Protecting ourselves

The good news is that aircraft manufacturers paid attention to the extensive research and full-scale crash testing done since World War II, so the crashworthiness of our general aviation airplanes has been steadily improving. The better news is that there are things that you can do to increase the probability that everyone will walk away from the airplane after a forced landing or other landing event (the most common type of general aviation accident). We’ll note here that accident data are showing that the best occupant protection is a full-airplane ballistic parachute—so what follows is for airplane without a BRS or airplanes
that have BRS but are outside the deployment envelope.

While crashworthiness is a complex subject, let’s set out the most important factors briefly and bluntly. Know and follow the three rules of crash survival:
1. All occupants fully strapped in—shoulder harness and seat belt—all the time;
2. Minimize the speed at touchdown (slightly simplified, force is a squared function—when you double the impact speed you quadruple the force of the impact); and 3. Give the airplane as much space as possible to decelerate between the initial touchdown and coming to a stop.

Strap in

Restraining the occupants is the foundation of crash survival. That is the only way that they get the benefit of the design of the aircraft to “crush” and absorb impact loads rather than transmit them to the frangible humans. A seat belt is not enough—they cause the occupant to jackknife and face plant into the panel. That means a head injury that is fatal or at least temporarily incapacitating so the person doesn’t get out if a fire starts.

Bottom line—the FAA reports that 88 percent of injuries and 20 percent of fatalities have been eliminated by the use of shoulder harnesses in general aviation crashes. That’s as close to a silver bullet for success in aviation as there is.

If your airplane does not have shoulder harnesses for all seats, see if they can be retrofitted—it’s possible in almost every seat in every general aviation airplane. The gold standard retrofit is AmSafe’s SOARS (State of the Art Restraint System), an airbag seat belt system (amsafe.com).

Slow down

Touching down as slowly as possible increases the probability that the airplane will be able to perform its final design function—crush and absorb energy, protecting the occupants.

Use all the flaps to minimize the stall speed, but don’t stall the airplane. That means loss of control and often a high vertical impact vector. The airplane and its seats are designed to handle some vertical load, but much more from a more frontal impact; plus, significant vertical velocity on dirt or grass may make it deform into a crater and stop the airplane in a matter of a few feet. Don’t touch down yawed—that means the occupants will be thrown into sidewalls or possibly structural
support pillars.

We humans do not have a visceral understanding of the power of the forces during even a relatively slow speed impact.As Bob Hoover was famous for saying, “Fly the airplane all the way into the crash.” So long as the airplane is moving, keep trying to make it go in the direction you want it to go. One hint—we tend to go where we’re looking, so if you’re trying to avoid a tree, don’t look at it, you’ll hit it. Look at the route where you want the
airplane to go.

By doing all that you can to spread out the deceleration distance, you reduce the G-loads on the occupants.

A tip that sounds obvious, but not following it results in too many injuries: Wait until the airplane stops to undo the restraint system. We humans do not have a visceral understanding of the power of the forces during even a relatively slow speed impact. If we’re wearing the shoulder harness, we can probably withstand on the order of 20 Gs for a short period of time during an accident. If we’re not, three Gs can kill us. No, you can’t brace yourself for a three-G impact—can you do a pushup with two people standing on your shoulders? If you’ve locked your arms against the panel, the chances are that they’ll simply fracture and then your head will hit it.

What surface?

Full-scale NASA crash tests uncovered something surprising—if you have a choice, touch down on pavement. If you do stall, there’s a fair likelihood that the pavement will translate the vertical vector of the impact into horizontal and the airplane will slide. That’s not the case with grass or dirt. That goes especially for gear-up or partial gear-up landings. The airplane was designed for them, so the fuel lines are above the bottom skin and are almost never ruptured in a gear up landing on pavement.

Full-scale NASA crash tests uncovered something surprising—if you have a choice, touch down on pavement.

By the way, research that has been going on for some years has yet to uncover a gear-up landing in a civilian airplane since World War II where someone was hurt or killed—unless the pilot tried to shut down the engine(s) and bump the prop(s) horizontal. Too many pilots who tried a prop-stopped glide to a landing when unable to lower the gear have been killed because they misjudged the glide. If you can’t put the gear down, land on pavement and keep the engine running until shortly before the flare so that you can control where you’re going to land.

Those are the basics to keep in mind—everyone strapped in all the time, touch down as slowly as possible without stalling, and fly the airplane all the way into the crash.