I had one of the scariest flights of my life tonight.
I had been having compass issues with both mini2 and mavic 3 all night the compass was off about 10 to 12 degrees on both drones even after calibrating them a couple of times. I just chalked up to the thunderstorms in the area.

   But the worst part came when after taking off with the Mavic3, I got about 300 meters just over a 1000 feet or so down the airport runway heading North and I lost all systems telemtry & i mean everything , Remoe ID, Compass, GPS and no RTH either auto or manual. plus the drone stopped sending or recording flight data as well.  the only thing i did not loose wias the radio transmission to the camera and the controls to the drone,thank god. I was able to fly it manually trying to get it back to the homepoint close as I could.   The drone was flying very squirrely and eratic trying to take off for the sky and flying foreward/backwards if you let up off the control stick.  I really had to struggle controlling it.    I barely got it landed. I set it down about 500 feet short of homepoint in the middle of the runway.


   once i got it on the ground safely. I turned ithe drone off. and looked it all really over good . I did not see anything out of the ordinary.  So I changed out the battery, rebooted the contoller and restarted the drone. I made 5 more flights &  It never did it again the rest of the night and i tried a number of times to reduplacate it.  but it never happened again, thought the compass caliabration was still off about 10 degrees,
   was this some weird glitch or is this something i should be worried about happening again . I am just glad th drone was close when it happened and not a mile out of a lake somewhere.

This screen capture of the flight data that was recorded

I uploaded the flight data and screen grabs

Hi there. Thank you for reaching out and we're deeply sorry for the trouble that this has caused. In ATTI mode, the aircraft cannot hover in place in horizontal directions, and the function of vision systems as well as Intelligent Flight Modes are unavailable. Therefore, the aircraft cannot position and hover itself and brake automatically, which increases the risk of potential flight hazards. It is strongly recommended that you find a safe place to land the aircraft as soon as possible if the aircraft enters ATTI mode. To reduce the likelihood of the aircraft entering ATTI mode and minimize hazards if it does enter ATTI mode, avoid flying in areas where the GPS signal is weak and in confined spaces. Thank you.

DJI Paladin Posted at 5-13 19:35
Hi there. Thank you for reaching out and we're deeply sorry for the trouble that this has caused. In ATTI mode, the aircraft cannot hover in place in horizontal directions, and the function of vision systems as well as Intelligent Flight Modes are unavailable. Therefore, the aircraft cannot position and hover itself and brake automatically, which increases the risk of potential flight hazards. It is strongly recommended that you find a safe place to land the aircraft as soon as possible if the aircraft enters ATTI mode. To reduce the likelihood of the aircraft entering ATTI mode and minimize hazards if it does enter ATTI mode, avoid flying in areas where the GPS signal is weak and in confined spaces. Thank you.

Thank you for your reply.
I still had GPS when it went into ATTI mode & I lost compass as well.
And I can vouch first hand. No Kidding it won't' hover in ATTI mode. I believe i even said i was struggling to keep it in the air. I baely got it landed safely
& if you look at my logs I had good gps single even after the aircraft went into ATTI mode. I was flying at a uncontrolled airport. there was nothing in my location to cause interference.

The only problem I was having was compass calibration before take off but as you can see i was getting better than 19 sat when the aircraft went into ATTI mode.
even when i landed i was still getting 19 sats according to the flight txt file

DJI Mavic3 flight data analysis

Ms Ivy Posted at 5-13 19:49
Thank you for your reply.
I still had GPS when it went into ATTI mode & I lost compass as well.
And I can vouch first hand. No Kidding it won't' hover in ATTI mode. I believe i even said i was struggling to keep it in the air. I baely got it landed safely

Hi,

Best to get advice and help is to upload your flightlog for this issue.
use this > https://www.phantomhelp.com/LogViewer/Upload/
Post the uploaded link on here.

ATTI mode is also there when the compass has a failure!  Large compass fail sets the drone in ATTI mode, even with receiving good GPS. In the log you will see all LatLlon data has been recorded.

But log will explain all.

cheers
JJB

Aside from the loss of telemetry, am I understanding that your drone entered ATTI mode and you were unsure how to control the drone during a loss of GPS situation?

I'm asking this not to be facetious, but because there are a lot of people out there who can't fly in ATTi mode and it's verging on stupid that DJI removed the ability to fly (and ultimately train in) this mode. Yes, the GPS is extremely reliable, but in situations like this you've got a lot of people who aren't prepared for this emergency situation.

