Compass Preventing Takeoff

[bkushner]

I'm having an issue where I'm trying to fly from a roof of a building. I'm getting compass error and it won't take off. In the past I seem to recall that you could still take off with the compass error and it would correct once it got up in the air.

Is there anyway to do this?

 

[Meta4]

I'm having an issue where I'm trying to fly from a roof of a building. I'm getting compass error and it won't take off. In the past I seem to recall that you could still take off with the compass error and it would correct once it got up in the air.

Is there anyway to do this?

You really don't want to launch from a steel roof.
Many Phantoms have been lost from doing just that.
You stand a good chance of having serious yaw error problems problems.
Launch from somewhere else or hand launch from several feet above the roof.

 

[Timinator]

Can you launch from the case or perhaps a plastic table or anything to create a buffer zone between the aircraft and the steel?

 

[WV. Rootman]

Launch from the roof with a compass error and your next post will be, “my quad crashed.”

 

[Speedmeister]

Try hand launching the phantom. I tried it with mine once on a crowded floating platform with a roof and the only safe way to launch phantom was on the side by hand. The phantom in my opinion should be able to fly like any normal non gps drone when it has bad compass. Just dont do RTH and dont expect any position hold. It is possible for the compass to go bad while in the air. When it happens, it goes on atti mode but you still have full control of phantom. If you dont have experience in flying ATTI then more chances of a crash. I have flewn my phantom with compass error before. It took off in atti mode but at some point it regained GPS. It would have been fine if it stayed on ATTI for the duration of the flight. If RC and AC loss connection while on ATTI then fine too since I was on walking distance of the phantom. The motors will not start if the compass interference is bad.

 

[DOC 1500]

Are there any transmitter antennas on the roof ? Cellular or two way communication ?

 

[Meta4]

Are there any transmitter antennas on the roof ? Cellular or two way communication ?

The issue is magnetic (compass error).
Antennas would only create radio interference - not a compass error.

 

[DOC 1500]

The issue is magnetic (compass error).
Antennas would only create radio interference - not a compass error.

I flew around some antennas on the top of a mountain and I got all kinds of warnings including Compass warnings I got out of there quick

 

[Meta4]

Just dont do RTH and dont expect any position hold. It is possible for the compass to go bad while in the air. When it happens, it goes on atti mode but you still have full control of phantom.

There have been many, many cases of people launching from steel or reinforced concrete surfaces and coming to grief.
Their flight data shows that they don't have a simple compass error.
They have a yaw error as well as a compass error and experience flying atti mode makes no difference because the Phantom runs away and is uncontrollable.

 

[bkushner]

Can you launch from the case or perhaps a plastic table or anything to create a buffer zone between the aircraft and the steel?

Will try that.

 

[bkushner]

Are there any transmitter antennas on the roof ? Cellular or two way communication ?

There are cellular at the other end of the roof

 

[Speedmeister]

There have been many, many cases of people launching from steel or reinforced concrete surfaces and coming to grief.
Their flight data shows that they don't have a simple compass error.
They have a yaw error as well as a compass error and experience flying atti mode makes no difference because the Phantom runs away and is uncontrollable.

This is a design flaw or defect that DJI probably addressed in there firmware releases. My spark does auto compass calibration after launching from top of washing machine.

 

[DOC 1500]

There are cellular at the other end of the roof

Just a suggestion but take off from another location and fly to your rooftop location see if you get any interference on the screen

 

[AuldGimpy]

There have been many, many cases of people launching from steel or reinforced concrete surfaces and coming to grief.
Their flight data shows that they don't have a simple compass error.
They have a yaw error as well as a compass error and experience flying atti mode makes no difference because the Phantom runs away and is uncontrollable.

Aaaha! I can confirm absolutely that this is indeed the case. Smart-*** me!

Luckily the Yaw and Compass Errors disappeared once I stepped off the new mesh grid sided bridge. (Steel sectioned) Even more luckily was that the RTH worked fine when it (P3 Pro) bolted for the Forestry Commission plantation .. twice!

This is a design flaw or defect that DJI probably addressed in there firmware releases.

Maybe? Possibly as I have not updated the FW on this bird for a while.

Once away from the metal bridge, I did get some good shots of the River Orchy. I'll post them once I've edited them down a bit. The waterfalls tend to be a bit hypnotic.