Original subtitles

NARRATOR: One of the world's most sophisticated warplanes

speeds down the runway at Guam.

FLIGHT DISPATCHER: 345 rotate.

Their mission that day was to return home.

NARRATOR: But the takeoff ends in disaster.

A billion dollar stealth bomber goes up in flames.

We want to know what the heck just happened.

NARRATOR: The entire fleet is grounded.

This could be the end of the B-2 Bomber program.

The plane goes full nose up.

NARRATOR: Investigators analyze the flight second by second.

What about this?

NARRATOR: And discover a hidden vulnerability

in the B-2's electronic armor.

There's no way a pilot would understand

the system well enough to realize what could happen.

What is going on?

You're good to go, sir.

Thank you.

NARRATOR: Major Ryan Link and Captain Justin Grieve

are ending a four-month deployment in Guam.

Better?

Yeah, it looks good.

OK.

Let's head home then.

Copy that.

NARRATOR: Andersen Air Force Base is both a training

facility and a launching point for US military operations

in the Western Pacific.

Generator one is on.

Engines ground idle.

25% confirmed.

Preflight checklist is complete.

GARRETT HARENCAK: Their mission that day was to return home.

Our time was up in Guam, and they were beginning

a 16-hour continuous flight back to Knob

Noster, Missouri, Whiteman Air Force

Base, which was our home base.

NARRATOR: They're one of two crews returning home

today in a unique warplane.

The B-2 Bomber.

REBECCA GRANT: It was a flying wing design and really

a marvel of engineering.

The Air Force ended up spending $44 billion

to develop and then field the fleet of B-2 Bombers.

NARRATOR: Developed in the 1980s during the Cold War,

the Stealth Bomber was designed to defeat Soviet radar.

There are only 21 of them in existence.

It can sneak in with much less chance of being detected,

either by enemy surface to air missile

defenses or enemy fighters.

Tower Death Five, startup is complete.

You can activate our flight plan.

Refueling number one.

Will be at ARCP Charlie at 0735 Zulu.

Expecting to onload 51,000 pounds.

Control Point Charlie, copy?

NARRATOR: Today, the 7,000-mile journey home from Guam will

require the crew to refuel near the Hawaiian Islands and then

over California before reaching Whiteman

Air Force Base in Missouri.

Major Link is a qualified instructor on the B-2.

Captain Grieves, an experienced pilot

with more than 2,500 hours of military flying experience.

They are among only 300 pilots qualified to fly the B-2.

The Aviators in the B-2 at that time were

the absolute best of the best.

They were handpicked.

They were vetted extensively.

They were truly an elite group of aviators.

NARRATOR: Grieve and Link are second in line to take off.

The plane they're flying is named Spirit of Kansas.

Every B-2 Bomber is named after an individual state,

except for two.

There's a Spirit of America and a Spirit of Kitty Hawk.

That's six plus one cleared for takeoff.

Maintain 5,000.

Pitot Heat is on.

Clear right.

Good to line up.

NARRATOR: The pilots must carefully

maneuver the massive 168-ton bomber

to the foot of the runway to ensure they don't put

any dents in the B-2's shell.

We try to taxi slowly because you're

a low observable platform.

So obviously, if you were to scrape the airplane,

you'd degrade the capability of the war fighting machine.

Dutch Five, go Channel Five.

Dutch Five, copy, Channel Five.

That's five check five.

Our lead is airborne.

We go in 60.

NARRATOR: On this flight, Captain Grieve

is the mission commander.

What's different is, the captain,

like you would think the aircraft commander,

is actually in the right seat.

And we call him a mission commander.

And the pilot is in the left seat.

Thrust time CT.

The very first time I flew the B-2, I felt like I was a bird.

It was so smooth.

You just slightly touched the flight controls,

and she does what you want.

100 knots.

What was that?

FCS Caution.

Stop or go?

Go.

Warning rescinded.

