This in-flight frost is called ice. I've never experienced icing conditions
but alway thought it was the leading edges that collect ice.

Well, duh... but I'm referring to "ice" accumulation when not flying through "visible" moisture. No rain, no cloud, just clear 10 mile visibility air. And the frost was not on the leading edges (since it was not due to impact with droplets) but rather, on the flat parts of the wing which have cooled radiatively. This is different enough from regular inflight airframe ice that I thought it warranted a new word, at least for now.

Jose
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