Mavic Fly-Away

[JordieShapiro]

Appreciate all the sloothing so far, and thanks Anthony for that helpful checklist, as I am a bit new at this and appreciate the reminders.

Interesting Note:
I happen to be certified to fly drones commercially. While waiting for my Mavic to arrive I got some study material and passed my 107 UA knowledge test. I learned quite a bit in the process, but ironically very little that pertains to successful flying in the real world, if you can believe that. Needless to say, all the advice I've gotten from you guys wasn't in the study guide.

So, just to round up your thoughts so far as to why I lost control...

1. Although it wasn't a particularly windy day, perhaps wind speeds around the 400 ft mark are much harder to contend with.
2. BD0G notes that my loss of control happened about the time my drone hovered above a large reflective rooftop. Perhaps that was the cause of a long lasting disconnection from the controls.
3. Metal in my roof top take off point may have effected the drone in some way
4. Perhaps I didn't give return home enough minutes to react.


Without discounting any of these culprits, I do still think its possible that no explanation sufficiently explains why I lost control so quickly and never regained it, starting while the drone was still in visual distance. We'll have to wait and see what DJI ends up ruling, but I still hold out hope that the drone's loss of controller response isn't explainable by the weather conditions or human error.

However it goes, I will report back here

 

[Valkman1291]

Wow! Still considering my purchase, but this thread is terrifying! Having never before flown a drone, I certainly am prepared for a steep learning curve and am fully committed to a lot of pre-flight study.

This single thread, however, really makes me question the merit of a purchase.

Sooooooooo many hardware and environmental conditions that appear to be totally outside of the control of the user.

I am hopeful that just like many of the motorcycle forums that I participate in, a majority of the postings emphasize problems that really aren't that common.

Please, no suggestions that I start with a cheaper, less technical drone.

Thanks.


Sent from my iPhone using MavicPilots

 

[Spy_Corfu]

I had many successful flights with my phantom 4 and now mavic pro with only one glitch while using litchi but i switched to sports mode and back and all ok.
Anyway my question is did you get a gps lock before flying? Otherwise your home point is not set so return to home will not work.
Basically return to home always works and you can even help it to go faster using the remotes sticks but it should not have flown to the opposite direction.
If there was strong wind which has happened to me on several occasions on the mavic also you get a message warning, did you get such a message? Then you would change to sports mode etc etc..
Even if there was interference on the remote it would not effect the return to home of aircraft (assuming it was recorded before take off).
If the gps signal is lost during flight.. very unlikely as now there are 2 gps receivers.. but say it happened then the drone would be flying in atti mode which would require use of its sensors and cameras to maintain position but at that height i don't think its possible.. they are designed to maintain position indoors.
So basically my opinion is a gps loss before or while flying depends what you answer.


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[Anthony]

I had many successful flights with my phantom 4 and now mavic pro with only one glitch while using litchi but i switched to sports mode and back and all ok.
Anyway my question is did you get a gps lock before flying? Otherwise your home point is not set so return to home will not work.
Basically return to home always works and you can even help it to go faster using the remotes sticks but it should not have flown to the opposite direction.
If there was strong wind which has happened to me on several occasions on the mavic also you get a message warning, did you get such a message? Then you would change to sports mode etc etc..
Even if there was interference on the remote it would not effect the return to home of aircraft (assuming it was recorded before take off).
If the gps signal is lost during flight.. very unlikely as now there are 2 gps receivers.. but say it happened then the drone would be flying in atti mode which would require use of its sensors and cameras to maintain position but at that height i don't think its possible.. they are designed to maintain position indoors.
So basically my opinion is a gps loss before or while flying depends what you answer.


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The ground sensors in the Mavic only have a range of 13 meters so as the Mavic was at 400ft and only made it down to 166ft before loosing power they were never going to help in this case ...

 

[Spy_Corfu]

very true so if there was no gps lock for some reason then it would basically drift away but then you could always navigate it back home manually if RTH was not set correctly, so that does not explain the loss of remote control navigation, unless there was also interference and then there was no connection at all between the drone and the remote?

 

[Anthony]

very true so if there was no gps lock for some reason then it would basically drift away but then you could always navigate it back home manually if RTH was not set correctly, so that does not explain the loss of remote control navigation, unless there was also interference and then there was no connection at all between the drone and the remote?

Yes agree ... the action here would be to swap your view to map view and follow the compass line back to your home point.

