Loss of airspeed renders the rudder limiter inoperative, which can
lead to vertical stabilizer overstress and possible failure. This may
have happened on Flight_447. One possible solution would be to add
strain gauges that directly measure the stress in the vertical
stabilizer and feed this data to the rudder limiter along with the
airspeed and altitude information. This would allow the rudder
limiter to continue functioning even when the air-data system fails.