During a training session with a newbie on Friday, 2 minutes into the flight, the trainee mentioned that the model was not responding to any control input. I released to training button to take control of the model and discovered the plane didn't respond to any stick movement. I was using a Dx-18 g2 connected by wire to a Dx-5e. The plane that was lost was a Apprentice that had only been flown 5 times. After that crash, did 10 flights with a foamy just to make sure there was no problem with the Dx-18. Have no idea why the plane crashed, guessed the tree gods just snatched it out of the air.