You are worried about ANY airplane that is no TB20, right?
But you are right, the Cirrus is not a “classic” airplane! ;-)) (Pun intended)
You just set it to any pitch and/or roll and press A/P, that’s it. And it will not even stall or overbank or anything. the DFC90 has a pretty sophisticated envelope protection, works very well although itÄs not AOA but speed based, obviously
You just set it to any bank and/or roll and press A/P, that’s it.
That is standard King AP behaviour.
And it will not even stall or overbank or anything. the DFC90 has a pretty sophisticated envelope protection,
Limits on pitch and roll is also standard King AP behaviour.
If you read my post, Alexis, you will see I was talking about the CWS button and how it should work. Sure, you don’t need it. But it is a huge asset to have.
This is absolutely zero, zilch, nothing to do with a TB20. Nothing whatsoever. I am talking about autopilots
Can you post a link to the user manual describing the DFC90 installation?
Don’t let me tease you :-)
I only know that CWS does not work with the SR22s automatic trim that is ctrld by the Autopilot. So experienced Cirrus pilots do that part a liitle bit different. The S-TEC55x equipped Cirri don’t have it either!
I’ll send you the manual tomorrow
While I have CWS and use it sometimes I must say I don’t think it is essential. I never use roll and pitch modes.
As I wrote in my last post, and as acimha’s vs Peter’s posts show also, the CWS does different things in different installations. In the KFC-150 equipped Bonanza, it did just what Mooney Driver and acimha says, and I used it in the same way as acimha – for short detours around convective buildups. As soon as the botton was released, the autopilot would take the airplane back to the original track/altitude/climb profile.
Hovewer, in the Avidyne/S-Tec-55 equipped Piper Six I sometimes fly, the CWS works as Peter describes – it resets bank angle and vertical speed to the airplane’s actual attitude the moment you release the switch. If in HDG/NAV/APP mode, it reverts to basic mode. If bank is less than 8 degrees, it maintains wings level. Then you have to select HDG/NAV/APP over again as appropriate. I find that I don’t use the CWS much in that aircraft, and neither does the owner. Rather, I select HDG mode to steer around clouds. And to change rate of climb/descend, I find it smoother and more accurate to adjust the setting on the S-Tec 55X autopilot panel. JasonC, I believe your CWS works something like this too.
CWS’s all disengage the servos for as long as the switch is pressed. What happens after that, however, seems to vary between equipment.
(For the record: overpowering the autopilot, especially in pitch, is a very bad idea. It seems my last post was not clear on that.)
Who uses the Flight Director?
The FD is a different presentation to the traditional CDI.
The CDI shows you the current deviation and you have to use your brain to work out the heading/pitch change required to intercept the trajectory. Whereas the FD shows you what you need to do to intercept the desired trajectory (horizontal and vertical).
The FD is normally driven from an autopilot and can be used to fly “on the autopilot” (by hand) if the autopilot servos have failed.
Jet pilots use the FD heavily, and AIUI a “raw data” ILS is actually flown using an FD, not a CDI like we do on GA checkrides.
I use it more and more. The FD of the Avidyne Entegra, combined with the DFC90 Autopilot is really so good that it’s a lot of fun. The perfect combination of hand flying and A/P … to me. I fly too little to really be an expert but I find it’s very precise and so much easier to fly than “raw data”.
Here’s a little movie I made the other day when I first started to test it, watch full screen:
Peter is quite right in that almost all airline flying is done using the FD and not using it is unusual.
Some of us try to practice raw data ( no FD ) as much as we can but if you are doing four sectors a day it is easy to get lazy and just use the AP & FD as much as you can.
If simulator time allows I try to get a raw data flight done with no FD at any stage but I am viewed as a bit of a Luddite for this as the reliability of the FD is such that failure of the system is almost unheard of.
There are situations were it is best to clear the FD from the screen, one is on a pure visual approach as the FD would require constant updating by the PM and this is far too distracting so it is best turned off.
The other time is during take off from places that require special procedures, due to close in obstacles at some airfields an immediate turn is required almost as soon as the aircraft is airborne ( 300ft is typical) at these places the FD can’t keep up with the need to turn away from the rocks so it is best left switched off.
I thought “raw data ILS” in the airline business did mean using the FD, not the CDI.
Might be, maybe i was wrong. I wanted to say that it’s much easier with the FD than with the crosspointer.
