Learjet N722BD Crash: Storm Dive and Possible Causes

November 1st, Learjet N722BD is

cruising at 35,000 feet over Palm Beach County, bound

for the Bahamas. South Florida is under

a flood watch with

storms buried in the rain and tops near 47,000 feet.

The crew reports moderate

turbulence, then light clear ice at

-47 Celsius. That's too cold for liquid water.

It's ice crystals, which can block airspeed probes.

Then the jet flies into a storm core.

Radar shows a strong echo right at its altitude,

and it starts to

climb.

Then the dive begins.

Within about four seconds, it's past its Mach limit.

The crew declares

a mayday, descending 10,000 feet a minute.

Then over speed, 20,000

feet a minute, about Mach .9.

The jet is rolling to the

right. In a bank this steep, pulling back

tightens the turn instead of raising the nose.

Passing 25,000 feet,

the dive begins to steepen.

The crew calls about 60 degrees of bank.

Our model from the track alone says 56.

On paper, there was still altitude to recover until

about 10,000

feet. Rolling the wings level was the key, and the track shows the

bank only kept growing.

The last radio call comes 11 seconds before impact.

76 seconds from the start of the dive to impact,

nine people

lost their lives.

The evidence points to a loss of control inside a storm core, most

likely started by

turbulence by iced air data probes or both

and never rolled out. The

voice recorder, trim actuator, and

engine computers will tell. A preliminary NTSB

report is due in about 30 days.