Dave Doe wrote:


The stall horn is preset to go off at a specific AOA. It does not give
the pilot any indication of the actual AOA being flown. AOA indicator
is typically used in large transport airplanes and military jets where
the operating envelope is large. For typical GA airplanes, the envelope
is so small that the airspeed indicator is a good indication of AOA
under normal operating conditions.

Isn't the texts on AOA about *critical* AOA? - the rest of it, is surely
the other angle - within the load envelope. The stall warning provides
a fixed measurement of the imminent critical AOA - what else does a
pilot need?

The only minor difference is that the stall warning does not tell you
where the critical AOA is. It just goes off at some predetermined angle
before reaching the critical AOA. However, as you say, a pilot of a GA
airplane does not need to know the exact AOA. This is why we don't have
AOA gauges in small airplanes. In fact, one could argue that you don't
even need the stall warning horn. As long as you are not doing any
high-g maneuvers, the ASI tells you how close you are to stall. The
dilemma is the lengthy discussions about AOA in texts that deal with
small airplanes. This causes all kinds of confusions that is not
helpful for the beginning pilot. You can read the archives from this
newsgroup and find how many people have been confused by this. We teach
them about AOA in the classroom, and then use the airspeed indicator in
the cockpit.