Electrical interference

[tgp142]

i was operating my Mavic Pro today over railroad tracks trying to get a cool POV shot. I was in pretty close proximity to power lines and upon take off the aircraft continued to gain altitude, even with input from controller. I was able to regain control, and had issues with the aircraft yawing to the right following that. Trying to safely land was a whole other issue in itself. Has anyone experienced something like this? What’s a safe distance to operate away from the power lines to avoid interference?

 

[Qoncussion]

I have a location where I fly frequently, where I have to launch pretty close to power lines - say, 15 feet or so. I am also about 50 feet from a very tall communications array, with numerous microwave and RF transmitters. I've never had any problems with EMI at this location. After I launch (anywhere) if something "seems" wrong, I land, shut-down and move several meters away.

If the interference you described was indeed the culprit, you should take a look at the RC signal icon in the app during flight. It will flash if it detects interference.

 

[Qoncussion]

You may want to recalibrate your IMU to see if that resolves the issue.

 

[tgp142]

I appreciate the info. I will for sure check that next flight. Thanks again

 

[tracer bullet]

upon take off

There's a chance then that you took off from a spot to close to metal and confused the compass. A few have reported take-off issues and that appeared to be the case. Don't forget rebar can be inside of concrete surfaces.

 

[Ron_Dog]

Too much metal too close,during setup/liftoff! I constantly fly across/along 345KV transmission lines without any problems,and they are along side a rail road. I experenced the same problems you did once by setting up,and lifting off,close to a big chain link fence at a ball park.

 

[Pathogen]

You can (and probably should, if I may be so bold) view the DAT file for that most unsettling of flights in a handy tool called 'CsvView'. I had a similar experience flying with a few feet of some heavy steel equipment, and for 30 seconds the Mavic misbehaved badly, and I was very lucky it avoided a high speed crash. The whole experience disturbed me to the point that I've had at least 3 dreams where my Mavic does not respond to the remote controller. One day I hope to recover psychologically from what happened that day, but until then I won't go within 10 ft of metal things. Thankfully the adverse effects of metal is more than likely an exponentially diminishing thing in the context of distance, but just to be sure I have changed the function of the sport switch to ATTI mode, and am always ready to fly manually when our beloved 'intelligent' features take a header.

 

[HltnCarp]

I and that problem once when I was visiting British Columbia. My mavic just started to fly away and couldnt control it with the remote. It flew about 200 m and then for some reason control came back. First and only scary moment I have had. I saw the large power lines across the street but thought I was far enough away. I think I was wrong

 

[scjerry]

It is worth playing lawyer and reviewing the all-encompassing warranty agreement that we implicitly agree to when we first fly our drones. See After-Sales Service Policies - DJI.
Warranty Repair Service will not be provided where:
× Damage caused by operating the unit in an environment with electromagnetic interference (i.e. a mining areas, close to radio transmission towers, high-voltage wires, substations, etc.).
× Damage caused by operating the product in an environment containing interference from other wireless devices (i.e. transmitter, video-link, Wi-Fi signals, etc.).

I get warning messages all the time about being cautious in areas with wireless interference. This suggests a DJI out in warranty negotiations, when filing a warranty claim, if they peruse your synched flight records.

If they have the ability to detect wireless interference, then their software should initiate appropriate action to ensure flight safety.

 

[Nomand Eloc]

It is without a doubt the massive amounts of iron in the rail tracks that are causing interference to your Mavic's compass. I live right next to a stretch of hardly used tracks and I can get my Mavic to go into Atti mode if I get to close to the tracks. The first time this happened to me was just north of Santa Barbara, Ca, on my way into work. I stopped at a random beach along the Gaviota coast. This stretch of coast has a single train track that runs very close to the beach. I guess I was too close to the tracks when I took off and it went into Atti mode for the first time. My Mavic started to with no input to drift in the wind out to sea. It was easy to fly back and regained GPS lock quickly but it was exciting.