FLOYD CARPENTER: In the B-2, there's two different

kind of caution lights--

the red one and a yellow one.

In this case, it was yellow, which is just precautionary.

A red caution light, you'd probably abort the takeoff.

145 rotate.

NARRATOR: The Spirit of Kansas lifts off the runway at Guam.

Almost immediately, the massive bomber pitches up dramatically.

The next thing they know, they're going straight up.

The momentum of that maneuver up caused their pilots

to experience about 1.6 Gs.

The aircraft's no longer doing what it's supposed to be doing.

Full power.

NARRATOR: The B-2 isn't gaining altitude.

It's still only 80 feet off the ground and losing speed.

Make believe you're in your automobile right now.

You turn left, but the car turns right.

What is going on?

That's not the way it's supposed to work.

That's the scenario these pilots were in.

NARRATOR: The pilots now feel their airplane

shaking violently and realize it's on the verge of stalling.

From my 15 years of flying the B-2,

the only time I felt the B-2 shake is in the simulator.

That's the only scenario where you will feel that shake.

You never feel it otherwise.

NARRATOR: The plane's left wing drops.

Grieve knows the plane is heading for the ground.

There's only one thing he can do to save his

and Major Link's lives.

They are trained to have that gut feel of when

to pull the ejection handle.

And don't forget, the Air Force wants these pilots

to eject and save themselves.

There is no shame in ejecting ever, even

from a billion-dollar bomber.

NARRATOR: Grieve doesn't have time

to think about his decision.

The B-2's left wing is now scraping the ground.

We've got to get out.

NARRATOR: Explosives tear a hole in the fuselage

above the cockpit, and rockets eject

the pilots from the aircraft.

The Stealth Bomber hits the ground and bursts into flames.

Alert one, alert one, runway six Romeo.

Runway six Romeo.

I'm stunned.

The B-2 has gone through 19 years and three wars

without a crash.

This is unheard of.

NARRATOR: One of the world's most advanced warplanes

has been incinerated during a routine takeoff.

The whole world is left wondering what went wrong.

For two straight days, firefighters at Andersen Air

Force Base in Guam battle the flaming wreckage of a B-2

Bomber, Spirit of Kansas.

With a price tag of more than a billion dollars,

this is the most expensive aviation accident of all time.

The crash at Guam did shake us to the core

in that we want to know what the heck just happened.

NARRATOR: Operations of the entire B-2 fleet

are suspended, even before an investigation is launched.

It's bad to have to stand down the B-2 flying operations.

On the other hand, they have no choice.

They have no idea what's gone wrong inside that B-2,

and they have to find out before they

risk any more B-2s in flight.

NARRATOR: The US Air Force appoints

the well-respected General Floyd Carpenter

to lead the investigation.

Because of the high-profile nature of this accident,

I think they expect a lot of media interest.

And so as a senior Brigadier General, I was picked, I think,

to get the airplanes back operational

and cleared to fly again.

You're never going to believe this.

NARRATOR: Investigators watched the accident

unfold on security video.

Great to have the video, and we were able to glean

a lot of information from it.

NARRATOR: Video of the takeoff shows that as the plane lifted

off, it pitched nose high.

Your first reaction, when you see that airplane pitch up,

is like, what are they doing?

NARRATOR: The plane then drifts left before the left wing

scrapes the ground.

FLOYD CARPENTER: The left wing falls off and hits the ground.

And through that whole thing, you're

thinking, where is the crew?

The first time you see it, you probably don't realize the crew

actually ejects.

Can you take it back for me, please?

Stop.

That's the pilots, one and two.

NARRATOR: The video shows the pilots injecting just

as the plane hits the ground.

Both pilots have been taken to the hospital for evaluation.

Justin Grieve has suffered a serious back injury from

the forces of the ejection.

It was a waiting process for us

and gathering all the other information

while we waited to talk to them and hear their side

of what really happened.

NARRATOR: Investigators study the mechanical and computer

systems that control the jet.

