For the laymen and amateurs out there:
It is clearly stated on our Flight Ops. Manual that after the holdover time for a given temp and precip. condition has elapsed (for one-step or two-step de-icing process), a uniformed crewmember, who is current on the same type of aircraft, can look at the top/leading edge of a wing and if clearly visible (often not enough light), he/she can try to determine whether any precip. has begun to freeze. If any surface condition is in doubt, you return for more de-icing, especially for the two-step process, which has a longer holdover time.
One-half inch of ice is far too much.
Research has proven that even particles as small as medium-grit sandpaper can increase the stall speed a significant amount.
Aircraft with no slats, such as the Fokker 28, DC-9 (-10 series) and CRJ are even more at risk from just "a little ice".
If in doubt, check the NTSB website.
The ATR-42 (American Eagle) turboprop was re-certified after a planeload of passengers and crew smashed into the ground in Roselawn, IN.
Before this tragedy, the US FAA had "allegedly" been notified of serious problems with European ATR-42 aircraft in icing conditions: these experienced 'aileron snatch'-but the FAA "allegedly" did nothing about it until body parts lay on the frozen ground in Indiana.
Last edited by Ignition Override; 22nd Mar 2006 at 00:52.