In the famous American Airlines training video Children of the Magenta about cockpit automation, the lecturer describes one of the most frequent comments in the cockpit: "What's it doing now?"
http://www.google.com/url?sa=t&rct...Fx0a5eBaonU2Mc7pil2iLCg&bvm=bv.95515949,d.cGU
I find myself saying that a fair amount. My autopilot has these problems.
I am running SV touch with the aux A/P panels and ver 12.2 in an RV-12. I've run lots of flight tests and the A/P can capture and maintain altitudes just fine. Most of the time.
Thursday I flew 0S9 - CLS and returned TDO - 0S9. The flight down at 3500 ft was uneventful and the A/P locked the altitude. On the return flight at 4500 ft, the A/P "lost it's way", as seems to happen sporadically, but continually.
The altitude hold going down held the altitude to within 4 or 5 feet and the V/S varied up to 100 fpm max. On the return flight, the altitude varied over 100 ft and the V/S exceeded 500 fpm. I have a lot of graphs confirming these numbers. The air was smooth.
In a typical event, with the A/P engaged and an altitude selected, and all annunciations normal, the airplane flies right through the selected altitude. Sometimes, it phugoids around the selected altitude with no indication it is ever going to settle down. While closing in the selected altitude during a climb, if I try to help it by reducing power, it will "rebel" by abruptly pitching up.
I do a lot of punching out (disconnecting) the A/P and asking the lead-off question - "What's it doing now?" . Reconnecting sometimes works - but often does not. I experienced the same problem before and after I upgraded to Touch.
I've spent many hours Tuning the A/P with the Tuning Manual. I've pretty much got it where I want it. Because when it's good - it's really good. But -- when it's bad.......
I pulled a Diagnostic file from the last flight if Dynon wants to take a look
Bob Bogash
RV-12
N737G
http://www.google.com/url?sa=t&rct...Fx0a5eBaonU2Mc7pil2iLCg&bvm=bv.95515949,d.cGU
I find myself saying that a fair amount. My autopilot has these problems.
I am running SV touch with the aux A/P panels and ver 12.2 in an RV-12. I've run lots of flight tests and the A/P can capture and maintain altitudes just fine. Most of the time.
Thursday I flew 0S9 - CLS and returned TDO - 0S9. The flight down at 3500 ft was uneventful and the A/P locked the altitude. On the return flight at 4500 ft, the A/P "lost it's way", as seems to happen sporadically, but continually.
The altitude hold going down held the altitude to within 4 or 5 feet and the V/S varied up to 100 fpm max. On the return flight, the altitude varied over 100 ft and the V/S exceeded 500 fpm. I have a lot of graphs confirming these numbers. The air was smooth.
In a typical event, with the A/P engaged and an altitude selected, and all annunciations normal, the airplane flies right through the selected altitude. Sometimes, it phugoids around the selected altitude with no indication it is ever going to settle down. While closing in the selected altitude during a climb, if I try to help it by reducing power, it will "rebel" by abruptly pitching up.
I do a lot of punching out (disconnecting) the A/P and asking the lead-off question - "What's it doing now?" . Reconnecting sometimes works - but often does not. I experienced the same problem before and after I upgraded to Touch.
I've spent many hours Tuning the A/P with the Tuning Manual. I've pretty much got it where I want it. Because when it's good - it's really good. But -- when it's bad.......
I pulled a Diagnostic file from the last flight if Dynon wants to take a look
Bob Bogash
RV-12
N737G