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

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I was reading earlier about the Geofencing 2.0 DJI put out recently (to keep up to date) and in the introductory video, DJI recommends you calibrate your compass before every flight. I keep getting contradictory info from people between is and it isn’t necessary. Although many of you have brought up some great arguments, I would like to know the specific reason why DJI insists in calibration before takeoff.
 

sar104

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I was reading earlier about the Geofencing 2.0 DJI put out recently (to keep up to date) and in the introductory video, DJI recommends you calibrate your compass before every flight. I keep getting contradictory info from people between is and it isn’t necessary. Although many of you have brought up some great arguments, I would like to know the specific reason why DJI insists in calibration before takeoff.
They don't insist. If they insisted then the aircraft would refuse to take off until you calibrated. They only advise, with completely contradictory advice depending on where you look. On the plus side, whatever your calibration preference you should be able to find a DJI document, manual or video that supports that preference.
 
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That was my impression as well. That is why I tried to stupify it halfway into the conversation. Hopefully the engineer understands what I ment and puts everything to rest.
The person you were in communication with did not seem able to read english properly as you mentioned more than once you were asking why you get different results to the same error message on different drones .As you have said hopefully the engineer will understand .
 
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They don't insist. If they insisted then the aircraft would refuse to take off until you calibrated. They only advise, with completely contradictory advice depending on where you look. On the plus side, whatever your calibration preference you should be able to find a DJI document, manual or video that supports that preference.
With my 2.0 they insist. My AC wont take off until I calibrate, which is every 2 or 3 flights. I tend to follow manufacturer’s advice. Here, I provided a link of the video from DJI that recommends (I guess for older models) to calibrate compass often.

Fly Safe – Drone Flying Tips, Policies & Regulations, and More – DJI
 
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The person you were in communication with did not seem able to read english properly as you mentioned more than once you were asking why you get different results to the same error message on different drones .As you have said hopefully the engineer will understand .
I admit that my initial contact tech guy was slow, but on the engineering reply, they answer my question accurately. Also, my main language isn’t english either, so I completely understand the language barrier when 2 people are trying to communicate with their second language.
 

sar104

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Then that's a different problem. You should either take a look at a DAT file when then happens, or post it here for analysis.
I don’t follow. DJI says it’s the way the 2.0 are programmed. I’m stuck doing the dance, unless I change for an older model.
 

sar104

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I don’t follow. DJI says it’s the way the 2.0 are programmed. I’m stuck doing the dance, unless I change for an older model.
If it has the same recent firmware as the Mavic 2 then it will request calibration every 30 days or when you move more than 50 km from the last location. That's not remotely the same as requiring it every flight.
 
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I fall into the 50km requirement, since I hardly fly in the same place twice.
 
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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.
 

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I am no expert, but I have seen with my own eyes how interference with the compass has caused my phantom to fly away, twice. I can complete my mision, be on my way returning home then the bird steers left on it’s own and flies away at full speed. It is a scary few milliseconds while I switch to ATTI and regain control. Ever since I do recalibration of the compass (even if it does it no favors), I haven’t had any more flyaways.
Apparently, you are using RTH instead of VLOS or FPV to return home after completing your missions. That's the real problem. Self induced scary milliseconds. Pilot control will prevent your so called "flyaways."
 

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These are interesting: We use this one : You have to get very close to the objects in question and if it could isolate to just IRON , it would be great, the problem we have is that everything sets it off as metal is everywhere.
Metal is everywhere ... but only iron and steel or live electrical equipment are going to have a magnetic effect.
Your eyes are a pretty good magnetic interference detector.
If you see steel items or reinforced concrete or live electrical equipment, don't launch from on top of them or close to them.
 
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Apparently, you are using RTH instead of VLOS or FPV to return home after completing your missions. That's the real problem. Self induced scary milliseconds. Pilot control will prevent your so called "flyaways."
Please don’t assume. I have never used RTH, not even once, and I always keep VLOS, hence why I have recovered control of my AC and have landed it safely.
 

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Edit: My point is, that when you calibrate, perhaps the drone takes into consideration any interference in the area and adjusts it’s math to consider this variable.
When you calibrate the compass, it is only identifying and measuring the magnetic fields that are part of the drone.
Anything that does not move with the drone as it is rotated, is ignored by the calibration.

Then in flight the Phantom's compass ignores the fields identified by calibration so the compass gives an accurate measurement of the local environment's magnetic field.
 
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GadgetGuy

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Please don’t assume. I have never used RTH, not even once, and I always keep VLOS, hence why I have recovered control of my AC and have landed it safely.
If the aircraft is truly engaged in a flyaway, you cannot regain control. That's the real definition of a flyaway. Not sure what is really happening, but if you are truly piloting your aircraft completely manually, you need to be in ATTI mode within VLOS. No chance for the compass then to have any effect on your return flight, after completing your mission.
 
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If the aircraft is truly engaged in a flyaway, you cannot regain control. That's the real definition of a flyaway. Not sure what is really happening, but if you are truly piloting your aircraft completely manually, you need to be in ATTI mode within VLOS. No chance for the compass then to have any effect on your return flight, after completing your mission.
I was flying in P mode when it decided to do a hard turn and fly at full speed ignoring my commands. The way I regained it was switching to ATTi. When I contacted DJI, they said it was magnetic interference. Since I was able to retrieve it safely, I didn’t give it a second thought, until it happened again. After the second time, I decided ti make this P4 a backup drone and switched to the 2.0. I admit I didn’t have the knowledge I have now about how Phantoms work. I always assumed that my particular one was a defect. If I knew then, what I know now, I would have saved the $1,500 that I spent in the 2.0
 

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I was flying in P mode when it decided to do a hard turn and fly at full speed ignoring my commands. The way I regained it was switching to ATTi. When I contacted DJI, they said it was magnetic interference. Since I was able to retrieve it safely, I didn’t give it a second thought, until it happened again. After the second time, I decided ti make this P4 a backup drone and switched to the 2.0. I admit I didn’t have the knowledge I have now about how Phantoms work. I always assumed that my particular one was a defect. If I knew then, what I know now, I would have saved the $1,500 that I spent in the 2.0
If it truly was magnetic interference (very unusual in the air), any DJI drone in P mode would respond similarly. ATTI saves the day. I suspect a defect, too.
 
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If it truly was magnetic interference (very unusual in the air), any DJI drone in P mode would respond similarly. ATTI saves the day. I suspect a defect, too.
This P4P has flown over 100 hours after those incidents (mostly when my brothers borrow it), and after I taught them to always look at the compass in the menu and make sure it’s green before and after takeoff, it has never done another flyaway. Still flies great, but I prefer my 2.0.
 

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This P4P has flown over 100 hours after those incidents (mostly when my brothers borrow it), and after I taught them to always look at the compass in the menu and make sure it’s green before and after takeoff, it has never done another flyaway. Still flies great, but I prefer my 2.0.
Good advice, as well as the advice above from @sar104, to make sure the directional arrow of the aircraft nose in the app on the map matches reality, before lift off.
 
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