SAN DIEGO, CA – Usually, flying an airplane is a pretty straightforward operation. But according to King Schools, flying in icing conditions seems to hold surprising pitfalls for pilots.
"First," says John King, co-chairman of King Schools, "there is the remarkable fact that the recovery from a tail-plane stall induced by icing requires a completely opposite technique from recovering from a wing stall."
"Every pilot knows that recovering from a wing stall requires applying forward stick to lower the nose and reduce the angle of attack of the wing," says Martha King, co-chairman of King Schools. "On the other hand, recovering from an icing-induced tail-plane stall is completely counter-intuitive. It requires applying aft stick pressure."
Why aft stick pressure? The Kings explain that while the wing is providing upward force (lift), the tail is providing downward force. This helps to make the airplane stable. Anything that increases the angle of attack of one, decreases the angle of attack of the other. So while a pitch-up increases the angle of attack of the wing, it decreases the angle of attack of the tail-plane. Plus, raising the elevator increases the camber of the tail-plane, reducing its stalling speed just the way increasing flaps increases the camber of the wing and decreases the stalling speed of the wing. The net result is that to recover from a tail-plane stall requires aft stick pressure.
"The problem is that it is extremely difficult to tell the difference between a tail-plane stall and a wing stall," says John.
"Adding to the difficulty is the fact that the mere presence of icing conditions seems to distract pilots enough so that they forget the basics," says Martha. "Recently there have been several crashes as a result of pilots in icing conditions failing to add power when leveling off from a descent or putting down flaps and gear."
According to the Kings, it is clear that pilots need help when dealing with icing conditions.
"That's why King Schools recently revised our online Icing Operations course to beef up the section on tail-plane stall recognition and recovery," says John.
"If you fly on instruments long enough, you will eventually encounter icing conditions," says Martha. "When you do, the information in this course will be vitally important. We want pilots to have the knowledge and confidence they need to do the right thing when it really counts."
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