Secondly, do you find yourself doing a lot of compass calibrations? I see some people just doing them for the hell of it and this is a bad sign. If you're getting a lot of compass calibration issues then it's worth looking at what environment you are doing the calibration. Take your drone away from any built up area, ideally a field, empty your pockets and keep anything metallic away from the drone during a calibration. In the Fly app you can verify the quality of the calibration, anything which shows a bad calibration should be done again.

ignore this post.

JJB* Posted at 5-14 01:37
Hi,

Best to get advice and help is to upload your flightlog for this issue.

JJB* the log and csv are at the bottom of post #1, the URL is visible in the 3rd screen capture. https://www.phantomhelp.com/logviewer/0ZNVYR0QX9MUXHLGI698/#

Sean-bumble-bee Posted at 5-14 02:53
JJB* the log and csv are at the bottom of post #1, the URL is visible in the 3rd screen capture. https://www.phantomhelp.com/logviewer/0ZNVYR0QX9MUXHLGI698/#

My bad, thanks for the correction.

Compass looks fine all flight, so a real ATTI mode ; no GPS position recordingsafter 2m48.8s
Happily she was able to bring craft back home, well done.

Would be nice to know if this failure is there on the next flight.

cheers
JJB

JJB* Posted at 5-14 03:11
My bad, thanks for the correction.

Compass looks fine all flight, so a real ATTI mode ; no GPS position recordingsafter 2m48.8s

No problem it's only by chance that I spotted them lol.

JJB* Posted at 5-14 01:37
Hi,

Best to get advice and help is to upload your flightlog for this issue.

Thank youfor the reply.
Phatomviewer is what I used to post all this data

For the first time this happened to me last night.  Flew the Mavic 3 several flights yesterday and then I was on a hyperlapse using course lock. Near the end of the hyperlapse it stopped recording and I lost all GPS data and saw the warning; Aircraft in ATT mode fly with caution.

I was able to manually fly it home however the controls were totally different. It wanted to drift and kept going after I let off of the controls.

During landing it said Landing in progress and would touch the ground but keep going.  Scraped a prop on the 2nd attempt to land. On the 3rd attempt I had it on the ground and had to put my hand on top of the drone and hold it on the ground because it wouldn’t shut off. The motors were going full speed.

Talk about scary!  I almost lost confidence in this drone after seeing how hard it was to land.  Not cool at all.  I have over 200 flights in the Mavic 3 standard and never experienced this.  Hope it does not happen again! I got lucky being able to hold it down

CloudVisual Posted at 5-14 02:29
Aside from the loss of telemetry, am I understanding that your drone entered ATTI mode and you were unsure how to control the drone during a loss of GPS situation?

I'm asking this not to be facetious, but because there are a lot of people out there who can't fly in ATTi mode and it's verging on stupid that DJI removed the ability to fly (and ultimately train in) this mode. Yes, the GPS is extremely reliable, but in situations like this you've got a lot of people who aren't prepared for this emergency situation.

well I do not fly indoorsa lot so I don't in ATTI mode much, so yes it I was unprepared for something like that to happen and if it would have Happen lets so I was mile out I am not so sure it would have made it back.  I have flown in ATTI a few times with the mini2 in a huge warehouse But that was the extent of my experience. Ive been flying over a year I am pretty fair at handling unexpected issues . like radio lost and unpected force landings. but never with the mavic I onl;y had this drone in the air 11 hours

But this was a first time I expreinces ATTI mode in the mavic and it flew like it was on drugs and something i care not repeat.
I only try to do compass calibrations  when I am in a new locations.  But yesterday I was having trouble to get the compass to point right on 2 drones to calibrate correctly. we did have a few thunrder stomes in the area.    But I never lost gps, & compass at the same time  when flying the controller showed the drone compass off about 10 degrees to the left of what it was actually flying looking at screen

I was using an android phone yesterday instead of my Ipad . could that have anything to do with it?  

I am going to another locations and see if it will repeat this ATTI mode again . I fly the mavic 3 a fair disatance most time from home point& even though i have the caqre refresh insurence for the drones  I want to make sure i do not experience this again or I'll get it fixed before I do loose the drone

Ms Ivy Posted at 5-14 05:01
well I do not fly indoorsa lot so I don't in ATTI mode much, so yes it I was unprepared for something like that to happen and if it would have Happen lets so I was mile out I am not so sure it would have made it back.  I have flown in ATTI a few times with the mini2 in a huge warehouse But that was the extent of my experience. Ive been flying over a year I am pretty fair at handling unexpected issues . But this was a first and something i care not repeat.
I only to compass calibrations  when I am in a new locations.  But yesterday I was having trouble to get the compass to point right on 2 drones to calibrate correctly . But I never lost gps for the mini2  just the Mavic3  when flying the controller showed the drone compass off about 10 degrees to the left of what it was actually flying looking at screen

"I only to compass calibrations  when I am in a new locations"

Bingo! Do not do this unless the drone tells you to calibrate or you may cause a false reading and then you end up with the issue you faced.