However it does look like the RC was having lots of issues maintaining a conection and it is possible that the RC was restarting continually. .... this has been reported on the forum already and DJI replaced the drone BUT i think the drone is needed to prove this so im really hoping that jordie finds his drone as that will help prove the problem ....

 

[BudWalker]

I looked at this flight some. It seems that the AC was attempting to RTH but the wind was too strong. When RTH was not in effect the AC responded normally to control inputs.

When the first RTH was initiated the AC turned towards home and, with one exception, kept that heading. It would more or less keep the same distance from home during the intervals where RTH was in effect but then drift away when RTH wasn't in effect.


At time 612 GoHome (light beige areas) was cancelled and rudder was applied in both directions resulting in a yaw away from the go home heading. When GoHome was again initiated at about 640 the yaw was brought back to the GoHome heading. During the previous cancellation of GoHome elevator was applied and the drifting away from home was arrested. Note, that in the other intervals without elevator input the speed away from home accelerated. Perhaps if Sport were used better progress towards home could have been made.

A couple of interesting points. At the very end of the flight the AC was yawing without rudder input. This is almost certainly due to a lack of propulsion in one of the motor/props.


At about time 740 it appears the Tablet (and I'm assuming the pilot) moved about 600 meters down the street in the general direction of the AC. Did this happen? It wasn't mentioned.

 

[ferraript]

I also looked at the log and I came to the conclusion that it was user error
he even had many chances to do something and save the Mavic, but he didn't

1. he took off in a moment when Mavic didn't have enough satellites even to set home point (it was set later, but... it's not good idea to do something like that)
2. at 32 seconds' flighttime, there was (or should have been) warning about high wind
3. as BudWalker wrote, that wind was so high, that even without user's stick input, Mavic was moving to the east and it was fighting the west wind
4. at flighttime 133, there is 5-seconds interval, when Mavic switched to ATTI - in that time it travelled 40 m - so the wind must have been stronger than 8 m/s and that's really too much - this was really good moment when user could abort the flight and return to home - distance was only 26 m, height 49 m, but no...
5. and the rest of the flight is simple - thanks to user's ignorance (and/or inexperience), Mavic was just blown away by the wind and RTH didn't have enough power to do something about it
6. however, user could always at least land somewhere, but no, even in flighttime 1009, when battery was at only 10%, he pushed throttle to gain more height - Mavic got to 140 m
7. starting at flighttime 1042, there is OSD.isNotEnoughForce = true, from 1048 Mavic is slowly starting to lose height, at 1053 first motor switched off, at 1055 the battery got to 0% and three remaining motors switched off, at the end, Mavic is freefalling at 13 - 20 m/s, end of story (and sad end of Mavic)

but let's see what will be the DJI's opinion on this flight

 

[stratos]

Not to lecture anyone but.

For the love of your Mavic, please do not take off unless you have more than 10 satellites acquired and upon take off, hover for about 10~20 seconds and manual record your home location.

 

[Manfrenjensen]

Not to lecture anyone but.

For the love of your Mavic, please do not take off unless you have more than 10 satellites acquired and upon take off, hover for about 10~20 seconds and manual record your home location.

Probably a dumb question, but... what do you mean by "manual record your home location"? How do you that?

 

[stratos]

Probably a dumb question, but... what do you mean by "manual record your home location"? How do you that?

When you take off the craft will automatically record its home location. However you can manually "request" to set the home location again.

While on the app after take off, click on the three dots on the right hand side, then on the menu that open the first option "Main controller settings" you can click on Return to home location.
Alternatively, if you are on the iphone app, slide from left to right and you will see the option.

 

[Manfrenjensen]

When you take off the craft will automatically record its home location. However you can manually "request" to set the home location again.

While on the app after take off, click on the three dots on the right hand side, then on the menu that open the first option "Main controller settings" you can click on Return to home location.
Alternatively, if you are on the iphone app, slide from left to right and you will see the option.

Thanks for the explanation!
Now one last question... why do that? It sets it automatically. Why do it again just moments later?

 

[stratos]

Thanks for the explanation!
Now one last question... why do that? It sets it automatically. Why do it again just moments later?

Well I do it for two reasons.

1) It just reassuring that you did it.
2) If you hover a bit after you take off, the Mavic will also take a short internal video and some pics of the ground for precision landing. It you take off and fly straight away, you dont give enough time for the craft to do that. Believe me the precision landing is great Ive tested it myself and the craft land as precise as 10~20 cms away from takeoff

 

[Manfrenjensen]

Well I do it for two reasons.

