I do not dispute LTD's observations and would welcome him or anybody else pointing out an apparently unsafe condition on any a/c I'm about to fly in.
But for argument's sake, lets consider that since the takeoff was successful, some factors had to have worked in their favor.
I would venture to guess that dry snow falling on a flying surface below freezing temperature in air below freezing temperature at low humidity (M03/M11 as reported in the METAR) does not adhere. Note also that adhere is the word used in the FAR previously cited.
In considering declining deicing in such conditions, I would very much want to know that the flying surfaces, especially the tailplane, were clean and cold before the snow began falling.
Without venturing into glaciology and avalanche science, a fluffy uncompressed accumulation will generally blow off whereas a settled accumulation may not.
It has been mentioned that some pilots are willing to decline deicing when in their judgement the snow will blow off. When the physics are in their favor, the takeoff will work. The majority will elect deicing and I'd rather be flying behind them.
Last edited by RatherBeFlying; 8th Dec 2007 at 03:51.