At ~3 seconds after you commanded Go Home, the aircraft began experiencing YAW, SPEED and COMPASS errors. When this occurs, the aircraft can not Return to Home, due to directional issues with the compass. The aircraft never auto switched to ATTI mode as it should have but that may be due to the length of the errors. I suspect the aircraft Auto Landed someplace in the trees. It was simply drifting in the wind when you lost signal. Your last reported position is shown with the red arrow in the image below the graph. Due to the drift, your search area could be anywhere within the red circle. This is an approximation without wind data.
The flight log shows the Spark did make some progress toward the home point after RTH was initiated. It looks like RTH was manually cancelled at 5m 29.4s. After that point, the Spark came to a stop and hovered pretty much in the same place until the end of the flight log.
At 5m 36s (at the end of the flight log), the Spark stopped using its GPS data. While the flight log doesn’t show this, I suspect the Spark switched to ATTI mode shortly after that point. And since it had plenty of battery power left to make it back to the home point, it makes sense that it was flying in ATTI mode after that point.
According to Airdata’s wind calculations, the wind was blowing toward the west at about 10 MPH (near the ground) to about 19 MPH (at the Spark’s highest altitude). If the Spark did in fact switch to ATTI mode and started drifting toward the west with the wind, I’m calculating it landed somewhere in this yellow box:
I agree, but erratically, due to the compass issue, which says to me that it did not auto-switch to ATTI during this portion.
That makes sense with the addition of the estimated wind data, especially with the aircraft at quite a high altitude. My estimation was without. It is interesting that the Spark did not switch to ATTI before the data ended. It most likely did at some point, but with the multiple errors, its speculation.
It could be a mix of both. You flew BVLOS which made it impossible to know what your Spark was doing after the uplink disconnected. As for the compass errors, that could have been caused by faulty hardware or maybe something you did to accidentally damage the hardware.
I’d recommend you do this:
Go search in the location I boxed off above.
If you cannot find your Spark, contact DJI Support for help. If they believe they are somehow responsible, they will likely offer to cover the entire or partial replacement.