Learjet 60 Crash: Weather, Ice and the Sudden Dive

The pilots had already spotted the bad weather, and they were trying to get away from it.

So why did this jet drop from over thirty-five thousand feet to eight thousand seven hundred and fifty feet in about a minute?

Let's rebuild what happened and break it down.

On November first, a Learjet 60 was flying from Texas to The Bahamas.

Over Florida, it came down from forty-one thousand feet to thirty-five thousand feet.

Here's the thing: A thunderstorm isn't just rain inside it.

Violent updrafts and downdrafts can shove a plane up or down without warning, and onboard weather radar mostly sees rain, not every dangerous gust.

The weather company MyRadar estimates that a nearby storm's top grew from thirty-three thousand feet to forty-eight thousand feet in about twenty minutes.

That peak was measured after the crash, but it shows how fast the sky was changing.

The jet flew on. The crew reported moderate turbulence, minus forty-seven degrees outside, and said they were dealing with ice.

They asked air traffic control if there was a smoother altitude ahead.

Why is ice dangerous? It's not the weight.

When ice builds up on a wing, it changes the wing's shape, messes up the airflow, and makes a stall more likely.

And here's something odd: The crew reported clear ice, which usually forms from supercooled liquid droplets.

But at minus forty-seven, those droplets are extremely rare.

Why they reported clear ice, nobody knows yet.

Soon after, the crew said they'd hit precipitation and asked to climb to thirty-seven thousand feet.

Controllers approved it, but higher isn't always safer.

Every plane has a speed window, a minimum and a maximum.

The minimum is stall speed. Wings need air rushing over them to hold the plane up.

The higher you go, the thinner the air, so you have to fly faster to grab enough of it.

Climb, and your minimum speed creeps up.

The maximum is about the speed of sound.

Get too close, and shock waves form on the wing.

The plane shakes and pitches down. One line rises, the other comes down.

Up high, the gap gets narrow. Where the two lines nearly touch, pilots have a name for it: The Coffin Corner.

That doesn't mean this jet was in the coffin corner, but it shows that climbing up high means thinking about more than just the weather overhead.

Right after the climb was approved, the jet rose briefly, then banked hard to the right and started dropping fast.

A mayday came over the radio. The crew reported descending ten thousand, then twenty thousand feet per minute, an overspeed, and a steep bank.

A sudden turn and drop like that makes people think of a stall.

A stall isn't the engines quitting. It's the wing meeting the air at too steep an angle.

The airflow peels off, lift collapses, and the plane can go out of control.

And once the nose is pointing down, a jet picks up speed incredibly fast.

Past its design limit, shock waves form on the wing.

The lift shifts backward, and the nose gets pulled down even harder.

The pilots have to pull out, but pull too hard and the airframe can't take it.

Pull too gently, and you can't catch the speed.

But whether this was a stall or whether it unraveled this way can't be determined from public tracking data alone.

So what turned a normal flight into an uncontrollable dive in about a minute?

That's the question investigators now have to answer.

Nine people were on board. None of them survived.

Our thoughts are with their families. Follow me, I'll break down the next one too.