All language subtitles for Mayday.S05E05.Invisible.Killer.1080p.AMZN.WEB-DL.DD+2.0.H.264-playWEB_track3_[eng]

A routine landing...

Ladies and gentlemen,

we are starting
our approach to DFW.

You're in good shape.

...turns
into a sudden fight
to the death.

You're going to lose it
all of a sudden.

There it is!

A passenger jet
mysteriously falls
from the sky

and rockets
towards a busy highway.

Push it up. Push it way up.

Delta, go around!

Hang on!
Son of a...

It's gonna crash!

A mysterious force
brings down a plane,

claiming 137 lives.

In the wreckage lies
the one clue that can stop it
from killing again.

August the 2nd, 1985.

Dallas, Texas.

It's a very hot day,
even by Texas standards.

See you all tomorrow.

Temperatures soar
to 101 degrees.

Rain coming.

Should cool things
down a bit.

In the late afternoon,

William Mayberry
is heading home from work.

The day's heat and humidity
are having an effect on traffic

at Dallas Fort Worth
International Airport, DFW.

Roughly the size of Manhattan,
DFW is the biggest airport
in the world.

It's also
one of the busiest.

The heat has triggered
some afternoon thunderstorms
at the airport,

creating a backlog
of planes waiting to take off.

American 631,
you are cleared for takeoff.

Air traffic controller
Gene Skipworth
is in the tower today.

He's been working there
for 14 years.

With him,
his controller, Mike Porter.

Skipworth was
not asking for help.

Nothing seemed unusual
other than the fact that

we were starting
to get busy

and aircraft
were starting to pile up.

One of
the many planes heading
towards Skipworth's control

is Delta Airlines Flight 191.

Weather is
6,000 scattered
to 1,000 scattered.

Visibility, 1-0.
Temperature, 101.
Wind, calm.

- A hundred and one?
- A hundred and one degrees.
Yes, sir.

Captain Ed Connors
and First Officer Rudy Price

are two of Delta Airlines'
most experienced pilots.

Second Officer Nick Nassick
is the other member
of today's crew.

The crew is flying
a six-year-old L-1011 TriStar.

The L-1011 is billed as one
of the safest planes in the sky.

There are 152 passengers
and 11 crew members on board.

They're scheduled to land
in Dallas just before
6:00 in the evening.

Good afternoon,
ladies and gentlemen.

This is your captain speaking.

Hope you're enjoying
your flight so far.

Traffic is backing up
at Dallas.

All total, we'll be about
10-15 minutes late
getting to the gate.

Please let us know if there's
anything we can do to make
your flight more comfortable.

The delay
bothers Chris Meier.

He's a frequent
business traveler
who's in a hurry

to get home to his family
for the weekend.

I'd been down
in Florida, Fort Lauderdale

for the last two weeks,

and it was
a Friday afternoon,

and I was due to go home
on Flight 191.

One of IBM's
best known executives
is also on the flight.

Don Estridge led
the development of
the IBM PC.

He and his wife
are traveling to Dallas
for a family visit.

963 turn right,
heading 620.

En route
from Florida to Texas,

Delta 191 will be
in communication

with several controllers.

...turn you into Blue Ridge,
it'll be about zero-one...

Every aircraft
is guided along its flight path

by a series
of regional air route
traffic control centers.

They direct each plane's
speed and altitude.

One-Niner-One, descend
and maintain one-zero-thousand.

Join the Blue Ridge,
010, radial and inbound.

We have a good area there
to go through.

Captain Connors
has some concerns

about the route
he's been given.

He sees a storm cell
along that path,

and he doesn't want
to fly through it.

Well, I'm looking at a cell
at about a heading of 2-5-5.

It's a pretty good-sized cell,

and I'd rather not
go through it.

I'd rather go around it,
one way or the other.

I've had about 60 aircraft
go through this area out here.
10-12 miles wide.

They're getting a good ride.
No problem.

Well, I can see a cell now,
about heading 240.

When I can,
I'll turn you into Blue Ridge.

It'll be about
the 0-1-0 radial.

