Answer:
pilot error and improper de-icing procedures.
Explanation:
In the article, we are told that Air Florida Flight 90 had bad weather prior to taking off, because of the snow it was supposed to undergo de-icing, however, the pilot didn't do so, also he failed to turn on the plane’s own de-icing system.
Thus, the National Transportation Safety Board concluded that pilot error and improper de-icing procedures were the cause of the crash.
