tends to make the newer birds ultra sensitive to errors I think and while that can be helpful to avoid problems, it can thrust you into them unexpectedly too. Once you know an area makes the bird twitchy such as you see in that area, I'd be very cautious and maybe even not fly there any longer. Good luck.

Meta4 · May 30, 2016

Karanba said:
So over them is no option ? Is it ok then to fly under them on 5m height ?.

Why do you think over flying is bad but under will be OK?
If you fly over, you can go high enough to keep a good separation distance.

Northern Observer · May 30, 2016

I think Shockwave you've nailed it correctly. The P3 sensitivity. Given my flight altitude over the lines, and considering the fact they were not energized makes them a red herring in this conversation. I think the excessive yaw and pitch acceleration the P3 makes automatically while in gps mode (especially in a moderate breeze) knocks it out of gps to atti mode temporarily. Once the bird is stabilized it comes back into gps mode. I took it up last night, and flew the entire flight in atti mode, no problems whatsoever. I'll post the log of the Powerline flight for comments.

Cheers.

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ianwood · May 30, 2016

Even if your powerlines are not energized, they can still carry a magnetic field. If you don't experience the issue away from the lines, you have your answer.

Northern Observer · May 31, 2016

The issue is experienced away from the power lines.

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ianwood · May 31, 2016

Northern Observer said:
The issue is experienced away from the power lines.

Then you probably have a bad calibration.

shockwave199 · May 31, 2016

ianwood said:
Then you probably have a bad calibration.

I agree with that. The construction site is probably a given for nasty magnetic field. But if you're having problems in areas you really shouldn't be and you can reproduce gps loss and compass errors just by zipping around flying, you have a problem. IMU and compass calibration would be a good place to start and if that doesn't help, it's more serious. And I wouldn't judge success or failure of those calibrations by that power line site either. It would be ideal if it did behave well in those areas but if it won't, it won't.