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Stalling

by Richard Collins
FLYING/NOVEMBER 2002

Reprinted and provided here under fair use doctrine.

A couple of months ago I wrote something to the effect that a pilot doesn't have to stall an airplane to be able to safely fly that airplane. Knowing that would elicit howls from purists, I did a little research on the subject.
      Almost all the stalls/spins, or mushes into the ground, that result in hurt begin at low altitude. Stalls-are done for the flight test, according to the latest FAA word, not less than 1,500 feet above the ground, and they are usually done higher. That means stalls as practiced bear only an apples-and-oranges similarity to what happens when a pilot loses control of an airplane at low altitude.
      The recovery from a stall looks pretty tame when you lose but a couple of hundred feet on the altimeter in a textbook stall recovery at altitude. If the airplane is 200 feet above the ground when control is lost, the recovery would be a lot more complex. And who is to say that the pilot who fouled up and lost control at low altitude could suddenly become a superb pilot who could regain that control in such a difficult environment?
      Even the FAA had dumbed down the stall and slow flight requirements for a private pilot applicant. For slow flight, it says that it must be done at an airspeed where any further increase in angle of attack, increase in load factor or reduction in power would lead to an immediate stall. That sounds good so far, but then it adds that the airspeed must be within plus-10 or minus-zero knots of the target. If it is at plus-10 the airplane is flying well above the stall and, in the case of even the heaviest singles, near the best angle of climb speed.
      For power-on or -off stalls the FAA says any angle of bank should not exceed 20 degrees, and for power-on stalls it requires no less than 65 percent power. On recovery it requires that the pilot recognize the stall and recover promptly after the stall occurs.
      In a typical stall accident that is not related to hot-dogging, the pilot is attempting to make the airplane do something that it is incapable of doing. Two of the leading elements here are an attempt to climb better than the airplane is capable of climbing or an attempt to make the airplane glide farther than it is capable of gliding.
      In the climb condition, the magic airspeed is Vx, the best angle of climb speed, which is about 1.2 times the stalling speed for the configuration selected. In a tight condition one of two things happens. Either the pilot maintains at or above that airspeed and flies over the obstacles or whatever is out there or flies into something under control at minimum forward speed and rate of sink. Or, the pilot flies slower and loses control and hits hard or finds himself operating an airplane that isn't climbing as well in relation to obstacles as it could climb. Being perfect at stall recoveries would do exactly no good because all that would save the day would be the ability to fly the correct airspeed and accept what comes next.
      When a pilot loses control in gliding flight it usually comes after a power loss. Again, there is but one correct speed to use in a glide. Go slower and you come down faster, a lot faster if the airplane is inadvertently stalled. Glide faster and the airplane won't go as far.
      Simply put, a pilot who does a good job of airspeed control and who understands the relationship between angle of bank and the stalling speed doesn't really need to know anything about stalls and stall recovery. Put another way, a pilot who has a full understanding of angle of attack, and how to control it, knows what is necessary to keep the airplane away from trouble.
      Lest you think I am not for a pilot knowing about all the things that an airplane will do, I feel strongly that all pilots should see spin demonstrations, especially out of turns where the angle of bank exceeds 20 degrees by a lot, so that they will know what an airplane does when you fail to manage angle of attack and lose control. Flying them upside down for a bit can't hurt, either, so long as the airplane and the pilots are equipped for and competent at that art. The beginning of a spiral dive is important to see because this event is rather like a stall. If the beginning of the condition is not recognized first thing, and the correct action is taken immediately to avoid the spiral, the pilot becomes an ex-pilot in a big hurry. I have had people look at me like I'm nuts when I mention that the rate of descent in a fully developed spiral dive can reach 15,000 feet a minute or more, but that's the case.
      It's my opinion that doing and teaching stalls as is presently done is spending time putting emphasis on the wrong thing. If anything, we are teaching pilots that a stall is pretty tame and recovery is easy. That's true at or above 1,500 feet but a complete fallacy at the low altitudes where lethal stalls are practiced.

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