I'm posting this here so I can link to it from the service request form.

After a normal takeoff, the MA2 had been flying for a couple minutes, low and slow, when it gave me a warning that said "Motor error. Check propellers and fly with caution (Code: 120652)". I'm new to the MA2 but I've got about 50h of air time with an MA1 and I'm used to seeing similar-sounding warnings which have never been a safety concern or had an impact on the mission. I double-checked everything, saw no issues, and cautiously continued my flight. About a minute later I got the error again and a few seconds after that I got another warning: "Not Enough Force/ESC Error. Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, land immediately (Code: 30168)." I was in the process of a slow ascent, getting a shot, and decided I would heed the warning, fly with caution while I finished my shot, and then bring it back and land.

I never got the chance. Suddenly, the camera goes crazy and the drone begins making some very distressing noises. I look up and it's plummeting out of the sky; not exactly in free-fall but flailing wildly and very far from anything that could be considered controlled flight. It bounced off the roof of my house and landed in the snow.

This aircraft has been flown 9 times for a total of 1 hour and 13 minutes. It has stock props, no prior damage, and has exhibited no previous issues. On the day of the crash, the temperature was 30F and humidity was 95%. Visibility was 6 miles and there was snow on the ground. Two days prior, I flew without problems when the temperature was 14F and humidity was 75%. During the flight, using the Smart Controller, I saw only these three warning messages, all of which said "fly with caution" and are classified as "low severity, impact on safety is likely not significant." In the log, however, there are dozens and dozens of these warning messages followed by error messages about a motor being blocked.

Here's a link to the flight at Airdata: https://app.airdata.com/share/MiQlMn

And a link to the video:

The issue does not seem to be related to the MA2 it self, it is more the pilot who was flying out of range of the given specs by DJI.
It looks like you had ice on your props during the flight. This can easily happen under the conditions you were flying at.

Maybe this video shows best your issue.

MySky Posted at 2-23 11:07
The issue does not seem to be related to the MA2 it self, it is more the pilot who was flying out of range of the given specs by DJI.
It looks like you had ice on your props during the flight. This can easily happen under the conditions you were flying at.

What was "out of range" here? 30F and ~800' MSL are well within the aircraft's published temperature and altitude ranges. Also, when I recovered the drone, there was no obvious ice on it. I didn't inspect it carefully before bringing it inside, and it did fall in the snow so I might have overlooked it, but I never actually saw any ice on the props. Based on what I've read and seen since the crash, it does seem likely that icing was the issue but I would never have expected that to be a problem while flying within the aircraft's published operational range like I was. If it was ice, it apparently happens with small amounts of it. Neither could I have anticipated "fly with caution" means that a motor failure is imminent. I routinely see "fly with caution" messages in various DJI apps.

I never specifically said this was a problem with the MA2 itself, but really, if it's not a problem with my specific unit then isn't it at least problem with the documentation and a shortcoming in the aircraft design? FWIW, my MA1 and my Inspire 1 have never had any issues like this.

Edit:
Perhaps it was my language about "light fog" that was confusing. Technically, there was no fog that day. Conditions were overcast and visibility was 6 miles, as you can see in the weather report at Airdata. Fog is defined as visibility under 1km. I used that phrase because I wanted to communicate that the sky appeared hazy to me and, in my post-crash googling, I had found mention of icing issues and so I wanted to report it for the sake of being thorough.

The issue is more than likely still icing, fiying below freezing in 95% humidity.   

The other thing is choosing to seemingly ignore what I would consider to be serious errors of motor issues considering the environment your flying in..  You should have come back to land when you received he first warnings..   You did not indicate whether the bounce off the roof and the crash landing in snow caused any damage to your MA2 other than perhaps props. If not, consider yourself lucky.   

Looking at the info on AirData, you had a few of motor warnings and a slew of force errors, I'm guessing the app displayed the motor warnings and not all the force warnings,  you should heed the warnings the first time you see them, and not try to fly on..  Not sure why force errors were classified low and medium risks, seems like force errors would be high priority too..  But perhaps thats just me and I don't want to crash my $800 MA2..

Your airdata sharing settings are minimal and do not let us download a more complete datalog. Is there a reason for that?

We see a lot of "motor blocked" messages, just the opposite of overspeed. Are they all free to turn now?

dwillis Posted at 2-23 15:19
What was "out of range" here? 30F and ~800' MSL are well within the aircraft's published temperature and altitude ranges. Also, when I recovered the drone, there was no obvious ice on it. I didn't inspect it carefully before bringing it inside, and it did fall in the snow so I might have overlooked it, but I never actually saw any ice on the props. Based on what I've read and seen since the crash, it does seem likely that icing was the issue but I would never have expected that to be a problem while flying within the aircraft's published parameters like I was. If it was ice, it apparently happens with small amounts of it. Neither could I have anticipated "fly with caution" means that a motor failure is imminent. I routinely see "fly with caution" messages in various DJI apps.

