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Crash following MA2 full power during hand landing

mackatacka

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Hi there everybody. First time poster (and drone user) so please forgive any mistakes.

Bought my Mavic Air 2 around Christmas time and have been having lots of fun with no incidents. Today I took it for quite a few flights around my farm. One flight in particular ended in my first incident/crash with the drone. I took the drone up and away from me, was still in control, and then I felt sprinkles of water on my hand (rain). Started to panic, activated sports mode, and immediately began coming back. Once I was over my head, I brought the drone down quickly. Usually I switch back to normal mode before landing but in my panic I tried to hand land (I live in a grassy area) in sports mode.

Once I grabbed the drone it started trying to fly away from my hand, even though the obstacle avoidance is supposed to be disabled in sports mode to my knowledge. Not wanting the drone to fly away from me, I held on, as it increased power trying to fly away. I couldn't simply reach in and turn the drone off (lest my fingers be sliced by full speed props) and the CSC was switched to emergency-only mode (and I was alone so I couldn't both hold onto the drone and mess with the app/RC simultaneously). This all happened very fast by the way if you're rightfully questioning any decision-making. I turned the drone upside down, but it kept running at full speed. Other than waiting for the battery to drain (not really an option) I saw no option but to drive the props into the grass to stop the drone. Even following this, they kept continuing to try and fly. I somehow got it to stop after that. The app never detected an impact to my knowledge.

I find myself very confused now and afraid to fly the drone again. I figured out how to obtain the .txt flight data and have uploaded that here if anybody knows how to analyse it. I can see in the DJI Fly app that the app gave me a "max power reached" warning during this incident. I took the drone up again soon after to test it, and it did fly, but I felt that it was drifting slightly unusually (not sure if that was actually the case or a placebo) and also had a "downwards sensor error" (I have had this sometimes even before the crash) so I brought it down again quickly and decided to post here before trying anything again. I am now wondering in regards to what I should do next. Any assistance would be greatly appreciated.
 

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iamcostas

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Hi Screenshot_2021-01-09-19-16-27-70.jpg
I just discover today an app which maybe could be useful.
If you have an android phone you could download the app airdata through Google Play .
After you could upload the flight text log to this app and you could see a lot of useful information about your drone and flight. Maybe this app will not give you an answer straight away but if you like you could try 🙂. The registration is very simple. Just an email address and a chosen password
 
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ICHOTT

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Well whilst you get replies helping solve the technical query, I& the drone ‘ok’ I would ASAP get it hoverin* and fly around a little and land etc, get your confidence back NOW whilst it’s all fresh, also you should always have a “where can i land if it goes wrong” plan and dont hand land without a lot of experience, get a landing pad of some sort as a minimum, I use a mat out of the car.

good luck and believe 👌😉
 

ICHOTT

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Also re your last comment, get everything and i mean everything, check user manual and YouTube, CALIBRATED, all aspects of drone and controller.

try a hover “before and after” calibration. Fresh battery, hover at eg 3 metres above a contrasting ‘target’ below, put gimbal to -90 looking straight down and video or monitor the drift without correcting it yourself other than big drifts ie give it a chance to self correct.
Then repeat after calibrating “everything”.
I could hover for 20+ minutes with ZERO drift above a landing pad.
 
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boblui

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Once I grabbed the drone it started trying to fly away from my hand, even though the obstacle avoidance is supposed to be disabled in sports mode to my knowledge.

In sport mode the bottom sensors are not turned off because they are needed not just for obstacle avoidance but also positioning when flying close to the ground and height detection when landing.

.... it increased power trying to fly away. ..... I turned the drone upside down, but it kept running at full speed.

That's because the drone received no intruction to land so it stayed in the flying state in which it would try to hold it's position in the air. When you moved the drone away from it's position with your hand, it would do all it could to move back to the original position.

The way to stop it is to pull the up/down stick all the way down or press the autolanding button on the app but the log indicates that no such actions was taken.

.... had a "downwards sensor error" (I have had this sometimes even before the crash) ....

This should have nothing to do with the incident but I do notice that near the end of the flight the output of the IR height sensor was stuck at 2 meters despite the fact that the drone was moved around. There can be some problems with the IR sensor. Suggest to do some more flying and post the log if the message shows up again.
 
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Phantomrain.org

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Hi there everybody. First time poster (and drone user) so please forgive any mistakes.

Bought my Mavic Air 2 around Christmas time and have been having lots of fun with no incidents. Today I took it for quite a few flights around my farm. One flight in particular ended in my first incident/crash with the drone. I took the drone up and away from me, was still in control, and then I felt sprinkles of water on my hand (rain). Started to panic, activated sports mode, and immediately began coming back. Once I was over my head, I brought the drone down quickly. Usually I switch back to normal mode before landing but in my panic I tried to hand land (I live in a grassy area) in sports mode.

