Heating: principles of operation -6, Failure warning -6, Further reading on angle of attack -6 – Dynon Avionics Heated AOA/Pitot Probe User Manual
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1-6 AOA/Pitot Probe and Heated AOA/Pitot Probe Installation Guide Rev. C
starts as AOA becomes moderately high and increases in frequency until it is a solid tone very
near the critical AOA.
Heating: Principles of Operation
Dynon Avionics Heated AOA/Pitot Probe utilizes a heating element whose temperature is
accurately measured and regulated by a microprocessor-based controller. The controller
monitors a temperature sensor embedded within the pitot body to regulate the heat for the
front half of the Probe to a constant temperature. There are several advantages to this,
including:
Lower power consumption,
Increased heating element lifespan,
Much cooler pitot on the ground when de-icing is not necessary.
This technique ensures that the pitot can be rapidly de-iced if required, but does not needlessly
waste electrical power when not in icing conditions.
The controller module is remotely mounted, in the wing near the probe, or elsewhere. See
Probe to Controller Wiring, and Controller Power Wiring for wiring considerations on where to
mount the controller.
While the Heated AOA/Pitot Probe does not operate like a normal (when switched
on, always hot) heated pitot, it will still get hot in normal ambient temperatures.
When turned on, it will soon regulate its internal temperature to about 158° F (70°
C) to 176°F (80°C). Initial temperatures can be as high as 194°F (90°C). These
temperatures can cause a burn if touched with bare skin for long.
FAILURE WARNING
The controller for the Dynon Avionics Heated AOA/Pitot Probe is designed to meet the
indication requirements of FAR 23.1326 by providing an output that can illuminate a PITOT
HEAT STATUS warning indicator in the cockpit whenever the probe heater is turned off or is not
functioning properly. While this is not required for Experimental and LSA category aircraft, this
feature provides feedback that your Heated AOA/Pitot Probe’s heater is working as designed.
FURTHER READING ON ANGLE OF ATTACK
Like many aspects of flight, AOA is a simple concept that needs to be well understood to be
truly useful. The following are some resources that explain AOA and its application:
John S. Denker: “See How it Flies” website, Angle of Attack Awareness and Angle of
Attack Management -
AOPA Air Safety Foundation online article “The Angle’s the Thing” -