Maybe Jason can fill in some detail on why they don’t work like in the big jets? Maybe @chrisparker knows?
The idea of an AT is that it makes it easier to manage the vertical profile without having to worry about speed. You don’t need it in level cruise. Plus – AF447 excepted – it gives you underspeed and overspeed protection; the SR22 implements underspeed via the crude measure of pitching the nose down, which is fine if you have plenty of air under you 
The big jets also fly differently. Yesterday I spoke to an Easyjet pilot who was surprised that we (GA) don’t fly continuous descents. I explained that it is simply not the way GA flies and even if it did, ATC would not let you do it. You get a descent to the IAP platform and then either procedural or vectors. The best we can manage is self-tweaking the VS to create a sort-of continuous descent from cruise altitude (i.e. avoid levelling-off) but this often results in a VS value which is quite low versus ATC expectations. Maybe an AT is a big help in flying these profile?
What’s certainly true about autothrottle is that it degrades one‘s skills.
Peter wrote:
but this often results in a VS value which is quite low versus ATC expectations
Why VS does matter GA & CAT will fly the same ILS glide path 3% to 6%? I guess you mean GA is not flying faster?
I guess commercial guys got used to is how easy to “lock-in” airspeed & heights (in Speed or Flch modes) into their screens, these inputs comes from “traffic flow & separation” given by ATC from their intuition or optimization software, this probably justifies zero need commercial pilots to manually touch the yoke or the throttle?
Thanks for the reference, will bee good have a look on the day to day job (not on my plate yet ), most of my stereotype impressions were mainly from those who relax from their day job by flying wooden gliders on weekends, doing what they call “real flying”
On automation, on the airliners side the underlying drivers are clear: solve pilot shortage, reduce human errors and cost cutting
I don’t think this how Cirrus Jet pilot owners view having a fully automated aircraft: as their flying machine? or just another mean of private transport? or personal luxury/wealth symbol?
Probably, the quest for too much automation in private GA world points to the latter, those who likes the flying aspect of it will probably keep a hand or foot on the thing…
The earlier design was not very subtle and would tend to overcontrol the throttles which often amplified autopilot oscillations.
The Garmin autothrottles are supposed to be quite good and the G5000 version is in the new latitude. If they are Garmin and similar then perhaps they are better than the normal light jet variety.
I still don’t know why you need the complexity in a light jet. I have never wanted A/T in mine. You can fly a continuous descent without them.
The greatest risk in FLC Autopilot modes (constant speed/Mach) without an autothrottle is a volatile v/s during descent as it chases the speed. But you tend to use VS in descent which works fine.
How you would use them is not so much during approach but during an arrival on a VNAV profile where you are flying a fixed say 3 degree path to an altitude at a waypoint. With an autothrottle you can say you want to fly it at 250 knots. Without one you have to set the throttle yourself.
Ibra wrote:
flying wooden gliders on weekends, doing what they call “real flying”
Fully agree to that statement. It’s not only the absence of automation and the seat of the pants flying that’s appealing but also escaping the tight knit framework of airline flying. It’s a bit like getting the best toys of the world but you’re only allowed to play in a small prison cell. No pilot hates the flying part – but there is so much other BS involved and it gets worse every year ;).
JasonC wrote:
I still don’t know why you need the complexity in a light jet. I have never wanted A/T in mine. You can fly a continuous descent without them.
The cirrus jet sells partly because of shiny jet syndrom. Autothrottle is cool, and helps that cause.
However I also think that speed control is one of the things that are challenging when going from a sep to the vision. Especially if one flies complex sids and stars single pilot with many constraints it’s nice to turn the speedbug or program the fms with alts and speeds and have more capacity to monitor.
I’m not saying one absolutely needs it. Far from it. Cirrus is in the selling airplanes business and constantly upgrading their product seems to work for them. Autothrottle was probably the „easiest“ thing to put in for the effort required. All the other gadgets are already there (satcom voice/datalink wx, infrared, synthetic vision, parachute, jet propulsion,m…). What else could they do? Reading my own lines a cat1 certified autoland could really be coming to the G3 ;).
What happens to position holders when a new version comes out? We had a guy on here a while ago who said he held a position (or more than one) in this jet, and he was constantly posting how great it was Can these positions be upgraded?
