Flight limits in falling snow

[ramen noodles]

The prevelance of snow generally precludes icing, since the two are opposites on how water is suspended in the air - supercooled ice cannot be snow.

The reason for snow limits on helicopters is almost always the threat that gobs of snow afford to the engine's air supply or inlets. The typical problem is with plenum fed engines, were the inlet is typically a hole or slot in a cowling, and the engine is inside somewhere, with its heated bell mouth far away from the initial opening. The deep pockets invite snow to collect where it can be partially warmed and then slog its way into the inlet.
Cures for snow ingestion usually involve shields or diverters that keep snow from forming near the plenum, or heating sections where the snow does for to melt it before it builds up. Flying a helo into snow when it is not approved is a very effective noise abatement scheme, once the engine(s) have quit.

Engines with exposed bell mouths or with heated inlet assemblies are virtually always immune to snow problems, since the ice tests for which the inlets are designed are far worse in heat requirements than the typical wet, heavy snow.

OT personal attack on crab@ deleted.

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