 

[Pathogen]

Nomand Eloc, please be wary of the situation where the ATTI mode does not kick in soon enough, and the Mavic reacts to corrupt GPS data. Being able to force ATTI mode without risk of automatic reversion to GPS mode may be useful in preventing a crash.

 

[Brojon]

There's a chance then that you took off from a spot to close to metal and confused the compass. A few have reported take-off issues and that appeared to be the case. Don't forget rebar can be inside of concrete surfaces.

Compass only affects heading. It wouldn't cause it to climb. Climbing would be a barometer issue since the MP uses that t determine altitude. Now *maybe* interference prevented the controller talking to the bird. I'm not sure how "sticky" the control signals are. In other words if you're climbing and you lose signal - does it keep climbing or stop? I'm guessing it would execute the signal loss behavior. Since the signals are encoded it is *highly* unlikely the drone received a bogus command.

 

[tracer bullet]

Compass only affects heading.

Right, and I would agree, except that a month or so ago was a thread here where someone took off from a parking garage and had problems, the drone wasn't just spinning laterally but trying to do a barrel roll and whatever the heck else as well. One of the experts here sifting through the data came up with the compass being way off.

That's how I remember it anyhow, I may have misread or have a crappy memory. But it ran through my mind as well "huh, all that because of the compass?".

 

[Pathogen]

Metal will reflect the signal from the GPS satellites and I presume that if the reflections dominate the direct signal, things can go very wrong.

 

[Brojon]

Metal will reflect the signal from the GPS satellites and I presume that if the reflections dominate the direct signal, things can go very wrong.

I agree - to a point. Any GPS system worth its salt has rejection algorithms to reduce the effects of multipath. This is where more satellites the better.
Also - GPS has no effect on altitude nor heading. Unsure how bad info could result in things like barrel rolls since the software has hard limits on the things that control tilt and speed.

 

[Ron_Dog]

I "think" that once you have a "clean launch" (All Systems Go),you can fly about anywhere you want. I constantly fly over high power transmission lines,with no effect at all. But I also fly well above them,as opposed to close to them. I also have had flights near Microwave Towers,with no effects. I have never went near a cell phone tower (repeaters) yet,as some operate on 2.4,and I think there could be a problem there? Watch this guy!

 

[Brojon]

I "think" that once you have a "clean launch" (All Systems Go),you can fly about anywhere you want. I constantly fly over high power transmission lines,with no effect at all. But I also fly well above them,as opposed to close to them. I also have had flights near Microwave Towers,with no effects. I have never went near a cell phone tower (repeaters) yet,as some operate on 2.4,and I think there could be a problem there? Watch this guy!

I have one right near me behind a church and I fly right up to it. I do however get an interference notice when I fly where it's between me and the drone.
Ditto on high tension wires - we have some that run parallel to some train tracks and I follow the tracks about 40 feet over the lines with no discernible effects.

 

[Ron_Dog]

I have one right near me behind a church and I fly right up to it. I do however get an interference notice when I fly where it's between me and the drone.
Ditto on high tension wires - we have some that run parallel to some train tracks and I follow the tracks about 40 feet over the lines with no discernible effects.

Yup! I think the solution is to keep a "reasonable distance" from them! Watching that Vision fly low down the rail road tracks,then under the over pass was something I would never try. I have to give him credit though! I would have used a "cheaper drone" for testing! He really pushes the limmits,but also states not to do so,just because he did it!

 

[Ron_Dog]

We have very few (if any) areas where we can fly without crossing power lines,even in rual areas,so we just keep a distance above them when crossing them. It may also have a greater effect on the signal at long range? I dunno?

 

[Brojon]

We have very few (if any) areas where we can fly without crossing power lines,even in rual areas,so we just keep a distance above them when crossing them. It may also have a greater effect on the signal at long range? I dunno?

I dunno if you saw the antenna mods post but the thing to keep in mind is that ALL electromagnetic phenomenon fall off by the square of the distance. Meaning for every doubling of the distance the intensity falls off by the square