Obstructions, sand, mud, wandering animals and other surprises like the end of the runway rushing up to meet you…these are just some of the hazards common to short and soft fields. We all think we’re trained for them, but there’s a big difference between training and reality. I’m not knocking what CFIs teach or what’s required on the practical tests, but what you learned in your training may be insufficient to prepare you for the real thing.
You may be thinking this article isn’t relevant—you’re not a bush pilot and have no interest venturing off pavement. Well, consider the hulking C-17 that mistakenly landed on a 3405-foot small-field runway at Tampa’s Peter O. Knight instead of the more appropriate 11,421-foot runway at MacDill Air Force base nearby.
I can only imagine how the pilot felt when he realized he was committed to landing on a runway 3.35 times shorter than expected. With apparently no option for going around or aborting, the pilot displayed some first-class impromptu short-field technique, helped no doubt by employing thrust reverse. Poor overall airmanship, but a great short-field landing.
Size Is relative
So what is a short field, anyway? As with so much of aviation, the real answer is: It depends. The military defines a short field as anything under 3000 feet, but chances are you don’t fly an F-15 or C-130. Short for a Boeing 747 is not short for a Piper Cub. Even the FAA falls short—pun intended—on providing a precise definition, probably because it’s a relative term.
A short field, then, probably is best defined by considering an amalgam of factors—aircraft performance, field conditions, field elevation, obstructions on the approach or departure, slope of the field, and weather considerations like wind and density altitude.
My definition is any field within two to three times my idealized takeoff or landing performance. A 3405-foot runway (like the one at Peter O. Knight) is a comfortable length for most pilots flying the average GA airplane; it’s neither particularly long nor short. But when that same strip is at 7000 feet msl, or there are obstacles near its threshold or in the way of the departure path, it is best considered as short.
Edges of the Envelope
Short landings are simply basic physics at work—the slower you land, the shorter you land. Landing distance required increases as a square of landing speed. So to land in the shortest theoretical distance, you would have to approach at the lowest theoretical speed—stall speed, which of course is insane.
Watch the YouTube videos of the short field landing competition in Valdez, Alaska. Their landing technique is to get behind the power curve, reduce to the slowest possible controllable airspeed right at the edge of a stall, and then when the wheels touch, simultaneously chop power, apply brakes and often retract the flaps. The winners can stop a plane in 50 feet, but these perfect performances are at the extreme edge of the envelope. When the landings slip outside the envelope’s boundaries, there are hard bounces, gear collapses and brake-induced nose-overs, and prop strikes, perhaps resulting in the plane embarrassingly oily-side up.
Most of us are not Alaskan bush pilots, so chances are we’ll never need to land at the limit of our plane’s envelope. But to be safe, we should aim for somewhere between ber short and blowing past the first half of the runway.
Short Means Firm
Don’t mix up a short or super-short landing and a greaser; they are different concepts. If you want a greaser, you need enough energy for a nice flare that will carry you further down the runway. A short landing requires a firm landing that sacrifices a degree of smoothness but gets the plane on the ground where brakes can be applied.
If landings are too firm, however, you can bounce and become airborne again. Besides losing style points, there are a lot of potential consequences. A bounce at the very end of your flare will prevent you from getting on the brakes, which in turn will result in a longer landing roll. A hard bounce with full flaps at the lowest controllable speed is just itching for an upset, because it forces you to make a difficult decision without hesitation—recover the landing or go round. Pick one; you can’t do both. And if the field is truly short, you can’t change your mind. Either way, you will be very busy getting the plane back on the ground or back in the air.
Careful with Those Brakes
To land short, you need to apply brakes, maybe aggressively, but not too aggressively. Poor brake control is one of the more common root causes of short-field accidents. For example, differential braking—one side grabbing asymmetrically—can lead to loss of control and departure from the runway. Overly aggressive braking on a nose-heavy or tailwheel aircraft can flip the plane tail-over-nose, such as when a tailwheel pilot attempts a wheel landing with aggressive braking.
Another issue with braking is the condition of the runway surface. Short fields are often grass, gravel or dirt, or a mixture of several of these surfaces. I recall landing on the beautifully manicured 1900-foot Mackay Bar airstrip, which is in a canyon with a blind approach. Since it is only 1900 feet long, I touched down very early, but what I neglected to consider was the dew on the grass on this early summer morning. I needed a lot of runway to get a fully loaded Cessna 206 to come to a stop on a surface that had all the friction of an air hockey table. Ironically, you can experience similarly low friction on tall dry grass or freshly mown grass. So remember, just because you need brakes to land short, the brakes may not always give you much to work with.
Meanwhile, it’s good to know how short your aircraft can land with maximum braking. You may actually need to know that number for real someday.
Practice, but don’t crash
The NTSB files are chock-full of accidents from short-field landing practice. These accidents are not landings on fields that are actually short, but practice landings that somehow end in hard landings, loss of control or both. Collapsed gear, prop strike, bent firewall, loss of directional control, bounce followed by porpoising, going around with too little speed, too little power and too much flap—all are found in association with the phrase “short-field practice.”