CloudVisual Posted at 5-14 05:08
"I only to compass calibrations  when I am in a new locations"

Bingo! Do not do this unless the drone tells you to calibrate or you may cause a false reading and then you end up with the issue you faced.

I was always told when in a new locations like a city or county  you should calibrate your compass , so I should not do that when I fly in a new location like a county or city?

dronethemoment Posted at 5-14 04:55
For the first time this happened to me last night.  Flew the Mavic 3 several flights yesterday and then I was on a hyperlapse using course lock. Near the end of the hyperlapse it stopped recording and I lost all GPS data and saw the warning; Aircraft in ATT mode fly with caution.

I was able to manually fly it home however the controls were totally different. It wanted to drift and kept going after I let off of the controls.

Again, this is why DJI needs to allow manual selection of ATTI mode so people can practice for this emergency.

You say the drone was drifting, but it's down to you not being able to practice for this scenario that you were unable to understand why the drone drifts and how to fly correctly in ATTI mode.

A very simple way to explain it is that your drone in ATTI is now an ice hockey puck. Fly forwards on a calm day and it'll keep doing that until to bring it to a stop, it will fly as if there is no resistance. If it's windy, the drone will get blown in the wind direction.

All I can say is that you need to give your drone time to get a locked home point. Lots of people just unfold their drone and take off as soon as possible. Give the drone time to warm up and find home, which you will know when you have at least 12 satellites and the symbol turns white, along with the audible home point recorded confirmation.

Ms Ivy Posted at 5-14 05:12
I was always told when in a new locations like a city or county  you should calibrate your compass , so I should not do that when I fly in a new location like a county or city?

I've flown from the UK to Mexico, Japan, Australia to name a few and didn't have to calibrate the compass.

Trust me, you do not need to recalibrate your compass. The ONLY time you do this is if the App tells you.

CloudVisual Posted at 5-14 05:16
I've flown from the UK to Mexico, Japan, Australia to name a few and didn't have to calibrate the compass.

Trust me, you do not need to recalibrate your compass. The ONLY time you do this is if the App tells you.

Thanks that good to know

dronethemoment Posted at 5-14 04:55
For the first time this happened to me last night.  Flew the Mavic 3 several flights yesterday and then I was on a hyperlapse using course lock. Near the end of the hyperlapse it stopped recording and I lost all GPS data and saw the warning; Aircraft in ATT mode fly with caution.

I was able to manually fly it home however the controls were totally different. It wanted to drift and kept going after I let off of the controls.

That is exactly how I felt lucky to get it landed. the drone was very squirrelly like you said I landed about 500 feet short of my landing pad. when I could see I had a clear landing area on the runway .
I was only a 1000 feet out. But if I would have been a mile out over Watagua Lake Who knows if the drone would have made it back . they was a fair steady 7-10 knot wind to. which made flying in ATTI mode a bit tricky
I am going to a new locations today and do some testing to see if I can duplicate it again or if it was a freak glitch,

Ms Ivy Posted at 5-14 05:22
Thanks that good to know

I would however, as mentioned above, calibrate your drone one last time. You need to do it in the open, no ferrous objects near you and then verify the compass is calibrated in the App. You will see a health bar indicating how accurate the compass is. Get it right once and for all and then never touch it again!

CloudVisual Posted at 5-14 05:28
I would however, as mentioned above, calibrate your drone one last time. You need to do it in the open, no ferrous objects near you and then verify the compass is calibrated in the App. You will see a health bar indicating how accurate the compass is. Get it right once and for all and then never touch it again!

Thank you for the advice. i'll do that
I only;y set the MUI calibration when i do firmware updates so maybe I'll start doing that for the compass as well

Ms Ivy Posted at 5-14 05:12
I was always told when in a new locations like a city or county  you should calibrate your compass , so I should not do that when I fly in a new location like a county or city?

hi,

Your ATTI flight was not beacuse of a bad compass, so calbration did not cause this error.

Once a compass has been calibrated, there is no need to do this bc you are in a different area or so.