I never specifically said this was a problem with the MA2 itself, but really, if it's not a problem with my specific unit then isn't it at least problem with the documentation and a shortcoming in the aircraft design? FWIW, my MA1 and my Inspire 1 have never had any issues like this.

I never specifically said this was a problem with the MA2 itself, but really, if it's not a problem with my specific unit then isn't it at least problem with the documentation and a shortcoming in the aircraft design? FWIW, my MA1 and my Inspire 1 have never had any issues like this.

Cold and moist conditions are inviting propeller icing and DJI's small drones with folding props are more susceptible to it than the bigger drones with fixed props.
The description of your incident and the warning messages are exactly what you would get with prop icing.
The props lose lift with.moisture freezing on them and changing the airflow.
The motors spin faster but because the props aren't properly providing lift, it just doesn't help.
Drone comes down.

Hello there dwillis. I am sorry for the trouble this has caused and thank you for reaching out. Since there was a crash that happened to your DJI Mavic Air 2 before. It would be best to contact our DJI Support Team at https://www.dji.com/support for us to be able to assist you further with regards to this matter. Again, I am sorry for the trouble and thank you.

Macinfo Posted at 2-23 16:42
The issue is more than likely still icing, fiying below freezing in 95% humidity.   

The other thing is choosing to seemingly ignore what I would consider to be serious errors of motor issues considering the environment your flying in..  You should have come back to land when you received he first warnings..   You did not indicate whether the bounce off the roof and the crash landing in snow caused any damage to your MA2 other than perhaps props. If not, consider yourself lucky.   

Yeah, as I said, it was most likely icing. I didn't ignore any errors though and, however many are in the logs, I saw only three on the screen, with the last two coming too late to do anything about it. The time from the last error to the aircraft exiting controlled flight was about 4s. When I saw the first error I heeded it immeditely, followed the instructions to the letter, and flew with caution. I checked the telemetry and kept the aircraft nearby and in a safe environment. Nothing seemed amiss and the warning wasn't recurring so I cautiously continued. Like I said, I routinely see motor-related warnings in other DJI apps and they are not a cause for concern.

The crash snapped one of the forward struts, busted a light/sensor out of one of the rear struts, and damaged the ESC in some manner that the app says requires service. Thankfully, I have DJI Care Refresh.




@GaryDoug

No, no particular reason. Is there location data in the datalog? I set the Airdata share to not provide any location data but I'm not sure what all that covers. I just thought it might be prudent not to share geodata if there wasn't a specific reason to do so.

All the motors were turning freely when I inspected them after bringing it inside. Although, if a motor were frozen up, I imagine the impact with the ground would be likely to break any ice loose.







@Labroides
I hadn't thought about the MA2's folding props vs the MA1's fixed props. Seems likely that's what makes the difference in this situation.


@DJI Stephen
I have already reached out to the support team and have begun the Refresh process. The intake form asked for a description of the incident but the character limit was too short so I posted here and just linked to it.

Near 100% humidity and below freezing temperatures are a sure recipe for prop icing. Unfortunately you ignored the warnings the app gave you.

dwillis Posted at 2-23 20:22
Yeah, as I said, it was most likely icing. I didn't ignore any errors though and, however many are in the logs, I saw only three on the screen, with the last two coming too late to do anything about it. The time from the last error to the aircraft exiting controlled flight was about 4s. When I saw the first error I heeded it immeditely, followed the instructions to the letter, and flew with caution. I checked the telemetry and kept the aircraft nearby and in a safe environment. Nothing seemed amiss and the warning wasn't recurring so I cautiously continued. Like I said, I routinely see motor-related warnings in other DJI apps and they are not a cause for concern.

The crash snapped one of the forward struts, busted a light/sensor out of one of the rear struts, and damaged the ESC in some manner that the app says requires service.  Thankfully, I have DJI Care Refresh.

Is there location data in the datalog? I set the Airdata share to not provide any location data but I'm not sure what all that covers. I just thought it might be prudent not to share geodata if there wasn't a specific reason to do so.

There is no data .. just a superficial summary report.
It's not possible to see how fast, high, what joystick inputs, what the drone did etc.
Unless you are flying  delivery runs from your meth lab of some such activity you need to hide, there's really no need to be so sensitive.
The genuine value of allowing data readers to see the useful data outweighs the very minimal issue of someone maybe working out where you flew.

