Black Nose Paint

[Nexus]

Ritter, several of my friends, who are aeronautical engineers says that ice bridging is a non-factor.

One of them sent me this snippet, which is from an AOPA article:
"The time-worn advice was to allow a certain amount of ice to form before inflating the boots. That theory was motivated by the belief that cycling the boots too often would cause ice to make a shell-like formation beyond boot-inflation limits. Ice bridging, it was called.

The latest research and scientific conferences, however, have come to the conclusion that ice bridging is a myth. It's true that more ice will shed if more ice is allowed to build on a booted surface. But experts now say there's no reason to believe that ice can continue to form and bridge over leading edges, and leave boots to helplessly pulsate behind an ever-growing sheath of ice.

Those yarns apparently got their start back in the 1930s, when boot inflation pressures were low, inflation times were lengthy, and there were fewer inflatable cuffs within the booted areas.

The most modern boot systems incorporate ice-detecting sensors that automatically initiate inflation cycles."

Now I've been taught like every pilot has, that we must not be too "trigger happy"  with the de-ice boots, but I'm left wondering now.
And the idea to try it IRL doesn not appeal to me  :-[
Any ideas  ???

[RitterKreuz]

Nexus - there is a lot of fact in your post but i would add...

ice bridging is a non-factor on the newer de-ice boots. The newer boots have more riges and remove ice more effeciently, however older boots may bridge up. Personally i have only had it happen on the inboard section of the right wing of an old aztec that had de-ice boots... we landed and sure enough they were bridged, i didnt know it until i landed though so it didnt have a notable effect on performance. Besides it was only about a 6 to 8 inch long section of ice that was paper thin, but definitely hallow beneath. a void separated the wing boot from the ice by perhaps as much as one quarter to one half an inch. it may not be the "ice bridging" of urban legend that will doom a flight but it was, technically, by definition, ice bridging.

i probably should have mentioned that on newer de-ice boots ice bridging is not really an issue just as you posted, but it can happen, and when it does... well... ice only breeds more ice which in turn creates more drag and more weight than anyone would care to have on their airplane. IMHO

im not sure why AOPA would imply that ice bridging is "impossible" or a myth - - highly unlikely yes - - - but not impossible. Part 121 training training encourage us to remain vigilant for the slim possibility of bridging... and to keep in mind that it is only slightly likely to occur in the most severe, emergency inducing ice accretion. (been there and done that - hired three seperate proctologists and they still have not been able to locate my seat cushion)

Do i think that ice bridging would occur along the entire span of the wing?  Nope, if that were to happen i would likely hit the lotto, take down vegas, discover mermaids and get hit by lightning all in the same day. but it can happen - even if on some small and insignificant scale.