Once I grabbed the drone it started trying to fly away from my hand, even though the obstacle avoidance is supposed to be disabled in sports mode to my knowledge. Not wanting the drone to fly away from me, I held on, as it increased power trying to fly away. I couldn't simply reach in and turn the drone off (lest my fingers be sliced by full speed props) and the CSC was switched to emergency-only mode (and I was alone so I couldn't both hold onto the drone and mess with the app/RC simultaneously). This all happened very fast by the way if you're rightfully questioning any decision-making. I turned the drone upside down, but it kept running at full speed. Other than waiting for the battery to drain (not really an option) I saw no option but to drive the props into the grass to stop the drone. Even following this, they kept continuing to try and fly. I somehow got it to stop after that. The app never detected an impact to my knowledge.

I find myself very confused now and afraid to fly the drone again. I figured out how to obtain the .txt flight data and have uploaded that here if anybody knows how to analyse it. I can see in the DJI Fly app that the app gave me a "max power reached" warning during this incident. I took the drone up again soon after to test it, and it did fly, but I felt that it was drifting slightly unusually (not sure if that was actually the case or a placebo) and also had a "downwards sensor error" (I have had this sometimes even before the crash) so I brought it down again quickly and decided to post here before trying anything again. I am now wondering in regards to what I should do next. Any assistance would be greatly appreciated.

Rain does get many pilots to Panic , Thus one of the reason why we make the Air 2 Wet Suits for the Drones.

Because you were in Sport Mode when you grabbed the drone , it is going to try and fly away even though the sensors were off so that is normal as you never really landed the drone.

Turning the Drone upside down did not work I think because you never really landed in other words it was as if you grabbed the drone in pure flight and tried to flip it over, it just kept wanting to fly and right itself.

So the Drone behaved exactly as it should have trying to survive the harrowing flight had you actually landed you would have been fine and the drone would have shut off when it flipped over.

Phantomrain.org
Gear to fly your Air 2 in the Pouring Rain and Land on Water.
 

iamcostas

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Hi again 🙂
I noticed at the notification section that at the end of the flight the GPS signal was weak (8 satellites).
Maybe because it was a cloudy day. Could you check at the next flight how many satellites could your drone pick up?
Also it says somewhere about blocked vision sensor(s). I wonder if that was when you was holding the drone.
Maybe weak GPS signal and no vision sensor contribute to the whole situation.
So, I guess next time pick a clear day , open area, buy a high speed SD card 128gb ( I got one from eBay for $30 if I remember well), fly the drone close to you , up, down, left, right , rotate and force it to land with pressing constantly the lever down. At the same time take a 4k video. Hopefully everything is fine 🙂
 

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mackatacka

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Also re your last comment, get everything and i mean everything, check user manual and YouTube, CALIBRATED, all aspects of drone and controller.

try a hover “before and after” calibration. Fresh battery, hover at eg 3 metres above a contrasting ‘target’ below, put gimbal to -90 looking straight down and video or monitor the drift without correcting it yourself other than big drifts ie give it a chance to self correct.
Then repeat after calibrating “everything”.
I could hover for 20+ minutes with ZERO drift above a landing pad.
I did exactly as you suggested. Here is video 1 before calibration. (I also have not replaced the propellers -- wondering if I should, I see no damage.) There was slight drift but I believe I have been seeing this since I got the drone. Also the downward sensor warning disappeared and I was even confident enough to take it further up and fly it around before landing it again.

I then calibrated the compass and IMEI and tried the test again. This time I saw significant drift to the point that my target was no longer in the frame. I guess I need to get out tomorrow and try calibrating again in case my calibration was off or made it worse.
The way to stop it is to pull the up/down stick all the way down or press the autolanding button on the app but the log indicates that no such actions was taken.
Thank you for your analysis boblui. I guess the log doesn't show it but I believe I did pull the stick down for a long time to try and active the landing, only for it to not work. I assumed that this is disabled in sports mode when it didn't work (I now know this is not the case, maybe I didn't pull for long enough?) So then I entered panic mode when that didn't work and the drone began attempting to fly away quickly, and the rest I've already written.
 

PhiliusFoggg

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If I may I would offer a slightly different wording of Boblui's etc. explanation for its fighting you.
This is based on my experiences with the MM, M2P and to some extent the P3adv.
After 'landing' I think the drone stops its motors because it detects that it is still i.e. not moving. (Given that some people advocate catching from the front, so that landing protection is not triggered, (and that catching from the front works) I do not think VPS height enters into the drone's 'thinking' during this or that VPS height is factored out).
Be it hand catching or landing on the ground I normally land manually, by holding the throttle closed and continue to hold the throttle closed until the motors stop but I have noticed that when, by chance, I have released the throttle before the motors stop the motors still stop so I presume this is an automated process.