MisterFrag Posted at 2-23 20:38
Near 100% humidity and below freezing temperatures are a sure recipe for prop icing. Unfortunately you ignored the warnings the app gave you.

I ignored no warnings. I took them literally and followed them exactly. It does now look like 30F and 95% humidity is a recipe for crashing, however this is within the aircraft's officially-stated operational range.

@Labroides
I've updated the sharing settings. Can you download the datalog now?

dwillis Posted at 2-23 20:51
I ignored no warnings. I took them literally and followed them exactly. It does now look like 30F and 95% humidity is a recipe for crashing, however this is within the aircraft's officially-stated operational range.

@Labroides

I've updated the sharing settings. Can you download the datalog now?
Yes .. it's all there now.

I ignored no warnings. I took them literally and followed them exactly.
It does now look like 30F and 95% humidity is a recipe for crashing, however this is within the aircraft's officially-stated operational range.
The specs don't mention humidity and the problem is a combination of small drones with folding props + freezing or close to freezing temp + moist air.
I've never seen any DJI drones with this issue in 6 yrs of reading forums.
But there have been more than a a dozen this year and they all show the same warning messages:
Motor error. Check propellers and fly with caution (Code: 30163)
Not Enough Force/ESC Error. Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists

Just guessing, but maybe DJI didn't test the Mini II and Air 2 in moist+freezing conditions.
They wouldn't have seen any need to based on >5 yrs experience with the earlier drones, but the small prop blades of these drones act differently from the way earlier and larger drones props behave.

Hi dwillis,

Had a look at your fligth too.

In addition to others about icing on blades, more and other interesting data found in the log.
Message motor blocked is not 'true', it does say that motor rpm < thresshold value set bij DJI, so probably spinning and not blocked.
The draw of amps, controlller wants more rpm ofcourse to keep height or increase height by your UP input, is huge! from approx 7 amps at start to 24 just before coming down!
Btw ; battey temperature at start about 20 degrees C, bit higher at the end of the flight.

At the end few more errors in the log:
- GPS signal weak. Positioning accuracy affected. Fly with caution
- Gyroscope initialization failed. Restart aircraft [ DJI should rewrite this message....being in-flight it is fun to read 'restart'...., should read 'land asap' ]
- IMU calibration required | IMU calibration required. Calibrate IMU | Not Enough Force

Finally craft in ATTI mode, IMO due to GPS/IMU 'fail'.
Baralt height values at the end minus 38 meter.
I have seen minus baro height values more in cold flights when falling out  of the sky, just nice to know for other analysis logs ; IMU related.

Why these errors as well ?  Or related somehow to the high amps, while batt cell values still above their low limit values. But more likely because falling down with high picth and roll angles causes the imu to go weird. see chart2  red = pitch, green = roll angle



cheers
JJB

JJB* Posted at 2-24 01:06
Hi dwillis,

Had a look at your fligth too.

Those charts were interesting. Thank you for sharing them. It seems clear that the motors were having to work harder and harder to maintain lift. By the time I got the warning about max power load it was too late. This was the most serious-sounding warning I received and it suggested that I land only "if this issue persists." But there was no opportunity for me to land: four seconds later the aircraft suffered a catostrophic failure. It seems like there are a number of unclear alert messages that DJI should re-write lol


@Labroides

"Just guessing, but maybe DJI didn't test the Mini II and Air 2 in moist+freezing conditions.
They wouldn't have seen any need to based on >5 yrs experience with the earlier drones, but the small prop blades of these drones act differently from the way earlier and larger drones props behave."



I think you're probably right.

dwillis Posted at 2-24 04:25
Those charts were interesting. Thank you for sharing them. It seems clear that the motors were having to work harder and harder to maintain lift. By the time I got the warning about max power load it was too late. This was the most serious-sounding warning I received and it suggested that I land only "if this issue persists." But there was no opportunity for me to land: four seconds later the aircraft suffered a catostrophic failure. It seems like there are a number of unclear alert messages that DJI should re-write lol

Hi,

yes, at the end all errors in a rapid sequence!
But first error 75 secs earlier before the SHTF ; a motor error. see the chart.

Not many (i know: my perception, hope i am wrong) will return a flight after the first message about motor errorwhile looking at the drone ; uh? motor error??  it does fly smoothly as far as i can see....

How to interpretet msg like "Motor error. Check propellers and fly with caution" ?  
Check propellers ?  when ?? and still fly with caution?  but how do i fly with caution?

