The left joystick on my ST16 was acting very strange for the rudder control. It would sometimes react normally while watching the response in hardware monitor but usually would only achieve 50 to 75 percent at full stick. I tried to resolve this through Yuneec as it is still under warranty but was very disappointed after getting the two hour estimated response when contacting by phone and an endless chain of auto response emails. The only vendor I could find to purchase an OEM joystick for my ST16 was Vertigo Drones. Shipping included at just under 20 dollars with good communication and quick response, I could not ask for more. Thanks to Vertigo Drones I am flying again in less than one week.