Dynon Avionics Heated AOA/Pitot Probe - Manual (Page 10)

Introduction
1-4 AOA/Pitot Probe and Heated AOA/Pitot Probe Installation Guide Rev. C
AOA Calculation: Principles of Operation
Most pilots are introduced to the concept of angle of attack (AOA) during their initial flight
training. However, as most GA aircraft do not provide a way to directly measure this critical
flight parameter.
WHAT IS ANGLE OF ATTACK, WHY IS IT IMPORTANT, AND WHO USES IT?
Angle of attack is quite simply the angle between the wing chord and the oncoming air that the
wing is flying through. This is an important concept, as aircraft wings stall when angle of attack
gets too large, at a value known as the “critical” angle of attack. As pilots are taught in flight
training, an aircraft can stall at ANY speed if this critical angle of attack is exceeded. Hence, a
great way to avoid stalls is to not let the angle of attack reach critical, and the best way to avoid
critical angle of attack is to know what your angle of attack is in the first place.
Navy pilots know angle of attack well. On carrier approach, they use angle of attack
measurement almost exclusively to determine if they are set up correctly for their “trap”. If
their angle of attack is too high, they risk stall before reaching the carrier. If it is too low they
will be carrying too much speed to land safely on the small patch of available deck space.
Airliners also rely on angle of attack information. Some make it directly available to the pilot via
a dedicated gauge or readout. Others incorporate it into the data that it uses to warn pilots
about impending stalls via stick shakers and other annunciators. In both cases, the pilot is able
to make better decisions because they are able to incorporate information about the measured
performance of their aircraft.
DYNON AVIONICS' AOA/PITOT PROBE
Dynon Avionics was the first manufacturer of affordable EFIS products to offer a way to
measure angle of attack. Through extensive wind tunnel testing, Dynon is able to offer an angle
of attack (AOA) / Pitot Probe that allows both angle of attack and airspeed to be measured
when connected to the EFIS unit or SkyView system. AOA can be shown graphically on Dynon
displays and optionally listened to via audible alerting that intensifies as the critical angle of
attack (stall) approaches.