Noticed that too, but I also saw that the Yaw button didn't work. Changed it in the aircraft.cfg from 0.00000 to 1.0000 (not sure about the number of zeros since I'm on another computer).
Thought that fixed the problem, but on another flight it started again and I was only doing Mach 1.
One other thing: the fuel rate needs to be changed. I ran out of fuel flying down to Spain and back. I changed it from 1.3 to .73 and still it ate fuel
