Posted for <bjburr@mwheli.com>:

 Brent,
 Once again I appreciate your continued explanations and am constantly
 your student on the Chelton system.  Your and Hamid's recent
 commentaries have been some of the most important dialog for me in the
 past several months on this LML forum.
 
 I am the true believer that it is the Pilot who ultimately must be able
 to operate the airplane in within the designed parameters and also to
 understand and operate the equipment available.  Practice, practice, and
 more practice, together with anticipation and recognition, is the only
 way to be ready for the unexpected.   While flying asking such questions
 as:
 
 Where do I land if the engine quits?
 What am I going to do if I get into icing?
 What is the maneuvering speed if I get into turbulence?
 
 The list goes on and on and repeats over and over.
 
For me the experience of flying my airplane is filled with anticipation
 and questions the entire time.
 
 Two things ring loud and clear.  Don't fly these airplanes near, around,
 or into thunderstorms!  And, stay out of ICE.  Both are usually
 predicted, forecasted, reported, depicted in charts, read in reports,
 seen on TV, broadcast on our VHF radios, shown on our avionics panels,
 etc.  They are not surprises.  The fact that pilots and their passengers
 find themselves in these conditions are only because they flew them
 there. It was their choice.  No one forced them to go and do it.
 
 Redundant systems are certainly great to have and should be installed
 whenever possible.  But in the case of redundant pitot tubes chances are
 that if one becomes iced over the other did too.  Even if they have
 separate heat circuits the chance that a pilot forgets to turn on one
 means he forgot to turn on the other.  The result is the same.
 Erroneous airspeed indications.
 
 I believe and trust in the hardware systems that are available.  It
 always is reassuring to be able to compare one system against another.
 It is very consoling to be able to get the same result or indication
 from two separate systems.  A.I. compared to EFIS, Airspeed compared to
 GPS groundspeed and AOA.  Altimeter compared to VS, Moisture and
 Temperature compared to visual inspection of the wing for icing.  Visual
 flap position compared to the flap indicator, the clunk of the gear
 relative to the green lights, Moving maps compared to paper charts,
 electronic databases compared to airport facilities directory, GPS
 Approach guidance flown concurrent with analog ILS/Glideslope VORLOC.
 Again the list goes on and on.  It is all an effort to not only have
 confidence in the systems but also to have a back up reference and plan.
 
 You are right, it is easy to sit here and run the scenarios in our
 minds, to write them on our computers and send our thoughts to our
 friends.  It is very difficult to deal with these situations in "real
 time".   The plan should be to stay out of the "real time" or only dwell
 in our comfort zone.  Our comfort zone can be expanded with practice,
 practice, and more practice.
 
 I have lost too many friends over the years to mishaps in aviation.  I
 know it can happen to me.  I know that no one is exempt or better than
 the laws and physics that make these machines fly and control our
 physical abilities.  It is only our respect for these laws that will
 keep us safe and alive.  I can only pray for the ability to discern and
 decide correctly.
 
 Bryan
 N132BB
 
 
 
 
 
 -----Original Message-----

...snip...
 It is NOT the hardware. It IS the pilot. The display was accurate (I
 have the data that shows that) but the pilot did not believe or
 understand it. A trusted standby instrument may have focused attention
 away from airspeed. You must consider the totality of the situation, NOT
 just individual displays or sensors. You are flying along and you hear
 the "STALL, STALL" Bitchin' Betty audio warning. You CONFIRM that a
 stall is imminent by looking at the airspeed tape. Yep, it is low. You
 crosscheck your standby and it agrees with your primary. You believe you
 have three pieces of information that all agree, because they do. You
 fail to recognize that all three are the result of a single inaccurate
 sensor. There is no direct "you are not stalling" indicator. You must
 infer your actual status from your attitude, engine power and airframe
 status (flaps, gear, ice) and because that takes significant mental
 effort you react by lowering the nose. What can it hurt? You will "fly
 the airplane" and then diagnose the problem.
...snip...