Snow & jets?

True true. This is typical of educators… we will argue the same point and both agree we are right..:D

I believe the DC8 and jets of a similar vintage used water methanol during take-off. (but certainly not relevant to this discussion)

To be honest, given the choice, I’d avoid flying into known icing conditions if it could be avoided.

Small amounts of water ingested into the intake, ie. snow, will aid an increase air density, and therefore INCREASE engine efficiency…
Snow occurs in cold air – which is better for the engine, ie. more dense, and will make the engine INCREASE efficiency…

Well you´re right! Water will increase engine performance up to a degree. Some turboprops (basically a jet engine turning a propeller) have water/methanol mixture injected into the engine to increase power. Off the top of my head, I can only think of the Garret TPE series and the RR Dart that used this method. Both are direct drive engines. Free wheeling turbines don´t seem to use this to increase power (the PT-6 does not) but I´m happy to be corrected! NO jet engine I know of has EVER used water/methanol spry during routine airline operations to increase power, but again, I´m always happy to learn something new.
While on the subject of water ingestion into jet engines, it can become too much at times. I know of one instance when flying through a monsoon rainshower with engines at idle, one engine flamed out at 15.000 feet due to rain.
With regards to cold, it is true. Engines perform better in cold environment, but for the purpose of the discussion it is hardly relevant.

Whilst Galdri is right in what he says – snow = bad, here’s some variables to throw into the mix (in addition to the variables he mentions….)

Small amounts of water ingested into the intake, ie. snow, will aid an increase air density, and therefore INCREASE engine efficiency…

Snow occurs in cold air – which is better for the engine, ie. more dense, and will make the engine INCREASE efficiency…

Despite these MINOR factors, SNOW = icing = bad.

Flying through snow has no effects on jet engines. The snow will melt in the heat inside the engine. However, snow/ice that builds up on the engine inlets can be a problem. It will disturb the airflow into the engine, and if it breaks off in big chunks can damage the engine, or cause flame out when it melts into lots of water.
That is why all jet engine inlets are heated by hot air taken from the compression section of the engine (bleed air). The bleed air is very hot (typically about 300°C or more) and is ducted to the front of the engine inlet. That is why, on most jet engines you´ll see a metal coloured stripe around the inlet. It is the heated portion of the inlet.
Taking bleed air from the compression section of the engine, will have effects on engine performance. During most of the flight, the engines are operating well below maximum power so when the engine anti ice is switched on the engine will automatically increase the power/fuel flow to compensate for the bleed air being drawn from it. The power increase is not apparent on any cockpit instrument except the fuel flow meter, and even on that instrument the change is so small as to be almost unnoticeable. For prolonged flight in iceing conditions a ball park figure for fuel flow increase is about 5% for most engines.
During take off, were engines are operating at maximum power, the small increase in power necessary to compensate for the engine anti – ice is not available. In that case, the loss of power is compensated for by reducing the maximum allowed take off weight. The amount of weight reduction is VERY variable and will depend on aircraft type, engine type, runway length and airport elevation just to name a few variables. I´ll not be drawn into discussing Flex/Assumed temp take offs, as that will be a can of worms at this stage! ;):D

I think the snow would be melted before it got anywhere near the crucial engine parts, snow and rain are no problem, however hailstones can cause damage