Hi, I had crazy experience with my MA, before taking off I checked for compass errors, emu errors and over status. everything was normal. After take off it recorded the home point and the n i started flying. 7 mins into flight I got multiple messages saying "in flight working compass encounter magnetic field interference, switch to anti mode". Whats scared the hell out of me is that the drone drifted almost 20 meters and was non responsive to any stick movements. At this moment I pressed RTH and luckily it started coming towards the home point. When the drone was near I cancelled RTH and landed the drone manually. Now I have 2 questions. 1. Why did the MA become unresponsive to the radio when it was having trouble having gps hold due to compass error or interference. 2. why did it respond to RTH (on the go4 app, iPad) and return safely when it was having compass issues. P.S- At no point did i have radio signal loss error on my i pad screen

Hi ARI,

Guess you had this message : "In Flight. working compass encounters magnetic-field interference.please switch to atti mode if craft behave abnormally"

Its a non-correct message by DJI as we cannot switch to ATTI by ourself.

In ATTI mode RTH does not function, so when you pressed RTH your MA was in GPS mode. (what happend before, well do upload your flightlog).

http://www.phantomhelp.com/LogViewer/Upload/

cheers
JJB

Hi, thanks for reaching DJI Forum. We do apologize for the troubles you had recently. I'd like to know the firmware version of your aircraft? We're here to help you. Let us know if you have more concerns. Thank you.

The best way I can explain this is. If you put your Aircraft on the ground in normal circumstances, start it up, then lift it up and turn it 90 degrees to the right both your compass heading and IMU will both move together 90 degrees and no problems.
If you put your Aircraft on the ground and there is magnetic interference only the heading of your compass will change, your aircraft will still take off. But when it clears magnetic interference compass will then move to correct heading which you would think was great. But No, what happens is IMU is then conflicted and confused because of this sudden movement by compass, so you receive IMU exceptional heading warning, your aircraft cannot deal with data conflict so decides to switch to Atti mode dropping gps in favour of compass simply because aircraft can fly without gps but not compass.

While I can’t be certain you picked up interference from the ground or surrounding area it is the most common cause.
I have seen many cases where people start their aircraft in or on their car in their house and then bring it outside so damage is already done and we will see exact same warnings and and reaction from aircraft.

We all should check our compass when we start our aircraft and maybe more of this could be avoided, you can do this by checking the compass values in your app also check small red triangle in the lower left corner of your telemetry, it should be on the same heading as your aircraft.

One last thing I will say is we must always try to land aircraft immediately when this occurs.

before taking off I checked for compass errors,
7 mins into flight I got multiple messages saying "in flight working compass encounter magnetic field interference, switch to anti mode"

Would need a few clarifications about how you checked for compass errors and how far away you were from ground at 7 mins into flight.  

But 7 mins into flight and having checked compass for errors, does not sound like magnetic interference at takeoff point.  

DJI Gamora Posted at 2018-9-29 04:46
Hi, thanks for reaching DJI Forum. We do apologize for the troubles you had recently. I'd like to know the firmware version of your aircraft? We're here to help you. Let us know if you have more concerns. Thank you.

[view_image]

Being OP has a Mavic Air, it sure won't be .0500 FW as pictured.

UPDATE:  Looks like DJI has Officially annouced .0500 FW release, at least HERE.  However, at this time - DJI's Mavic Air Download area is still showing 05/03/2018 (.0400 FW).

hallmark007 Posted at 2018-9-29 12:39
The best way I can explain this is. If you put your Aircraft on the ground in normal circumstances, start it up, then lift it up and turn it 90 degrees to the right both your compass heading and IMU will both move together 90 degrees and no problems.
If you put your Aircraft on the ground and there is magnetic interference only the heading of your compass will change, your aircraft will still take off. But when it clears magnetic interference compass will then move to correct heading which you would think was great. But No, what happens is IMU is then conflicted and confused because of this sudden movement by compass, so you receive IMU exceptional heading warning, your aircraft cannot deal with data conflict so decides to switch to Atti mode dropping gps in favour of compass simply because aircraft can fly without gps but not compass.