If this message is a prelude to serious sh*t than write "Motor error, land ASAP and check propellers".  Well  just my 2 cents.

cheers
JJB

JJB* Posted at 2-24 05:10
Hi,

yes, at the end all errors in a rapid sequence!

I completely agree. An issue like this needs to be conveyed in clearer, more urgent language. "Fly with caution" is not at all the same message as "land immediately."

This is the same error you get on the Mavic Minis.

The error relates to the motor not being able to draw enough power through the motors.

Your problem was one or a combination of these things

Flying when the ground temp is below freezing. Air temp at altitude will be lower.
Flying without pre heating the batteries in cold weather.
Excess wind force correction required for the state of battery and temperature.
Icing of the Propellers causing additional weight and reducing lift putting more strain on the motors current draw.

Historically people who have this same incident always report these same errors.

As soon as you see  this first warning, reduce altitude, and land immediately. If not you will lose your craft.

Cheers

bjr981s Posted at 2-24 06:32
This is the same error you get on the Mavic Minis.

The error relates to the motor not being able to draw enough power through the motors.

The issue, per the preceding discussion, would seem to be the props icing.


"reduce altitude, and land immediately. If not you will lose your craft."

Yes, this is what the warning should say instead of "fly with caution."

JJB* Posted at 2-24 05:10
Hi,

yes, at the end all errors in a rapid sequence!

How to interpretet msg like "Motor error. Check propellers and fly with caution" ?  
Check propellers ?  when ?? and still fly with caution?  but how do i fly with caution?
If this message is a prelude to serious sh*t than write "Motor error, land ASAP and check propellers".

I agree that "fly with caution" warning doesn't sound too urgent. But reading all the similar issues (minis previous winter) I guess in challenging conditions it is smart to avoid rapid maneuvers and S-mode flying right after take-off, easy with sticks and check the AC behaviour in short distance first...

virtual Posted at 2-24 08:36
How to interpretet msg like "Motor error. Check propellers and fly with caution" ?  
Check propellers ?  when ?? and still fly with caution?  but how do i fly with caution?
If this message is a prelude to serious sh*t than write "Motor error, land ASAP and check propellers".

yes, for experienced flyers all is easy to understand and perform a proper risk assesment on each errors etc.
But for non-tech and non-aviation-experienced remote pilots, it is not that easy to fly a drone in all its capabilities and non-capabilities.

So DJI should, imo, rewrite some messages for better understanding

cheers
JJB

dwillis Posted at 2-23 20:22
Yeah, as I said, it was most likely icing. I didn't ignore any errors though and, however many are in the logs, I saw only three on the screen, with the last two coming too late to do anything about it. The time from the last error to the aircraft exiting controlled flight was about 4s. When I saw the first error I heeded it immeditely, followed the instructions to the letter, and flew with caution. I checked the telemetry and kept the aircraft nearby and in a safe environment. Nothing seemed amiss and the warning wasn't recurring so I cautiously continued. Like I said, I routinely see motor-related warnings in other DJI apps and they are not a cause for concern.

The crash snapped one of the forward struts, busted a light/sensor out of one of the rear struts, and damaged the ESC in some manner that the app says requires service.  Thankfully, I have DJI Care Refresh.

While the warnings may have indicated to fly with caution, perhaps it should have said, land immediately if not sooner..  To me, motor warnings of any kind should be a red alert that something is seriously wrong.   
While its still likely that you would have not had enough time to land before the loss of power, perhaps you could have maneuvered it lower and to some place where a snow landing instead of roof bounce and fall to the snow would have limited or eliminated the damage.  Course if the snow was like ice, may not have made any difference.

IT looks that I Am not the only One who got MAVIC AIR 2 Suddenly plumbering and crashing, I Don't even received any emergency or warning prompt..y one just stopped motors and boom

dwillis Posted at 2-23 20:51
I ignored no warnings. I took them literally and followed them exactly. It does now look like 30F and 95% humidity is a recipe for crashing, however this is within the aircraft's officially-stated operational range.

@Labroides

Um, yeah, you did. You were told to decrease altitude and fly with caution, and land immediately if the problem persisted. Instead you were climbing and trying to get your shot.
"Not Enough Force/ESC Error. Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, land immediately (Code: 30168)." I was in the process of a slow ascent, getting a shot, and decided I would heed the warning, fly with caution while I finished my shot, and then bring it back and land.

Labroides Posted at 2-23 20:42
Is there location data in the datalog? I set the Airdata share to not provide any location data but I'm not sure what all that covers. I just thought it might be prudent not to share geodata if there wasn't a specific reason to do so.

There is no data .. just a superficial summary report.

Very well said.

@dwillis  ... You can always change the settings or even remove the entire log later if you want.