I seldom perform a compass calibratation, only do it when the FlyApp informs me to do so.

BUT a good compass calibration never harms you drone, do it before eacht flight, not a problem.
Only a waist of time....

What is important to do before each flight is to check if the compass heading of you drone in the map view FlyApp is the same as the actual heading!  
If not the same : DO NOT FLY.  (switch off drone, move another spot and try again)
This is the most important check for a DJI drone.

cheers
JJB

Would a high KP cause this?  I know we were in a solar storm off and on the past few days.  

JJB* Posted at 5-14 05:34
hi,

Your ATTI flight was not beacuse of a bad compass, so calbration did not cause this error.

Thank you for the Good advice.
I have over 600 flights with my mini2 . and not once had this problem .
I only have 23 flights on the mavic3 its a new drone less than few weeks old. So I was afraid I was having some kind of issue.

its funny I was flying off a helicopter pad in the middle of a uncontrolled airport tarmac. like I said I was not experience any gps issues. right until it went ATTI and even then I had 19 sats according to the flight data    But the compass for both my drones were off about 10 degrees according to the flyapp which I chalked up to the thunderstorms that have been in the area.  
I'm going to go to a new locations today with my ipad instead of the pixel android phone and d some testing and see if I can replicate the issue again
thankfully I was not a mile out over a lake or in a city around building

Tom_765 Posted at 5-14 05:42
Would a high KP cause this?  I know we were in a solar storm off and on the past few days.

the UVA forecast said the KP index was 2.7 that day the wind was 5 knots with T-storms in the area.
it also showed 27 sat locks as well so. it could have been but the UVA forecast was telling me something different

Most likely caused by the rebar in the helipad causing your compass to read incorectly. When you gained altitude and the compass corrected itself, the IMU was then incorrect. In other words, regardless of GPS, the drone did not know its true heading. It was confused by conflicting information between GPS and IMU. When you get the "compass needs calibration" warning, instead of calibrating, just move takeoff point.

CloudVisual Posted at 5-14 05:14
Again, this is why DJI needs to allow manual selection of ATTI mode so people can practice for this emergency.

You say the drone was drifting, but it's down to you not being able to practice for this scenario that you were unable to understand why the drone drifts and how to fly correctly in ATTI mode.

Hi thanks for the reply.  The hockey puck on ice is exactly how it was flying. Just kept sliding along.

I do however ALWAYS wait for full GPS and Home Point Updated before I take off. I also take off and hover above my home point.  I do not hand launch especially the Mavic 3.  I was flying at my home base which are where about 70% of my flights take place and I fly responsibly.   This is the first time in 800+ flights between the mini 3 pro and Mavic 3 that I have seen this occur.  

I was in a 750 frame hyperlapse and everything was performing great until the end after 20 minutes of flying.  In this screen shot before the issue happened you can see I had 21 satellites.

Over 1,000 miles flown and never seen this especially in my local home base.  

Weather was good, RC signal was good. VLOS maintained.  No reason other than a fluke / glitch.  

The next flight worked perfectly.

I agree ATT mode would be great to practice this type of emergency.

Mobilehomer Posted at 5-14 06:29
Most likely caused by the rebar in the helipad causing your compass to read incorectly. When you gained altitude and the compass corrected itself, the IMU was then incorrect. In other words, regardless of GPS, the drone did not know its true heading. It was confused by conflicting information between GPS and IMU. When you get the "compass needs calibration" warning, instead of calibrating, just move takeoff point.

Hi,

Rebar...

But not a single compass error in the log.
Plus GPS off 2m28s in flight with only forward input...
Plus before that few times yaw input (wich normally triggers a compass error if influeneced by rebar)

So i am not convinced it is a compass error wich led into ATTI mode.

In the chart the compass data line and a compass reference line, if the line depart from each other = compass error.

Plus   if a compass is in error;  flightmode into ATTI because if this  but GPS is still recording the Lat Lon positions, not in this log.

cheers
JJB   [ Charts by FRAP ; the 'best' software for flightlog analysis ]

CloudVisual Posted at 5-14 05:14
Again, this is why DJI needs to allow manual selection of ATTI mode so people can practice for this emergency.

You say the drone was drifting, but it's down to you not being able to practice for this scenario that you were unable to understand why the drone drifts and how to fly correctly in ATTI mode.

