Gravity Always Wins - The 4 Forces Acting on an Aircraft

The 4 forces acting on a weight shift control (WSC) aircraft in flight are lift, thrust, drag, and gravity. Of these gravity will always win unless energy is expended. In WSC flex wing aircraft and ultralight trikes students always seem to have a problem with this concept. When landing, the control bar is pulled in to increase energy and power reduced beginning the decent and increasing airspeed. When it comes time to round out or flare students have a tendency to not only allow the control bar to return to trim but push out rapidly. This results in ballooning where the aircraft rises and rapidly losses energy (airspeed) and can result in a stall while the aircraft is still a foot or two off the ground. In serious cases of ballooning the aircraft stalls higher and results in a bounced landing if your lucky, something more expensive if your not. Once ballooning starts the student will try to counter by pulling in. This makes the problem worse since the aircraft is now slightly nose down and rapidly approaching the ground. So the student pushes out again, back and forth like sawing wood, a nightmare for the instructor who is watching their life flash before their eyes and trying to correct the problem. The solution to the problem - sit back relax and realize that Gravity Always Wins.

First abort the landing and go around, allowing the student to demonstrate good aeronautical decision making skills (in other words please don’t slam me into the ground). Then try again, If when rounding out or flaring the power is at idle and control bar is allowed to return to trim, the aircraft will have the correct attitude and will eventually settle on its own. Obviously, this applies to calm conditions without cross winds but that’s the best training air and your not trying to land on a postage stamp, right?

Another useful tool for correcting problems with either timing or altitude when rounding out is the low pass. If the student can fly the length of the runway at 1 foot then they got it. If not then more practice.

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