asking the pilot.

That makes Mary Schiavo, who is a former Inspector General of the Transportation Department, think the plane may have lost its navigational instruments just as a storm moved across its path on radar. The plane also descended sharply from its cruising altitude of around 24,000 feet to around 10,000 feet, according to preliminary data from flight tracking site FlightRadar24.

 Something bad happened with this big drop, and they flew into this big storm. It's a terrible place to have a loss of your instruments and be flying blind,  said Schiavo, who is an aviation attorney.  It's very easy to get disoriented and not know if you're turning, climbing, descending, etc. 

More crews are expected to continue searching on Monday, likely about 20 miles off the coast of Nantucket where the debris field was found. More information from officials is expected as the search continues.

AP Transportation Writer Josh Funk, Associated Press writer Amy Taxin and Associated Press reporter Laura Turbay in Little Rock, Arkansas, a corps member for The Associated Press/Report for America Statehouse News Initiative, contributed to this report. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.