Consequently I suspect that, when the drone 'landed' in your hand, your hand moved enough for the drone to detect the movement and so it 'thought' it was still airborne, it therefore
a) tried to remain stable and
b) follow any command inputs it was receiving.

I occasionally use this behaviour to 'hover' the MM or M2P off my hand. Using the CSC maneuver I start the props and, once the props are idling, I move my hand enough for the drone to detect the movement. It then tries to maintain its position and adjusts the motor speeds, once this is felt I carefully lower my hand and the drone 'hovers' off it. (I am deaf so do not hear motor speed changes.)

It also occurrs to me that it might have been possible that the drone was descending so quickly that it was in your hand by the time it reacted to registering that it was getting close to your hand. However I would think this is unlikely as it is my experience that both the MM and M2P slow their descents (due to VPS registering the approaching ground?) well above any possible hand catch height so I think that it would not have been descending fast enough for this to be possible, unless you suddenly moved your hand into its flight/descent path, i.e. to underneath the drone.

What does surprise me is the fact that the twist did not stop it. I am left wondering if inverting the drone is twisting it too far?
I have had to do a snatch and twist landing with the M2P, because of an out of control dog that was going for the drone, I had exhausted the battery waiting for the dog's owners to regain control, they didn't.
I recollect the motors stopped by the time the drone was at 90deg of tilt, which is just as well as I had whipped it around behind me and against my back.

Once the drone was 'safely' upside down in the grass I would have switched the CSC response to "Anytime" or whatever the relevant word for the MA2 is and stopped the motors. I really dislike the "emergency only" thing but think the trigger time for "Anytime" if far too short for it to be left as the acting response to the CSC position.
 
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boblui

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Thank you for your analysis boblui. I guess the log doesn't show it but I believe I did pull the stick down for a long time to try and active the landing, only for it to not work. I assumed that this is disabled in sports mode when it didn't work (I now know this is not the case, maybe I didn't pull for long enough?) So then I entered panic mode when that didn't work and the drone began attempting to fly away quickly, and the rest I've already written.

OK. It seems that you were using FLY APP 1.2.2 . The flight log produced by this version of the APP is readable only on AirData which is not that great for log analysis.

I have checked the data again in Excel and got some new observation :

Near the end of the flight down throttle was repetitively applied and the craft descended in response. However, at 247.5 sec , the craft stopped responding and stayed at a height of about 7 feet. This is abnormal. For some reasons the craft did not want to land ! You then kept applying down throttle and grabbed the craft 3 seconds later followed by wrestling with it for some 20 seconds before the motors finally stopped.

1610202620524.png

So the core problem is why the craft didn't respond to throttle-down input ?

I have run into such problem when playing with the bottom sensors of my M2P. If I tape up the cameras at the bottom, the craft will occasionally stop descending and stay at a height of about 4 feet despite the application of full down throttle. I had to turn off the bottom sensors before it would resume responding to the throttle input.

You have mentioned that the "downwards sensor error" warning has shown up occasionally even before the incident and that the craft drifted slightly unusually when you flew it again. May be there are some problems with the bottom sensors ?

Unfortunately further analysis is impossible because the log files produced by the new version of FLY APP cannot be read by CsvView which has been my main software tool for the purpose. I would suggest you to return the craft to DJI together with the log. I believe this case should be covered by warranty.
 
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mackatacka

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OK. It seems that you were using FLY APP 1.2.2 . The flight log produced by this version of the APP is readable only on AirData which is not that great for log analysis.

I have checked the data again in Excel and got some new observation :

Near the end of the flight down throttle was repetitively applied and the craft descended in response. However, at 247.5 sec , the craft stopped responding and stayed at a height of about 7 feet. This is abnormal. For some reasons the craft did not want to land ! You then kept applying down throttle and grabbed the craft 3 seconds later followed by wrestling with it for some 20 seconds before the motors finally stopped.

View attachment 121285

So the core problem is why the craft didn't respond to throttle-down input ?

I have run into such problem when playing with the bottom sensors of my M2P. If I tape up the cameras at the bottom, the craft will occasionally stop descending and stay at a height of about 4 feet despite the application of full down throttle. I had to turn off the bottom sensors before it would resume responding to the throttle input.

You have mentioned that the "downwards sensor error" warning has shown up occasionally even before the incident and that the craft drifted slightly unusually when you flew it again. May be there are some problems with the bottom sensors ?

