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Oct/Nov '99 Issue
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This issue's featured book: Portraits from the Desert : Bill Wright's Big Bend (available at Amazon.com)

SW Aviator Magazine
3909 Central NE
Albuquerque, NM 87108
Phone: 505.256.7031
Fax: 505.256.3172
editor@swaviator.com
Taking Takeoffs and Landings to the Max
"Back To Basics"
by Cordell Akin
Just thinking about it is pure enjoyment. You fly into a remote airstrip in the mountains of the Southwest in your own airplane and pitch a tent beside a stream. The trout are hungry. You laze away a few days under a turquoise sky with a warm summer breeze singing through endless stands of pine trees. Or perhaps you’d prefer to pitch that tent in a meadow surrounded by golden aspen trees and set out to track the huge bull elk. Either option appeals to me, but the most interesting part is exercising the skill required to fly into and out of a challenging remote airstrip.

The very geographical nature of the Southwest invites pilots to visit short, high, sloping, dirt or grass airstrips or airports with obstacles in the approach and departure path. Anyone flying their birds to such perches should become well practiced in the area of maximum performance maneuvers. You remember what they are from training days: short field and soft field takeoffs and landings. If you stay sharp on these maneuvers, your passengers may not talk about you like they did the pilot in the following story.

After a successful hunting trip, a pilot who was flying passengers for the second year in a row loaded three 200 pound hunters and the entire elk in a four place airplane and departed from a short airstrip. They all survived the crash right after takeoff, and one hunter said to another, "You know, Zeke, we sure have a skilled pilot. This is only 100 yards from where we crashed last year."

The Short Field Departure With Obstacles
Most short, unpaved airstrips will not have a taxiway, so you must back taxi the takeoff runway and turn around, wasting as little runway as possible. Be careful when making the turn that your aircraft’s tail does not strike something at the end of the runway (e.g., a stump). We're talking real bush here.

Straighten the nose wheel, hold the brakes and apply full power. If the strip is at high altitude, lean the mixture at full power to get maximum performance from the engine. Before releasing the brakes, check all the engine instruments for normal readings and normal power. Be ready to abort the takeoff if anything appears, sounds, or feels abnormal.

Hold the aircraft on the ground until Vx (best angle of climb) speed is reached. Rotate and maintain Vx until the obstacle is cleared, then increase speed to Vy (best rate of climb). As the aircraft leaves ground effect, and induced drag (drag resulting from the production of lift) increases, the initial pitch angle of the nose will need to be lowered slightly to maintain Vx. You must not give in to the urge to lift the nose prematurely when you see trees coming closer at an alarming rate. If the situation is tight, the speed you need is Vx, because it will give you the best climb over obstacles.

So, if you practice short field takeoffs you can depart from an airstrip whenever you want, right? Wrong. Sometimes the density altitude will not allow the clearance of obstacles no matter how good your technique. It will help to plan your takeoff in the early morning when the temperature and density altitude is lower. If possible, always take off downhill and avoid tailwinds. Ground roll will be increased about 10% for each two knots of tailwind.

It is a good idea to increase all POH figures for 50 foot obstacle clearance by 25% in order to take into account engine hours, extra parasite drag from the addition of antennas or the removal of wheel farings, and your own skill level. Keep in mind that published obstacle clearance distances do not take into consideration the real world realities of turbulence and downdrafts. These could place you in the position of looking squarely into the face of a knothole halfway up a tree on takeoff. If the situation is truly marginal, do a pattern with just yourself on board. Then, add passengers one at a time in successive patterns to see how the aircraft performs under the actual conditions.

Short Field Arrivals
Clearing the trees on takeoff will be a mute question if you run off the end of the runway on arrival. Of course it could extend your vacation while you try figuring out a way to get back home.

There is a reason why the practical test standards for private pilot stipulate that the aircraft must touch down within 200 feet of a selected point. On a short field arrival you want to touch down as close to the beginning of the runway as possible. The key to doing this involves both pitch and power. Once established on final approach with full flaps, pitch the aircraft to achieve the short field airspeed given in the Pilots Operating Handbook. Next, reduce power until the aircraft begins to sink, then increase power just to hold a straight glide path to the beginning of the runway (assuming no obstacles).

With this approach, when power is reduced, the aircraft will sink. When power is added, the sink will stop. This makes possible an accurate straight line descent to the aiming point in the windscreen. The most common mistake pilots make is to leave in too much power and get high on the approach. Then, even though power is reduced to idle and the proper airspeed maintained, the landing point is exceeded by a good distance.

