Which receiver are you using? In this area, we have had a high failure rate with the R149DP receivers. I have personally had one quit, acting exactly as you describe. It has been working fine since being serviced. With another flier, 2 out of 2 have quit. The first one was also intermittent, and after being serviced and thoroughly tested on the ground, locked up and caused a crash which totaled a 33% IMAC plane. The other is still working after being serviced by Futaba, but the person is seriously considering switching to JR. Can't say as I can blame him

Later;

D.W.