Whiteout
Defined by the American Meteorological Society as “An atmospheric optical phenomenon of the polar regions in which the observer appears to be engulfed in a uniformly white glow”. That is, you can only see dark nearby objects – no shadows, horizon or clouds, and you lose your depth perception. It occurs over unbroken snow cover beneath a uniformly overcast sky, when the light from both is about the same. Blowing snow doesn’t help. Once you suspect whiteout, you should immediately climb or level off towards an area where you can see things properly.

Taking off
In snow, the accepted takeoff method is the towering type, because a normal one may produce a large snow cloud to blind air and ground crews, and a failed engine (you may be able to blow a lot of loose snow away with a little application of collective before the take-off proper). If a white-out does happen, apply maximum collective for an immediate climb and forward cyclic
(i.e. no hover), keeping the ball centred and using the A/H if necessary, but the real key is keeping a visual reference. If you have it, exercise the gear once or twice to dislodge slush, etc. that may have stuck to the legs, to stop it freezing. With any piston engine, use carb heat regularly and check frequently for carb icing. Have carb heat fully on or off, but not on for prolonged periods—it increases fuel consumption markedly (see also Engine Handling, in Techie Stuff).

The Cruise
Mountain wave clouds can be loaded with heavy ice at remarkably low temperatures (remember that low pressures and low temperatures will cause your altimeter to read high). When using anti-icing, take into account the inaccuracy of the temperature gauges, so if you must turn it on at 4°, and the temperature gauge is only accurate to within 2, start thinking about it at 6°.
Wet and sticky snow has more chance of icing, and is associated with low visibility, which would indicate that you shouldn’t be flying anyway. Luckily, light powdery snow tends not to accumulate, but will still give you the leans. Whatever you fly in, make sure the baffles are fitted.
Visibility, by the way, includes the inside! When it’s very cold, water vapour (from clothes, breath, etc.) will freeze on the windscreen, so warming up the machine before passengers get in will help a lot.
Navigation
Sun Tables are used for resetting your DI in the Arctic, with true sun bearings taken every 20 minutes or so (assuming you can see it), based on the fact that we know where the Sun will be with reference to True North for a given time, date, latitude and longitude. Having obtained the local time, look in the tables for the Sun’s bearing, point the nose towards it and set the DI to True North. The two types of navigation used are True North and Grid North (to find Grid North, add your longitude to True North, and vice versa). In True North navigation, headings have to be measured from your point of departure, using its longitude as a base line. Every time you cross a longitude, you add a degree going East, and subtract going West, so if you cross 10 longitudes enroute on a heading of 090T, your return heading will be 280T, not 270.