 At supersonic speeds the F-16 gains stability (eventually positive) due to aerodynamic changes.To counter the tendency to depart from controlled flight—and avoid the need for constant trim inputs by the pilot, the F-16 has a quadruplex (four-channel) fly-by-wire (FBW) flight control system (FLCS).The flight control computer (FLCC) accepts pilot input from the stick and rudder controls, and manipulates the control surfaces in such a way as to produce the desired result without inducing control loss.