Nice explanation Hallmark.  
This exact scenario happened to me with my AIr when flying on a beach near Frinton, so there were loads of houses less than 100 metres away, and despite having no warning's on the ground, I suffered multiple interference in flight which resulted in the Air flipping into ATTI mode and zooming off with the wind.  Happened 3 times in the same afternoon; each time luckily the interference stopped at some point allowing me to head back home.
This was the day I lost my faith in the Air. Great little drone and still use it when I'm way out in the countryside or hiking, but it's too easily confused when there's interference around....

Ian

Best way is reset/refresh firmware version of MA

hallmark007 Posted at 2018-9-29 12:39
The best way I can explain this is. If you put your Aircraft on the ground in normal circumstances, start it up, then lift it up and turn it 90 degrees to the right both your compass heading and IMU will both move together 90 degrees and no problems.
If you put your Aircraft on the ground and there is magnetic interference only the heading of your compass will change, your aircraft will still take off. But when it clears magnetic interference compass will then move to correct heading which you would think was great. But No, what happens is IMU is then conflicted and confused because of this sudden movement by compass, so you receive IMU exceptional heading warning, your aircraft cannot deal with data conflict so decides to switch to Atti mode dropping gps in favour of compass simply because aircraft can fly without gps but not compass.

Hi hallmark,

I do not agree about your remark about the red triangle.
This triangle does show the heading of your drone (info from mobile device) if the mobile device compasses and drone are well calibrated. (so both headings are equal)

If the drone compass is OK and the mobile device compass (that`s the red triangle) is NOK you get an incorrect heading. But safe to fly beacuse drone compass is OK. (not wise to fly imo, its so usefull to have them both aligned so you know where to look in the sky where your drone is flying)

Flying that red angle back to the center will always bring the drone back home, even if the mobile device compass is given the wrong heading.

A great example is this video : (about 180 degrees error on the mobile device!)
https://forum.dji.com/forum.php? ... D534%26typeid%3D534


cheers
JJB

HedgeTrimmer Posted at 2018-9-29 21:19
Being OP has a Mavic Air, it sure won't be .0500 FW as pictured.

UPDATE:  Looks like DJI has Officially annouced .0500 FW release, at least HERE.  However, at this time - DJI's Mavic Air Download area is still showing 05/03/2018 (.0400 FW).

Hi Ari, we appreciate your patience but we just recently launched the new firmware for the Mavic Air. Thank you.

I was flying in my house last night and encountered this, I had to recal and all is well again...

JJBspark Posted at 2018-9-30 01:04
Hi hallmark,

I do not agree about your remark about the red triangle.

While you may not agree and tell others that it is ok to fly without checking this, you will read in link below, this comes from one of the most well respected and knowledgeable people on dji drones, you should check out what he has to say on the matter. Fly Safe.

http://www.phantomhelp.com/Tips/ ... e-complete-guide.38

The only way to tell what may have happened is to look at the flight log.
People can speculate all they like but without an experience person checking the flight log everything is pure speculation.
You will not find the answers you are looking for from just an explanation.
Use the link in post #2 then copy a link to the file here so that it can be checked, then you may get the answers you seek.

I start to think that this is a dji problem with some firmware version, because I have read many cases similar to this. In my case it happened exactly the same, but the result was very bad, because my drone fall into a pool.
In the most cases the persons achieve to controll the drone (as it was in your case), because the time allow them, but in my case the flight only lasted 51 seconds (It was just starting and lost control at 39 seconds).
I leave my thread´s link.
My case

DJI only have asked me many things about accident, I have sent they whole evidences about the fatal flight and I still don´t have some answer.
I have the impression that they want me to get bored, but they will not achieve it, I will send them everything they ask me until I have specific answer.

hallmark007 Posted at 2018-9-30 14:18
While you may not agree and tell others that it is ok to fly without checking this, you will read in link below, this comes from one of the most well respected and knowledgeable people on dji drones, you should check out what he has to say on the matter. Fly Safe.

http://www.phantomhelp.com/Tips/prevent-a-crash-or-flyaway-with-your-dji-drone-the-complete-guide.38

Well, not the first time that well respected people are wrong or do not have the whole picture.

