Plane & Pilot
Tuesday, December 20, 2011

Landing Without Flight Controls


Under some conditions, it’s possible to land an airplane without using normal aerodynamic controls



If you're ever faced with a control jam or failure, it's most important to never give up thinking. Don't submit to panic; instead, focus on resolving your situation.
There are five possible controls that are subject to failure: elevator, ailerons, rudder, flaps and speed brakes. These are connected to the cockpit by steel cables and pulleys in some airplanes, by pushrods and bell cranks in more expensive models.

The elevator is perhaps the most critical of these, but also arguably the easiest to overcome. As should be obvious, flying with elevator trim as the primary pitch control is a little different from operating with normal controls. Even the fastest of elevator trims, manual or electric, works considerably slower than a standard elevator. (One exception is the elevator trim on the Champion line of taildragger aircraft. It's essentially a direct repeater of the stick.) That means you need to stay well ahead of it and apply trim well BEFORE you think you'll need it. It's obviously a trick that works best in smooth air.

The tendency is to use too little input at first, then to overcontrol and use too much. Try it in your own airplane, and you'll gradually zero in on the proper amount of trim to apply.

Don't be afraid to try Schiff's trick of flying with trim alone for pitch control, but do it in increments, starting at high altitude. As you approach the runway, remember that ground effect complicates things. You'll need to apply a slight nose-up pitch as the airplane enters ground effect half a wingspan above the runway. You may even need to add a very small shot of power in addition to the up trim. The trick is to know how much to use and when.

When we shot the video, it was obvious Schiff had practiced the procedure and knew exactly how much trim to apply during the flare. At least, he had a working elevator control if he had needed it.

A decade after Schiff's story aired, a client hired me to accompany him to Europe in his 340 on his vacation. The day before we were scheduled to leave California, the client attempted to take off from Santa Monica with the control lock still in place. The airplane ran off the end of the runway, rolled down an embankment and caught fire, killing both occupants.

No one will ever know if my client tried to apply elevator trim for liftoff, but at least one other 340 owner saved himself and his passengers in a similar situation by doing exactly that. Halfway through the takeoff roll and too far along to abort, he discovered the yoke was immobilized. He used electric trim to get the airplane off the ground, climbed to a safe altitude, and after some experimentation, managed to get the airplane back on the ground safely.

In fact, a pilot may have several other options for aircraft control when the yoke no longer works as it should. Simple weight shift can have more effect than you'd imagine on some airplanes, especially on lightweight models with the dominant CG directly beneath the front seats.

Many years ago, when I was trying to help my wife learn to fly our Globe Swift, I used to wait until she had the elevator perfectly trimmed; then, I'd ease forward or back in the seat just enough to cause the airplane to slowly pitch down or up. After that, I'd ask her to retrim, and we'd play that game three or four times until she caught on. I'd typically sleep on the couch that night.

Even if you're not sitting directly on the balance point as we were in my old Swift, another obvious trick some pilots can use is simply to move the seat forward or aft in its tracks to pitch the nose as necessary, especially if you have someone in the right seat to complement your move. This doesn't work very quickly, but it will cause a gentle pitching moment. You don't want to adjust the seat so far in either direction that you overcontrol, but in light aircraft with an appropriate CG, a sliding seat can be a partial lifesaver in the event of a control failure.



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