Flight Control Failure

A sudden binding of a control surface (as opposed to progressively stiffer ailerons, for example) can have several likely causes. The easiest to diagnose and rectify could be a passenger or loose cockpit item that is interfering with the controls. Sometimes ice can restrict the movement of the cable/pushrods or the control surface itself. In this case try descending to warmer air, wait a few minutes, and try again. If the stuck surface is the elevator, then descend using reduced power.

A more serious problem could be that a cable has jumped its pulley, perhaps because the pulley mount has failed or the cables have too much slack in them. A  wiring bundle behind the instrument panel or other obstruction may be interfering with full and free control movement. These problems can only be solved by a mechanic on the ground and the pilot will need to compensate during flight using other techniques.

Loss of elevator control is the most serious type of control surface failure. In this case, pitch should be maintained using trim. To counter a nose down attitude, nose up trim should be used; and nose down trim should be used to counter a nose up attitude. The aircraft will probably oscillate up and down until the pilot discovers the right amount of trim to maintain stabilized flight.

The big challenge will be landing. The pilot will need to properly manage the five variables that affect pitch: flaps, power, center of gravity, trim, and ground effect. Flaps should not be used. Flaps are designed to allow a steeper descent to the runway. This nose-down attitude will necessitate a larger pitch change during the flare and increase the likelihood of touching down with the nose wheel first. Applying or reducing power will result in the quickest pitch changes. The propeller slipstream creates a downward force on the horizontal stabilizer which in turn pushes the nose upward. Reducing power reduces the downward force on the horizontal stabilizer, causing the nose of the aircraft to drop. To achieve the required pitch-up attitude needed for the landing flare, power should be briefly added. Shifting the CG aft by moving heavier cabin items to the rear will also help the pilot attain a nose-up attitude for the flare.  Upon entering ground effect (about 20 feet above the runway), downwash from the wing is reduced. Downwash pushes down on the horizontal stabilizer which in turn causes the nose of the aircraft to pitch upward. Therefore, pilots should expect the nose of the aircraft to drop as ground effect is entered. This movement should be countered by the application of nose-up trim and short bursts of power to maintain the proper aircraft attitude for the flare.

Pilots can compensate for aileron failure by using the rudder to make shallow, skidding turns. Aircraft with two cockpit doors (such as a Cessna 172) can also be turned by pushing out on the doors. Pushing out on the left door causes the aircraft to yaw to the right; pushing out on the right door causes the aircraft to yaw to the left.