11-1 At some time during the period of rectangular courses
or S-turns, your instructor will demonstrate an elemen- tary emergency landing or “simulated emergency,” as you may hear it called.
Engines nowadays are very reliable. Cases of engine failure are rare, but you will still be given emergency- landing practice because pilots still run out of fuel and leave oil caps off. It is still possible, too, that the engine could fail structurally, so it’s better to be prepared.
The elementary emergency is given below 1,000 feet and requires a 90° gliding turn at most. The instruc- tor will pull the carburetor heat and close the throttle at some point during the maneuvers and demonstrate the procedure.
If it is at all possible, you want to land into the wind. If the plane stalls at 50 K and you have a 15-K headwind, your groundspeed (or relative velocity to the ground) at touchdown will be 35 K. The advan- tages of this are obvious. However, sometimes a field may not be available for an upwind landing. Or if the field is steeply sloped, it’s better to land uphill even if it’s downwind. Obstacles may require that you land downwind.
Sometimes students who’ve been doing the rectan- gular course or S-turns for several minutes and have
been correcting for a stiff wind forget the wind direc- tion as soon as the throttle is closed for the simulated emergency.
Picking the right kind of field (at low altitude you don’t have much time to shop around) comes with experience. If you’ve lived on a farm, you can spot a good field without much trouble.
Table 11.1 is a list and description of various types of fields with comments about each type.
Obviously there will be times when some of the landing spots labeled “poor” and “very poor” will be the only ones available. It then becomes the case of making the best of a bad situation. As one instructor put it, “Hit the softest, cheapest thing in the area as slowly as possible” — which pretty well covers it.
11-2
carburetor may have iced up and will clear out when heat is applied. Normally you will have some warn- ing beforehand, such as the rpm dropping, but you may not have noticed. The carburetor heat should be pulled ON immediately because if the engine is dead, it will be cooling and any residual heat in the system will be dissipating rapidly. If you wait too long, there may not be enough heat left to clear out any ice (if that was the problem).
3. Pick your field and start the approach.
4. Switch to another fuel tank (if your airplane has more than one).
5. Electric boost pump ON (if equipped).
6. Mixture RICH.
Do not waste time trying other methods of start- ing. Do Items 4 – 6 after you have the field selected and the approach set up. Then get back to your approach.
Don’t try to use the starter.
The propeller usually windmills after an engine failure and will start again if the fault is remedied. If it does, climb to an altitude of 2,000 or 3,000 feet while circling the field. If you are sure of the reason for the failure (tank run dry, carburetor icing, etc.) and have remedied it, continue your flight. Otherwise keep your high altitude and pick a route of good terrain back to the airport.
Once you have selected a field, you have very lit- tle time to change your mind. Pilots have been killed trying to change fields in an emergency because they made turns too steep and stalled at low attitudes.
A normal glide is a must for an emergency landing.
If you are high and dive at the field, the airspeed goes so high that the plane “floats” and you still overshoot, or go past the field.
If you try to “stretch a glide,” the rate of descent actually increases as the angle of attack gets into the critical range. It’s better to hit something when you have control than to stall and drop in (Figure 11-1).
If you are going to land in trees, don’t stall the plane above and drop in. Get as slow as possible, still having control, and fly into the trees.
It’s impossible to list exact procedures for every sit- uation, but you’ll try to keep the airplane under control without stalling, and you’ll try to pick a landing point that will allow the lowest deceleration (something soft like shrubs or weeds, rather than a stone wall or a solid tree trunk). As for when to turn off all switches before impact, your Pilot’s Operating Handbook will have such information. Your primary goal is to keep the cockpit intact.
Sometime after you have had the simulated emer- gency demonstrated, the instructor will close the throt- tle and say, “Emergency landing.” You will then go through the procedure. The instructor will let you glide to a reasonably low altitude or an altitude where you could see whether the field could be made, then will say, “I’ve got it,” open the throttle, take the plane up, and point out any mistakes you may have made.
Review the Pilot’s Operating Handbook for infor- mation on these procedures.
Probable Errors
1. Failure to establish a normal glide promptly.
2. Indecisiveness in selecting a field.
3. Trying to stretch the glide if low and to dive if high.
4. Making steep or uncoordinated turns close to the ground.
Figure 11-1. It’s better to have control at impact than to stall or spin the airplane in.