1) It just reassuring that you did it.
2) If you hover a bit after you take off, the Mavic will also take a short internal video and some pics of the ground for precision landing. It you take off and fly straight away, you dont give enough time for the craft to do that. Believe me the precision landing is great Ive tested it myself and the craft land as precise as 10~20 cms away from takeoff

Wow, I didn't know that. Thanks again for the info.

 

[Spy_Corfu]

As i have both the phantom 4 and the mavic i use the phantom for high wind situations rather than the mavic as i find the phantom much more stable and powerfull to maintain position and fly against the wind on its way back to the home point.
The mavic is much smaller, lighter, and the motors are less powerfull than the phantom so it is more prone to drift away in high wind conditions.
In any case when i had a situation like that and it was obvious that at full throttle the drone was not moving at all (and over water) i switched to sport mode and using the controllers compass to direct the drone towards me and not away i saved my drone.
Oh and very important so not to drain the battery too much if even in sports mode you can see that its not covering enough distance then do zig-zags and lower the altitude. Not straight line to return home but left and right for some distance 20-30 degrees away from you and when it gains more speed as its not flying against the wind then try and move towards home position untill you fill it you have too much resistance so then do a zig zag away from you and on on...
This is like sailing techniques which they do that all the time to go against the wind.

 

[J-Dub]

Great preflight and flight info in this thread, flying over populated areas is a challenge, lots of electromagnetic irregularities everywhere, so we must rely on a lot of systems working flawlessly really. One setting to consider is HOME POINT LOCK. I'm nearsighted, and can barely see the Mavic a couple hundred feet away, very difficult to see the heading without looking at the controller Flying LOS is just that, a load of... we all use our Phones/Tablets/Notes/iPads/40" 4K Sony Trinitrons? To fly our drones. So I use Home Lock. Set your home point and get all your sats locked, etc, hover about 20 feet away (at least 5m) from your home point and activate the Home Lock function. Then whenever you want to bring the bird home, pull back on your pitch stick, she will fly towards home regardless of heading, and then you can rotate/yaw the craft whichever direction and film... The bird will hover that 20 feet from home point, you must Stop the home point function in order to bring it closer and/or land.

 

[bakerboy]

Not to lecture anyone but.

For the love of your Mavic, please do not take off unless you have more than 10 satellites acquired and upon take off, hover for about 10~20 seconds and manual record your home location.

Number of satellites doesn't always mean good positioning, but yes, if it doesn't say ready to fly (GPS), then you're not ready to fly

Or if you chose to, don't create a thread about how it drifts or "fly's away" because you don't know how to fly in atti mode

 

[Spy_Corfu]

Taking off in atti mode only means that you do not get a home position lock but it does not mean you will not get a full gps signal once you are up in the air.. which you almost always will as you are high above interference from trees building or whatever..

 

[spiderpig]

Wow! Still considering my purchase, but this thread is terrifying! Having never before flown a drone, I certainly am prepared for a steep learning curve and am fully committed to a lot of pre-flight study.

This single thread, however, really makes me question the merit of a purchase.

Sooooooooo many hardware and environmental conditions that appear to be totally outside of the control of the user.

I am hopeful that just like many of the motorcycle forums that I participate in, a majority of the postings emphasize problems that really aren't that common.

Please, no suggestions that I start with a cheaper, less technical drone.

Thanks.


Sent from my iPhone using MavicPilots

If you've never flown a drone before, get yourself a Phantom 3 Standard at 400 dollars and learn on that. Learn to fly it without the aid of all the automated modes. Once you can handle that one fine, move up to the Mavic. I think the Mavic is a bit much for a first drone.

 

[JordieShapiro]

Following up with my conversation with DJI.

They have ruled that high winds were to blame (i.e user error), and because of the input on this thread I am inclined to accept and understand their ruling. What's frustrating about dealing with DJI about these matters is there isn't a way to speak to an expert regarding the finding. The person I spoke to did offer me the option to contest the ruling, so in an email, while making it known that I respected their analysis I contested. I included data that indicates the wind speed at the time of my flight. My hope, is that DJI might meet my due diligence with a discounted price for a new Mavic.

I was told it would likely take 10 days to get an email returned from DJI. Let ya know the deets at that time



Thank you all for your input, and for not being too hard on me for my costly and traumatic rookie error. It's been a bummer, but ultimately, it'll be a big lesson learned.