Mavic 2 Pro Flyaway

[Gbshen]

You can get State Farm insurance just for the drone with a stand alone policy that covers any loss with no deductable. $60 for a $1000 limit.

 

[cubelodyte]

So I couldn't resist the Mavic 2 Pro. It's my first drone.

For the five days I had it, I was impressed by the incredible piece of technology it was and excited about the new photographic possibilities.

I was flying on 9/11. Took off from the front of my house. When I connected the controller, it said there was mag interference, but the message went away. The drone established a home point and I took off, climbed to 150 feet (100 feet above the highest obstacle for about a half mile radius) for about a minute and a half, directly above my position, and looked at the sunset and lights. Everything seemed fine. At about 1:45, I turned and flew forward about 300 feet, and the drone just disappeared. No intermittent signal. It just totally dropped.

I immediately paused control inputs and waited about a minute, but it may not have been that long. Thinking the RC may still be connected i attempted to ascend to see if I could regain connection, and tried to get input on the map view, but it was not responding. Initiated RTH command, but don't believe it was ever received by the drone. The controller was continuously beeping and displaying "connecting..." Thinking the failsafe would kick in and it would come home, I waited about 5 min. Nothing. Walked directly under the last known point, still attempting to connect. Nothing. Took controller and drove in direction of flight path. Nothing.

Someone waited at the launch point in case it returned, but it did not.

Not being that experienced, it feels like a total in flight power failure, but I was hoping for some feedback.

DJI is reviewing records now. I attached the flight log.

Any advice appreciated.

Lincoln

I had a very similar experience this summer. My luck was a little better. I actually managed to force the thing to land before it got out of sight.
Sorry for your loss.
It turned out in my case that I was able to fix the problem by recalibrating the compass. If you manage to find yours, you will definitely want to do that.
Since you say you are new to flying, is it possible you never ran the initial calibration before you started flying?

 

[ChopperLinc]

I had a very similar experience this summer. My luck was a little better. I actually managed to force the thing to land before it got out of sight.
Sorry for your loss.
It turned out in my case that I was able to fix the problem by recalibrating the compass. If you manage to find yours, you will definitely want to do that.
Since you say you are new to flying, is it possible you never ran the initial calibration before you started flying?

I calibrated it a couple days before. Unfortunately in my case there was 0 connection to give any kind of control input.

 

[Inspirephil]

Hahaha. You are a good person for defending me against me! I’m the OP. A little self-deprecation to admit how dumb it was of me not to put it on there. Oddly, didn’t even cross my mind.

Well we live and we learn! Sometimes it’s the hard lessons that teach us the best lessons! But don’t let this one incident stop you from flying. I hope DJI is good to ya and they send you a replacement Mavic.

 

[MavMac]

The Mavic 2 Pro is the most technologically advanced drone on the market. That being said would every one of you please calibrate IMU and compass after you open it up. Both of those devices are important to the functionality of the drone and it navigational abilities. It is not wise to think that you should not have to do these things.

 

[BJR981S]

The compass is the most misunderstood aspect of flying.
Forums (and even some DJI manuals) are full of myths.
It's completely unnecessary to recalibrate the compass or anything else before flying.
Whether you travel 10 miles or 2000 miles makes no difference at all.

Not true. You need to watch some Air Crash Investigations episodes like the pilot that only calibrated his compass three times in the flight and few into a hill and killed all aboard.

Why is it that people don't understand the difference between Magnetic North and True North used in GPS route calculations????

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Here is a good reference from NOAA.

Magnetic Declination (Variation) | NCEI

The deviation from True North is totally dependant on your location. Here is a site that will show the deviation from Magnetic North to True North where you are located. Plug in some cities and see what results you get.

My local declination is Magnetic Declination: +12° 35'

Magnetic Declination on Map

Your compass error on a factory shipped drone with no calibration will be the factory Location near Shenzhen, Guangdong, China and at your home location.

Yes you will get away with no calibration if you shift locations 99 times out of 100 and never need a RTH but its that 1 that makes you lose your drone or kill all onboard, that is the rub.

