From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: Sterling Ainsworth accident
To: lml
Date: Mon, 26 Jun 2006 18:07:10 -0400
Message-ID: <web-1207135@logan.com>
In-Reply-To: <001401c69927$19d128f0$0500a8c0@mountain0676a7>
References: <001401c69927$19d128f0$0500a8c0@mountain0676a7>
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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