EE444 Embedded Systems Design - Student Projects: Peters & Nagari

Disclaimer: This page was created by A. Nagari and D. Peters.

All opinions expressed here are those of their author(s) and not of D. Raskovic

Carburetor Ice Risk Indicator

for General Aviation

For what is this device used?

Many aircraft engines in the civil aviation category still use the carburetor for fuel metering. Certain atmospheric conditions are conducive for ice formation due to a temperature drop in the carburetor, blocking airflow and resulting in decreased performance or engine failure if severe enough. Ice formation is predominately dependent on humidity and can occur on a large temperature interval of -15ºC to 35ºC, hence the conditions are not necessarily obvious to a pilot. A Carburetor Ice Risk Indicator gives a pilot real-time information about the ice formation probability on a scale according to a chart published by various aviation authorities. This real-time information helps a pilot better determine when it is suitable to use the ancillary carburetor heat control. For a complete description about the danger of carburetor ice in aviation click here:

http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=detail&id=1168

How does the device work?

The embedded system has a temperature and humidity sensor. It calculates the dew point from the temperature and humidity data obtained from the sensor. Based on a predefined graph it calculates the risk level of the ice formation and displays it on an OLED display screen.

The Device:

The graph used :

This data is used to create the dial gauges on the display. The lines correspond to assigned angles of gauge needles:

The gauge depicted here shows conditions which are quite dry (Alaska air). Note that even with a large dewpoint - temperature spread, there is still a high risk of accumulating carburetor ice at descent power. Some aircraft require carburetor heat to be used for all descents, regardless of the conditions. The indicator helps a pilot assess the environmental conditions conducive for carburetor icing.