August 21, 2008 Can I Land On That? |
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August 21, 2008
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| Off-Airport Landings |
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When a pilot is forced to contemplate an off-airport landing, several emotions may interfere with the ability to deploy his or her training. According to the FAA's Airplane Flying Handbook (FAA-H-8083-3A), these may include:
Reluctance
A pilot who allows the mind to become paralyzed at the thought that the airplane will be on the ground, in a very short time, regardless of the pilot's actions or hopes, is severely handicapped in the handling of the emergency. An unconscious desire to delay the dreaded moment may lead to such errors as: failure to lower the nose to maintain flying speed, delay in the selection of the most suitable landing area within reach, and indecision in general.
Preserve the Airplane
The pilot who has been conditioned during training to expect to find a relatively safe landing area, whenever the flight instructor closed the throttle for a simulated forced landing, may ignore all basic rules of airmanship to avoid a touchdown in terrain where airplane damage is unavoidable.
Fear
Fear is a vital part of the self-preservation mechanism. However, when fear leads to panic, we invite that which we want most to avoid. The survival records favor pilots who maintain their composure and know how to apply the general concepts and procedures that have been developed through the years. The success of an emergency landing is as much a matter of the mind as of skills.
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| Off-Airport A-T-C |
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Attitude
The most critical and often the most inexcusable error that can be made in the planning and execution of an emergency landing is failure to maintain an appropriate aircraft attitude.
Terrain
The only time the pilot has a very limited choice is during the low and slow portion of the takeoff. Even then, however, changing heading only a few degrees may ensure a survivable crash.
Configuration
Properly configuring the airplane -- landing gear and flaps, especially -- can make or break an off-airport landing. That doesn't mean both should be deployed, however. Since flaps increase drag and decrease gliding distance, balance their use against a desire for a low-speed impact. Similarly, extended landing gear can dig in and flip the airplane when landing on water or soft terrain. Usually, though, you'll want both deployed.
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| Go With The Flow |
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Roads might seem like appealing places to land in an emergency because they are paved and relatively straight, but they can be straddled by power lines that can snare a plane like a fly in a spider's web. Interstate highways, however, can be quite useful, as the pilot of a 1943 North American T-6 discovered when his engine quit on the way to EAA AirVenture in 2007.
Video of the aircraft landing on a highway near Fond du Lac, Wis., was posted on the Internet and showed the aircraft passing over several cars before the pilot landed with the flow of traffic and came to a stop. He and his passenger walked away unharmed. Fortunately for them, traffic was not bumper-to-bumper and the pilot was able to find an open space between moving vehicles.
If you are faced with a similar situation and determine that a highway is your best available landing surface, it might be possible to get the police to block traffic, but keep in mind that the time it would take to do this depends on how fast the police can get to the scene. Air traffic controllers have access to hotlines to state and local police, search and rescue, military and other agencies that can assist an aircraft in distress, so dialing 911 from your cell phone probably won't get you help any faster than declaring an emergency to ATC with your specific location.
If you have enough altitude and a handheld GPS to play with, you could switch it to automobile mode to help ATC communicate to the ground-based rescue crews exactly where on the highway you think you'll be landing. There's no guarantee teams on the ground can make it in time, but it can't hurt to let them know you're coming. In any event, don't put this ahead of flying the airplane until it stops.
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| Deceleration Is Key |
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When facing an off-airport emergency landing in terrain making extensive airplane damage likely, pilots should keep in mind that avoiding injuries is largely a matter of keeping intact the cockpit/cabin structure. Preventing what the FAA calls "forceful bodily contact with interior structure" -- what we call impacting the instrument panel -- is a function of slowly decelerating the aircraft and ensuring its occupants are secured.
Consider the wings, landing gear and fuselage bottom as disposable: Use them to absorb and dissipate the aircraft's energy during the landing sequence before that energy is transferred to the occupants.
According to the Airplane Flying Handbook, "The advantage of sacrificing dispensable structure is demonstrated daily on the highways. A head-on car impact against a tree at 20 mph is less hazardous for a properly restrained driver than a similar impact against the driver's door. Accident experience shows that the extent of crushable structure between the occupants and the principal point of impact on the airplane has a direct bearing on the severity of the transmitted crash forces and, therefore, on survivability.
