Pitch Sensitivity VS Gain

[rfazio1951]

Can someone please explain to me the difference between sensitivity and gain in the autopilot settings? I am trying to get the pitch, set, to follow the glideslope on an approach and can't seem to get it right. She follows alt hold and climb and descend to altitudes fine. but on the glideslope she porpoises badly.

 

[Raymo]

The AP tuning guide has the answers. Below is an excerpt but there is more to read.

The Flight Director provides a valuable tool for evaluating the performance of the AP. If the autopilot is not able to keep up with Flight Director command bars, sensitivity should be increased. If the autopilot can keep up, but gets a late start and lags behind the flight director, PITCH GAIN or ROLL GAIN can be used to speed up response. Use sparingly! Excessive PITCH GAIN and ROLL GAIN can result in rough performance.

 

[William_Ince]

The AP tuning guide has the answers. Below is an excerpt but there is more to read.

The Flight Director provides a valuable tool for evaluating the performance of the AP. If the autopilot is not able to keep up with Flight Director command bars, sensitivity should be increased. If the autopilot can keep up, but gets a late start and lags behind the flight director, PITCH GAIN or ROLL GAIN can be used to speed up response. Use sparingly! Excessive PITCH GAIN and ROLL GAIN can result in rough performance.

In other words:

Sensitivity = Correction Accuracy
Gain = Aggressiveness

 

[rfazio1951]

Thanks guys, that helps a lot.