Posted for <bjburr@mwheli.com>:

 Brent,
 Once again thank you for your respected insight and explanation. As an
 owner/operator of the Chelton system I am always interested in learning
 more and more about it.
 
 Considering the Chelton EFIS, and its attitude display it relies on the
 AHRS.  Using accelerometers and magnetometers it replicates the
 information that could be provided by a gyroscopic instrument, no? What
 would make the PILOT more suited to maintain control using a gyroscopic
 instrument over the attitude display of the Chelton.  Airspeed
 indications aside?  Probably that the PILOT training used these older
 but more familiar instruments and he had more confidence in them? I am
 constantly comparing the attitude indications of my Chelton to the
 indications of a gyro in my panel.  The two match perfectly.  I am
 becoming more and more reliant and confident in the Chelton.  I have to
 say that my gyro is located in front of the co-pilot and not in front of
 me.  This could be classified in the "poor panel layout" category?
 
 How would the lack of accurate airspeed indications make the attitude
 indications of the Chelton system not reliable?  If the attitude shows
 straight and level and if the airplane is still flying then the common
 sense of the pilot should be to not do anything drastic.  Especially
 give up valuable altitude or make anything but subtle control inputs.
 As a secondary check for airspeed can't one use a gps groundspeed
 reading for at least a crude verification of speed.  Granted the
 correlation between gps ground speed and indicated airspeed can be a
 large number but I know that if my gps ground speed is 200 kts the
 chance is low that my indicated airspeed is close to stall speed.  I
 also know that if my gps ground speed is increasing that my indicated
 airspeed is most likely increasing (or remaining constant) as well.
 
 I assume the airplane had an autopilot.  Was Ainsworth stick flying this
 airplane or was he getting electronic assistance?  Wouldn't this also
 help keep the airplane fly straight and level or with a minimal decent
 angle or decent rate (FPM) that could be used while trouble shooting the
 other failed systems (airspeed indication).  I would think that if I
 were decending at 1500 fpm and the engine power had remained unchanged
 that I certainly would have enough airspeed to not stall and that I
 would easily be getting into the yellow and close to the red.
 
 One has to also assume that if the pitot tube had iced then there was
 also visible ice on the wings.  Certainly a concern for any pilot and
 the realization that deteriorating airspeed could be expected.  And,
 given rapidly building ice this certainly creates a priority in the mind
 of the pilot to the point where all ability to reason and react become
 difficult at best.
 
 And lastly, doesn't a lot of this lack of good flight information get
 resolved with a good AOA indication?
 
 Bryan
 N132BB