Hoping DJI can chime in on this. I know there are several posts on this however I have some questions around this. After reading external forms (I know they can be BS) I am reading that calibrating your compass prior to every flight can actually cause more issues then not calibrating. So here's where my questions sets in...

If flying in the exact same location multiple times is it required to calibrate still?

Is it actually a best practice to calibrate before EVERY flight?

If calibrating prior to every flight what is sure could arise?

Thanks eh......

The calibration of the compass is necessary to ensure the aircraft flies well, but it is not necessary to do it every time you fly. Once you get a good calibration, it is good for anywhere you fly for hundreds of kilometres around you. The instructions say that you only need to recalibrate if you fly more than about 100 km from where you last performed the calibration.

In actuality, the only changes that can occur are mild deviations in the earth's magnetic field, and these are so minor that the Phantom will hardly even notice them.

So to answer your questions:

"If flying in the exact same location multiple times is it required to calibrate still?"
No.

"Is it actually a best practice to calibrate before EVERY flight?"
No, in fact it is a waste of your time and you could end up with a bad calibration.

"If calibrating prior to every flight what is sure could arise?"
You could get a bad calibration due to metal in the area, then take off without knowing it and have problems once in the air.

Geebax Posted at 2016-3-7 12:56
The calibration of the compass is necessary to ensure the aircraft flies well, but it is not necessa ...

Couldn't have said it better.
It sounds like what the OP was reading elsewhere might not be BS at all.

Geebax Posted at 2016-3-7 09:56
The calibration of the compass is necessary to ensure the aircraft flies well, but it is not necessa ...

Agree totally,
I reckon i have 100 flights+ from my yard (live on an acreage) since my last compass calibration...No issues at all....

Before each flight as part of your checklist, every pilot should take a look at the SENSORS page in the DJI GO App before take-off. DJI provides accuracy readings for us to KNOW how our P3 sensors, including the compass, are performing. The P3 compass is on the bottom of the left landing leg as you're looking at the front of the P3 --> little rectangular box on the bottom of the left leg holds the sensor.

The GO App page that lets you judge the accuracy of your SENSORS is under Main Controller Settings (MC Settings)/Sensors. What you’ll find there are real bias values for the gyro, accelerometer and compass. When level, the gyro should be showing no angular rate on any axis – the three x/y/z values should all be 0.00. Likewise, the accelerometer should be showing no left/right or front/back acceleration and x/y should be 0.00, but gravity is accelerating the sensor, so z should show as -1.00, offsetting gravity.

Our P3 compass offsets gyro procession, so it’s bias values are also shown. The compass values shows x (north/south); y (east/west) deviations and z, vertical inclination.  This Phantom Pilots Thread is a good overview. While these individual x/y/z values provide feedback, DJI gives us a statistical tolerance analysis of these values called MOD values.

In statistics, the Root Sum Square (RSS) provides a tolerance measure for accuracy ([value 1 squared + value 2 squared + value 3 squared] and take the square root of that sum and that’s the MOD value). So before each flight simply look at the MOD values and compare them to the NORM, which for Gyro is ZERO; for Acceleration is ONE; and for Compass it’s between 1200-1500. The compass MOD is so broad because of variations in the earth’s magnetic field, but it will be consistent based on where you fly.

So once you get a good calibration of your P3 compass with no magnetic influence within 5 meters of your P3 (no metal), pay attention to your MOD values. It should stay consistent for your immediate flying area as GeeBax states. If it's not within a few hundred of your standard compass MOD, then be careful and consider performing a new calibration. If it's not between 1200 and 1500, then suspect METAL somewhere affecting your compass.

Where I fly, my standard MOD value for the Compass is closer to 1500. After several calibrations in an area, I can tell in a second if my compass is off by simply looking at the consistency of the MOD value.

Good luck, plan you flights, and fly safe!!

Compass needs to be calibrated if you've changed the place of the flight or change the place where you store the aircraft. It's not necessary to calibrate the compass before every flight if you're flying at the same position or environment.