0-1-0. Roger.

We're going to
hold you to that.

Captain Connors
gets his way.

He's given permission
to fly around the storm.

Once past it, he'll line up
for a landing
on Runway 17 Left.

I'm glad we didn't have to go
through that mess.

Friday afternoons
are a busy time at airports.

The afternoon rain
is making this Friday
even busier.

Twenty three-niner,
down to 6-18-96.

The main priority
for the controller on duty

is to keep the incoming planes
a safe distance apart.

He wants them at least
4.5 kilometers from
each other.

That distance allows enough time
for the violent air turbulence
behind one plane

to die down
before the next plane
touches down.

Right now, Connors and Price
are getting too close

to the plane
just ahead of them,

a corporate Lear jet.

Delta 191 heavy,
turn left ten degrees.

Reduce speed to 1-8-0.

To put some distance
between the two planes,

the controller asks
the Delta crew
to slow to 180 knots.

Delta 191...

330 kilometers an hour.

Wilco.

Ten degree flaps, please.

You're listening
to Dallas 105 FM.

It's a wet one
out there, folks,
so drive carefully.

Heading home
along Highway 114,

William Mayberry
will soon be passing DFW.

Flight 191 is now just
50 kilometers from
the foot of the runway.

Ladies and gentlemen,

we are starting
our approach to DFW.

Please make sure your seats
are in the upright position

and your seat belts
are securely fastened.

The crew begins
their final descent
into the Dallas Fort Worth area.

Attention,
all aircraft listening.

There's a little rain shower
just north of the airport...

Connors now switches
radio frequencies

and contacts a local
DFW airport traffic controller

for approach instructions.

As the passengers and crew
of Flight 191 prepare
for their landing,

a deadly force
takes shape in their path.

Critical decisions
and missed information
conspire against them.

The crew will soon be engaged
in a 47-second struggle,

which will become one
of the most important moments

in the history
of modern aviation.

August the 2nd, 1985.

The crew
of Delta Airlines Flight 191

has been skirting
a line of heavy storms

between Florida
and their destination, Texas.

Thirty kilometers from
the Dallas Fort Worth airport,

First Officer Rudy Price
notices rain ahead.

We're going to get
our airplane washed.

What?

We're going to get
our airplane washed.

It seemed like
the closer we got in to DFW,

the worse the weather got.

And we was turning in to the...

the rain
instead of going around it.

and the pilots
never said anything
about the bad weather.

Delta 191
is still closing in
on the Lear jet ahead of it.

Price and Connors need
to slow down even further

to put some distance
between the two planes.

Delta 191 heavy,
reduce speed to 150.

Speed to 150.

Nine kilometers
from Runway 17 Left,

Delta 191 is handed over
to another controller,

Gene Skipworth,
for final approach and landing.

Zero-nine-zero, at five...
Gusts to one-five.

Tower, Delta 191 heavy,
out here in the rain.
Feels good.

Delta 191...

Skipworth tells the crew

to expect
a manageable crosswind
of up to 15 knots.

Winds, 090 at five,
gusts to 15.

Thank you, sir.

First Officer Price
will be at the controls
for the upcoming landing.

Pilots and co-pilots
routinely alternate
flying duties.

As Flight 191
is coming in to land,

William Mayberry
is just north of the airport.

He's caught in the same storm
that Price and Connors

are just beginning
to fly through.

Before landing check.

- Landing gear?
- Down. Three green.

Flaps? Slats?

Thirty-three. Thirty-three.
Green light.

The crew
suddenly notices
that they'll be flying

into more than
a bit of rain.

Lightning coming
out of that one.

What?

There's lightning
coming out of that one.

- Where?
- Right ahead of us.

A thousand feet.
I'll call them out to you.

All right.

We're not getting
any bad warnings

from the weather, or from

other pilots, which we rely on
as they come through it.

Uh...

They...

They need to report to us,
and they do, if they have...

turbulence,
or they have trouble

on final, or ran
into anything abnormal.

The Lear jet ahead
of Flight 191 lands safely.