Perfect.

What about the actuator?

We had so much the aircraft already available,

actuators, engines.

All of those things are what you're really looking

for in this type of accident.

NARRATOR: They quickly determined

that all of the plane's flight control surfaces

were functioning on takeoff.

Pretty quickly, we were able to rule out that the fact

that the engines were not a problem.

The hydraulics weren't a problem.

The flight controls were not a problem.

I pulled these from the video.

Up.

Up.

Up.

It's a beautiful sunny morning.

Why does the bomber pitch its nose up and crash in a fireball

on the runway at Guam?

Is this a weight and balance issue?

In any deployment like that, it's

not uncommon to load aircraft with spare parts

or other equipment that you might want to get

home and not wait to ship home.

Some classified material going back to Whiteman.

Personal belongings.

Gear.

So the center of gravity became a big issue for us.

Could it have been that?

Not enough to disrupt their balance, sir.

NARRATOR: The B-2 is capable of carrying

40,000 pounds of weaponry.

But Spirit of Kansas wasn't carrying

any bombs or other heavy cargo that

could have shifted on takeoff.

FLOYD CARPENTER: We found out that there really

wasn't a lot of equipment.

There were no munitions being carried.

So everything was in balance as it should have been.

And so the center of gravity was ruled out pretty quick.

NARRATOR: Investigators looked more closely at the takeoff

roles of both B-2s on the day of the accident for clues

as to why Spirit of Kansas couldn't get

airborne like the plane just ahead of it,

Spirit of South Carolina.

OK.

Pause it right here.

OK.

So South Carolina lifts off just past that taxiway.

Right about here.

Because we did have video, we were

able to look at the takeoff roll of the lead aircraft

compared to the second aircraft.

And stop.

OK.

Our guys lift off just past that runway light,

which is this guy right here.

Look at that.

We found out that Spirit of Kansas

took off 1,500 feet shorter than its lead aircraft.

What is going on?

Again, video helped us understand

that the takeoff roll was shorter,

but didn't understand why.

NARRATOR: The investigators turned

to data from the bomber's flight recorder for answers.

The plane is still on the ground

546 feet above sea level.

Not 682.

So the altitude is off by 136 feet.

Now, sir, there is no way he got up to 145 knots

using only this much runway.

Agreed.

Something happened that caused this airplane to pitch up,

but so far we've ruled out all the easy stuff.

And so now we start looking into other situations

that could have caused the aircraft to do what it did.

Now here, sir.

The nose is lifting off the ground,

but the plane registers a pitch down of minus 8 degrees.

Now, obviously, this plane is not pitching down,

but the computer thinks it is.

That is why it tried to lift the nose

higher and higher and higher.

Until it stalled.

Once we got the performance parameters of the aircraft,

then we were able to determine that the airplane

thought that it was negative 8 degrees angle of attack.

Then you start going back to say, why did it think that.

NARRATOR: The heart of the B-2 Bomber

is its sophisticated onboard computer, known as its flight

control system or FCS.

Without it, it would be impossible for pilots

to make all the calculations necessary to keep

the unusual aircraft flying.

You don't have a tail.

Think about that.

You don't have any kind of vertical empennage.

It's just a big flying wing.

NARRATOR: Accurate data is crucial.

On a B-2, pilots tell the computer what they want

the plane to do, and the computer determines

how to accomplish that.

The flight computers move the surfaces of this airplane

in a way that's not intuitive to any pilot

of any other aircraft.

Simply put, it'd be nearly impossible to fly

this airplane safely without flight computers.

So their speed, climb angle, and altitude are all off.

How does that happen on this plane?

NARRATOR: Investigators need to determine why the Stealth

Bomber was getting faulty data.

Let's see what the pilots can tell us.

We weren't looking to blame them

or point the finger at them.

But there were tough questions to ask.

NARRATOR: Three weeks after the accident,

the pilots of Spirit of Kansas agreed to be

interviewed by investigators.

