Mavic 2 Pro fell out of the sky yesterday....

[Paul2660]

Hi Sar104, I understand the log stops, so that shows I assume a total power failure. My question is did the battery drop to 0% and the drone shut off, or did something internal within the drone, processor or other reboot/shutoff for whatever reason.

I was thinking that if the battery did drop to 0, from the level it showed instantly, and the drone shut off, then did the battery have a bad cell or logic etc. If the battery after the crash still had power, and allowed power back on, doesn't it point to a system failure which if so does concern me. Such a system failure seems not to be definable and repeatable, the worst kind.

There have been a few other cases like this on this site all seemingly within enough power range to land with control.

Paul C

 

[sar104]

Hi Sar104, I understand the log stops, so that shows I assume a total power failure. My question is did the battery drop to 0% and the drone shut off, or did something internal within the drone, processor or other reboot/shutoff for whatever reason.

I was thinking that if the battery did drop to 0, from the level it showed instantly, and the drone shut off, then did the battery have a bad cell or logic etc. If the battery after the crash still had power, and allowed power back on, doesn't it point to a system failure which if so does concern me. Such a system failure seems not to be definable and repeatable, the worst kind.

There have been a few other cases like this on this site all seemingly within enough power range to land with control.

Paul C

The battery was at 20% and all cells were well above the critical threshold, so it's very unlikely that the battery voltage suddenly collapsed. It could have been a physical battery disconnect, but unlikely in a pre-landing situation. It could have been a battery firmware problem that caused the battery to shut down, or it could have been an FC system crash. Unfortunately there's no way to know without being able to read the aircraft DAT file.

 

[Roamer105]

The battery was at 20% and all cells were well above the critical threshold, so it's very unlikely that the battery voltage suddenly collapsed. It could have been a physical battery disconnect, but unlikely in a pre-landing situation. It could have been a battery firmware problem that caused the battery to shut down, or it could have been an FC system crash. Unfortunately there's no way to know without being able to read the aircraft DAT file.

Since the battery fell out on the drop... maybe it was not “clicked in” well enough. That most certainly would explain sudden loss of power with an OK battery.

 

[DanMan32]

Since the AC DAT is encrypted, it would have been nice if the app could retrieve the missing transactions for the last few flights. At least when it's idle.

 

[MaxHam]

Thank you for this, I'll have to do this when I get home from work. Is there anyway to access the flight log from Airdata.com?

Here is your log at PHANTOMHELP:
DJI Flight Log Viewer - PhantomHelp.com

Here is your log at Airdata:
Airdata

You made an essential mistake and this might be the reason for the fall:
You took off at 70%. This you should never do.
You can't go by percentage if you don't start with a fully charged battery.
Even voltage reading can be off as far as I understand.

There are loads of threads about why for an reliable battery reading the battery must be full when you start.
I can't explain it technically but Google will find you these threads, esp. at the DJI forum.

I never take of with a battery lower than 95%. And this only if it has 95% because I wasted time on ground
with settings etc and not because it was charged two weeks ago the last time.

 

[CanadaDrone]

Before the battery charge level can be trusted, the battery has to go from completely full to almost dead in the aircraft at least one time. Otherwise you are getting an estimate. Because the Mavic doesnt yet know what "dead" really is. Every battery is a little different. Brand new batteries, that have never been deep cycled can not be trusted below 30%

It is definitely not recommended to let the battery get anywhere near zero - not only is it really bad for the battery, but if it happens in flight you are asking for trouble.

 

[pwr406]

Well I may have discovered the source of the problem but it could also be the result of the crash... The battery connector in the drone had one of the black end pieces broken (pic attached) and the battery itself has a crack in the plastic connector piece (on the right side of the photo). Maybe a result of the crash but I wonder if the crack was there

 

[pwr406]

Here is your log at PHANTOMHELP:
DJI Flight Log Viewer - PhantomHelp.com

Here is your log at Airdata:
Airdata

You made an essential mistake and this might be the reason for the fall:
You took off at 70%. This you should never do.
You can't go by percentage if you don't start with a fully charged battery.
Even voltage reading can be off as far as I understand.

There are loads of threads about why for an reliable battery reading the battery must be full when you start.
I can't explain it technically but Google will find you these threads, esp. at the DJI forum.

I never take of with a battery lower than 95%. And this only if it has 95% because I wasted time on ground
with settings etc and not because it was charged two weeks ago the last time.

Thanks for looking. Technically I started the at 99% but landed to wait for the sun to peek out behind a cloud. I really think it was an issue of the battery shifting and disconnecting at this point...Guess I'll see what DJI has to say.

 

[djwgates]

Your last warning message is Event ID:24 Gimbal Roll Reached Movement Limit Flight time: 20m 57s Altitude: -3.0 feet Above Sea Level: 3,628 feet Home Distance: 123 feet meaning it was powered on and probably spinning. Did you find the piece of the broken prop? It may have broken off in flight.

 

[Juninhosboots]

Had a horrible day yesteday ... was at a real estate shoot using my M2P for only the 5th or 6th time. Everything went great on my first battery, no issues what so ever. Switch over to my 2nd battery and flying like a dream. I'm starting to finish up my job, just trying to get the last video shots when I receive the low battery warning. No problem I think, I still have time to get one more shot here before I switch out to my final battery. Luckily I only have the drone 4 to 5 feet off the ground because out of nowhere, the drone just falls from the sky. I still had 22% battery remaining but it fell like it completely lost power. The drone hit the ground hard, the battery went flying out and I broke a prop. Doesn't appear to be any damage to the rest of the drone but my nerves were shot and I called it a day with out testing anything with my last battery.