"Avoiding forcible contact with interior structure is a matter of seat and body security. Unless the occupant decelerates at the same rate as the surrounding structure, no benefit will be realized from its relative intactness. The occupant will be brought to a stop violently in the form of a secondary collision."
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Safety
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You are a skilled, proficient and responsible pilot. You do everything in your power to avoid dangerous situations, but there are a few unavoidable moments during each flight where, if the unthinkable happened, you'd be left with few options. Flying is, after all, an exercise in risk management, not risk elimination.
Imagine that you're departing from Mega City Municipal. With a healthy climb rate established, you tuck away the landing gear, set climb power and prepare to enter the soup. Just as the airport fence slides underneath the belly, your sole engine shivers and goes silent. You're only 500 feet above the ground, so turning back to the runway is not a reasonable option. You look out the window and all you see is a patchwork of gray and black boxes. Can you land on that stuff?
The answer depends on what exactly "that" is. Here's where a little homework could save your bacon.
Fly the Airplane
The FAA ensures that you have at least one obstacle-free way of getting into and out of any given airport, but has little to say about what types of low-lying structures lie below the flight path. Many airports are surrounded by warehouses or industrial property, because community zoning boards and airport managers generally agree that most people don't want to live near an airport. The good news -- if we can find a silver lining here -- is that you are more likely to find yourself over some sort of industrial property at 500 feet agl with a dead engine, not a neighborhood packed with people. So, there you are. What are you going to do?
First, you need to calm down, slow down and fly your airplane. In his article titled "Turnbacks Reconsidered" (Aviation Safety, Jan. 2006), decorated flight instructor and aerobatic pilot Rich Stowell suggested that landing straight ahead is by far a pilot's best option when faced with a forced landing at low altitude, such as immediately after takeoff.
"A shallow impact angle and low speed affords the airplane's occupants the greatest measures of time and distance within which that energy is dissipated," Stowell wrote. "Survivability does not depend on where the crash occurs, but rather how the crash occurs. Contacting obstacles and terrain -- trees, water, buildings, parking lots, ball fields -- while low and slow, in the landing attitude and with at least some distance over which the airplane can decelerate, all significantly increase the chances of survival."
So there is at least some chance that you will walk away from a landing on something other than a cow pasture or a runway but, when faced with non-traditional landing surfaces in an emergency, are some more survivable than others?
Up On The Roof
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This aerial view of Teterboro (N.J.) Airport (TEB) is pretty much a poster child of bad choices for an emergency landing shortly after takeoff.
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Allyn Kilsheimer, CEO of KCE Structural Engineers, P.C. in Washington, D.C., said that it might be possible for a small aircraft to land on the roof of a warehouse building, but it would have to be a very soft touchdown, and there's no guarantee the aircraft would stay put for long.
"Most roofs are designed to support 30 pounds per square foot," said Kilsheimer, who played a key role in the analysis and rebuilding efforts at the Pentagon following the Sep. 11, 2001, terrorist attacks. Elevated automobile parking decks are designed to support about 80 pounds per square foot, he said, but a 3000-pound airplane will impose much more load than that once it settles to the ground.
"When you put the weight on two points, it's possible that [the plane] could roll and then the tires could punch through the deck," Kilsheimer said. Still, punching through a warehouse roof at low or no forward speed is far preferable to taking one's chances by, say, landing on a tree-lined residential street.
Speed Kills
The key would seem to be getting the plane as slow as possible without stalling, holding it in ground effect until it settles to the surface, and flying it all the way through the touchdown and obstacle-riddled rollout. Do your best to steer in between things like HVAC structures and antennas that are frequently mounted on the roofs of industrial buildings.
If you are one of those pilots who tacks on "a few knots for the wife and kids," you might want to get out there and practice full-stall landings, because in a real off-airport landing, any extra speed you are carrying at touchdown is energy that will have to be absorbed by something, including your own body.
Whether or not you survive such an arrival will depend partly on your approach and partly on luck, because you have no way of knowing how sturdy that rooftop really is. But if you're faced with a choice between landing on a warehouse and plowing into, say, an oil tank farm, common sense dictates you should take your chances with the warehouse.