Also flying in ATT mode wasn’t a big issue for me. I have aircraft piloting experience and can compensate for the drifting. Got it back home no problem, however why it refused to shut off on landing and kept trying to take off again is another story.  Once it touched the ground I hoped the motors would shut off, but I had to risk it to walk up and put my hand on top and hold it down even though it was running full motor speed.

Trying the emergency shutoff with both sticks down and inward only made the drone try to move while on the ground and caused it to scrape a prop.  Not cool!   I imagine a few Mavic 3’s getting destroyed like this.

Was this a concrete runway? If so, the amount of rebar (and who knows what other wires/electronics) could have contributed to the false calibration(s).

Mobilehomer Posted at 5-14 06:29
Most likely caused by the rebar in the helipad causing your compass to read incorectly. When you gained altitude and the compass corrected itself, the IMU was then incorrect. In other words, regardless of GPS, the drone did not know its true heading. It was confused by conflicting information between GPS and IMU. When you get the "compass needs calibration" warning, instead of calibrating, just move takeoff point.

The rebar makes a lot of sense . But after take off the compass was the same thru out the whole flight .
I never did have any MUI errors

KLRSKIR Posted at 5-14 06:44
Was this a concrete runway? If so, the amount of rebar (and who knows what other wires/electronics) could have contributed to the false calibration(s).

The helicopter pad was concrete about 20'x20' 6 to 8" thick
the airport runway is pavement or asphalt
there is a radar tower with a night beacon  1/2 miles south of the field and no runway lights on the runway and the drain pipes look like the pipe in are composite , properly fiberglass or cement. they don't look they are made of steel.
you can see for your self how the airport is laid out from the pictures in this thread. https://forum.dji.com/forum.php?mod=viewthread&tid=290329

after some thinking . there would have to be a boat load full of steel in the heli pad to make my compass off. Because I have a 15'x15' deck that is concrete  that has a lot of wire and rebar in the mix we just had it poured last fall. it over hangs the hill we live on and it had no effect what so ever on my compass on either of the drone's I just went to test it after seeing the comments about the rebar.

JJB* Posted at 5-14 06:42
Hi,

Rebar...

thats good intel to know , thank you for sharing how to check that compass errors

Maybe the drone was just having a bad day?  

Hi Ms Ivy

A few observations from your log.

Homepoint updated twice 2.4s and 12.4s

Satallite count jumps from 19 to 32 at 165.2s and 165.4s then returns to 19

GPSLevel drops to 0 at 169s and remains at 0 for rest of flight

ATTI mode at 169.2s until end of flight

See attached

Regarding the landing pad, take a normal magnetic compass and, away fron the landing pad, locate north. Then place the compass on the pad, at launch point of the drone, and check whether or not the compass still thinks north is in the same place.

With regards to ATTI mode.
When we fly our drones in the normal way, with GPS and or VPS, the drone automatically holds position or speed & course and, when we command a reduced speed, brakes. I.e. if you where flying forward (nose down ) and release the elevator the drone will actually go nose up to brake and come to a halt more quickly.

In ATTI mode none of this automated control takes place, we are not only reponsible for holding true to a particular flight path but we have to apply the brakes. So if, in ATTI mode, your drone encountered head or tail winds its ground speed would, for a given elevator setting, vary. If, in ATTI mode, it encountered a side wind it will be blown down-wind sideways and it is up to you to apply aileron/roll to counter the side wind.
Those behaviours may make it appear as if the drone were drunk.

Pleomax Posted at 5-14 10:40
Hi Ms Ivy

A few observations from your log.

That is very interesting. The question is now is what happened to make it do that and will it do it again?
Spike in Kp rating?

Sean-bumble-bee Posted at 5-14 10:44
Regarding the landing pad, take a normal magnetic compass and, away fron the landing pad, locate north.Then place the compass on the pad your launch point the drone and check whether or not the compass still thinks north is in the same place.

With regards to ATTI mode.

Thank you for that great explanation. that was exactly how the drone acted.  I was lucky to be ina place I could do a emergency landing on the runway . but this could have been bad if I was out a ways over water  or flying in a city  park. I didn't have much flight expeince with ATTI I am afraid .
after i had landed did a good check of everything and put in a new battery & took off  and landed in  5 more flights about 30 minutes with out a bit of problems . I hope what happen was a once off it sounds like a few people experience the same issue as i did yesterday

Ms Ivy Posted at 5-14 10:49
That is very interesting. The question is now is what happened to make it do that and will it do it again?
Spike in Kp rating?

Don't honestly know. Unusual to lose GPSLevel completely but don't think it's any way connected to Kp rating.
Did you reset your Home Point?