Copilot in deadly Florida jet crash identified in reports as 20-year-old

The NTSB confirmed that after the jet took off from Austin, the crew transmitted to air traffic control that they were encountering ice and moderate turbulence.

"We are picking up precipitation, requesting to climb to 37,000 feet if able," the crew said.

NTSB member Tom Chapman said that less than 30 seconds later, the plane began to descend and the crew issued a mayday call.

The transmission then became "unintelligible", he said, adding that: "Sadly, all aboard were lost."

Flight analysis indicates the jet was plummeting hundreds of feet per second before crashing.

In air traffic control audio, a crew member can be heard declaring an emergency, shouting "we are in an overspeed condition descending 20,000ft per minute", before saying, "we are going to crash into the ground".