I use airdata.com to log my flights but I'm not seeing a lot of info in there other than the final notification I received was "Gimbal roll reached movement limit". I spent some time on chat with DJI this morning and just completed a repair request ticket (I do have DJI care refresh as well). Really confused by this whole process though...I would prefer not to have to send in my drone unless I know there is a serious issue with it but don't know enough about the flight logs to really troubleshoot what happened.

Edit: I've attached the flight log here but the .DAT file was too large to upload.

My drone fell from the sky on 1st October when I switched back from POI mode. It is with DJI for analysis - but there could be an emerging issue here.

 

[FatherXmas]

How low do you typically let your batteries go down to when flying?

All of my drones are set to 30%. As soon as it starts complaining, I fly home and land it.

 

[LV2FLY]

Since the battery fell out on the drop... maybe it was not “clicked in” well enough. That most certainly would explain sudden loss of power with an OK battery.

As a point of reference I took off recently with my Mavic 2 Pro to a height of about 4 feet. The aircraft was at that height for about 30 seconds. I then received an error from the DJI GO app. The error told me the battery was not properly seated in the drone. Basically I was shocked and somewhat confused.... Needless to say I landed. Upon inspecting the battery it was not pressed all the way in. It had not snapped completely in. It was making electrical contact but not locked in.

It was the second battery of the day. It was a quick remove battery #1 and replaced with battery #2. That sensor probably saved my Mavic from swimming with the fishes. Lesson learned!

So the moral to the story is the Mavic 2 Pro has a sensor to determine if the battery is properly seated in the battery compartment. Thanks DJI!

 

[sar104]

As a point of reference I took off recently with my Mavic 2 Pro to a height of about 4 feet. The aircraft was at that height for about 30 seconds. I then received an error from the DJI GO app. The error told me the battery was not properly seated in the drone. Basically I was shocked and somewhat confused.... Needless to say I landed. Upon inspecting the battery it was not pressed all the way in. It had not snapped completely in. It was making electrical contact but not locked in.

It was the second battery of the day. It was a quick remove battery #1 and replaced with battery #2. That sensor probably saved my Mavic from swimming with the fishes. Lesson learned!

So the moral to the story is the Mavic 2 Pro has a sensor to determine if the battery is properly seated in the battery compartment. Thanks DJI!

That is very interesting - I've not heard any previous reports of such warnings. I wonder if that means that the clips have switches in them. If so, it seems like it would be better simply to prevent takeoff rather than warn about it afterwards.

 

[WithTheBirds]

That is very interesting - I've not heard any previous reports of such warnings. I wonder if that means that the clips have switches in them. If so, it seems like it would be better simply to prevent takeoff rather than warn about it afterwards.

We were wondering the same thing. My guess from that is it might simply be an issue detected with the telemetry bus connection. Meanwhile I’m wondering, looking at mine, how you might not manage to install the battery correctly. It’s either in or it isn’t. There could be some tolerance issues with the battery housing or bay in the AC. That could be a concerning issue if it is ultimately determined to be the installed height of the connector in the AC or battery.

 

[sar104]

We were wondering the same thing. My guess from that is it might simply be an issue detected with the telemetry bus connection. Meanwhile I’m wondering, looking at mine, how you might not manage to install the battery correctly. It’s either in or it isn’t. There could be some tolerance issues with the battery housing or bay in the AC. That could be a concerning issue if it is ultimately determined to be the installed height of the connector in the AC or battery.

On mine it is quite easy to engage the clip on one side only.

 

[WithTheBirds]

On mine it is quite easy to engage the clip on one side only.

Well- that might be good news if it is one explanation for the few in flight failures that have been reported.

 

[ScubaBob]

That’s why I’ve already landed at 30%.

I have been flying an MP for over a year on a regular basis. My low battery warning is at 30% and when it goes off I start my path back to home. I lower to no more than 50 feet (17 meters) and keep my MP in an open space where I can see it all the time. I never let my MP out of my sight for more than a second or two. I have never had a problem that was not able to be solved by descending.

 

[BudWalker]

As a point of reference I took off recently with my Mavic 2 Pro to a height of about 4 feet. The aircraft was at that height for about 30 seconds. I then received an error from the DJI GO app. The error told me the battery was not properly seated in the drone. Basically I was shocked and somewhat confused.... Needless to say I landed. Upon inspecting the battery it was not pressed all the way in. It had not snapped completely in. It was making electrical contact but not locked in.

It was the second battery of the day. It was a quick remove battery #1 and replaced with battery #2. That sensor probably saved my Mavic from swimming with the fishes. Lesson learned!

So the moral to the story is the Mavic 2 Pro has a sensor to determine if the battery is properly seated in the battery compartment. Thanks DJI!

I just tried to replicate this but didn't have much luck. The battery was installed with neither clip "clicked in". The M2P was powered up with no props and then the motors run up to simulate a launch. After a few minutes the M2 was turned over by hand and the battery fell out. I didn't see the Go App say anything about a loose battery and there was nothing in either the .txt log or the .DAT log.

 

[AnneP]

Just a guess here, but I recall when I bought my Mavic Pro 18 months ago there were a few falling out of the sky. From memory it seems people weren't making sure the battery was clicked in properly. Wonder if this may have occurred if you were under time pressure? Sorry to hear about your accident.

 

[WithTheBirds]

Just a guess here, but I recall when I bought my Mavic Pro 18 months ago there were a few falling out of the sky. From memory it seems people weren't making sure the battery was clicked in properly. Wonder if this may have occurred if you were under time pressure? Sorry to hear about your accident.

While we can, and suspect all do, feel for those who have lost their M2’s recently it might bring some comfort to learn the failures are as simple as a poorly installed battery. That would be good news. It seems however (there is at least one reported instance) there may be another issue given DJI has agreed to replace an M2 lost at sea based on the flight log analysis (DJI GO4 log).