I use a Spektrum 2.4 Rx. It has a base and remote receiver each with 2 small hair-like antenna (1" or so long) extending out the side. I lost control once but was lucky to "reconnect" and regain control. My remote Rx was hidden behind the servo tray and the other was just behind the tube. Recommendations were made to move the main Rx in front of and above the tube & move the remote away from the servos. No other problems since. But that's a Spektrum dual Rx implementation.

With your single Futaba Rx - perhaps get the Rx off the tray. The instructions suggesting that Rx location were written in the ealy 90's before 2.4 using a long external antenna. 

I have heard that 2.4 Rx sometimes unbind themselves when the battery goes into "amperage" starvation. When it happens to a Spektrum it takes 3-5 seconds of "no control" for the Rx to recover itself. Then, all is well if the plane is still flying.

Did you check the condition of your battery after the mishap?

My first SSE lost a wing in a high rate roll. No, I didn't fly it in a knife edge until I was about to land! I recovered the engine and a couple of servos. At night they just begged me to get another SSE flying 'cause they liked it so much.

Hope ya resolve your problem soon,</p>