Flight envelope protection

Anti-stall systems are used on most modern swept wing aircraft,[citation needed] and are used on a large variety of civilian and military jet airplanes.

[5] In this flight incident, the crew was forced to overstress (and structurally damage) the horizontal tail surfaces in order to recover from a roll and near-vertical dive.

In order to keep the attacker off balance and out of the cockpit the crew had to perform extreme maneuvers, including a barrel roll and a dive so fast the airplane couldn't measure its airspeed.

American Airlines Flight 587, an Airbus A300, crashed in November 2001, when the vertical stabilizer broke off due to excessive rudder inputs made by the pilot.

A flight-envelope protection system could have prevented this crash, though it can still be argued that an override button should be provided for contingencies when the pilots are aware of the need to exceed normal limits.

US Airways Flight 1549, an Airbus A320, experienced a dual engine failure after a bird strike and subsequently landed safely in the Hudson River in January 2009.

Air France Flight 447, an Airbus A330, entered an aerodynamic stall from which it did not recover and crashed into the Atlantic Ocean in June 2009 killing all aboard.