Notes Special Procedures To Recover From Tail-Plane Stalls
Usually, flying an airplane is a pretty straightforward
operation... but King Schools notes flying in icing conditions
seems to hold surprising pitfalls for pilots.
"First, 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," said John King,
Co-Chairman of King Schools,
Added Martha King, the other Co-Chairman of King Schools, "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. 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 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," said John.
"Adding to the difficulty," says Martha, "is the fact that the
mere presence of icing conditions seems to distract pilots enough
so that they forget the basics. 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 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," Martha adds. "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."