Phantom 3 severe crash while performing auto take off

ImJim · Jul 21, 2015

baazju said:
Checking MOD value has been added to my pre-flight checklist, thanks for this tip.

Could you share your checklist with us please?

ranges · Jul 21, 2015

BuckRogers said:
I just read your post. I can't stress this enough. Check MOD value before every flight. Mine did the same as yours. I lifted up under GPS mode and it went backwards. You have to be ready. Did I check mod value? No. After 125 flights, I only calibrated before the day began. I was flying near a huge metal civic center. I caught mine soon enough, shifted to atti mode and was able to recover. It was difficult because it almost hit my truck. Anyway.. the lesson I learned from it was to pop over to the sensitivity screen and make sure my mod value was normal. Haven't had an issue since. You can't control things you can't see, like the rebar or electromagnetic interference. You can't make sure your compass is spot on.

DJI should move the MOD value to the main screen.

dmcgrew · Jul 21, 2015

ImJim said:
You're a little rude with it bro

I'm not sure what you mean. I'm just stating an opinion, not being rude to anyone.

BuckRogers · Jul 21, 2015

ranges said:
DJI should move the MOD value to the main screen.

I agree with this. Seeing compass is ok and ready to fly can give a false sense of security. You need to know what the mod value actually is.

F6Rider · Jul 21, 2015

ranges said:
DJI should move the MOD value to the main screen.

Maybe we can get them to add MOD value screen to the options under C1 & C2?

Trilithon · Jul 21, 2015

Nominal MOD values are?

ImJim · Jul 21, 2015

dmcgrew said:
I'm not sure what you mean. I'm just stating an opinion, not being rude to anyone.

I meant you're rude with your bird mate

You don't trust her enough

flax · Jul 21, 2015

Maybe a dumb question, but what should the mod value be? You all say check it, but for what value?

BuckRogers · Jul 21, 2015

flax said:
Maybe a dumb question, but what should the mod value be? You all say check it, but for what value?

~1500 on the compass

Luap · Jul 21, 2015

znqfly said:
Unfortunately my brand new Phantom 3 advanced had a severe crash on its 3rd flight while performing auto take off.

Video

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What happened

I was waiting to get the fully green flight status (with GPS signal)

Once I got that status, I initiated auto take off from the DJI Pilot app

At first, the Phantom 3 started and gained altitude

However, then, before even touching any of the controls the Phantom 3 immediately reversed and dropped to the ground with high speed

It crashed hard and flipped over

At this point the motors were not running anymore

I picked up the Phantom 3 and as soon as I turned it around the motors started going full speed like crazy (I'm trying to hold the drone in my hands right now)

While trying to not get cut by the blades I attempted to turn off the drone at the battery, which didn't work at all.

I asked a bystander for help to turn off the remote

After a few seconds the Phantom 3 finally stopped spinning

I force-ejected the battery

Flight Record

Attached are the flight record files. Interestingly they say a couple of things that just don't make any sense.

Max altitude: 113 feet (34 meters)

The drone was never higher than what auto take off does, which is supposedly 1.2m

Max speed: 104.85mph

There was no horizontal speed at all and also the Phantom 3 doesn't fly that fast

Max distance: 58 feet (17 meters)

The drone was always at the same position (auto take off --> immediate crash), so this doesn't make sense either

Summary

This is clearly a technical issue. From what I've read online it seems some people also have had experiences where the Phantom 3 went crazy after auto take off.

I've contacted DJI Europe for support and will post updates here once I receive them.

Checking the flightlog the csv shows some weird stuff going on.

Only checking the center battery details:
CENTER_BATTERY.errorType is indicating
2147483648and then
2952790016 and back to
2147483648
Usually error type = 0
SMART_BATTERY.status
shows a
BatteryCommunicateError 32 seconds into the flight
APP_WARN.warn
shows "battery error" 31 seconds into the flight
CENTER_BATTERY.current
jumps from 11.658amps to 32.768amps (thats about twice the normal current in hover)
Watts increase to 486 (phantom3 hovers at between 120 - 150)

Certainly a battery problem but will check in Dashware whether I can see if this happens before or after the crash.

RyanK · Jul 21, 2015

Ok, I should probably start checking the mod value more often myself, but I'm wondering why we need to (fortunately haven't had any issues because of it yet)? Can't DJI program into its own preflight checklist to NOT give you the green "Safe to Fly" unless the mod value is at a reasonable number?

BuckRogers · Jul 21, 2015

RyanK said:
Ok, I should probably start checking the mod value more often myself, but I'm wondering why we need to (fortunately haven't had any issues because of it yet)? Can't DJI program into its own preflight checklist to NOT give you the green "Safe to Fly" unless the mod value is at a reasonable number?

I don't know the answer to this but my compass said safe to fly before I took off and when I landed, it was >1800. I don't know how to look at the flight data to see what the mod value was before I took off. As far as I know, the flight data converters out there only give certain data but the flight log has lots of data in it. I'd like to know. And to say you will do it more often, it only takes missing it once and off you go. I'd do it before every flight.

denodan · Jul 21, 2015

I think for auto take off it does not use gps, but relies on the vps. If this goes haywire or turned off, this may well cause auto takeoff issues.

envisionabove · Jul 21, 2015

We'res the mod value hid? I always use auto launch and use lots of stick to about 10 to 12 feet then hover inspection and if all looks good after a moment or two I fly.

Huskerfan · Jul 21, 2015

How do you record the flight data? Is there a setting?

ianwood · Jul 21, 2015

Checking mod value before takeoff is a good idea. However, it looks like this incident is not related to the mod value and rather something to do with the battery.

BuckRogers · Jul 21, 2015

ianwood said:
Checking mod value before takeoff is a good idea. However, it looks like this incident is not related to the mod value and rather something to do with the battery.

Please explain. How does a battery issue cause the phantom to fly in reverse on auto take off?

Molokai · Jul 21, 2015

sergekouper said:
Me neither, No auto take off or auto landing. specially auto landing. Phantom don't know much about guts of wind at ground level.

In all honesty, I NEVER even land anymore. Hand catching only for me.

N017RW · Jul 21, 2015

BuckRogers said:
Please explain. How does a battery issue cause the phantom to fly in reverse on auto take off?

Did you watch the video Buck?
The OP used the term reversed to indicate it was no longer climbing. Ambiguous, sure but the video clears that up.

BuckRogers · Jul 21, 2015

N017RW said:
Did you watch the video Buck?
The OP used the term reversed to indicate it was no longer climbing. Ambiguous, sure but the video clears that up.

I did. I just watched it again. I mainly noted the last few seconds of the video from the second person view where it flipped back in to reverse and hit the ground. Maybe it's not what happened.