OK, Captain.

How about we take it from the top.

We started up at 9:15.

A few minutes later, Major Link saw the calibration message

during startup.

NARRATOR: The pilots tell investigators

that they received an unusual computer

message shortly after startup.

I've never seen that.

Me neither.

Hey, Chief, we're seeing an Airdata Cal message.

Can you send someone up here to clear that up?

NARRATOR: Airdata Cal stands for Airdata Calibration.

In the simplest terms, the Airdata Calibration

gives the aircraft its orientation to the universe.

NARRATOR: There are 24 sensors flush-mounted near the nose

of the B-2 that constantly measure air pressure.

The plane's computer uses those readings to calculate altitude,

airspeed, and angle of attack.

All 24 systems have memory in them,

and they're measuring themselves against all the others.

And so if they get out of balance,

if one is reading too low or too high,

it calls for an Airdata Calibration,

and the pilots see that.

When that occurs, they call out maintenance.

OK.

Let's see what we can do to clear this for you.

Can you put it in maintenance mode for me?

That's good.

You're good to go, sir.

Thank you.

So they have these 24 sensors.

They make sure they're communicating correctly.

And if they do, they let it go forward.

Pitot heat is on.

NARRATOR: Less than an hour later--

Clear right.

Good to line up.

NARRATOR: --the pilots maneuver the massive bomber

to the start of the runway.

OK.

Go on.

Everything was 100% routine until we had 100 knots.

That's when we got the FCS Master Caution.

You got a Master Caution while you were still on the ground?

Yes, sir.

Just a flicker.

100 knots.

Before I could even push the button, it rescinded itself.

What was that?

FCS Caution.

After 100 knots to our decision rotate speed,

we will abort for safety of flight items.

We define safety of flight as, we are unable to control

this airplane or there's something on the runway

you're going to hit.

Stop or go?

Go.

Warning rescinded.

In that scenario, if I was the pilot in command,

I would continue.

Why?

It's not safety of flight.

145 rotate.

When we hit 145, I called for Major Link to rotate.

Then it all, very quickly, went to hell.

They lift off.

The flight control computer senses a problem,

so it pitches up.

The pilots try to go nose down.

Full power.

They go max power, but the airplane is trying to stall.

JUSTIN GRIEVE: Major Link was trying to push it back down,

but it wasn't working.

He wasn't having any effect on the plane.

We were basically just along for the ride.

And then the left wing just drops, and I know we're done.

We've got to get out.

Then I pulled the handles.

If the airplane did not perform as advertised,

it was time for them to get out and give the aircraft back

to the taxpayers.

Thank you for your time today, Captain.

Thank you, sir.

They were extremely forthcoming in their testimony.

They survived it, but they had no understanding

of what happened either.

NARRATOR: Investigators need to know more about the calibration

that Grieve reported in his testimony.

It's not part of the plane's regular startup procedure.

If a sensor provides a reading that differs significantly

from the others, a recalibration is

done that tells the wayward sensors how much they're

off in order to bring them back into agreement with the others.

These three weren't just off by little.

They are way off.

And they need a very big adjustment to get

them in line with the rest.

And we're not sure why, sir.

100 knots.

A Master Caution alarm that flickered on for a few seconds

just before takeoff becomes a key piece of the puzzle.

At that point, we really didn't

know how they're related, but we figured they might be.

There was too much coincidence starting to happen

that pointed to these things.

What was that?

FCS Caution.

The recalibrated sensors started

providing faulty airdata again.

NARRATOR: Six seconds later--

Stop or go?

Go.

NARRATOR: --the flight computer resolved

the discrepancy between the sensors

and canceled the warning.

What is going on with this plane's sensors?

To have a mystery flaw in the B-2

puts the 509th and the Air Force under a lot of pressure.

They have to find out exactly what went wrong with the flight

controls in order to return that fleet to safe operations,

and the world will be watching them.

