Loss of power after takoff - Analysis required

I took my quad out yesterday but after a couple of good flights I had a nasty crash.
The quad took off normally and all was going well until I experienced a sudden loss of power and it dropped to the ground.

I’m not really sure what the problem is and I was hoping someone could help me analyse the log (attached).

The flight details can be found here:
http://www.droneshare.com/mission/22732

I was using an APM 2.5.

GoPro video is available if this helps.

Thanks in advance for any help.

CTUN.ThrIn dropped to zero. Probably a radio issue with out proper failsafe. No RCIN logging.

Thanks Jon.