How does the A321's fly-by-wire system protect the aircraft?

• A. It limits engine thrust to protect the engine
• B. It imposes flight envelope protections that limit pitch, roll/bank, and load factor in normal flight to prevent overstress or stall
• C. It disables autopilot in turbulence
• D. It protects the wings from flutter

Answer: (B)

The system uses flight envelope protections that automatically keep the aircraft within safe handling limits. In normal flight, the flight control computers monitor your inputs and the airplane’s state and limit pitch, roll (bank) angles, and load factor. If you try to pitch up too far, roll beyond safe limits, or demand a load factor that could overstress the airframe, the controls trim or constrain the surface movement to stay inside the envelope. This prevents overstress and helps prevent stall, acting as automatic safeguards even if the pilot pushes the controls toward the edge of safe performance.