Connors and Price are now
less than a minute behind.

Without warning, the intensity
of the storm increases.

The L-1011 is being pounded
by a driving rain.

I knew we was
getting ready to land.

But at the same time,

you felt a surge.

Like the pilots was revving up
the engine for something.

The plane's
air speed is increasing
for no apparent reason.

Watch your speed.

Price pulls back
on the throttles
to slow the plane down

and maintain it
at the requested 150 knots.

The plane is just 180 meters
from the ground.

You're gonna lose it
all of a sudden.

There it is.

Then the plane
drops rapidly.

It's as though
an invisible force
is pushing it to the ground.

Push it up!

Push it way up!

Way up! Way up!
Way up!

The crew is
pushing the plane's jet engines
to their full power,

but can't get more speed,
or get the plane to climb.

So I pulled my seat belt
tight as I could,

but at the same time,
you could hear a pin drop.

Nobody was talking.

But I mean,
you got dead silence.

As suddenly
as it began,
the crisis seems to end.

The plane stops falling
and begins to pick up

some of the speed
Connors and Price
have been fighting for.

That's it.

But before the crew
can take another breath,
the plane drops again,

rocking violently
from side to side.

And then, it dips
wildly to the right.

And I just knew
we shouldn't be that close
to the ground that soon.

Hang on to the son of a--

About two kilometers
from the runway,
it plows into a field

and rockets
towards Highway 114.

When we hit the ground,
it felt like you was in a car

running over railroad tires.
It was real bumpy.

The crew
somehow manages to get
the plane back in the air.

At that moment, Gene Skipworth
catches sight of Delta 191.

He's gonna crash!

Delta, go around!

But it's too late.

The plane's engines slam
into William Mayberry's car

on Highway 114.

He is killed instantly.

The plane hits the ground again
north of the runway.

It's traveling more than
350 kilometers an hour.

I must have
caught sight of him just at
the last millisecond,

and he cartwheeled
into the tank
in just an instant.

And then, of course,
there was...

Fire. Not a ball of fire,
but a wall of fire.

It seemed like it was
only a few seconds.
Five seconds at the most.

I don't know how long it was.

We was...
Everything was stopped.

The resulting explosion
is so powerful

that the rear section
of the plane
is blasted backwards,

away from the fireball.

Then all of a sudden
you look up,

and it's just
nothing there.

It's...
Everything's gone.

You just see
the whole big picture outside.

Like the plane
just opened up.

Remarkably,
the tail section containing
the last ten rows of seats

is relatively intact.

People just thrown around
on the ground.

Some with clothes on,
some without clothes on.
Some were burned.

It was something that

you can't describe
unless you were there
to see it.

It is something that you will
never get out of your mind.

Help! Over here!

Hang in there.
Help's on the way.

Then,
as suddenly as it had started,
the rain stops.

It takes firefighters
less than a minute
to get to the crash.

And when I arrived
on the scene,

I truly believed
that there wasn't anybody

that had survived
this plane crash,

'cause there was just
devastation everywhere.

What I hadn't pulled up on
at the time,

was the wing section,
which is the portion

of the aircraft
that carries the fuel.

So there was
a large amount of fuel
and a large amount of flames.

The front of the plane
has all but disintegrated.

I knew
I had to get out there.

At the time, I was a stringer
for Time magazine.

Worked with them
on a part-time basis.

Called their
Atlanta headquarters for
this portion of the country.

They said one word. "Go."

Firefighters need
only a few minutes

to get the raging fire
under control.

They then turned their attention
to pulling survivors
from the plane.

It wasn't until
the fire started
to subside a little bit

that I saw the tail section

where there was some hope
of some people surviving.

There were these two women
that were walking
through the smoke.

Ladies! Ladies, clear the area.

Get out of the way.
Clear the area.

And it
kind of surprised me.

So I knew that there was hope
and that there were
people out there.

Only 27 people
survived the crash.

I had seen death before
as a medic in Vietnam.

But it had never
been aimed at civilians,

and certainly not
on a mass casualty situation.

