Phantom Rain : Magnetic Interference is the Phantom Killer in disguise:

simon5 · Dec 3, 2018

I believe this to be an update I have a Mavic pro and a phantom for pro version two. My Mavic hardly ever has me calibrate the compass before taking off where as the phantom does it on almost every flight

PhantomWetSuits · Dec 3, 2018

Andy9 said:
Yes that is correct. Calibrating the compass in a magnetic compromised area won't do any good. It just takes the data of that altered magnetic field as normal one. So you put the drone in a condition that normal magnetic field on a different location could be recognized as not normal, therefore you can have problems then. Automatic switch to ATTI is safety measure against compass problems. Of course you must noticed that and fly according to that ATTI situation - manually. If there is rather windy doing nothing would cause the craft to fly with the wind. If you get interference at take off location just pack and go to a different one and everything will be normal without calibration. I fly 3A and 4P for more than three years now and never do a compass calibration.
But there can be a radio frequency interference as well. The cure is equal.

There seems to be two distinct groups : Those of us that do not need to do compass calibration and those that do.
Because we as Pilots all fly with different firmware , the story will not be the same for everyone.

Having the right firmware as many of us know is key:

sar104 · Dec 3, 2018

PhantomWetSuits said:
There seems to be two distinct groups : Those of us that do not need to do compass calibration and those that do.
Because we as Pilots all fly with different firmware , the story will not be the same for everyone.

Having the right firmware as many of us know is key:

I think there are two separate issues. Firstly, the question of whether the firmware requires regular calibrations and, secondly, whether pilots habitually calibrate frequently or not.

The more recent firmware version for the P4P v2 seems to have implemented something similar to the Mavic Air and Mavic 2 firmware, requiring compass calibration every 30 days and if you change location by more than 50 km. Those checks are recorded in the DAT file event stream, and so there is no ambiguity in the process. Why DJI has implemented that is not clear, since neither time nor distance inherently changes the magnetic characteristics of the aircraft itself, which is all that calibration is measuring. Previous guidance from DJI has varied but mostly comprised the advice to calibrate only when the FC requested it, so this is a new philosophy.

The other question - whether pilots calibrate frequently - is mostly related to which of the previous conflicting DJI advice they followed and how well they understood the technical reasons for calibrating.

vgo195 · Dec 3, 2018

The first thing I do in every flight before taking off is to check the sensors. Sometimes I get a calibrate compass prompt but it is due to interference. Then I move the drone and see if the compass sensor comes back to normal. Do I have to turn off and turn on the drone in that situation as suggested in this thread or not? I usually move the drone while it is on and find a spot without interference and take off. Is this correct?

sar104 · Dec 3, 2018

vgo195 said:
The first thing I do in every flight before taking off is to check the sensors. Sometimes I get a calibrate compass prompt but it is due to interference. Then I move the drone and see if the compass sensor comes back to normal. Do I have to turn off and turn on the drone in that situation as suggested in this thread or not? I usually move the drone while it is on and find a spot without interference and take off. Is this correct?

The sensor readings (I assume that you mean the interference level shown in the GO app) are not actually the best indicator of magnetic interference, and if they are out of spec then the app will warn you anyway. The most reliable check is simply to ensure that the aircraft orientation arrow on the map is pointing in the correct direction relative to north.

If the arrow is pointing in the wrong direction then move the aircraft and restart it - the reason for that is that the IMU yaw value will have been incorrectly initialized on startup. That needs to be correct before takeoff, and the simplest way to guarantee that is a restart.

PhantomWetSuits · Dec 3, 2018

vgo195 said:
The first thing I do in every flight before taking off is to check the sensors. Sometimes I get a calibrate compass prompt but it is due to interference. Then I move the drone and see if the compass sensor comes back to normal. Do I have to turn off and turn on the drone in that situation as suggested in this thread or not? I usually move the drone while it is on and find a spot without interference and take off. Is this correct?

NO you should turn the drone off and than move and restart. This will give you the best odds of a successful flight.