I have been flying and sailing for some time with GPS based navigation. I have built and flown DJI based CP Helicopters. With Naza H and Wookong H flight controllers. The install procedure was to install the Compass / GPS module and offset the forward arrow of the GPS / Compass module to your local area once you determine the True North declination in degrees. i.e. rotate the module by those degrees.

I haven't dug through the FC code of more modern FCs but my assumption is that the true north calculations is done when you have a GPS fix and then perform the Compass calibration. It would be a excessive and pointless exercise for the flight controller to attempt this on the fly. Make sure you never do a Compass calibration indoors. The warning that appears is a warning that there is a magnetic anomaly too close to the drone and you should move away. This warning is not related to basic Compass calibration but a warning to move or recalibrate your compass due to severe magnetic interference, if it persists, you are flying near a significant magnetic anomaly.

If anyone has seen an incidence of the " I initiated a RTH and the drone flew back towards me but missed by about 50 feet and just keep going" Now you now know why. The GPS location of Home is recorded, the drone knows its current GPS coordinates and the FC calculates the vector to fly. It flies a vector (Bearing) based on True North as GPS coordinates are mapped by true north not magnetic north. It misses the Home Point decision radius and then just keeps flying. You see this issue more with flyers that are at extreme latitudes.

These issues are even more prevent with non DJI drones. Like Arducopter based drones flying waypoint missions. Arducopter pilots are very critical about getting a good fine tuned compass calibration.

My motor yacht does this to me all to often, if I am travelling at speed 30+KN, it will miss the waypoint radius and then get lost.

People that claim the DJI manuals are wrong and everyone else on the forums are wrong, need to have a serious think about how they have reached their conclusions. But then again, some people think we never went to the moon, and the earth is flat.

Cheers

 

[sar104]

Not true. You need to watch some Air Crash Investigations episodes like the pilot that only calibrated his compass three times in the flight and few into a hill and killed all aboard.

Why is it that people don't understand the difference between Magnetic North and True North used in GPS route calculations????

Quick description

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

Watch this video if you want details of compass Deviation and Declination.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

Here is a good reference from NOAA.

Magnetic Declination (Variation) | NCEI

The deviation from True North is totally dependant on your location. Here is a site that will show the deviation from Magnetic North to True North where you are located. Plug in some cities and see what results you get.

My local declination is Magnetic Declination: +12° 35'

Magnetic Declination on Map

Your compass error on a factory shipped drone with no calibration will be the factory Location near Shenzhen, Guangdong, China and at your home location.

Yes you will get away with no calibration if you shift locations 99 times out of 100 and never need a RTH but its that 1 that makes you lose your drone or kill all onboard, that is the rub.

I have been flying and sailing for some time with GPS based navigation. I have built and flown DJI based CP Helicopters. With Naza H and Wookong H flight controllers. The install procedure was to install the Compass / GPS module and offset the forward arrow of the GPS / Compass module to your local area once you determine the True North declination in degrees. i.e. rotate the module by those degrees.

I haven't dug through the FC code of more modern FCs but my assumption is that the true north calculations is done when you have a GPS fix and then perform the Compass calibration. It would be a excessive and pointless exercise for the flight controller to attempt this on the fly. Make sure you never do a Compass calibration indoors. The warning that appears is a warning that there is a magnetic anomaly too close to the drone and you should move away. This warning is not related to basic Compass calibration but a warning to move or recalibrate your compass due to severe magnetic interference, if it persists, you are flying near a significant magnetic anomaly.

If anyone has seen an incidence of the " I initiated a RTH and the drone flew back towards me but missed by about 50 feet and just keep going" Now you now know why. The GPS location of Home is recorded, the drone knows its current GPS coordinates and the FC calculates the vector to fly. It flies a vector (Bearing) based on True North as GPS coordinates are mapped by true north not magnetic north. It misses the Home Point decision radius and then just keeps flying. You see this issue more with flyers that are at extreme latitudes.