Practicing short-field technique is unlike most aircraft operations and may be as close as you will ever come to being a test pilot. It requires maneuvering near the ground at the edge of control with minimal chance for recovery. Practicing must be viewed as a deliberate approach to the edge of the controllable envelope. Just because it is a basic requirement of the FAA’s practical test standards doesn’t make it easy.
While you may be tempted to start your practice by replicating the Valdez showmanship, the smarter approach is to sneak up on the sweet spot. Start with a bit of extra energy, then slowly dial in the approach. Remember, the NTSB files have more accidents caused by failed practice landings than failed landings at short runways.
The way to avoid becoming a statistic is to measure yourself.
When my own backcountry missions involve targeting a particularly short field, I prepare a week or two before by practicing my short-field technique until I am certain I can comfortably land inside the target distance. By doing a lot of practice beforehand, I am generally ready for the challenge when it is actually required.
Mud, Sand, Muck and more
Flight school policies often keep their planes on pavement, so most students get little-to-no soft field experience. We practice soft-field work on hard surfaces, where we pretend there are soft conditions to demonstrate we understand the technique. As a result, there are fewer practice accidents associated with soft-field conditions, but there are a lot of off-airport landings that go awry due to soft-field conditions.
Soft-field ground handling technique calls for keeping the nose up and the power in to keep the mains from sinking.
When I earned my private, I transitioned from the pavement at my flight school to a pasture runway at my family’s farm that previously had been a hayfield. My first takeoff and landing scared me to death. It wasn’t just the deafening noise of vibrating metal and the violent shaking, but thinking something was wrong with the plane. No one had prepared me for that first roll-out on a rough field and the amount of throttle it took just to get the plane started and keep it moving through tall grass.
In 2010, I got further calibration and valuable experience at an event now known as SploshKosh. It was held at the same location as EAA’s AirVenture, except that year a few weeks of rain had turned the prairie soil into a bog. I had some advance warning, so I brought a few plywood disks to keep the 182 I was flying from sinking into the mire.
Unlike most soft-field situations, SploshKosh had a very experienced ground crew who knew the exact locations of the softest spots. They would come to the window, point out particular puddles and ruts, and say, “You’re going to need to gun it to get to the other side. We’ll stay out of your way, but you need a good head of steam or you’ll sink.” Between that and their emphatic gestures, I have an indelible memory of how much speed and oomph is needed to carry a loaded airplane through a mucky patch.
A remote desert strip in Utah called Hidden Splendor is the opposite end of the spectrum. The runway is nice, firm gravel, but the taxiway to the parking area is soft sand, requiring another oomph not for the timid.
Of the two, a grass-covered bog is better than sand. Both require substantial engine power to gain even the tiniest forward movement, but in a bog, you can run the engine up to full power if you need to. You are just spraying grass bits, mud and mosquitoes at those who are unfortunate enough to be behind you. In sand, you need to add enough power to get moving, but not so much you suck rocks into the prop, and sling dent-inducing cobbles and sandblasting grit at the paint on your horizontal stabilizer. You have to find the right balance.
Most of us don’t have big, 29-inch bush wheels for soft fields. So remember, the smaller the tire size and heavier your aircraft, the more insane the rpms you’ll need to apply so you don’t get stuck.
Gutless aircraft
You’ll recall the FAA says in FAR 91.103 you need to know all information about your flight, which means you need to know more than just how to stick the landing on a short or soft field. In fact, the rule emphasizes “runway lengths at airports of intended use, and the following takeoff and landing distance information: (1) For civil aircraft for which an approved Airplane or Rotorcraft Flight Manual containing takeoff and landing distance data is required, the takeoff and landing distance data contained therein.”
You need to know at least as much if not more about your eventual departure. If you can barely make it into a short or soft field, as is the case with most of our garden-variety aircraft, you will definitely not make it out without some assistance from wind and cool temperatures, or by leaving some useful load behind.
Like it or not, most of us fly gutless, underpowered aircraft. For our purposes, we’ll define “underpowered” as any airplane that can land shorter than it can take off, which pretty much captures the entire GA fleet with the exception of some Super Cubs, Maules, experimentals and some light sport-class craft with horsepower to burn. If your plane can take off and land in about the same distance, it has exceptional intestinal fortitude. If, however, you can land in 500 feet, but require 1000 feet for the takeoff roll and 1300 feet to clear a regulation 50-foot obstacle, your plane meets the definition.
Here is a safety tip: Admit that your plane is gutless, and stay away from short field s that are inside your landing envelope, but outside your takeoff envelope. You don’t want your excellent short-field landing technique to ipso facto be the cause of your short-field takeoff accident.
This article originally appeared in the February 2014 issue of Aviation Safety magazine.
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