Tail Stalls?

the only tail stall I am familular with results from Ice or in a langing configureation (full flaps on a Cessna slipping etc.)

Depending on the aircraft you will recover differently.

In small piston acft, it is no different than your normal stall, power on? pull the power push it over pull the flaps.

Power off? add power push the nose over. pull the flaps.

In a jet, it is always the same. Full power and pull it out, DO NOT drop the nose.


NASA did some very cool videos they used to give out for free. Now you have to pay sportys

clips

Here

and

Here
 
Tail stalls occur from ice accumulation on the tail of the aircraft. The Cessna situation is a bit different and very rare.

The strange part about ICTS is that to recover you need to apply back pressure on the yoke and decrease power. No that is not a typo. Allow me to ellaborate.

In normal flight the tailplane or horizontal stabilizer doesn't lift up, it pushes down. It does this by acting like a normal wing but upside down. When ice accumulates on it and stalls the aircraft will pitch down because it has no force keeping the tail from rising. Back pressure on the yoke is needed to raise the nose back up.

Adding flaps will make the situation worse because of the change in airflow. The air flow that was once coming from in front of the horizontal stabilizer is now coming from above it. Remember not to think of this in terms of a normal wing stall, that is not what is happenning here. The horizontal stabilizer is acting like an upside down wing so when the airflow comes from above it this actually increases the angle of attack resulting in the stall becoming worse. Adding flaps also decreases the AOA of the aircraft and requires more force from the horizontal stabilizer.

Addition of power has the same effect, it increases downwash and the situation again becomes worse.

If this situation is encountered you want to remove any flap extensions, increase pitch, and decrease the power. I know it sounds crazy, but keep in mind all inputs will be opposite from a wing stall.

NASA did research on the subject and made a 15 minute long video that can be found at your local FSDO. If you want to understand this better I suggest you check it out. The video will illustrate this situation far better than I can on a computer.

Here is an AC with more explanation into the subject.
AC
 
Tail stalls can also be done by yawing the tail back and forth quickly, thus "stalling" the rudder and rendering it ineffective until pilot input stops. It's like flying in a 50 degree slip.

Nick
 
I'm not following you on that. If you don't mind please ellaborate on the aerodynamics of what you are saying. Are you saying that by pilot induced yaw oscilations you can stall the rudder or the elevator?
 
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