Air France Flight 447:
"...The investigation is increasingly focused on whether external instruments on the Airbus A330 may have iced over, confusing speed sensors and leading computers to set the plane's speed too fast or slow â€" a potentially deadly mistake.
The French agency investigating the disaster said airspeed instruments on the plane had not been replaced as the maker had recommended, but cautioned that it was too early to draw conclusions about what role that may have played in the crash."