Airbus A340 Series, Brochure

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STL 472.502/90 Issue 6
Pitch attitude protection
• Design aim
To enhance the effectiveness of AOA and high-speed
protection in extreme conditions and in windshear
encounter.
• Principle
Pilot authority is reduced at extreme attitude.
• Result
Pitch attitude limited :
- Nose-down 15°
- Nose-up 30°reduced to 25° at low speed
Bank angle protection
- When the stick is released above 33°, the aircraft
automatically rolls back to 33°.
- If the stick is maintained, bank angle greater than 33°
will be maintained but limited to 67°.
- When overspeed protection is triggered :
. Zero bank angle is commanded with stick at neutral.
. Max bank angle is limited to 45°.
- When angle-of-attack protection is triggered, max bank
angle is limited to 45°.
Low energy warning
A low energy aural warning “SPEED, SPEED, SPEED” is
triggered to inform the pilot that the aircraft energy
becomes lower than a threshold under which, to recover a
positive flight path angle through pitch control, and at
which the thrust must be increased.
A340 Flight Controls - EFCS
5.31
High angle-of-attack protection
• Principle
When the AOA(*) is greater than AOA prot, the basic
objective defined by sidestick input reverts from
vertical load factor to AOA demand.
• Result
- AOA protection is maintained, if sidestick is left
neutral.
- AOA floor results in GA power with an ensuing
reduction of AOA.
- AOA max is maintained if sidestick is deflected
fully aft.
Return to normal basic objective is achieved if the
sidestick is pushed forward.
α
α
α
α
α
α
(*) AOA =
α
α
α