And certainly not
this suddenly.

I could tell
how bad it was.

You could see and smell
and feel the death.

We felt like we did everything
that we could, and we were just,

you know, we were just pleased
that there were survivors.

I was scheduled to sit on...
off Seat 15A.

And I told them
that wouldn't be no good,

'cause that was
a non-smoking section.

I was a smoker,
so I had to be in back.

That probably
saved my life.

Captain Connors,

First Officer Price,

and Second Officer Nassick
are killed.

So are
five other crew members
and 128 passengers.

IBM's Don Estridge and his wife
are among the dead.

In the tower, there was silence
for probably one to two minutes.

Of the... Except for just
an occasional transmission.

But basically
it's just quiet

and you just
sit there stunned,

and wishing you could do
anything to take it back.

This is
a monumental crash.

Investigators from the National
Transportation Safety Board

arrive at DFW,
determined to find the cause.

One of our field
investigators would have been
on scene

trying to locate
the flight data recorder

and the cockpit
voice recorder,

which is a...

you know,
very important part
of the investigation.

Investigators begin
looking for evidence
of mechanical failure.

They examined the wreckage
for clues that the plane
was not responding

to the pilot's command.

It's essential...

in any approach,
or departure accident

to establish
what the airplane's
configuration was.

To assure that it was not
a factor in the accident.

But everything was normal
on this aircraft.

Investigators turn
their attention
away from the plane...

and to the skies.

After any accident

in commercial aviation,
there are theories galore.

A couple of them
prevalent that evening...

First, that lightning
had struck the airplane.

Secondly, that it had been
hit by a mini tornado.

There's lightning
coming out of that one.

Where?
Right ahead of us.

15 different witnesses
including flight crews

report seeing lightning
as Flight 191 was descending
towards the runway,

The investigators
have to consider
the possibility

that Flight 191
was hit by lightning.

Lightning is always something
that you have to investigate

to determine the possibility
that lightning disabled

some part of the airplane.

In 1963, a Boeing 707
was struck by lightning.

The lightning ignited
the fuel in the plane's tank.

The plane crashed.

Eighty-one people died.

There had been a handful
of similar crashes since then.

Key pieces of wreckage
from Flight 191

are taken to the NTSB lab
in Washington, D.C.

Bud Laynor is the investigator
in charge of examining
the wreckage,

as well as the data
from the plane's
cockpit voice recorder.

Sometimes to might be
very difficult to find,

to, to determine
where the airplane

might have been struck
by lightning and where
the exit point was.

Lightning coming
out of that one.

Where?
Right ahead of us.

If the plane
was hit by lightning,

there would be
evidence left behind.

A device called
a static discharge wick

is attached to the trailing edge
of an airplane's wings.

It redirects static electricity
into the outside air

instead of into the plane,
where the charge
could cause a fire.

If the plane
was hit by lightning,

one of the pieces
that would be
visibly damaged

is the static discharge wick.

Nothing there.

With lightning
ruled out, investigators
go looking elsewhere.

They would soon discover
the real culprit.

It had actually
been caught on tape.

A Delta Airlines L1011 crashes
after entering a storm
near Dallas.

One hundred and thirty-seven
people die.

Investigators rule out
mechanical problems
and lightning

as causes of the crash.

Nothing there.

The NTSB's Bud Laynor

turns his attention to the plane
just ahead of Delta 191,

the corporate Lear jet.

He learns that it was
less than a minute ahead,

and flew through
the very same storm.

After we had passed
about 5 miles

from the end of the runway,

we entered a rain shower.

What we thought was
a light rain shower,

it had turned out to be
the heaviest rain.

I've ever seen before,
or since.

In spite of the rain,

Rufus Lewis managed
to land his plane safely
on Runway 17 Left.

When we
broke out of the clouds,
we were high and hot.

So we had to use
all of the runway

at DFW Airport.

We landed,
we're able to turn off
at the end of the runway.

So why
was the much larger L-1011

unable to land
just moments later?

Delta 191 Heavy,
reduce speed to 150.

