Air Ontario Flight 1363 was an Air Ontario flight of a Fokker F28-1000 Fellowship which crashed near Dryden, Ontario on March 10, 1989 immediately after take-off en route from Thunder Bay to Winnipeg via Dryden. The aircraft crashed after only 15 seconds because it was not able to achieve enough altitude to clear the trees beyond the end of the runway due to ice and snow on the wings, causing the death of 21 of 65 passengers and 3 of 4 crew members.
A dead heading crew member (Captain) noticed the build up on the wings and when asked why he didn't advise the operating crew cited it would have been professionally in courteous to interfere with another crews operation.
SPEAK UP.
Then there was the Air Florida 737 into the Potomac with terrible loss of life.