The Washington Post quoted National Transportation Safety Board (NTSB) member Steven R Chealander as saying that in the wake of the crash and the determination of its cause, the agency has sought tighter federal regulations to require pilots to disengage automatic flying systems in icy weather.
He also pointed to the flight manual of the airplane, a Bombardier Q400 turboprop, which calls for pilots to shut off the system in 'severe' icing conditions, but Chealander stopped short of saying the pilots acted improperly by activating the system.
Weather conditions have emerged as a central part of the investigation. On Friday, the NTSB disclosed that the cockpit voice recorder captured the pilots talking about ice buildup on the wings and other parts of the plane shortly before it plummeted from the sky.
A safety alert issued late last year by the NTSB noted that autopilot systems can mask handling problems associated with icing. It urged pilots to hand-fly to get a better sense of the plane's performance.&13;&13;