Taking off near metal? How bad is it?

[jhatfield]

I have seen people taking off from the top of their cars without any issues, and others report that it's a risk to take off anywhere near a metallic structure.
I've also heard that it is okay to takeoff near metal as long as you don't calibrate the compass near the metal, so when the drone gets further from the metal it will stabilize.
But what exactly is true?

I have had a negative experience when taking off near metal, but it was with an Arducopter drone, not a DJI drone. This happened back in 2020, with an old APM 2.8 flight controller, so I don't know if this issue also affects DJI drones, but in short here's what happened: I turned on the drone while it was on the ground, a couple of meters away from a metallic structure, a tall one, I waited for GPS and took off, as soon as I ascended and went a couple of meters away, the drone started making random yaw turns, when I tried to counteract it would just fight back, so I switched to manual mode (something like Angle Mode on Betaflight, or Stabilize mode in Arducopter) even more manual than ATTI on DJIs, and safely landed the drone nearby. I was lucky I had that mapped to a switch in case of an emergency!

Could this have happened with a DJI drone too? What would be its behavior in this situation?

My past experience using a a dji Phantom 3 Pro, it was not a good idea. Took off once from a Ford truck tailgate and she took off like a scaled dog into the side of my neighbor's jump trampoline safety net. I was extremely blessed nothing got broken. Another time I took off with same unit from a round marble outdoor table that had iron support legs. This time the unit wanted to fly off in one direction, but I was able to throw the joy stick in the opposite direction to hold it in one place while bringing it down into some brush. So far with my dji Mini 3 Pro, I have no idea what would and or could happen since I learned my lessons well, and don't take off from any known magnetic material what-so-ever now.

 

[Meta4]

I powered up a Mavic 2 Pro and took off from a large concrete pier that was reinforced with plenty of rebar, from what I read later. The drone seemed somewhat lethargic near the pier and was drifting at times which required me to fight with the control sticks a little bit. Especially when landing back onto the pier. When flying away from the pier during the flight, it was fine. I'm pretty sure it was that rebar. It was the only time the drone acted like that.

If your drone was affected, you were lucky it didn't turn out worse.
Most yaw error incidents are uncontrollable and end badly.
The steel reinforcing might not have been the cause of what you observed.
The recorded flight data might show whether you actually had an IMU initialisation problem or not.

 

[Osmosis]

I do it all the time in the winter. Zero issues.

 

[GaryOC]

If your drone was affected, you were lucky it didn't turn out worse.
Most yaw error incidents are uncontrollable and end badly.

I believe you. I felt fortunate at the time to land successfully after seeing it act like that. Since then I always launch from back on the shore, usually in the parking lot, and then head out over the water if that's what I'm planning.

 

[Cecil]

I have flown off both aluminium and steel bodied cars with no issue with my Mavic 3. I used to have a Mavic Air and that wouldn't take of unless it was calibrated every flight before take off, never tried to take off a vehicle with it.

 

[mattvenn]

I have seen people taking off from the top of their cars without any issues, and others report that it's a risk to take off anywhere near a metallic structure.
I've also heard that it is okay to takeoff near metal as long as you don't calibrate the compass near the metal, so when the drone gets further from the metal it will stabilize.
But what exactly is true?

I have had a negative experience when taking off near metal, but it was with an Arducopter drone, not a DJI drone. This happened back in 2020, with an old APM 2.8 flight controller, so I don't know if this issue also affects DJI drones, but in short here's what happened: I turned on the drone while it was on the ground, a couple of meters away from a metallic structure, a tall one, I waited for GPS and took off, as soon as I ascended and went a couple of meters away, the drone started making random yaw turns, when I tried to counteract it would just fight back, so I switched to manual mode (something like Angle Mode on Betaflight, or Stabilize mode in Arducopter) even more manual than ATTI on DJIs, and safely landed the drone nearby. I was lucky I had that mapped to a switch in case of an emergency!

Could this have happened with a DJI drone too? What would be its behavior in this situation?

Hi Yaros,

I had a terrifying experience with taking off from reinforced concrete that totally changed my attitude towards drone flying.

Mavic mini 2 flyaway and crash

Hi all, new member and mavic owner here. I've flown 250s for a few years, always 2d and with minimal gyro assistance so this is all amazing to me. I got the mavic mini 2 drone yesterday and flew about 10 times. Very impressive. Today I tried another flight and was hovering about 6m up, full...

mavicpilots.com

I was just lucky it didn't crash into a person or a road.

Now I am much more careful about following all the rules and have 3rd party insurance. I also never take off without checking the compass on the drone match the handset.

For me the lesson was that however careful you are, the drone could experience a bug that will make it do something uncontrollable.

I have heard this is a mini2 bug, and not a problem on other drones.

 

[Yaros]

I have heard this is a mini2 bug, and not a problem on other drones.

This is yaw error, can happen on any drone, DJI or not, doesn't matter.
As you can see in my post, something similar happened to me on an Arducopter, which is not a DJI drone.

This is why I'm careful when taking off near metal, especially when calibrating the compass, you shouldn't be anywhere near metal.

---

My first ever drone flight was a crash simply due to this as well. Let me explain.
I was following a YouTube tutorial on how to build an Arducopter drone, and the guy showed the calibration process indoors, and I followed it also calibrating it indoors, very bad idea.
I take off, not knowing the controls, anything, the drone rises up very fast (because it was a light and powerful custom F450 build), when it reaches about 20 meters it starts rotating on the yaw axis and flying away (toilet bowling), I panic, hit RTH, but nothing happens, the drone starts flying even faster away from me to a construction site, luckily no one was there at the moment, the drone crashes into the crane. I had to climb the fence and retrieve the drone, there was damage, landing gear was broken, and one motor was bad.

Yeah, not the best first flying experience, but you learn from mistakes, don't you?

---

So now I get confused when people tell me that calibrating the compass and taking off near metal is no big deal.

 

[Meta4]

I have heard this is a mini2 bug, and not a problem on other drones.

You have heard wrong, a yaw error could occur with any DJI drone, if you power up in an area of magnetic interference.
Launching from reinforced concrete surfaces is the most common cause of yaw error incidents.
Because you can't see the steel under the concrete, you can't tell how close your compass sensor is to the problem.
You could do it 10 times without a problem, or you might have a problem the first time you try.

 

[TrabSeyn]

You didn't have to recalibrate anything as there was no change to your compass calibration.
DJI's message about magnetic interference is very badly worded.
All that's necessary is to turn the drone off, move away from the problem and start again.

Fly was giving me the error and being demanding. In hindsight I should have moved to a different location, power cycled, and flown normally. This was a night flight on a muddy construction site so finding a dry spot to calibrate was tricky. Good info to know. Thank you.