These issues are even more prevent with non DJI drones. Like Arducopter based drones flying waypoint missions. Arducopter pilots are very critical about getting a good fine tuned compass calibration.

My motor yacht does this to me all to often, if I am travelling at speed 30+KN, it will miss the waypoint radius and then get lost.

People that claim the DJI manuals are wrong and everyone else on the forums are wrong, need to have a serious think about how they have reached their conclusions. But then again, some people think we never went to the moon, and the earth is flat.

Cheers

To address just the key issue that you raised:

"I haven't dug through the FC code of more modern FCs but my assumption is that the true north calculations is done when you have a GPS fix and then perform the Compass calibration."
​

The compass, once calibrated to subtract the magnetic field of the aircraft (which generally doesn't change), measures magnetic north. The FC uses a global model of the earth's magnetic field to determine the local declination, which it then adds to the magnetic heading to get true heading. No calibration at all is required for that process and, in fact, there is no way for calibration to play any part in that process.

 

[Chopstix Kid]

Hey sunshine, why kick a guy when he's down? Your post offered nothing of value, other than to make you feel better.

Go back and read that again. He was calling himself stupid for not having the information on his drone.

 

[coliwabl]

So I couldn't resist the Mavic 2 Pro. It's my first drone.

For the five days I had it, I was impressed by the incredible piece of technology it was and excited about the new photographic possibilities.

I was flying on 9/11. Took off from the front of my house. When I connected the controller, it said there was mag interference, but the message went away. The drone established a home point and I took off, climbed to 150 feet (100 feet above the highest obstacle for about a half mile radius) for about a minute and a half, directly above my position, and looked at the sunset and lights. Everything seemed fine. At about 1:45, I turned and flew forward about 300 feet, and the drone just disappeared. No intermittent signal. It just totally dropped.

I immediately paused control inputs and waited about a minute, but it may not have been that long. Thinking the RC may still be connected i attempted to ascend to see if I could regain connection, and tried to get input on the map view, but it was not responding. Initiated RTH command, but don't believe it was ever received by the drone. The controller was continuously beeping and displaying "connecting..." Thinking the failsafe would kick in and it would come home, I waited about 5 min. Nothing. Walked directly under the last known point, still attempting to connect. Nothing. Took controller and drove in direction of flight path. Nothing.

Someone waited at the launch point in case it returned, but it did not.

Not being that experienced, it feels like a total in flight power failure, but I was hoping for some feedback.

DJI is reviewing records now. I attached the flight log.

Any advice appreciated.

Lincoln

Had you updated the IMU and compass before flying?

 

[HDBOB]

Did you have your FAA numbers written on the drone? I put mine on each battery with my phone number on a printed label .... and on the drone. An honest person can then get it back to you.

 

[BJR981S]

The FC uses a global model of the earth's magnetic field to determine the local declination,

I don't believe that this is the case. It would require enormous storage in the drone. And the field is constantly (Subtly) changing. It would need the GPS coordinates to then define the location on the magnetic map. But if it has the GPS coordinates then it can determine the Declination without a map.

If it was going to determine declination it would have to do it Via the Home point GPS coordinates set procedure or the compass calibration procedure. It needs an event to trigger the calculation. My guess would be that it only does this when a compass calibration is done. It would then be part of an overall compass procedure module in the code. At least that is they way I would write it.

It would require many CPU cycles to do this on the fly. And this would mean that all compass calibrations are meaningless. The CPU is way too busy doing other stuff.

Also the most precious resources in the FC is CPU cycles and fast executable memory. Executable storage is very precious. And CPU cycles generate heat. The developers have to keep their FW code as small as they can get it. All functionality is a decision based on priorities.

Without digging into the code it is pretty much conjecture.

The descriptions I gave relate to the actually technology not necessarily directly related to the implementation in a particular flight controller. My litmus test is what does the Manufacturer recommend.

Cheers.

p.s. I only went to this level of detail in the post reply as the poster I responded to used the same words as an introduction to a post that was very rude and abusive on another forum.

