Airbus Alpha Floor Protection

Alpha floor is a low speed protection in normal law which is purely an autothrust mode.

Airbus alpha floor protection.

The system automatically increases the thrust of the aircraft when speed is predicted to reach or exceed the critical angle of attack. The alpha floor function is not available below 100 feet ra or during single engine operation with flaps at conf 1 or greater. As the aircraft decelerates into the alpha protection range the alpha floor is activated even if the autothrust is disengaged. When activated it provides toga thrust.

If alpha prot is reached and the pilot still maintains aft sidestick alpha floor protection set between alpha prot and alpha max will be reached. Alpha floor protection a system designed to prevent an aircraft from reaching very near its critical angle of attack because of slowing down too much. Alpha floor protection is inhibited in some cases. If high angle of attack protection is active the bank angle is limited to.

These newer aircraft including the a320 a330 a340 a350 and a380 operate under airbus flight control laws. This protection triggers the application of toga thrust and the aircraft will start to climb at a relatively constant low airspeed. On 26 june 1988 it crashed while making a low pass over mulhouse habsheim airport icao airport code lfgb as part of the habsheim air show. Alpha floor is also triggered if the pilot applies a large aft stick input while either pitch attitude or angle of attack protection is active.

From the airbus fast magazine 20 refer to flight manuals for latest info. The flight controls on the airbus a330 for example are all electronically controlled and hydraulically activated. The speed speed speed voice alert repeats every 5 seconds while the condition exists. When alpha exceeds alpha prot elevator control switches to alpha protection mode in which angle of attack is proportional to sidestick deflection.

Alpha max will not be exceeded even if the pilot applies full aft deflection. Airbus aircraft designs after the a300 a310 are almost completely controlled by fly by wire equipment. Air france flight 296 was a chartered flight of a new airbus a320 111 operated by air france for air charter. High angle of attack protection alpha.