To put some distance
between Delta 191
and the Lear jet

the controller
had asked Price to
slow his plane several times.

When Laynor plots
the bigger plane's speed...

Then down to 150.

...he finds that it was coming
in to land at 150 knots.

Delta 191 heavy,
reduce speed to 150.

Investigators consider the possibility

that Flight 191
had been traveling
too slowly for a safe landing.

If you don't have
a lot of extra energy,

you don't have anything to trade
in case you get in trouble.

So it's... A lot of times,
in adverse conditions,

the pilots should...

they add another ten knots
for mom and the kids.

Crews don't have to follow

a controller's speed request
if they think it's unsafe.

Price did reduce his speed.

He knew this plane
extremely well.

He had actually helped
to rewrite the L-1011's
operating manual.

If the captain decided
that 150 knots was too slow,

they would have told
the controller it was too slow

and they wouldn't have flown it.

Laynor consults
the airplane's manufacturer

and interviews
other L-1011 pilots.

He concludes
that neither the controller

nor First Officer Price
made any errors
regarding speed.

Delta 191 heavy,
reduce speed to 150.

This plane should have
been able to land at 150 knots.

Speed to 150.

Bud Laynor
still doesn't know

what slammed Flight 191
into the ground.

But soon he finds the clues
he needs on the plane's
flight data recorder.

It logs every
adjustment pilots make
to the plane's controls.

The device also records
external elements

like temperature, wind speed,
altitude, and air pressure.

Whatever Connors and Price
were fighting,

there's a good chance
it left its fingerprints
on the flight data recorder.

This flight data recorder
gave us several parameters
we didn't have before.

Engine power,
longitudinal acceleration...

And those kinds of parameters

really enabled us to do
a more in-depth analysis.

The plane's
data recorder has documented

a combination
of rapidly shifting winds.

Then it shifts to a down draft.

In a matter of seconds,

the plane was hit
with strong winds
from the front,

then from above,
and then from behind.

There you have it.

For Bud Laynor,
that sequence
could only mean one thing.

A microburst.

A microburst
is a violent shaft of air
falling from a storm cloud.

Back in 1985,
few people knew more
about encounters

between microbursts
and airplanes
than John McCarthy.

If you're at the kitchen sink
and you turn on the water

and it goes straight down
and it splashes out
in all directions.

And that's
kind of what
a microburst is,

except that it is
extremely bad news

if you're an airplane flying
through it at low altitude.

A plane first faces
a strong headwind,
which lifts the plane skyward.

Then a downdraft,
which slams it
towards the ground.

Finally, the microburst delivers
its most dangerous punch,
the tailwind.

And you would get
a rapid descent,

a loss of lift
and a rapid descent
towards the ground,

and easily crash
the airplane.

A plane's wings
need a steady flow of air
moving over them.

That's what gives them
their lift.

By inhibiting that flow,
the tailwind reduces lift.

There's no better recipe
for a microburst

than the weather conditions
at Dallas Fort Worth

on the day of the crash.

It had been
extremely hot all day,

and hot air rises.

When that hot air meets
the cold moisture
in the storm clouds,

it cools instantly and rushes
violently back to earth.

A microburst.

It is a tiny thing.

Meteorologically speaking,
compared to a... a big storm,

or a snowstorm or a hurricane,
it's just a...
like a needle in a haystack.

At its maximum strength,
it's...

It's no more
than two miles across.

And it lasts
no more than 15 minutes.

So, if you look at that
little space and time window,
it's very small.

And so the probability
of hitting one is low.

The odds may be slim,
but planes do fly
into microbursts.

In 1975,
an Eastern Airlines flight

landing in New York
flew into a microburst.

It slammed the plane
into the ground,
killing 113 people.

Then, in 1982, a microburst
killed another 153 people

when it struck a Pan Am 727,
taking off from New Orleans.

It was clear that 136 people
on Flight 191

had become the latest victims
of a microburst.

Investigators had
their culprit.

Unbelievable.

And thanks
to Flight 191's
advanced data recorder,

they could paint a remarkably
accurate picture of it.

