Can someone explain what a tailplane stall is when referring to planes?

Question

I have been told that it is very bad and would like to know what it is and why it is so bad.

Answer 1

It's when the horizontal stabilizer of an aircraft stalls.  Without getting too in depth, when an airplane flies, it requires a downward force on the tail to balance out the other forces acting on the aircraft.  Without this force, the nose of the aircraft will drop, and controllability will be virtually impossible.  When a tailplane stalls, it is no longer developing this tail-down force.  Tailplane stalls are usually due to ice accumulation on the surfaces, which degrade its ability to produce lift, and also add weight to the airfoil.  They're also dangerous because they are hard for even experienced pilots to recognize, and the recovery technique seems counterintuitive to a lot of pilots.