Flight performances

	A340-200	A340-300
Wing span	60.3 m	60.3 m
Length	59.39 m	63.6 m
Wing area	361.6 m2	361.6 m2
Payload	30 800 kg	41 000 kg
Max take-off weight	275 000 kg	275 000 kg
Passenger capacity	261 (239)	295
Crew	2	2
Cruising speed	938 km/h	976 km/h
Max speed	988 km/h	937 km/h
Operational ceiling	41 100 ft	41 100 ft

Supplementary Reading Flight Controls

Flight controls have advanced considerably throughout the years. In the earliest biplanes flown by the pioneers flight control was achieved by warping wings and control surfaces by means of wires attached to the flying controls in the cockpit. The figure shows the multiplicity of rigging and control wires on an early monoplane.

When top speeds advanced into the transonic region the need for more complex and more sophisticated methods became obvious.

The controls used by a typical commercial airliner are described below.

Pitch control is exercised by four elevators located on the trailing edge of the tailplane or horizontal stabilizer. Each elevator section is independently powered by a dedicated flight control actuator, powered in turn by one of several aircraft hydraulic power systems. This arrangement is dictated by the high integrity requirements placed upon flight control systems. The entire tailplane sec-

tion itself is powered by two or more actuators in order to trim the aircraft in pitch. In a dire emergency this facility could be used to control the aircraft, but the rates of movement and associated authority are insufficient for normal control purposes.

Roll control is provided by two aileron sections located on the outboard third of the trailing edge of each wing. Each aileron section is powered by a dedicated actuator powered in turn from one of the aircraft hydraulic systems. At low air speeds the roll control provided by the ailerons is augmented by differential use of the wing spoilers mounted on the upper surface of the wing. During a right turn the spoilers on the inside wing of the turn, that is the right wing, will be extended. This reduces the lift of the right wing causing it to drop, hence enhancing the desired roll demand.

Yaw control is provided by three independent rudder sections located on the trailing edge of the fin (or vertical stabilizer). These sections are powered in a similar fashion to the elevator and ailerons. On a civil airliner these controls are associated with the aircraft yaw dampers. These damp out unpleasant ‘dutch roll’ oscillations which can occur during flight and which can be extremely uncomfortable for the passengers, particularly those seated at the rear of the aircraft.