Airspeed. Older planes show it as miles per hour, and newer ones show it as knots. There is indicated airspeed, calibrated airspeed, and true airspeed. None of these speeds should be confused with how fast you are going anywhere, because that is ground speed. What is a Cessna 150s airspeed at takeoff? I never look. Landing? It depends. Stall? I don't know.

Airspeed isn't a speed, it is a feeling and it is a sound. Light airplanes are not flown by the technician's measure, they are flown by the artist's eye. Normal takeoffs occur when the plane flies itself off the ground in a slightly nose-high attitude. Landing occurs when the plane runs out of lift as it skims level over the ground. As the plane approaches the runway, it is flown at a speed that provides a slight reserve of buoyancy.

Airplanes become buoyant and float up into the air because of speed, and more speed makes more buoyancy. A plane with lots of buoyancy makes crisp reactions to a pilot's control inputs, while a plane that has lost most of its buoyancy provides only dull and sluggish responses. Even a student pilot on the first lesson can sense a lack of buoyancy in the airplane, but contemporary instructional techniques use this sensation only to define "DANGER" and then warn the new pilot to stay away from it.

Buoyancy is one of the sensations that "natural" pilots tune into, almost without being told. If a lack of buoyancy is identified as just another of the airplane's many "feels," the student is more inclined to sense how the airplane's feel changes as its buoyancy changes. The airplane's feel is difficult to narrate but numbers are easy to specify and to see, so flight instruction too often is dulled down to the level of paint-by-numbers.

The best way to enhance a student's perception of buoyancy is to put a cover on the airspeed indicator. Deprived of the artificial input of numbers, the sounds of too much or too little speed start to emerge from the other noises of flight. Ears monitor speed, eyes monitor the nose pitch, and the fingertips monitor the buoyancy. The wisdom thus gained becomes the pilot's safety kit which always travels with him from plane to plane and through thick and thin.

As the pilot flies the landing approach, control inputs must inevitably be made to maneuver the plane around the airport, and to accommodate the lumps and bumps of the air that the plane is flying through. Each time that the controls are moved, the pilot has an opportunity to feel how crisply the plane responds. Sometimes a pilot will test the buoyancy by gently twitching the elevator control, and gauging the airplane's response. If the plane reacts eagerly to this elevator input, buoyancy is probably excessive, but if the airplane is unresponsive, buoyancy is poor.

Like I said earlier, buoyancy is difficult to narrate. It is so much easier to specify a particular approach speed and then offer the simple guidance that "you are too slow" or "you are too fast." Another meter-reading technician is born, but another artist is lost. It is much better to start out with the concept that the airspeed indicator is just a can-full of levers and gears, and that it is helpful only in calibrating your natural-born senses.