Taking off near metal? How bad is it?

[Yaros]

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?

 

[GFields]

I, for one, have never been able to take off from my truck or car. Upon trying I always get a compass error. Therefore, if you proceed flying with a compass error, you might not get a good GPS lock and risk a fly away.

 

[old man mavic]

@Yaros ,actually a compass error has nothing to do with getting a GPS lock directly
what happens is once the drone has taken off and climbed far enough away from the magnetic interference is that the IMU detects an anomaly ,between what the sensors are telling it is magnetic North based on it location ,and what the compass thinks is magnetic north when it was on the ground ,this can cause the drone to fly in an uncontrolled manner, which is referred to as toilet bowling ,it does not seem to happen as much now with the latest generation of drones

 

[Bob in Savannah]

Bottom line is... ...It is NOT reccommended. Period.

Having said that, I see it all the time around here but I ALSO see your type of post just as often. If you CAN fly from your car or around "metal" then I guess that is fine if once you lift off and check everything before zipping off...

But you should never complain if something happens like a whacked out compass and then you lose your drone.. Youre taking (no matter how small) a risk if you fly this way. I'm sure even those that can do this regularly will agree that it's only possible because of their particular car and/or situation. They would agree that they understand the risk involved with doing this.

Personally, until you have nearly a hundred hours of flying in would I suggest you attempting Unrecommended flying habits which can and are possible with the correct precautions.
Its a slippery slope.

 

[akdrone]

I wonder if it is the type of metal...steel...aluminum...because I'm one of those people, as is my flying buddy, who takes off regularly from his truck's front hood because it's often snowy and nasty around and it's easier than putting out a landing pad and trying to secure it in the wind. I have never had any kind of problem with my 2007 Chevy Silverado, nor has my friend with his 2019 Toyota Tundra. He lands on the hood...on the roof.... So yeah...apparently some folks have an issue with it but at least with our two trucks it seems to be a total non-issue. I will admit it's a slippery slope so I'm careful to land near the windshield lest is slide off the front. LOL. I used to be a full time hang glider pilot. I'm not terribly risk adverse and I have the titanium plates in my body to prove it!

 

[Meta4]

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.

This is very confused and anyone suggesting it doesn't understand what they are saying.
And metal is not the problem .... ferrous metal is.
Starting up the drone close to iron or steel can cause a yaw error which can be a major problem.
This is because they can deflect a compass or magnetic sensor so that it gives incorrect directional data.
The whole process of getting a yaw error is complicated and has been explained in many posts in the forum.

 

[lensimages]

This is very confused and anyone suggesting it doesn't understand what they are saying.
And metal is not the problem .... ferrous metal is.
Starting up the drone close to iron or steel can cause a yaw error which can be a major problem.
This is because they can deflect a compass or magnetic sensor so that it gives incorrect directional data.
The whole process of getting a yaw error is complicated and has been explained in many posts in the forum.

I sympathise with people that live in an area where there is not enough flat and clear ground to fly their drone from . I have found that where I live , South Wales U.K. if is snows my plastic landing pad stays on top of the snow without any problems, no need to fly off my vehicle the landing pad serves me well even when the ground is soaking wet . Would I ever take off and land from my car roof or bonnet/ hood you must be joking. I cannot and will not risk any of my drones doing that. There have been loads of members getting takeoff problems and there are are members on here that are brilliant at reading the records of drone flights so I would rather listen to them, if they after analysis of a faulty drone flight state that taking off on or near metal caused the problem who am I to disagree. I cannot understand these flight records and am very grateful to those that can and take the trouble to do so, cheers Len

 

[waynorth]

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?

The important step is when you power up the drone. This must be done away from ferrous metal objects. After startup you can move your drone to the car roof if you like, and take off.

 

[Felix le Chat]

The important step is when you power up the drone. This must be done away from ferrous metal objects. After startup you can move your drone to the car roof if you like, and take off.

It isn't just ferrous metal that can cause compass calibration problems, EMF from dodgy electrics can trigger the calibration warning too. If I boot up either of my drones on the kitchen worktop, the compass throws a complete wobble. I do it on the living room coffee table less than 10 feet away and no problems. Anything that creates an electrical field also creates a magnetic field too.

 

[Yaros]

I asked this question because of this reply to my comment by Ken Heron on one of his videos:

 

[waynorth]

I asked this question because of this reply to my comment by Ken Heron on one of his videos:

View attachment 160155

Ken is only partly right. It is important to be aware of the difference between powering up and taking off.
Never power up the drone close to ferrous metal (or other strong magnetic fields).

 

[BobaFut]

I usually power up and take off from maybe 5-10ft away from my car and never had a problem. However, my DJI FPV Goggles will usually always give me an interference error when I'm standing next to my car or sitting in the seat with the door open, but it goes away as soon as I step away from the car. So I guess I fall in the camp of "probably not a good idea to take off from the hood of the car, but other than that I wouldn't worry about it." Meanwhile, you'll run into guys that think a drone will absolutely crash if you try and take off within like a half-mile from any steel-reinforced concrete structure...which, obviously, is just dumb.

 

[Bob Bartlett]

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?

I have a air2 & use the cover on the back of my truck to take off in the winter time everything works great !

 

[MavicAir2Marc]

Some car bodies are aluminum which is a non-ferrous metal which is why some people may be able to get away with taking off from the hood of their car whereas others with steel body work may have issues. Powering up away from any big lumps of metal is still best practice. Once the compass is initialized, you should be able to take off from wherever you want. Electromagnetic fields would also cause compass issues but outside you usually don't run into electromagnetic anomalies aside from a running vehicle of some kind.

 

[YVRGUY]

It’s more being around magnetic fields than being around metal that will affect your drones flight. Even then, those magnetic fields either electromagnetic or natural have to be very strong.

 

[Meta4]

It’s more being around magnetic fields than being around metal that will affect your drones flight. Even then, those magnetic fields either electromagnetic or natural have to be very strong.

The strength of the magnetic field required to deflect the compass, depends on the distance it is from the compass sensor.
We've seen plenty of cases where serious yaw errors were caused by a bolt in a deck or under a table.
A weak field can cause issues if it is close enough to the sensor at startup.

 

[Paul Stocum]

I often take off/land from the cover over my truck bed. It’s plastic, level but around a lot of metal. Never an issue.

 

[TrabSeyn]

If your vehicle is running the engine it uses the body as ground. I've had compass issues trying to take off from a running vehicle (to run A/C or heat depending on conditions). Had to recalibrate the compass about 20 ft. from vehicle then was able to fly without issues. The issue is almost non-existent if the vehicle is not running the engine or powered on. Shut the vehicle down, pull the key, and give it a test.

 

[Meta4]

Had to recalibrate the compass about 20 ft. from vehicle then was able to fly without issues.

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.

 

[GaryOC]

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.