Plan Ahead
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If you can find a field like this near your metro airport, be spring-loaded to go there if your engine fails.
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This may also illustrate a valid reason for avoiding an intersection departure from a runway that launches you out over buildings and power lines. Sure, your little airplane can get up and away in half the available runway length, and an intersection departure might be more convenient to your FBO of choice, or make the tower controller's life easier. But if the engine fails to perform during those first few seconds of flight, wouldn't it be nice to have a mile of pavement ahead of you, or at the very least, the option of turning slightly right or left and landing on an intersecting runway or taxiway?
The satellite imagery available from Google Maps is an excellent resource for pilots traveling to unfamiliar airports, because it lets you see exactly what you'll be dealing with before you even leave home. Simply type the name of the airport into the search box and, when the map appears, click on the link that says "Satellite."
While there is no way to know for sure exactly when the image was generated, you should be able to get a pretty good idea of how closely the neighbors have encroached upon the airport and its traffic pattern, and what types of structures exist there. If you zoom in and notice a big patch of dirt near developed property, don't assume the patch is still vacant. Call the airport manager and ask.
Shopping-mall or office-complex parking lots can and have been used for emergency landings, but watch out for light poles, concrete barriers and parked vehicles. According to the NTSB, on Oct. 3, 2006, a Beech 36 landed in a parking lot in Centennial, Colo., after the aircraft lost power on final approach to the airport. During the forced landing, the airplane impacted a light pole and three parked vehicles, but the pilot sustained only minor injuries.
Handbook Exercises
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As attractive as they may seem in an emergency, urban highways offer their own set of unique risks, including high-speed traffic, barriers, light poles and power lines.
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How many feet will your airplane need to come to a stop once you touch down? Is that parking lot big enough? Here's another way Google Maps can be a useful tool. Take a look at the area around your airport of choice, locating a nearby parking lot. Notice that the satellite display, as well as the regular map display, offers a distance scale. If you zoom in enough, the scale will be calibrated to as little as 50 feet.
Take a look at the Palisades Center in West Nyack, N.Y., for example. This shopping mall is located adjacent to Interstate 287 about 12 miles northwest of the Westchester County Airport (HPN) in White Plains, N.Y. I've flown directly over the mall on several occasions while being vectored for a visual approach into HPN. The mall's parking lot is the last relatively open, flat, paved surface, not including the interstate (see "Go With The Flow" at right), before crossing the Hudson River inbound to the airport.
Let's pretend you are over the mall at about 1500 feet agl on a vector to land on Runway 16 at White Plains when things get quiet. With gusty southerly winds, you're unable to glide to the golf driving range located about a half a mile to the south of the mall. Your options to the north include a rock quarry, a lake and trees. It looks like the parking lot is your best shot.
The satellite view of the mall shows large parking areas on both the north and south sides of the mall. Based on the scale, it would appear that the longest stretch of potentially obstruction-free pavement in the south lot is about 2000 feet long and 50-100 feet wide -- enough room to land many light single-engine aircraft, if proper technique and airspeed are used.
However, note that the rows of parking spaces run perpendicular to the longest stretch of the lot, creating possible hazards from objects like concrete barriers or shopping carts. Landing in between rows of cars would provide approximately 1000 feet to stop with about 25-30 feet in between the parked cars -- again, probably enough room to land a light single-engine airplane and slow down enough to prevent killing yourself.
But then there are the shoppers getting into and out of their cars. You probably want to avoid them, so the more humane choice would probably be to land across the rows on the edge of the lot and hope you don't hit anything. If it's a busy weekend shopping day, you're probably out of luck there.
The suburban areas where most GA airports in metropolitan areas are found can be daunting places to confront the need for an off-airport landing. This is especially true right after takeoff when altitude, airspeed and choices are in short supply.
In situations like this, pilots must accept the airplane is likely to suffer some damage before it comes to a stop. The keys to walking away involve maintaining control, touching down at the lowest possible airspeed and choosing your landing area wisely. Some pre-flight research of the area surrounding your airport, along with a little luck, won't hurt a thing.
More AVweb safety articles are available here. And for monthly articles about safety, including accident reports like this one, subscribe to AVweb's sister publication, Aviation Safety.
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