Care to elaborate? I'm curious because to me the point of PFDs is to solve the clusterfudge-of-information problem inherent to six-pack/partial panel display format. If a PFD leads you to a loss of instrument cross-check that's more mentally challenging than partial panel setups, then holy false economy batman....
Departure into IMC, at about 300 AGL, right after I went into the soup the attitude indicator and HSI on the Aspen indicated I was rolling into a big left turn. At least 45 degrees of bank. I started banking right in an effort to stop the turn. At the same time this event took place ATC handed me off to departure, my eyes left the instruments to reach over to switch the radio, then I looked back and saw my left hand turn wasn't getting better. At the same time I was reaching over to the radio I was trying to mentally figure out in my head why the hell the heading on the HSI was what it was because it was significantly different then the runway heading and I had only been flying for a "little while". My eyes started scanning all of the other instruments and my brain determined the Aspen was full of **** and I was actually in a right hand turn that I entered when I tried to stop the left.
All in all it was only a couple of "seconds" of time, but it wasn't a particularly fun couple of seconds. Multiple indications on the Aspen said the left hand turn was happening and they were a complete lie.
Even more disappointing then the above was the fact that the Aspen did not indicate any failure or warning messages until at least 15 minutes later during which it was displaying incorrect attitude and heading information the entire time.
Throughout this couple hour flight, the Aspen would start working again, and all would be well. Suddenly it'd do the same damn problem again. The HSI would stop once it turned 90 degrees and i recall the attitude being jacked no matter what. A good 15 minutes later and it'd finally display a warning/failed message. Hour after that it would "fix" itself and warning messages would go away.
It was fixed after that and has been trouble free since. One thing I know for sure though, there is no way in hell I would depart into IMC with nothing but Aspens for attitude, even if I had two of them.
Why do I say it's "more" mentally draining? Probably because it's showing you so much information on one display you're parsing. Problem is all of that information can become jacked. At least with a six pack, typically, you'll only lose one or two things and the others will keep telling the right story.
There's just a lot more **** to think about and start comparing. You also tend to think you'll get a warning if it has a failure but clearly that logic doesn't work perfectly.
Your brain has to parse all of the information on the Aspen, the airspeed, attitude, altitude, HSI, etc. Then you have to compare that to all of the steam instruments you have left which likely aren't in the most visible or user friendly locations then parse all of them. Figure out which ones are correct, which isn't, if part of the Aspen is incorrect, or if it all is...Etc..Etc.
Is my attitude actually what I think it is?
Is the entire Aspen displaying bad information or just part of it?
Maybe the Aspen is completely right and I just lost vacuum so my steam DG and AI are what is actually broken.
Maybe the Aspen is half broke and my steam AI is also broke but my steam DG isn't.
Do the steam gauges actually work right in this damn thing? I know they worked during the taxi but I haven't flown this airplane in six months. Maybe they've been broke for months and nobody noticed.
Lots to think about.
There's a lot of combinations of things providing you information and when one isn't telling you the right thing there's a lot more to start comparing.
In this case, I went to what I know the best, the steam gauges, and parsed all of them to determine if they were correct or failed then made my correction from them and said screw the Aspen.
Failures are one thing when you're expecting them to happen because there is a CFII in the right seat that just covered them up or turned something off. They're a whole different set of trouble when you're not expecting them, you're doing a couple tasks, the warning messages aren't working, and you're just making the mental transition into IMC from VMC.
I also fly probably 10 different airplanes a month, always rotating, and they all have different systems and failure modes. I'd certainly be at an advantage if I flew the same airframe all the time. But the reality of what I do, isn't that, and my proficiency isn't incredibly high in any one airframe even though I've logged 40 hours in the last ten days.
One reason I'm really loving Foreflight with SV and my Stratus 2 is it's the one consistent thing that I have no matter what I fly and so far has yet to let me down to any degree. I would put a lot of "trust" into what it's telling me if I have a panel full of conflicting information in front of me.
They took it away on a truck. A GA plane would not have come home.
