DJI Drone Help Forum

Phantom 4 pro crashed - Help

Hi,
I have crashed on my Phantom 4 pro.
Looks like it is because of compass error.
Below is the link to my log data.
Question is :

  1. Is there is any other cause besides the compass issue?
  2. Why did compass error happen? considering I’m fly this every day using a full auto method (DJI GS Pro same flight plan). I assume in this area should be no magnetic issue.

https://www.phantomhelp.com/LogViewer/U76MR0E8PIZCQQYYBFNQ

Thanks,

Cho

Looks to me like there was a propulsion issue at the very end. I suspect the compass error you’re talking about occurred because the P4Pro was tumbling.The P4Pro pitched up and rolled right which indicates the a problem with the rightBack. This is consistent with the CW spin that started.

If you want to know more we’ll need the .DAT from the P4Pro. Look here to see how to do that
Retrieving a V3 .DAT File from the AC

or

Retrieving a V3.DAT from the tablet

FLY517.DAT is the one you want.

Thanks Bud,
Really interesting…

here the DAT file

Cheers

The evidence isn’t as compelling as I would like but I’m gonna guess that the P4Pro ran into some tree tops.The main problem is that the Google Earth data and the GPS:heightMsl indicate that the P4Pro was 142 meters AGL when the incident started. If it weren’t for that I’d say this is clearly a case where the P4Pro started running into tree tops.

The incident starts at 558.56 with an abrupt uncommanded drop in the leftFront motor speed.The acceleration data doesn’t show that the P4Pro hit something, at least not very hard

After that there attitude instability.

The Z axis gyro shows the P4Pro doing a very abrupt CW rotation.

All the motors except the leftBack are commanded at one point to 100%. Usually, just one of the motors will be commanded to 100% if there is a propulsion issue. Here it seems the P4Pro got tangled up and then loose several times

Most interesting is that the ultrasonic sensor starts indicating the P4Pro is close to something. I’m thinking the top of the trees.

Were there any physical indications like scratch or scrape marks.