While turning final I was again reminded that the river, as with all water in sight, was filled to the brim with piranha. I didn't have time to wonder whether a native Nebraskan such as myself had a corn-fed flavor. I'd looked at the homemade map and knew the tiny box clearing ahead was exactly 427 feet long. It ended conclusively at the foot of a rocky cliff rising abruptly out of the jungle. Go-arounds were discouraged. And impossible.
Just 427 feet of runway, and I was flying a twin-engine airplane full of cargo. Sure, it was an Evangel 4500 bush plane, but bush plane or not, 427 feet looks really short, especially when it's a diminutive box whacked into the jungle and rimmed by 80 foot trees, a river, and rocks. And I knew the grass was damp. Everything was damp in that part of South America. Likely there'd be little braking. It was probably rough, too, so again, the brakes wouldn't help much.
Obviously I didn't become an insignificant pile of rubble deep in the Colombian jungle. In fact, it wasn't even close. Someone looks out for people like the Wycliff Bible Translators, with whom I was flying. It's a good thing, too, because when it comes to folks like those, working short strips is nothing more than a part of the job. Ditto for those guys in the north country where a smooth runway has rocks smaller than a watermelon and a long runway is at least 200 feet long and less than a 30-percent grade.
The concept of the short runway is interesting because much of it is a matter of definition. After a week or two bouncing around the jungle, I found our 1,400-foot home strip to be ridiculously long. But then again, in Colombia I flew an airplane made for the job. For that airplane, the definition of "short" was entirely different from that of another airplane. Ask a Learjet pilot what's short and you're likely to get 4,500 feet as an answer.
The definition of "short" is subject to a number of important factors, all of which have a bearing on pilots. Few of us are going to be challenging football-field runways in the jungle or 30 percent slopes on a glacier. We will, however, find ourselves faced with what we consider to be short runways, and the parameters we use to define "short" are what makes a runway short, not its actual length.
An excellent example is the runway at Aeroflex-Andover in New Jersey. I cite this airport because for 22 years I instructed off of its 2,004-foot runway, each end of which drops off like an aircraft carrier, into a lake. It's one of the prettiest airports in existence, and I don't know one pilot based there who considers the runway short.
Many of the urban flight schools in the area, however, positively forbid any of their airplanes to land there. If you watched some of them try, you'd know why. The layer of rubber on the end of the runway isn't from landing, but from people trying to stop. More than a few have been unsuccessful. The locals don't have that problem. They make it a game to make the midfield turn-off. No sweat.
A runway that is short to one pilot may not be to another, and that is based on several criteria, some real, some perceived. The actual operational length of a runway should include:
Pilots need to take one other thing into account - taking off after we've landed. This usually applies only to ridiculously short strips that most of us will never use, but it's quite possible to land in a space we can't fly out of.
For the most part, general aviation pilots start thinking a runway is short when its length drops below 2,500 feet, depending, of course, on the airplane they are flying. Numbers less than 2,000 feet really start them sweating. Sometimes it should, sometimes it shouldn't. It depends on the factors outlined above. As the length drops below 1,500 feet, it's time for most pilots to get serious, unless they are flying a Piper Super Cub or something similar.
The definition of "short" should start with the pilot. The best bush airplane in the world is useless if the pilot can't hold a speed, wanders around the runway's extended centerline, and generally can't put it on a given spot at as slow a speed as practical (not as slow as possible). The entire focus of a short-field landing is to put the airplane exactly where you want it. If it's a medium short runway (2,000 feet or so), you want it down in the first 300 to 500 feet. If the runway is much shorter than that, you want to pick a point as close to the end as practical (obstacles may not let you put it right on the end) and be determined to put it there.
Do not attempt to land on a runway shorter than you're used to without first mastering the ability to consistently put the airplane on the runway at a predetermined point. Then, if the airplane isn't solidly on the ground and rolling at least in the first quarter of the runway - be prepared to take it around. And don't force it on. At Aeroflex, it was tragic to watch airplanes come over the end of the runway high and fast, and to continue the landing even though they hadn't touched down at the halfway point. What are pilots thinking in that situation?
There is absolutely nothing wrong with taking it around. There is, however, a lot wrong with continuing in that situation.
