Ice det equals about . 0.5mm ice accretion. It holds the signal for 60secs. if after 60 sec no ice detected it resets. Once it detects it heats the probes and sheds the ice. If it does this 7 times in a row / Then Sev ice det. = about 5mm ice.
the ice changes the oscillating frequency of the probe. Just like a quick dip in a frosty pond one could say.
something like that.
when you select Wai on resets the counter.
ice det is NAI on. Sev is NAI and WAI.
detected from the vibrating ice det on the lower part of the nose (2 of them).
or you can look at the horn on the window centre pillar