I have some problems with the connection with RC.
I use a FUTABA T14SG and Navio2.
Could you please show how you launch APM?
I was also wondering what made you believe that something’s wrong? It seems like you just haven’t calibrated RC!
If you think that you have a problem with RC, I suggest trying to
cat /sys/kernel/rcio/rcin/ch2 and move throttle stick back and forth. If values change, there’s no problem with RC whatsoever.