Putting the airplane on a spot in calm air is one thing. Doing it when you're getting your brains beat out is something entirely different. In that case, you'll probably be carrying a little extra airspeed and you won't have the glidepath wired. Also, if it's that windy, chances are you'll encounter some up- and down-drafts at the end of the runway, right where you will be the slowest and most vulnerable. This, by the way, is what really tests rudder coordination and attitude control. If you're having an off-coordination day, go around for another try - or find a longer runway.
An airplane's landing speed is probably the biggest factor in defining a runway as short. Energy is a function of the square of the speed (weight's effect is linear), so if one airplane lands 10 mph faster than another, it's going to take a lot more runway to get it stopped. As a general rule, faster landing airplanes are also larger, and their weight works both for and against them. In turbulence heavier airplanes are easier to put on the point, but they have a lot more kinetic energy going for them so they're harder to stop.
Besides affecting the landing speed, the airplane's wing loading also makes a difference in how it handles turbulence. Although a Piper Cub is barely moving and can stop on a dime because of its light weight and slow speed, in turbulence it is going to be like landing a piece of thistledown, and the pilot will have to work at it. A heavier airplane, like a Cherokee, will cut through the turbulence but will still require much more runway because of its speed and weight.
Springy gear is another characteristic that can affect a short-field landing. If the pilot of an airplane with spring-steel main landing gear plants it on the ground before it's ready, the gear will throw it back in the air and the extra speed will keep it flying. Stiffer gear lets you plant it with less spectacular results. In either case, holding the airplane just off the runway long enough to make sure it's done flying cures the problem. However, because holding the airplane off means wasting runway, that also means you have to arrive at this point with very little extra airspeed. More on that later.
Energy is a linear function of weight, so the more weight the more energy, and the longer it takes to get stopped. Don't forget that after you land you're going to want to fly out, and the airplane's weight is probably more noticeable on takeoff than on the landing. That may be because looking at the trees while you're wishing your airplane would climb over them is a lot scarier than looking at the trees while wishing your airplane would stop. If you go in heavy and barely get stopped, make sure you go out light, in the early morning, and with some wind on the nose.
Wind is your friend, even if it's crosswise to the runway and gusty. Unless it is dead 90 degrees across the runway (in which case, if it's a marginal runway for any of the foregoing reasons, you find somewhere else to land), a percentage of it will be on the nose, which is as good as adding length to the runway. On a calm day 2,000 feet can seem awfully short, but it seems absolutely humungous with only 10 knots of wind on the nose.
Wind is almost a necessity when you take off from a very short field. Wind is your insurance. Even if it means waiting until it warms up, wait for some wind on a marginal runway. This is especially true if you have trees or other unfriendly objects at the end of the runway.
Trees, wires, or giraffes at the end of the runway can make a fairly good-sized runway look minuscule - especially on approach. Even the big-flapped bush planes can come down only so steep, even when dropping them over the edge of the trees with power. At the same time, when the approach is clear, it's amazing how long a short runway feels. This is because you can use every foot of it, assuming you have the skill to put it on the end. That's why the strip I used to fly from was so long. The approach over the lakes made every foot usable. The same strip with even short trees at the end would have been much more challenging.
A 2,000-foot New Jersey strip with an elevation of 400 feet MSL is one thing. If the same 2,000 feet is just outside Flagstaff, where the elevation is 7,000 feet MSL, the strip is an entirely different animal. But a strip doesn't have to be located far above sea level to have thin air nibble at its length. My current home airport's elevation is 1,500 MSL, but in August the usual density altitude is more than 5,000 feet.
When you operate from a short field, it's not just the height above sea level, as marked on the charts, that you have to take into account. The density altitude (DA) is what counts. The DA is what determines how much power the engine produces and how effective the wings will be. Basically, what a high DA says is that the wings have to be going faster (as measured by ground speed - the indicated airspeed doesn't change) to generate the same amount of lift. (At the same time, the engine is putting out less, sometimes much less horsepower, at a high DA.