OK.

So let's start at the top.

Why the need to recalibrate in the first place?

It was a procedure that a lot of pilots had never seen

and maintainers didn't do very often.

NARRATOR: Investigators look for any abnormalities

in the mission that might have had

an effect on the B-2's sensors.

Huh.

So they got delayed by a day.

What had happened was, Whiteman Air Force Base

in Missouri had a severe snowstorm.

It was snowing quite heavily.

Visibility was near zero.

So what we did is we delayed the mission to come home 24 hours.

NARRATOR: The Spirit of Kansas was left on the tarmac

while the pilots waited to resume their mission.

OK.

So the jet was left outside for 24 hours because of the delay.

So what?

Check the weather.

Second to last page.

Holy smokes.

That is one hell of a lot of rain.

NARRATOR: Weather records show that a tropical rainstorm

settled over the air base the night before the accident.

Tell me a rainstorm didn't

take down a $2 billion airplane.

Decisions were made, and these B-2s were left outside in this

particularly heavy rainstorm.

OK.

Let's fly these two.

NARRATOR: Investigators run tests on B-2 sensors

to determine the effect rain may have had on them.

And stop.

You've got to be kidding me.

NARRATOR: Tests confirmed that the sensors exposed

to the heaviest rainfall got saturated

and needed recalibrating.

Even prior to that, when it was in test and development,

we'd never experienced that much rain on the system,

so no one really knew how that would adversely affect

the operations of the B-2.

NARRATOR: The reason no one realized how heavy rain affects

the B-2 is that it's almost always

parked inside a hangar at Whiteman Air Force Base

overnight.

Even if it's flying a mission over Afghanistan or Libya,

it returns to Missouri.

The B-2's occasional deployment to Guam

presented different weather conditions.

Could heavy rain be the simple explanation for this accident?

REBECCA GRANT: This would not have happened

in a desert environment.

This would not have happened at Whiteman.

But Guam is very unique.

They left the B-2 parked out all night in the rain.

The moisture got in there.

See, something just doesn't add up.

They did the recalibration.

You're good to go, sir.

But they still ended up with faulty data.

That nearly killed them.

Yeah.

Full power.

NARRATOR: A state-of-the-art military jet put itself

into a stall because it was getting faulty

data about its climb angle.

Investigators still don't know why.

The B-2 is always operated under

so much pressure and scrutiny.

If they can't figure out what went wrong that morning

on Guam, honestly, this could be the end

of the B-2 Bomber program.

OK.

So they recalibrate at 0934.

Nearly an hour later, the Master Caution lights

up because of an airdata issue.

So what happens in those 56 minutes?

NARRATOR: Investigators review what the pilots

told them about the flight.

Routine taxi.

They hit the Pitot Heat, wait for the timer, and they're off.

So what about this?

NARRATOR: There are small heaters connected

to each of the plane's sensors.

Just before takeoff, the pilots activate the heaters

so the sensors don't freeze up when

the plane reaches cooler temperatures

at higher altitudes.

We can't take off, advance the power and go down the runway,

until we put the Pitot Heat on.

Pitot Heat is on.

It's essential that those sensors are getting heated.

NARRATOR: Investigators wonder if the Pitot

Heat could have affected the recalibrated sensors.

Clear right.

Good to line up.

FLOYD CARPENTER: We didn't know enough to really put them

together, and so we had to go get better

understanding of the system.

And we did that through engineers

that actually built the system.

When he saw the frequency of our calibrations,

he was surprised and concerned.

And then, they turn on Pitot Heat

when they get to the runway.

And then, he was really concerned

when he saw and understood, like he only could,

that with moisture in the system,

and the data that we were putting into it to fix it,

could cause such a problem.

NARRATOR: On the day of the accident,

turning on the Pitot Heat had a consequence

that no one anticipated.

Recalibrating the sensors brought the three wet ones

in line with the others.

But turning on the Pitot Heat boiled

away the moisture, bringing the sensors back out of alignment.

