by John Rafferty
Stalls and Engine Failures
Long Island/MacArthur Field
All flight training programs include procedures for handling in-flight problems and emergencies. In particular, at an early stage in their training, student pilots learn how to recover from stalls and how to respond to an engine failure.
Such emergencies are easy enough to walk away from on a simulator, of course, but the procedures for handling them are still worthy of your attention. They'll improve your sense of confidence, and they'll also increase your sensitivity to the airplane and its controls.
Besides, the exercises are fun to do.
You'll take off from MacArthur Field and use the same general practice area as before. First, you'll put the airplane into some intentional aerodynamic stalls, and then you'll simulate loss of engine power and make an emergency power-off landing on the beach.
The Nature of Stalls. In aviation, this term refers to aerodynamic stalls, which are quite different from the kind of stalls most of us are accustomed to in connection with autos: Aerodynamic stalls have nothing to do with the engine.
Rather, an aerodynamic stall is a situation in which the airplane loses its lift for one reason or another and simply ceases to fly. In a way, it's almost as if the airplane suddenly changes from a flying machine into a rock, and such a stall can even happen with the engine at maximum power, as you'll soon see for yourself.
Causes of Stalls. Stalls result from inadequate lift, which is associated with too low an airspeed. The airplane needs a certain forward speed in order for the wings to generate enough lift to keep it up, and if it slows down to its critical stalling speed, it stops flying and begins to fall.
Turns reduce the wings' lift, so turns at low airspeed are a particular threat. Similarly, the airplane will stall if you try to make it climb at too steep an angle.
Stall Characteristics. Different airplanes behave differently when they approach a stall. Some stall very abruptly, with little warning; others may have one wing drop first, putting the airplane into a spin, from which recovery can be difficult. Some airplanes will just sort of waffle in the air for a while, making recovery relatively easy. Gentle, easily-corrected stall behavior is a desirable characteristic in a the basic aerodynamic design of a conventional airplane.
Stall Recovery. When an airplane begins to stall, the stall-warning horn will sound, telling you that a stall is imminent. You correct the situation by lowering the nose and increasing the engine power, thus increasing the airplane's airspeed and getting it flying again.
Of course, if you're already very close to the ground, there's no room to lower the nose and generate airspeed before you make an abrupt "unscheduled landing." This is why the expression low and slow is synonymous with danger in aviation.
In any event, you'll find that the simulator airplane has excellent stall characteristics. When you raise the nose way up, the airspeed will fall off rapidly; when the stall is about to occur, the airplane will nose down by itself, with the wings level, so that in most cases recovery is relatively easy—often automatic—if you have enough room below you.
Power-Off Landing. If you lose engine power, the airplane will continue to fly—as long as you don't keep the nose too high and cause it to slow down and stall. If you establish a proper glide, you can cover a considerable distance without any power at all.
On losing power, the nose will begin to fall off, and on this airplane you'll get a comfortable power-off glide if you ease back on ths stick—holding up the nose—just enough to establish an airspeed of about 80 knots. Gliding at that airspeed will give you a rate of descent of about 1000fpm; thus, if you lost power at 3000 feet you could remain airborne for about three minutes.
With that particular airspeed and configuration, however, the airplane will usually land safely by itself. In fact, actual airplanes have been known to do that.
From the Right-Hand Seat
|Set-Up for MacArthur Field:
Departure. You're parallel to Runway 6. Taxi ahead; turn left 180° onto the runway; complete your checks; and take off with a heading of 059°. On the climb, turn right to 180°, toward the shore. Climb to 3000 feet and turn down along the shoreline on a heading of around 280°.
When you're straight and level, save the flight parameters.
Departure Stalls. A dangerous type of stall is one that occurs during takeoff, because you're so close to the ground; this is a major concern when flying on instruments.
To simulate such a stall, increase the throttle to full power. Then ease back on the stick to raise the nose. Watch the vertical slide indicator as you do so, and ease back until the indicator slide jumps up about five small increments.
The airplane will nose up, rapidly lose speed, then nose down and recover by itself. Leave the elevator where it is, and and the simulator will repeat the process over and over again.
Return to normal cruise power, then repeat the exercise at normal cruising RPM. The response will be the same, but the airplane will take longer to recover because of the lower power.
Power-Off Stalls. Throttle back all the way now, and try it again—but this time pull the stick back all the way, until the vertical slide is at the top of the indicator.
After the parameters reset (ahem), go ahead and experiment a bit.
Power-Off Landing. Line the airplane up with the shoreline, and then throttle back all the way. As the nose falls, gradually nudge the stick back, to establish a glide at 80 knots. You'll be in a definite nose-down attitude, and your rate of descent will be about 1000fpm.
Aim for the beach, then sit back and let the airplane land itself. (On IBM and 68000 versions, don't forget to drop the gear before you touch down).
Who says flying isn't easy?