I had the other day a flight with my MA, first one with mobile device 1 ; red arrow pointing same direction as the drone. I switched (drone same position) with my second device ; red arrow 90% offsett. Why? compass on that device needed a calibration.
So misalignment red arrow not neccesarily an indication magn interference.

Guess the video i pointed had not a magn interference problem as well.So if the red arrow is not aligned but steady indication and after take-off checks are OK (turn left, turn right and all the other stick inputs) than its safe to fly.

When disconnect this red arrow will change direction when mobile device is moved around, mayby that`s where the confusion starts, the north and compass 360 turnes not the red arrow, but because the white mark stays at the top it looks that the arrow is turning.

See this (in between flight changing batt on my MA);
cheers
JJB

JJBspark Posted at 2018-9-30 22:57
https://vimeo.com/292656329Well, not the first time that well respected people are wrong or do not have the whole picture.

I had the other day a flight with my MA, first one with mobile device 1 ; red arrow pointing same direction as the drone. I switched (drone same position) with my second device ; red arrow 90% offsett. Why? compass on that device needed a calibration.

It’s very simple if your compass is off in your device or not calibrated on your device, if you know how much it’s off you can still check it, if the arrow moves after you start up there is a good chance that you have mag interference, telling people it is ok to fly in this situation is not good advice, common sense should prevail.
If you can then it would be wise to calibrate your device, above can be easily tested by just setting your drone on the bonnet of your car and you will easily see the the red triangle moving. It seems like you are just picking at what is good practice and common sense.
So yes for those who have device properly calibrated my point stands, and for those who don’t either check in your app or watch closely to see if triangle is moving when Aircraft is started and on the ground.

hallmark007 Posted at 2018-10-1 06:06
It’s very simple if your compass is off in your device or not calibrated on your device, if you know how much it’s off you can still check it, if the arrow moves after you start up there is a good chance that you have mag interference, telling people it is ok to fly in this situation is not good advice, common sense should prevail.
If you can then it would be wise to calibrate your device, above can be easily tested by just setting your drone on the bonnet of your car and you will easily see the the red triangle moving. It seems like you are just picking at what is good practice and common sense.
So yes for those who have device properly calibrated my point stands, and for those who don’t either check in your app or watch closely to see if triangle is moving when Aircraft is started and on the ground.

Think we agree more than we disagree on this!

If your mobile is offset and the offset angle is a steady one and the red angle is not rotating on its own : safe to fly;  there is no magnetic interference!.
Not wise to do but safe. Not wise beacuse its usefull to have it aligned with the drone to have good understanding where drone is. If you can re-think in your mind that 90 degrees offsett to the left means 90 degrees to the right where its flying...

Well, not all drone flyers knows about this compass in the app, see all the video where there are flying with a mobile device compass offset.

Fun is that with a connection video fail (some people start to panic), this red arrow still gets its information from the drone and when the outer compass heading ring is good aligned its so easy to bring the drone back home!

cheers
JJB

DJI Gamora Posted at 2018-9-30 02:30
Hi Ari, we appreciate your patience but we just recently launched the new firmware for the Mavic Air. Thank you.

[view_image]

thanks, have upgraded to the new firmware

ARI\@28 Posted at 2018-10-5 00:25
thanks, have upgraded to the new firmware

No worries Ari, should you have any queries don't hesitate to reach us again. We're here to help you.

I think there is a design issue with the compass or firmware on the Mavic Air. I have had two of them and they both report magnetic interference and force me to do a calibration. Normally I always have to do it the first flight of the day (even if I go to the same area as before) and then it is fine for the rest of the day. If I go back to the same spot the next day (an open field) it makes me do it again. Two different Mavic Airs have had this issue.

Some here say you should never have to recalibrate, well the compass interference warning never goes away on its own even if you move the drone to the middle of a field. Maybe a restart would work, but most the time the only way to get rid of it is to recalibrate.