What might have sent a private jet over Palm Beach plummeting from the sky? The Learjet lost about 26,000 feet, roughly 7,900 meters, in around 70 seconds, and all nine people on board died. Minutes earlier, the pilot, cruising at 35,000 feet, had reported light, controllable icing and moderate turbulence. At that height the air is so thin that a jet's safe speed range shrinks sharply, because going too slow means the wings cannot produce enough lift, while going too fast creates shock waves that disrupt the airflow over them. Ice may have narrowed that range even further, since a layer as rough as sandpaper can cut lift by as much as 30 percent.

The crew reportedly wanted to climb to find a smoother ride, but a higher altitude means thinner air and an even smaller safe speed margin. One possibility is that a single severe jolt was enough to stall a wing and drop the nose. The pilot later radioed that the plane was overspeeding and descending at 20,000 feet per minute, but flight data suggests the real rate topped 30,000 feet per minute, which is like dropping the height of a 40-story building every second. That would mean no major mechanical failure was required, since icing, turbulence, and the climb arriving in the worst possible order could have been enough. Still, this is only one theory, as the NTSB has not determined a cause and a preliminary report is expected within about 30 days.