Well it happened. I crashed!!!

[Chrislaf]

Today I was running some AutoPilot Follow missions where my P3S would follow me on my skidoo. I have done many of these missions without incident. I was on my third mission and I was having the AC follow me as I snowmobiled on a skidoo trail. The mission started in a field and then proceeded through a stand of trees. I thought I had had the AC up high enough (30m) to clear all the trees but obviously not as it hit a tree branch and came tumbling down. AutoPilot can adjust for changes in terrain but I chose fixed height because there was not that much of a change in height and I thought I was high enough. This was totally pilot error and my fault.

There was no visible damage to the AC except a scrap mark on the top shell from hitting the tree. The camera and gimbal were attached and appeared undamaged other than being covered in snow. The AC landed in about a 30-50cm of snow and the props were still spinning when I found it. I used a CSC to stop the motors. One prop was completely broken off and another had the tip broken off.

When I got it home and dried it out, I started it up and the camera and gimbal worked perfectly - did its gimbal dance and I had a camera feed. The only problem I am having is that the IMU is requesting calibration. I have tried a number of times but calibration fails. I will try later.

AirData is indicating that I was up at 3268m which is not correct and that the AC was auto landing. The AC was set to be at an altitude of 30m and distance of 17m. I think I got the correct DAT file off the AC, but when I ran it through DatCon and uploaded the csv file to DJI Flight Log viewer, I got an error message.

Here is the link to the Dropbox file, if anyone has time to take a look.

Dropbox - FLY418.DAT

Any ideas on how to solve the IMU problem?

Thanks for any help.

Chris

 

[Fly Dawg]

I ran it through DatCon and uploaded the csv file to DJI Flight Log viewer, I got an error message.

The log viewer is not configured for .dat files, converted .csv or not. That is why you got the error message. Not really sure what you are looking for with the aircraft .dat. If you already know what occurred.

 

[Chrislaf]

Thanks for you reply. Just wondering why AirData is registering such a high altitude and auto landing.

 

[Fly Dawg]

Just wondering why AirData is registering such a high altitude and auto landing.

That was at the end of the flight after impact with the trees. Your altitude was 28 meters until impact. Basically an IMU concussion.

 

[3rdof5]

The autolanding is odd. I've never used autopilot but if i recall correctly, using follow me mode in Dji go, there is a setting for what the AC will do if it gets farther than a set distance away from what its following (unable to keep up for example) and it can be set to hover or autoland I believe. So maybe it's possible the autoland initiated due to that?

 

[Chrislaf]

That was at the end of the flight after impact with the trees. Your altitude was 28 meters until impact. Basically an IMU concussion.

View attachment 108805

Thanks for the info.

Chris

 

[Fly Dawg]

So maybe it's possible the autoland initiated due to that?

As per above...the impact caused the bogus data.

 

[Chrislaf]

The autolanding is odd. I've never used autopilot but if i recall correctly, using follow me mode in Dji go, there is a setting for what the AC will do if it gets farther than a set distance away from what its following (unable to keep up for example) and it can be set to hover or autoland I believe. So maybe it's possible the autoland initiated due to that?

AutoPilot has dynamic home point so it updates constantly. It also adjusts speed to keep up. If it does loose contact it will hover. I was only driving about 30km/h so it had no problem keeping up to me.

Chris

 

[3rdof5]

As far as the IMU not successfully recalibrating, is that still an issue?

 

[Chrislaf]

Yes, but I will have to troubleshoot that in a couple of hours as I have to head off to my sons dance performance.

 

[Fly Dawg]

As far as the IMU not successfully recalibrating, is that still an issue?

I suspect that the IMU was damaged upon impact. The post impact data is quite bizarre. That is most likely why the calibration is failing.

 

[3rdof5]

I suspect that the IMU was damaged upon impact. The post impact data is quite bizarre. That is most likely why the calibration is failing.

You could be right. I did find this thread on this issue:
IMU fail after 2% also after minor crash

 

[Fly Dawg]

You could be right.

A hard impact at 30kph/20mph will do that sort of thing...

 

[Chrislaf]

I have tried re-calibrating numerous times without success it just gets stuck at 1% and says a re-calibration is needed.

Where is the IMU located on a P3S? Is it on the main board or on the camera board? I am trying to determine if it is worthwhile to send it in for repair. If the cost of repair and shipping is almost as much as I paid for it then it is not going to be worth it.

Chris

 

[3rdof5]

I have tried re-calibrating numerous times without success it just gets stuck at 1% and says a re-calibration is needed.

Where is the IMU located on a P3S? Is it on the main board or on the camera board? I am trying to determine if it is worthwhile to send it in for repair. If the cost of repair and shipping is almost as much as I paid for it then it is not going to be worth it.

Chris

It's on the mainboard.

 

[Chrislaf]

It's on the mainboard.

Thanks. I found a video online that shows how to repair the IMU. In the video the guy takes off the top shell, unclips the IMU and then gives it a few hard knocks with the but of a screw driver to get it unstuck. I may try this first and see if it works before I send my P3S off for repair.

Here's the video:

phantom 3 standard IMU repair

Chris

 

[3rdof5]

Thanks. I found a video online that shows how to repair the IMU. In the video the guy takes off the top shell, unclips the IMU and then gives it a few hard knocks with the but of a screw driver to get it unstuck. I may try this first and see if it works before I send my P3S off for repair.

Here's the video:

phantom 3 standard IMU repair

Chris

Yes the thread I copied a few posts back says to try the same thing. Good luck!

 

[MotorCycle-Man]

Chrislaf : Hope the knock on the IMU works for you.......Gee i hated to read of the mishap ....good luck.

 

[Chrislaf]

I’m going to try opening up tomorrow and giving the IMU a few taps. Got nothing to lose as AC in long out of warranty. If I can get the IMU unstuck it’ll save a trip to the repair shop.

Chris

 

[4thdpi]

Today I was running some AutoPilot Follow missions where my P3S would follow me on my skidoo. I have done many of these missions without incident. I was on my third mission and I was having the AC follow me as I snowmobiled on a skidoo trail. The mission started in a field and then proceeded through a stand of trees. I thought I had had the AC up high enough (30m) to clear all the trees but obviously not as it hit a tree branch and came tumbling down. AutoPilot can adjust for changes in terrain but I chose fixed height because there was not that much of a change in height and I thought I was high enough. This was totally pilot error and my fault.

There was no visible damage to the AC except a scrap mark on the top shell from hitting the tree. The camera and gimbal were attached and appeared undamaged other than being covered in snow. The AC landed in about a 30-50cm of snow and the props were still spinning when I found it. I used a CSC to stop the motors. One prop was completely broken off and another had the tip broken off.

When I got it home and dried it out, I started it up and the camera and gimbal worked perfectly - did its gimbal dance and I had a camera feed. The only problem I am having is that the IMU is requesting calibration. I have tried a number of times but calibration fails. I will try later.

AirData is indicating that I was up at 3268m which is not correct and that the AC was auto landing. The AC was set to be at an altitude of 30m and distance of 17m. I think I got the correct DAT file off the AC, but when I ran it through DatCon and uploaded the csv file to DJI Flight Log viewer, I got an error message.

Here is the link to the Dropbox file, if anyone has time to take a look.

Dropbox - FLY418.DAT

Any ideas on how to solve the IMU problem?

Thanks for any help.

Chris