So, with high density altitude an airplane not only has to go faster, it has less power to go faster with. That's why we have so many accidents here in Arizona, where flat-landers can't believe their airplane won't take off and clear the trees at the end of a 5,000-foot runway. With our density altitudes, their Cessna 172 may have only the horsepower of a 152, and it needs to be going 7-10 mph faster across the ground to generate the usual lift.
With these factors working against the airplane, even a 3,500-foot strip becomes a short one for many airplanes. It's doubly so if you have obstacles at the end of the runway, which demand that the airplane climb. It's quite common for an airplane to take off reasonably well, and then for the pilot to discover that his airplane can't climb out of ground effect without an agonizingly long run at low altitude to gain enough speed. Even then, the climb performance is only a fraction of normal because the airplane just doesn't have the horsepower.
Pavement length is one thing. The distance to the trees off the end, however, is what counts.
Getting it down is one half of a short-field landing. Getting it stopped is the other half of the equation, and stopping usually is a function of the runway surface and the braking it affords.
Normally, when we think about runway surfaces we think wet or icy, and these are, indeed, major factors. However, paved runways are seldom really short. It's only pilot technique that makes them short.
Grass or so-called "unimproved" runways present a wide series of possible surprises when you touch down. Grass, for instance, offers much less braking simply because it's slicker than asphalt or concrete. Early on one of those beautiful spring mornings we love so much, the grass might as well be ice because the dew makes it almost that slick. So does rain. Ditto, frost. Moisture can take a fairly healthy grass strip and make it very unhealthy - for pilots, anyway.
Then we face the question of how smooth the surface is. It doesn't take much in the way of bumps and dips to keep the tires from making solid contact. While bumping along, applying the brakes and wishing the airplane would stop, the tires are stopping in midair part of the time.
On takeoff, wet or tall grass grabs the tires and slows the airplane down. You might think about making a soft/short-field takeoff. A better idea would be to wait for the grass to dry out or to go find a lawnmower.
A rough runway almost always launches you off the ground prematurely on takeoff, so you have to do your best to keep the airplane on the ground without holding it down so hard you either get the prop or burn up so much runway you can't clear the obstacles.
The decisions get really difficult in those situations and it requires that the pilot "feel" his (or her) airplane, knowing when it will fly out of a bounce without forcing it to stay up. Then he has to fight the urge to bring the nose up. Best angle of climb speed is best angle of climb speed and forcing the nose up before that number shows up on the airspeed indicator can be a fatal mistake.
At least as important as feeling the airplane is knowing when it's time to call it a day and not even attempt a takeoff until conditions improve. A really good pilot is one who waits it out, not the one who clears the trees by a hair.
Runway Slope
Given a choice, always put gravity on your side. It's the one irrevocable force that can make or break your takeoff or landing. Unless the wind is blowing something like 15 knots, or you're flying a really slow airplane, the slope will generally have more effect than the wind.
But how much slope is a slope? If it's enough of an upslope that you can actually see it, the normal under-150-hp light airplane will feel its effect and may take 10 to 15 percent more runway to get off. If it looks fairly steep, then it really is steep and you'd be amazed how hard the airplane has to work to get up to speed. Couple that slope with a less-than-perfect surface, higher-than-normal density altitude, and a heavy load, and most airplanes won't make it off the ground unless the wind is blowing briskly. Turn the airplane around and go downhill, even with a tailwind, and you'll reach takeoff speed in plenty of time.
Just the opposite is true on landing. Going uphill works wonders. Landing downhill scares the wits out of you because the airplane doesn't want to land and then doesn't want to stop once it touches down.
Landing techniques
The subject of short-field landing technique has been covered a million times, but suffice it to say that the goal is to hit the exact point with minimum safe airspeed consistent with prevailing conditions. That means don't hang it on the prop unless you know what you're doing, and on a checkride, don't ever drag it in with power because that'll be the end of your practical test. The private pilot practical test standards calls for a stabilized approach at the recommended approach speed, with the gust factor applied, if necessary.
In reality, with just a little practice in the average light airplane, smooth runways with reasonably clear approaches shouldn't be classified as short until they get down to around 1,500 feet, depending on conditions and pilot proficiency. The name of the game, however, is practice and more practice. Don't try what you don't know for sure you can do. Once you know where that limit is, you'll know your own definition of "short."
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