12-1 A stall is a condition in which the angle of attack
becomes so great that the flow over the airfoil breaks down and the wings can no longer support the airplane.
An airplane can be stalled at any speed, attitude, or power setting — as many a dive bomber pilot found out when he tried to pull out of a dive too quickly. He may have been doing 400 K, but the plane was stalled as completely as if he had climbed too steeply. What hap- pens is shown in Figure 12-1.
With the knowledge that a stall is caused by too great an angle of attack, the proper recovery is always to decrease that angle of attack and get the air flow- ing smoothly again whether you are doing 40, 400, or 4,000 K.
You won’t be doing accelerated stalls like that just discussed until later, but if you know what a stall is, the accelerated stall will be no different from the first elementary ones. The stalls in this phase will be done by gradually pulling the nose up and slowing the plane to the stalled condition.
In the earlier days of aviation, keeping the wings level during stalls was a problem. In the older planes, control effectiveness in the stall was lost in alphabeti- cal order — AER. The Ailerons were the first to go,
followed by rapidly decreasing Elevator effectiveness, and, last of all, the Rudder. Generally, if power was used during the stall, the rudder was effective throughout.
In many cases, use of ailerons alone to raise a wing during a stall resulted in an opposite effect to that desired. When the aileron was applied, the down aileron on the low wing caused adverse yaw effects, resulting in a further slowing of that wing and causing it to stall first. This was disconcerting, to say the least, and led to some interesting wing-leveling techniques.
Pilots found that it was possible, for instance, to raise the low wing during the stall by applying opposite rud- der — which yawed the plane in that direction, speeded up the low wing, gave it added lift, and caused it to rise.
Sometimes this opposite rudder was applied so enthu- siastically that the high wing was slowed to the point that it abruptly exceeded the critical angle of attack and stalled first, thereby causing a great deal of adrenalin to flow in occupants of the plane.
Planes type-certificated under the Federal Aviation Regulations (as U.S. general aviation planes are now) must meet certain rolling (ailerons) and yawing (rud- der) criteria throughout the stall. The Federal Aviation Administration, therefore, now encourages the use of
Stalls and Slow Flight 12
Figure 12-1. Pilot releases bomb, discovers that altitude is very low; pulls back stick abruptly. Plane changes attitude but momentum carries it down. Result — a high-speed stall. Lacking altitude for a smooth pull-out, plane strikes the ground.
12-2 Part Two / Presolo
will probably have you practice landings from a nor- mal glide at 2,000 or 3,000 feet above the ground. It’s impossible to see the ground by looking over the nose of the average trainer when it’s in the landing attitude;
so as soon as you start the transition, switch your scan to along the left side of the nose, noting the plane’s attitude out of the corner of your eye and keeping the wings level through coordinated use of the controls.
Once the nose is at the landing attitude (the instruc- tor will show you the proper nose position), it becomes a matter of pinning it at that position by continued back pressure.
coordinated controls to keep the wings level during the stall. While keeping the wings level is not critical at the altitudes where stalls will be practiced, it will be very important when you start landings, as will be shown later.
There is one very important point: Get the nose down (decrease the angle of attack) first before trying to level the wings. Once the angle of attack is below the stall value, the ailerons and rudder are less likely to get you into trouble in any airplane.
Several methods of design are used to aid lateral control throughout the stall. The idea in each case is to have the wing tips stall last. If a wing tip stalled first (and it is unlikely that both will stall at exactly the same time), a dangerous rolling tendency may occur as the stall breaks.
The tips may be made to stall last by “washout.”
The manufacturer builds a twist into the wing so that the tips always have a lower angle of incidence (and a resulting lower angle of attack) and will still be flying when the root area has stalled (Figure 12-2).
Another method of having the root stall first is the use of slots near the tip. The opening (Figure 12-3) near the leading edge allows the air to maintain a smooth flow at angles of attack that would result in a stall for the unslotted portion of the wing.
Still another method is that of stall strips (Figure 12-4), or spoiler strips, being placed on the leading edge of the root area of the wing, breaking the airflow and resulting in an earlier stall for this portion. Some airplane wings have higher lift-type airfoils at the tip, causing the wing tip to stall last. In some cases several of these design techniques may be combined.