At the short field approach airspeed and just enough power to hold the glide path, reduce power to idle just before the intended touchdown point and there will be no speed left to cause float down the runway. Allow the main wheels to contact the surface in a modified flare so that maximum braking can begin as soon as possible. A good short field landing will not be a greaser, but a firm touchdown—the opposite of a soft field landing. It is not necessary to retract the flaps immediately after landing, since the drag they produce is more beneficial than retracting them to put the weight on the wheels. On a rough, short strip the wheels are going to be bouncing without a lot of braking action initially. The drag of flaps will help slow the aircraft.

Soft Field Departures
It has been said that if it takes full power to taxi, you have either forgotten to remove the chocks or the tail is still tied down. I would like to add one more situation to that. One time I landed on a dirt airstrip after a heavy rain in a pressurized 210. Slowing to taxi speed occurred very quickly and then it took full power to taxi in the red mud—with about 2 inches of it on all the wheels.

A soft field takeoff starts with the taxi. The control wheel should be full back to allow the propeller slipstream to increase down pressure on the elevator and lighten the nose wheel. During taxi and takeoff in soft conditions the nose wheel must be protected. If the nose wheel happens to be on the rear of the plane, the soft field task is easier.

Refer to the POH for your aircraft regarding flap setting for a soft field takeoff. It will be 10 degrees on some light aircraft. This flap setting allows enough lift in relation to drag to get the aircraft in the air in ground effect as quickly as possible, allowing the weight to be shifted from the wheels to the wings. When full power is applied with the control wheel full back , the nose will initially rise higher than needed. At that point reduce the back pressure just enough to keep the nose wheel off the muddy surface. With the wings in this high angle of attack position the aircraft will lift off into ground effect at an airspeed too slow to sustain flight above ground effect. Therefore, once liftoff occurs, a slow but positive forward pressure must be applied to the control wheel in order for the aircraft to level out in ground effect and accelerate to Vx before trying to climb. The flaps can be retracted once the aircraft is climbing.

Ground effect occurs within one wing span of the runway, increasing closer to the runway. It is the result of the runway surface interfering with the wingtip vortices and the average relative wind around the aircraft that produces induced drag. The reduction of drag in ground effect is quite pronounced, being about 25% at one-forth of the wingspan above the runway.

Soft Field Arrivals
If the airstrip is soft, touchdown must be made softly on the main wheels and the control wheel held full back to protect the nose wheel. I once landed on a soft grass strip and held the nose off as long as possible as the aircraft rapidly slowed. When the nose wheel finally touched down at a slow speed, it sank into the soft dirt halfway up the tire. There was no damage, but the aircraft had to be pushed by hand to firmer ground.

Assuming there are no obstacles in the approach path, a soft field landing is normally made with half flaps and a normal approach speed. Half flaps work better than full flaps in most cases due to the fact that the pitch change in the flare is less pronounced because the approach angle is not as steep. The most consistently soft landings can be made if the power is reduced to slightly more than idle on short final and left there until the wheels touch. The throttle may then be reduced to idle. In an actual soft field situation the power may be increased after touchdown to keep the nose wheel elevated until firmer ground is reached

It is important to keep raising the nose in the flare to hold the wheels off the runway as long as possible with the stall warning horn activated. Once the main wheels touch, maintain full back pressure to keep the nose wheel off the surface until it falls by itself, then continue the back pressure until the taxi is completed.

Whether or not you ever fly into a remote airstrip in the Southwest with that fishing rod or hunting rifle, staying proficient in maximum performance takeoffs and landings will make you a better pilot. Besides, the airplane tires, landing gear and airframe will benefit from constant softer field landings, even those you make with full flaps. And, by the way, your self esteem will also benefit when your passengers tell you what a great pilot you are.

Cordell Akin is a CFII, MEI with a total of 10,000 hours and 3,000 hours as a flight instructor. He spent 15 years in East Africa flying a C-185 and a P-210. He is the owner of Akin Air at Coronado Airport in Albuquerque.

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The material in this publication is for advisory information only and should not be relied upon for navigation, maintenance or flight techniques. SW Regional Publishing, Inc. and the staff neither assume any responsibilty for the accuracy of this publication's content nor any liability arising out of it. Fly safe.