Unfortunately further analysis is impossible because the log files produced by the new version of FLY APP cannot be read by CsvView which has been my main software tool for the purpose. I would suggest you to return the craft to DJI together with the log. I believe this case should be covered by warranty.
Thank you so much for this analysis. I believe this is correct as it lines up with my recollection of the events. That aircraft did not want to land.

I have hand caught my Air 2 many times before but this abnormal behaviour is what prompted me to grab it and what led to the incident. I will be opening a case with DJI as I am now nervous to fly the drone, since it hit the grass running at full power.
 

DanMan32

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Perhaps sport mode changes how it responds to what it detects with the downward sensors and twisting AC to stop motors.

Another feature the AC has is landing protection. If it sees that the ground is unsuitable to land, it won't and will prompt if it should land anyway. With all the hand maneuvers under the AC, that may trigger landing protection and that in turn may have it ignore down throttle. To make matters worse, all the manipulation did not keep it steady so it didn't think it was on the ground yet.

I don't think this would be a warranty issue, especially if it doesn't repeat but DJI might be able to explain why it behaved as it did, if you get the right tech.

This is a very unusual and perhaps unorthodox approach to landing. With hand landing, best approach is have it hover above eye level for safety with the props, put your hand under the AC but keep it steady, then down throttle until it lands in your hand and stops motors. If it goes up some in response to your hand, don't chase it, just keep your hand where it is and down throttle.
 

BossBob

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From the time that you start the motors and have the blades spinning to the time that the blades stop spinning following a command to land or motor stop the drone is trying to hold its position according to the sensors that are enabled or carry out the pilots commands.
You can throw it into the air, it will spin up the motors and hold position. Hand catch (without stopping the motors) then let go again and it will hover.
If you try to fly(take off) from a moving object, (down,left,right, forwards or backwards) the drone will appear to you to move straight after the motor start command, but the drone is just trying to hold its position relative to the earth, not relative to you or the vehicle.
If you were to land leaving the motors spinning (by gently bringing the drone to the surface not using a land command) and move the surface, the motors will spin up and the drone will try to hold position relative to earth.
So the answer to this incident is, when you hand catch, initiate a motor stop before you move the drone or it will fight violently to keep its position relative to earth.
I think that DJI will refer the pilot to the manual and its instructions on landing.
 
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Tyranttrent2020

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Hi there everybody. First time poster (and drone user) so please forgive any mistakes.

Bought my Mavic Air 2 around Christmas time and have been having lots of fun with no incidents. Today I took it for quite a few flights around my farm. One flight in particular ended in my first incident/crash with the drone. I took the drone up and away from me, was still in control, and then I felt sprinkles of water on my hand (rain). Started to panic, activated sports mode, and immediately began coming back. Once I was over my head, I brought the drone down quickly. Usually I switch back to normal mode before landing but in my panic I tried to hand land (I live in a grassy area) in sports mode.

Once I grabbed the drone it started trying to fly away from my hand, even though the obstacle avoidance is supposed to be disabled in sports mode to my knowledge. Not wanting the drone to fly away from me, I held on, as it increased power trying to fly away. I couldn't simply reach in and turn the drone off (lest my fingers be sliced by full speed props) and the CSC was switched to emergency-only mode (and I was alone so I couldn't both hold onto the drone and mess with the app/RC simultaneously). This all happened very fast by the way if you're rightfully questioning any decision-making. I turned the drone upside down, but it kept running at full speed. Other than waiting for the battery to drain (not really an option) I saw no option but to drive the props into the grass to stop the drone. Even following this, they kept continuing to try and fly. I somehow got it to stop after that. The app never detected an impact to my knowledge.

I find myself very confused now and afraid to fly the drone again. I figured out how to obtain the .txt flight data and have uploaded that here if anybody knows how to analyse it. I can see in the DJI Fly app that the app gave me a "max power reached" warning during this incident. I took the drone up again soon after to test it, and it did fly, but I felt that it was drifting slightly unusually (not sure if that was actually the case or a placebo) and also had a "downwards sensor error" (I have had this sometimes even before the crash) so I brought it down again quickly and decided to post here before trying anything again. I am now wondering in regards to what I should do next. Any assistance would be greatly appreciated.
1. First must important rule even your flying is never panic.
2. Do a site survey of your flight area, any structures or wires. This also includes the weather. If it looks like rain in the ground is probably already raining in the air.
3. Pre- flight this includes making sure landing protection is turned off for launching from your hand. Being your new I and yes it is easy but is running your remote way with one hand? You shouldn't have attempted this for your case for obvious reasons. Nice landing pad might have saved your drone.

Biggest thing is never panic that's usually when accidents happen. Let go of the controls the bird will stop. Gather your thoughts and continue.

Good luck
 

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