Tuesday, May 15, 2012

Prevention of a Secondary Stall


In instrument conditions recovery from a spin or inadvertent stall this technique may save your life or prevent unusual attitude motion sickness.

If you are in a recovery situation from a primary stall, and you have it under control, you want to return to straight and level flight. The vertical speed indicator is important to recovery.

When you recover from a primary stall I was taught to back off on power and apply forward pressure on the yoke. You are trying to reach a level wing flight attitude while keeping a continual scan of the vertical speed indicator.

As the airplane recovers you will see a decrease in the rate of losing altitude on the vertical speed indicator and corroborated by the altimeter. Your airspeed is higher, at this point, than your normal cruise speed.

Once the vertical speed indication indicates no rate of loss you will still experience resistance to keeping the nose of the aircraft from rising. 

This is important: When the vertical speed indicator stops moving upward or downward your airplane attitude is in level flight with greater airspeed that cruising airspeed. Keep forward pressure on the stick or wheel until the airspeed slows to your aircraft cruising speed. At this point the pressure on the yoke (wheel or stick) will abate to normal if you were properly trimmed before the stall ever began.

It is at this point you can slowly increase power to maintain altitude and cruising speed.

Note: while you were doing this the vertical speed indicator has remained at its neutral position that shows no rate of gain or loss. You are flying level.

You must return, even though the seat of your pants may disagree, to normal flight according to your instrument training. Your sensory input from your body may take a few minutes to agree with what your instruments are telling you about the correct attitude of the airplane - straight and level with respect to the earths surface at normal cruise speed.