Thrust time CT.

So the data that was put in on the calibration

now is invalid again, and the flight

computers are now trying to resolve

the issue with these sensors.

NARRATOR: But the discovery doesn't explain another key

event during the short flight.

What was that?

FCS Caution.

NARRATOR: Why did the faulty airdata warning disappear

six seconds after it came on?

Stop or go?

Go.

Warning rescinded.

It's seconds from takeoff.

NARRATOR: US Air Force investigators

look into the logic guiding the B-2s flight computer.

So it has to make the choice.

GARRETT HARENCAK: That flight data computer needs a solution.

And what we mean by that is, it can't spend even a second

or a millisecond wondering where it is

and what needs to be done.

NARRATOR: The B-2's flight computer

is constantly receiving four separate data

streams from all 24 sensors.

If there's a discrepancy in the values of those channels,

the computer is programmed to select any two of the channels

to proceed.

It just chose wrong.

Yeah, we should fix that.

So now it's voting as to throw out bad data, what they think

is bad data, keep the good data, and it resolves the issue.

The light goes away.

The flight computers are now good to go.

And so the pilots are now, OK.

Well, that must have just been a glitch.

Let's keep going.

Stop or go?

Go.

Warning rescinded.

NARRATOR: The flight computer chose

the two channels that included the faulty sensor data.

145 rotate.

NARRATOR: 12 seconds later, the plane

pitched up abnormally because of the faulty airdata readings.

Once they rotated the aircraft on speed as they thought

and left the ground, they were along

for the ride at that point.

NARRATOR: But if recalibrating the plane's sensors

before turning on the Pitot Heat can be catastrophic, why was

that the official procedure?

So hardly any at all then?

NARRATOR: Investigators learned that recalibrations

are rarely done while the B-2 is at its home base in Missouri.

But during a deployment in Guam in 2006,

maintenance personnel were performing

frequent recalibrations.

Copy that.

I'm on my way.

FLOYD CARPENTER: They knew there was a challenge,

but they didn't know what it was.

And they did speculate that because of the weather

in Guam, raining a lot more than at home,

that it might be an issue of moisture.

NARRATOR: Technicians in Guam spoke to an engineer in the US

who suggested a procedure to remedy the frequent Airdata

Calibrations.

Yeah.

Then we have to do an onboard recalibration.

They were able to talk to an engineer that said, well,

before you do a data calibration,

try turning on the Pitot Heat and burning

that water out of the system, and see

if that'll take care of it.

I haven't tried that.

Good idea, though.

NARRATOR: The technician passed on the suggestion

to the B-2 pilots in Guam.

TECHNICIAN: Try turning on your Pitot Heat for 40 seconds

instead.

PILOT: Copy.

Apparently, that should do it.

Yeah, but our guys didn't do that.

Can you think of a reason why?

NARRATOR: Investigators learned from technicians at Whiteman

Air Force Base that the procedure for activating Pitot

Heat in response to an Airdata Calibration message

was not officially adopted.

Really?

Why the heck not?

NARRATOR: Some crews knew about it.

Some did not.

The pilots back at Whiteman who were not

there never heard of it, and the maintainers

had never heard of it.

There's nothing.

There's nothing anywhere about using Pitot Heat when

a calibration message appears.

You're good to go, sir.

Neither Ryan Link, Justin Grieve,

nor the maintainer assigned to their plane,

was ever told about the moisture issue or the informal procedure

for rectifying it.

Better?

Yeah, it looks good.

The maintainers that morning were following

the tech orders which tell them exactly

what to do in the preflight.

But for some reason, this new workaround

to compensate for the moisture just

hadn't made it into the manual, and that's

a little bit of a tragedy.

So these three are wrong.

What if they had used Pitot Heat instead of recalibrating?

It would have burned off the excess moisture

and solve the problem.

No faulty airdata. No accident.

