I thought I’d post some education I’ve received from flying with the 55X autopilot now for a while.
On two occasions, I’ve found the autopilot pulling the plane up into a nose-high, dropping airspeed attitude. The first time I ascribed it to problems I’ve been having with the altitude preselect (today diagnosed by LAC Avionics to a loose connector). However, the second time I wasn’t using the preselect, and I realized it was just a dumb pilot.
In both cases I was using the AP for the climbout to altitude. I selected a VS to provide a cruise climb of 110-120kias. Then I got busy with other stuff. Of course, as we climbed, the available power dropped, and the airspeed to maintain a constant rate climb dropped. Once the airspeed drops below Vy (100kias on the SR22), things go to hell in a hurry as the AP tries to climb at a VS it can’t achieve. Now I know to watch the airspeed much more closely and keep adjusting the vertical speed to maintain airspeed.
I guess what I’d really like is a constant speed climb for initial climbout, not constant rate.
Thought I’d pass this observation on for any other autopilot newbies.
-Curt