Flight controls and guidance.

The A310 flight controls consist of primary flight controls and secondary systems. The primary flight controls comprise ailerons, roll spoilers, trimmable horizontal stabilisers, elevators and rudder, while the secondary flight controls consist of full-span three section leading edge slats, trailing edge cambered tabless flaps, and roll spoilers and speed brakes, all of which can be used as lift dumpers. The primary flight controls are mechanically controlled and fully powered by three independently supplied hydraulic servo-jacks, with no operational reduction after a single hydraulic failure. The tailplane actuation systems are fail-safe ball screwjacks driven by two independently controlled hydraulic motors, which are electrically controlled with an additional mechanical input.

The primary systems provide attitude control in pitch, yaw and roll. Pitch control and trim is achieved by two elevators hinged on the horizontal stabiliser, each actuated by three servo-jacks controlled by a dual mechanical linkage. A duplicated artificial feel system creates load feel at the column, which is variable with flight conditions. Autopilot actuators are located adjacent to the left hand elevators, providing control via a detent lever, which can be overridden by the crew.

A stick-shaker (a variation on aerospace electric motors) is installed on each control column, to provide stall warning to the crew. Pitch trim is achieved by adjustment of the horizontal stabilisers, either manually by trim wheel operation, or automatically by autopilot trim, Mach trim or alpha (angle of attack) trim functions. Electrical and automatic trim signals are processed by two FACs (Flight Augmentation Computers), which control two aerospace electric motors. Elevator and horizontal stabiliser positions are indicated on the right ECAM display unit.

Hydraulic actuators.

For roll control, the A310 has on each wing one all-speed aileron mounted behind the engine, powered by three servovalves, and five roll spoilers, each powered by one servo actuator. All are operated by the pilots' control wheels through a spoiler servo and mixer assembly. An auto pilot actuator is attached to the right hand wing rear cable quadrant, which is again controlled via a detent lever and can be overridden by the crew.

The aileron trim control is electrically powered, and the roll spoilers are electrically signalled by two identical digital computers, designated EFCU (Electronic Flight Control Unit). Yaw control is provided by a single-piece rudder, which is operated by three independently-supplied, mechanically-controlled servo-jacks. The rudder receives pilots' input from the pedestal mechanism by a single cable run up to a spring-loaded artificial feel unit, connected to the trim screwjack. Commands are delivered by two independent rudder travel channels of the FLC (Feel and Limitation Computers), which receive inputs from the ADC (Air Data Computer) and SFCC (Slat/Flap Control Computers).

There are two inner and two outer speed brakes located on the upper surface of each wing, controlled by single servojacks, supplied by different hydraulic systems. The outer speed brakes are also used as lift dumpers/roll spoilers and are selected by a lever situated on the pedestal. Speed brake and roll spoiler surfaces are used on the ground as ground spoilers, being automatically extended after touch-down when specific conditions are fulfiled.

High-lift control on each wing is achieved by three leading edge slats, continuous across the engine pylon, and a Krueger flap, in conjunction with single Fowler flap outboard, vaned Fowler flap inboard, and drooped all speed ailerons. The all speed ailerons droop down to 10' to maintain flap continuity in the region of the engine efflux. The Krueger flaps are provided to complete the wing leading edge profile when the slats are extended and to obtain better aerodynamic characteristics. The flaps are operated by individual hydraulic actuators. Each flap and slat surface is driven by two ball screwjacks. Two identical SFCCs (Slat Flaps Control Computers) provide continuous monitoring of the high-lift control system.

All models of the A310 are equipped with a digital AFS (Automatic Flight System). This has been designed to provide cruise guidance with fail soft characteristics; approach guidance with fail passive characteristics to permit Cat II automatic approach and landing and Cat I normal approach; approach guidance with with fail operational characteristics to permit Cat IIIb automatic approach and landing; and flight augmentation with fail operational capability by duplication of the system. At the heart of the system are two FCC (Flight Control Computers) for flight director and autopilot functions; a single TCC (Thrust Control Computer) for speed and thrust control; two FAC (Flight Augmentation Computers) to provide yaw damping, electric pitch trim and flight envelope monitoring and protection; and two FMC (Flight Management System Computers) for position computation, navaids auto-tuning, flight plan construction and lateral and vertical guidance along the flight plan. Options are improved availability of speed and thrust functions with a second TCC, and transfer switch to allow crosstalk of FMS CDU and ND after one FMC failure.