Drone smashed into the ground - why?

[Krieg]

Hi everyone

I'm new to this and have a Phantom 4.

I used RTH and the P4 came back to me and started landing at 60M in the air. I saw a guy with a dog approaching so I cancelled the auto landing at approx 30M. I started to lower the drone manually and at approx 25M it started going down, FAST.

I pushed the stick upwards and got no response. It smashed into the ground and bounced back up, at which point I was able to control it again, bringing it to a safe landing.

However, a piece broke off and a component was hanging out of one of the legs. I've put it back in and everything works fine, but it's been making a creaking noise since when I touch it, and the piece has been trying to fall out again.

WTF happened here? I've reviewed the logs and it just cuts out at 25M to the ground and doesn't show anything after that.

I have the video footage of it hitting the ground which has me partially in shot and I can see that I wasn't even on the throttle so wasn't me that smashed it into the ground. Bit strange that the DJI Go app has no info after it was at 25M in the air, isn't it? Does that suggest a Phantom problem to you?

 

[msinger]

Please upload your TXT flight log here and post a link back here.

 

[Krieg]

Here you go:

Phantom Log Viewer - PhantomHelp.com

 

[SolarLittleHelper]

Hi everyone

I'm new to this and have a Phantom 4.

I used RTH and the P4 came back to me and started landing at 60M in the air. I saw a guy with a dog approaching so I cancelled the auto landing at approx 30M. I started to lower the drone manually and at approx 25M it started going down, FAST.

I pushed the stick upwards and got no response. It smashed into the ground and bounced back up, at which point I was able to control it again, bringing it to a safe landing.

However, a piece broke off and a component was hanging out of one of the legs. I've put it back in and everything works fine, but it's been making a creaking noise since when I touch it, and the piece has been trying to fall out again.

WTF happened here? I've reviewed the logs and it just cuts out at 25M to the ground and doesn't show anything after that.

I have the video footage of it hitting the ground which has me partially in shot and I can see that I wasn't even on the throttle so wasn't me that smashed it into the ground. Bit strange that the DJI Go app has no info after it was at 25M in the air, isn't it? Does that suggest a Phantom problem to you?

Did you upgrade to the latest aircraft firmware recently?

 

[Krieg]

Flight took place on 23/07/16. I updated the firmware the day I got the P4, which was 16/07/16.

 

[Krieg]

Oh and I'm happy to upload the footage if you need it to diagnose what happened/advise accordingly.

 

[Krieg]

Anyone?

 

[allentc2]

Patience, Grasshopper.

 

[Wibble]

Oh and I'm happy to upload the footage if you need it to diagnose what happened/advise accordingly.

Uploaded footage would help a lot.

 

[toddff]

I am thinking you didn't wait for the P4 to log its home location. The green lights should strobe before you take off. It may have logged its home location as it was in the air and not on the ground before takeoff. If it logged its home location in the air it will act like its on the ground and shut off in the RTH mode.


Sent from my iPad using PhantomPilots

 

[msinger]

I am thinking you didn't wait for the P4 to log its home location.

The flight log indicates the home point was set prior to takeoff.

It may have logged its home location as it was in the air and not on the ground before takeoff. If it logged its home location in the air it will act like its on the ground and shut off in the RTH mode.

The home point only records the latitude and longitude location of the Phantom. When returning to the home point, the Phantom would never shut down mid-flight. The motors will only stop after the Phantom has landed.

 

[msinger]

Oh and I'm happy to upload the footage if you need it to diagnose what happened/advise accordingly.

Please upload your video.

 

[Krieg]

Thanks everyone. Appreciate all of your responses.

I'll upload the footage - won't have access to it until tomorrow though.

Do you also need me to upload the visual representation of what I was doing on the sticks or is the log enough? I've seen people upload that before but not sure how to go about it.

 

[msinger]

The stick commands are in the log you uploaded above. If you post the full video, those commands and be displayed on top of the video in Dashware.

 

[Krieg]

Crash at 0:51.

The log file just stops at 25m descent even though the flight continued.

You can see at 0:59 as the P4 is hurtling to the ground that I don't even have my thumb on the throttle.

 

[Gnormand]

beautiful scenery...where is that?

 

[msinger]

The log file just stops at 25m descent even though the flight continued.

If you match up the flight path in your log with the video you posted above, it looks like your entire flight is in the log. The altitude is way off at the end of the log though. When your Phantom was coming down fast, it was auto landing. That's the next thing it'll do after reaching the home point when returning home. It appears you didn't actually cancel the RTH.

I cannot explain why it was descending so quickly though. Perhaps there is some kind of logic built in that tells it to descend faster until it reaches a certain altitude. I've never seen such a thing documented anywhere, but I'm not sure what else would make sense.

 

[Krieg]

beautiful scenery...where is that?

It's Sandal Castle in Wakefield, England.

If you match up the flight path in your log with the video you posted above, it looks like your entire flight is in the log. The altitude is way off at the end of the log though. When your Phantom was coming down fast, it was auto landing. That's the next thing it'll do after reaching the home point when returning home. It appears you didn't actually cancel the RTH.

I cannot explain why it was descending so quickly though. Perhaps there is some kind of logic built in that tells it to descend faster until it reaches a certain altitude. I've never seen such a thing documented anywhere, but I'm not sure what else would make sense.

I'll try to match it up now.

 

[WetDog]

Barometer failure?

 

[Benedict]

Vortex ring state from descending to quickly?