NEW YORK, May 23 (UPI) -- Flight recorder data suggest faulty airspeed indications distracted pilots of the Air France jet that crashed in the Atlantic in 2009, aviation experts say.
The distractions caused the pilots to fail properly to manage other vital systems and to adjust engine thrust, sources familiar with the preliminary data from the recorders told The Wall Street Journal.
The sources said the crew of the Airbus A330, evidently confused by alarms they received from various automated flight-control systems, failed to follow standard procedures to adjust thrust to keep the aircraft's nose level, the Journal reported Monday.
The aircraft was in forecast turbulence on its route from Rio de Janeiro to Paris but also faced unexpectedly heavy icing at 35,000 feet. Such icing can often make airspeed-indicators and other external sensors unreliable.
The Journal's sources said the crew did not employ standard procedures to sustain or increase thrust to keep the aircraft's nose level, while troubleshooting the cascade of failures and waiting for the airspeed sensors and related functions to return to normal.
A previous report by France's Bureau d'Enquetes et d'Analyses -- which is heading up the accident investigation -- showed the pilots never received the proper training to handle an emergency of that kind at high altitude.
Investigators say they will release more information Friday about the sequence of events leading up to the crash of Air France Flight 447 that killed all 228 people aboard.