Less than a minute later it issued an emergency call for a sudden descent. The nine occupants of the plane died. The recording allows those last moments to be reconstructed, but it still does not establish why the aircraft lost altitude.
The plane had taken off from Austin, Texas, and was bound for North Eleuthera airport, in Bahamas. It crashed around one in the afternoon, local time, near Palm Springs, within Palm Beach County. It was an executive Bombardier Learjet 60 jet, with registration N722BD.
From the turbulence warning to the emergency call
In the audio of the communications with the Miami control center, released by LiveATC and reported by Reuters, a voice from the cockpit first explains that they are dealing with the presence of ice and are looking for a more stable flight area. The tone of the exchange changes when the crew issues the distress signal and reports a descent of about 10,000 feet per minute. Seconds later it reports that rate has doubled. These are vertical speed figures transmitted from the plane, not the altitude at which it was flying.
The impact occurred next to a road, near access to a residential area. Local authorities organized the evacuation of some 600 people to two shelters, according to county commissioner Joel Flores.
What remains to be clarified about the Learjet 60
The National Transportation Safety Board of the United States (NTSB) has sent investigators to the site. Bombardier has offered its cooperation. The weather is part of the context: there were storms in the area and the crew spoke of ice. What remains to be determined is what happened between that first warning, when they were still looking for better flight conditions, and the descent they could no longer stop.