A Diamond Katana shows off its slotted-flap design.

by Mike Friedman

For many pilots, wing flaps are those things we only use in the pattern; we deploy them at regular intervals when the airspeed is in the white arc as we fly a traffic pattern. Some airplanes require their use on takeoff, or for maximum-performance on less-than--ideal runways. But the many different kinds of flaps installed on personal airplanes have specific characteristics—both good ones and bad. Unless a pilot understands those characteristics and how to use the flaps properly, bad things can happen. …