 

[richsemc]

just gone and put my name,zip code,tel number on quad after reading this. sorry for your loss

 

[ChopperLinc]

just gone and put my name,zip code,tel number on quad after reading this. sorry for your loss

Awesome! If it prevents another loss, some good will come of it!

 

[CRCs Reality]

just gone and put my name,zip code,tel number on quad after reading this. sorry for your loss

Yep, first thing I did with mine.. Name, phone# and "reward if found" on the drone and each battery.. I've never needed it, but IF I have a flyaway/crash and an honest person finds it, that's a cheap way to improve my odds.

 

[ChopperLinc]

Bear in mind that it was at 45 m altitude and moving at 12 m/s on a track of -133° when the downlink stopped:

View attachment 46462

Estimating the resulting ballistic trajectory from that point indicates that it could have travelled another 20 - 40 m while falling which would likely have cleared the house that it was approaching, and it certainly would not have ended up on the street:

View attachment 46463

Have you checked with the owners to see if it landed on the roof or in their swimming pool?

Sar104,

Your trajectory was dead on. Neighbor recovered it in his back yard exactly where you pointed.

Thank you so much.

Not sure if I should continue my warranty claim or use DJI Care Refresh as it seems like it did just fall out of the sky. Totally busted up.

Thanks to everyone else who helped with advice as well.

 

[Gbshen]

Unfortunately your rates will go up because you had a claim. You will be paying for the new drone many times over. I know somebody who submitted a claim for his crashed Phantom.....he was sorry.

I have not had a claim. If I do and the rates go up, probally still a better deal then paying for DJI Care and another $79 for repair - providing they would. No coverage if your drone flys off into the sunset never to be seen again with Care.

 

[Billyboy72]

****!!! Im sorry to read this. I certainly hope DJI does the right thing especially since you did actually spend the extra coin on refresh. More and more a reason why ill wait til the 2nd run to order mine. Ill just stick with my trusty ole MavicPro for now anyway.

 

[Flying Dragon22]

So I couldn't resist the Mavic 2 Pro. It's my first drone.

For the five days I had it, I was impressed by the incredible piece of technology it was and excited about the new photographic possibilities.

I was flying on 9/11. Took off from the front of my house. When I connected the controller, it said there was mag interference, but the message went away. The drone established a home point and I took off, climbed to 150 feet (100 feet above the highest obstacle for about a half mile radius) for about a minute and a half, directly above my position, and looked at the sunset and lights. Everything seemed fine. At about 1:45, I turned and flew forward about 300 feet, and the drone just disappeared. No intermittent signal. It just totally dropped.

I immediately paused control inputs and waited about a minute, but it may not have been that long. Thinking the RC may still be connected i attempted to ascend to see if I could regain connection, and tried to get input on the map view, but it was not responding. Initiated RTH command, but don't believe it was ever received by the drone. The controller was continuously beeping and displaying "connecting..." Thinking the failsafe would kick in and it would come home, I waited about 5 min. Nothing. Walked directly under the last known point, still attempting to connect. Nothing. Took controller and drove in direction of flight path. Nothing.

Someone waited at the launch point in case it returned, but it did not.

Not being that experienced, it feels like a total in flight power failure, but I was hoping for some feedback.

DJI is reviewing records now. I attached the flight log.

Any advice appreciated.

Lincoln

If there is too much electricity in the air or kp index is above 5, DON'T fly. Prevention better than cure. If you are using outside, non DJI app, switch from P mode on controller to S mode and back to P mode and press Home on controller. Exit the app. Reboot the app. If able, will connect to UAV. Press Home in outside app. If both fail, See the first statement on conditions before flying.

 

[Kingram]

Current Kp-index - Homepage of Michael Theusner

 

[Flying Dragon22]

"Mag interference" = Magnetic interference. This falls under the EM spectrum that includes radio waves. That would be too much EM activity, it would be interferring with radio controls ie too much electricity in air.