From: yiannis@ccad.uiowa.edu (Yiannis Papelis)
Subject: Re: PC based simulators (long)
Organization: CAD-Research, University of Iowa, Iowa City
Date: Tue, 18 Aug 1992 04:17:38 GMT

In some article  rdd@cactus.org (Robert Dorsett) writes:

>The FAA's position is best described as very conservative.  They define 
>flight training in psychological "deconditioning" terms, thus require any
>training devices to be accurate, *real* representations of a flight-training
>environment, with tactile, large-scale controls and displays.  Highly 
>conceptualized interfaces, or PC-only interfaces are not tolerated, even 
>though the part-task transfer rate (such as practicing how to track a VOR) 
>can be excellent.
>
>The most disturbing trend is what Elite's doing.  If PC-based trainers are
>to work, they must be part-task devices: "kitchen-sink" programs, even if 
>professionally produced (and, so far, the simulator companies have kept 
>well away from the market; it's all private developers backed by vendors) can
>be counter-productive.  Elite's not really a "kitchen sink" program, but 
>Azure is trying to hawk their most unique, most difficult-to-repeat aspect, 
>which is the flight model.  They're publishing papers, and trying to "seed" 
>the academic literature with the idea that a flight model is the most im-
>portant part of a simulator.  

In a way, an accurate model is important because without it you can't
extract information to use in generating motion and control feedback.
A simplistic model without appropriate state variables cannot be used
to drive motion bases or other smaller transducers.

I doubt that it is very hard to come up with a model that 
is as detailed as Azure's.  Their model does not take into account
ground effect, pitch is limited to +-30 degrees and roll
is limited to +-60 degrees, and stalls are not really simulated,
they use tricks (add down pitch moment and roll towards the lower
wing) to emulate (rather than simulate) stall behavior.  The net effect
is equations that always operate in very linear regions.
Any one willing to get into the simulation game could use 
dynamics that model the same set of effects as Azure's.

I have no relation to azuresoft and I'm not trying to defent them
in anyway but IMHO, what they are trying to do is distinguish 
their program from other 'game-like' products.  
I don't buy their 'floating point model' stuff 
but some of the other things they claim are valid.  For example, they
model P factor, compass acceleration errors, constant speed prop 
operation and other similar goodies.  Their product, when combined
with their full cockpit interface where buttons and switches are manipulated
as in the plane instead of with a mouse, can give a useful instrument
training platform.  BTW, they had the full cockpit setup at their
booth in oshkosh, I got to fly it for some time and it seemed 
very realistic, the only think missing was the motion, which in 
instrument flying you're supposed to ignore anyway.  
(these opinions are mine only, and to further discredit myself I only
have about 4 hours under the hood, or which 0.3 only are actual).

The azure people hope to have certification from the FAA after
the FAA completes some training transfer studies.
What certification means, is that under CFII supervision and
when using the full cockpit interface, the practice time would be
considered as ground trainer.  Refer to recent rec.aviation 
thread about what this means/worths.

For differences between a ground trainer and the full motion 
flight simulators used for ATP check rides etc. see Robert's 
reference below :

>You may wish to contact the FAA and get a free copy of AC120-45A, "Airplane
>Flight Training Device Qualification" and AC120-40B, "Airplane Simulator
>Qualification."  They're free:
>
>	US Department of Transportation
>	Utilization and Storage Section
>	M-443.2
>	Washington, DC  20590
-- 
Yiannis E. Papelis,            - Electrical & Computer Engineering, U of Iowa
Center of Computer Aided Design- Home of the Iowa Driving Simulator & future
e-mail: yiannis@ccad.uiowa.edu - home of the National Advanced Driving Simulator