SAAB 2000 Autothrottle

[flipside]

How can I fix the tendency for the autothrottle to constantly rise and fall? It causes the aircraft to not maintain a constant speed. It is extremely irritating. It is like not having an autothrottle. I could maintain a constant speed manually. But that would require more work as my throttle control is pretty sensitive.

[JerryH]

I think I can help you with this, flipside. There are two values in the Autopilot section that need to be changed.

1. The default value for autothrottle_max_rpm is usually set at 90. It should be much larger; I use the rated_N2_rpm value from the Turbine section, ranging from about 15000 to 30000 for various turboprops.

2. The default value for max_throttle_rate is always 0.10. In most cases it should be smaller, typically from 0.01 to 0.05. In some aircraft, you may find it needs to be higher than 0.10.

So, pick a value for max_throttle_rate and begin the process of trial and error. And please let us know how it turns out.

Regards,
JerryH

[flipside]

I set the max_throttle_rate to 0.00 and it works fine. Thanks!

[JerryH]

Thanks for the feedback. I'm glad to know it worked for you. I didn't think a value of 0.0 would be valid. We learn something every day.

JerryH