JJB* Posted at 2-24 10:39
yes, for experienced flyers all is easy to understand and perform a proper risk assesment on each errors etc.
But for non-tech and non-aviation-experienced remote pilots, it is not that easy to fly a drone in all its capabilities and non-capabilities.

So DJI should, imo, rewrite some messages for better understanding

... and rewrite user guide.

MisterFrag Posted at 2-24 18:54
Um, yeah, you did. You were told to decrease altitude and fly with caution, and land immediately if the problem persisted. Instead you were climbing and trying to get your shot.
"Not Enough Force/ESC Error. Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, land immediately (Code: 30168)." I was in the process of a slow ascent, getting a shot, and decided I would heed the warning, fly with caution while I finished my shot, and then bring it back and land.

You should read more carefully. The first warning told me to fly, not land. The final warning said to land "if this issue persists." I actually took the warning more seriously than it suggested because I did not wait for the issue to persist and began landing immediately. "Finishing my shot" simply means smoothly transistioning out of it. This was about a 2s process. As I have said, and you can plainly see in the data, I had a total of 4s from the time that message was logged to the time I lost control and 1-2s of that was needed to see and understand the message leaving me with about 2s to react to it. So what exactly should I have done differently?

You are conveniently glossing over the “decrease altitude” part in your response. You read the warning and decided to keep flying and climbed at full throttle in order to “get the shot”, so you clearly had no intention of landing.

Don’t get me wrong, I am sympathetic to your situation. I have crashed drones before (not the MA2, yet), and it is a sickening feeling. The important thing is to learn from the event so you can avoid a recurrence. Being aware of the weather conditions and their suitability for flying and extra precautions that may be needed is one thing. I would urge you to get an app called UAV Forecast to find out which obvious and not so obvious factors may prevent you from flying — if the app warns against it, don’t risk it unless you have disposable income.

MisterFlag Posted at 2-25 16:02
You are conveniently glossing over the “decrease altitude” part in your response. You read the warning and decided to keep flying and climbed at full throttle in order to “get the shot”, so you clearly had no intention of landing.

Don’t get me wrong, I am sympathetic to your situation. I have crashed drones before (not the MA2, yet), and it is a sickening feeling. The important thing is to learn from the event so you can avoid a recurrence. Being aware of the weather conditions and their suitability for flying and extra precautions that may be needed is one thing. I would urge you to get an app called UAV Forecast to find out which obvious and not so obvious factors may prevent you from flying — if the app warns against it, don’t risk it unless you have disposable income.

I glossed over nothing. You have no basis for accusing me of lying about my intentions and you can't possibly argue that the two seconds of reaction time I had was enough to change the outcome if only my intentions were different. You're a troll.

MisterFrag Posted at 2-25 16:02
You are conveniently glossing over the “decrease altitude” part in your response. You read the warning and decided to keep flying and climbed at full throttle in order to “get the shot”, so you clearly had no intention of landing.

Don’t get me wrong, I am sympathetic to your situation. I have crashed drones before (not the MA2, yet), and it is a sickening feeling. The important thing is to learn from the event so you can avoid a recurrence. Being aware of the weather conditions and their suitability for flying and extra precautions that may be needed is one thing. I would urge you to get an app called UAV Forecast to find out which obvious and not so obvious factors may prevent you from flying — if the app warns against it, don’t risk it unless you have disposable income.

Just thought you might be interested to see the official response I got from DJI:

"Here's the result of the data analysis on your case:

ESC Error
Incident date: 2021-02-18
Incident time: 323 seconds
FLY027
1.    The aircraft worked under GPS mode and responded to the pilot’s command well;
2.    Flight time T=323s, relative height H=79m, distance to home point D=19.2m, motor 1 stalled causing the unit to fall.

According to the analysis, the incident was caused by non pilot error. Therefore, it is concluded to warranty.​"

I've been very pleased with DJI's customer service the few times I've had to use it.

dwillis Posted at 3-8 11:45
Just thought you might be interested to see the official response I got from DJI:

"Here's the result of the data analysis on your case:

A nice result for you and a good response from DJI  

Fly safe.

dwillis Posted at 3-8 11:45
Just thought you might be interested to see the official response I got from DJI:

"Here's the result of the data analysis on your case:

Good news, thanks for the update

Many happy landings with the replacement!

cheers
JJB

Yea!! Glad to hear you were treated well. Look, Look ,up in the sky! Isn't that your new MA2. Have fun.

dwillis-- That's great news!

JJB- - does your SW show separate motor telemetry, ie 1 thru 4, or all of it as one? I couldn't tell but that would be very useful if that is available via APIs and in your SW!