If information had been shared from previous deployment

2006 to 2008, this accident could have been prevented.

Hey, Chief, we're seeing an Airdata Cal message.

Can you send someone up here to clear that up?

The maintenance personnel that came out to the aircraft

hat day of the accident did everything exactly right.

They were just doing the procedure they were taught.

I mean, it doesn't seem like anybody understood what

these recalibrations could do.

NARRATOR: The investigation has uncovered a catastrophic gap

in the B-2 crew's understanding of a link between calibrating

sensors and flight controls.

145 rotate.

There's no way a pilot or a maintainer

would understand the system well enough

to realize what could have happened when

they did that data calibration.

NARRATOR: That lack of understanding

left the crew of Spirit of Kansas

vulnerable to the effects of the faulty data.

Investigators now wonder if there

is something the pilots could have done to save their plane.

18 seconds to get this plane under control.

Was it even possible?

NARRATOR: Investigators re-examine the crash sequence

to see if the pilots of the B-2 Bomber, Spirit of Kansas,

could have prevented their aircraft from crashing at Guam.

145 rotate.

Certainly, no B-2 pilot wanted to be

the first to eject from a B-2.

The plane goes full nose up.

He pushes full forward and goes full power.

The plane starts yawing and rolling left.

He applies right stick.

He's fighting.

NARRATOR: Investigators determined

that Major Link took the correct action to save the B-2 Bomber.

But because of its low altitude and slow speed,

disaster was unavoidable.

GARRETT HARENCAK: Ultimately, this was a no-win situation

for the crew.

As we determined with hundreds and hundreds of simulations

afterwards, no one could have flown this aircraft out

of that situation.

NARRATOR: The data also shows just how close the pilots

came to losing their lives.

They are seconds away from impact,

and they still hadn't pulled the handle.

If they had delayed even a fraction of a second

later to eject, they most likely would not have survived.

NARRATOR: The video of the accident

shows that the plane's left wing was already scraping the ground

when the pilots ejected.

We've got to get out.

They are heroes in the sense that these guys waited till

the very last possible second.

I don't know of many other people that

can say that they waited till the wingtip

hit the ground before ejecting.

Can you imagine that?

GARRETT HARENCAK: All pilots in the Air Force

are good or maybe even great, but these guys

were truly outstanding.

And they were very, very close, despite everything, to actually

saving that aircraft.

NARRATOR: One of the most sophisticated

warplanes on Earth was brought down by a combination

of poor weather--

Who would have guessed that a bit of moisture

would have led to all this?

--and poor communication, which left Grieve and Link

without an understanding of how recalibrating

their sensors could lead to a serious flight control issue.

100 knots.

This accident didn't happen because of bad data.

Not because of bad software.

Not because of bad weather.

Not because of bad decision-making.

145 rotate.

FLOYD CARPENTER: It happened because of bad communication.

REBECCA GRANT: Well, in the end, safety is everything.

It doesn't matter if it's an airliner, a fighter jet

a space plane, or a stealth bomber.

Full power.

REBECCA GRANT: Safety is critical,

and safety depends on communication.

NARRATOR: The Air Force investigation underscores

the need for pilots to be kept informed about the technology

controlling their airplanes.

Do you really, really want to leave the defense

of your families, your children, your grandchildren,

to a computer?

Or do you want to leave it to the greatest asset

that we have?

And that is the human brain.

NARRATOR: In spite of being involved in the most expensive

aviation disaster in history, Major Ryan Link

and Captain Justin Grieve went on to have

successful military careers.

The B-2 fleet was back in the air two months after the crash.

The flight computer was redesigned

to prevent faulty airdata.

The procedure for using Pitot Heat instead of recalibrating

the sensors is documented in Air Force manuals

and technical documents.

There hasn't been an issue with faulty airdata since.

TONY MONETTI: Northrop produced an amazing aircraft.

And I commend them and the maintainers

and the aviators that continue to make

the B-2 the envy of the world.