>With all this talk about stalls and AOA<

Of course, I have to comment about PLI and AOA.  Most PLIs (pitch limit
indicators) use an AOA vane as their primary input.  The Sierra flight
system uses a calculated input to the PLI.  It is better than nothing but
not the real thing and as I understand their product, it does not include
gross weight and CG inputs which can have a significant effect on AOA.

About half of the Lancair fatalities over the past years may have been
avoided with an active stall warning device.  A stall warning device must
include an aural warning and warns well in advance of reaching the critical
angle.  Stall strips do not give adequate warning (2-4 knots) and generally
would not even meet the minimumal Part 23 rules nor do they provide an
aural warning. Did you notice that the Colunbia has strips but still was
required to have an active stall warner.

The ultimitate system is a true full range AOA that reads what is happening
at the wing aerodynamically.        

James B. Frantz
Proprietary Software Systems, Inc. www.angle-of-attack.com
LFrantz@compuserve.com
(952) 474-4154