The killer had essentially
been caught on tape.

But what
the flight data recorder
doesn't explain

is how such an experienced crew
fell victim to a killer...

You're in good shape.

...they were
all trained to overcome.

When Laynor
compares the pilot's actions

to the actions
of the microburst,

Watch your speed.

He uncovers details
of a fight to the death.

A fight that the Delta pilots
almost won.

...lose it all of a sudden.

There it is.

He seemed to know
what he was going to hit.

Watch your speed.

The increase
in air speed prompted
First Officer Price

to reduce power to his engines.

Power that he would
desperately need
in just a few seconds.

You're going to lose it
all of a sudden. There it is.

When Price and Connors
entered the downdraft...

Push it up. Way up.

...they were
less than 250 meters
from the ground.

The captain knew
the characteristics
of a microburst.

He'd obviously been given
an introduction to wind shear

and microburst characteristics
in his flight training.

When Connors
and Price encountered
the microburst tailwind,

there was very little
they could do.

They had insufficient speed
and altitude
with which to maneuver.

If a pilot encounters
a strong tailwind
at 3,000 meters,

he can point his nose down
and dive to pick up speed
and generate lift.

It's called trading altitude
for airspeed.

But that trade wasn't available
to Price and Connors.

They were just 150 meters
off the ground
when the tailwind struck.

The only way for them
to gain airspeed
was from their engines.

Push it up! Way up!

Co-pilot responds,
the airplane stabilizes.

I can say that
most pilots would say,

"Well, we're through
with that," and...

it's going to...
Rain's going to stop.
We're gonna land.

Momentarily,
their efforts seem to pay off.

Their air speed increases,
their plunge is halted.

But with Flight 191 less than
150 meters from the ground,

this particular microburst
delivered the ultimate blow.

A fierce crosswind
that forces their plane to bank
dangerously to the right.

Turn the son of--

Combined with the microburst's
other winds,
the crew was defenseless.

TOGA!

TOGA is Take Off,
Go Around mode.

And what it means to a pilot

in that regime of flight

is, first,
abandon the approach.

We're no longer going
to try to to land this airplane.

We want to do everything
we can now to survive

the wind condition
that we've entered.

The skill
and experience of the pilots

were no match
for this microburst.

It was too big,

it's winds too powerful
and unpredictable.

The entire fight
lasted only 47 seconds.

The pilots
of Delta Flight 191

did their very best
to recover from this situation.

And it didn't work out.

Investigators were left with one
perplexing question.

Why had Connors flown
into the storm
in the first place?

Prior to 1985, the radars
on board the aircraft

were built
to detect thunderstorms.

191...

Essentially, heavy areas
of precipitation.

They were not effective,
they were not even designed
to detect a microburst.

So those radars
were essentially useless
at low altitudes

for looking into
microburst phenomena.

Microbursts are invisible,

but they generally emerge
from storm clouds.

That's why pilots are trained
not to fly into storms
if they see lightning.

It's
a pretty good sized cell.

And I'd rather not
go through it.

I'd rather go around it
one way or the other.

When I can,
I'll turn you into Blue Ridge.

It will be about 010 radial.

010. Roger.

Captain Connors
was not a risk taker.

He was known
as a cautious pilot.

I'm glad we didn't have to
go through that mess.

It's hard to blame
the air crew.

Their job is
to avoid thunderstorms, and...

There's probably a forecast
for thunderstorms every day
at Dallas in the summertime.

Which ones do you avoid?

And it's, you know...
It's a very difficult problem.

Earlier in the flight,
Connors had flown
around bad weather,

Investigators can only conclude
that he underestimated

the storm in his path
at the foot of Runway 17 Left.

When you're
in a landing sequence

at an airport like Dallas
or Atlanta, or Chicago,

and you see
other airplanes ahead
that are landing uneventfully,

you might get
the impression that
there's a thunderstorm there,

but I'm going to pass
through it very quickly

and it's not gonna be
a factor for me.

Airports like DFW

have sophisticated systems
in place to provide
weather information to pilots.

A thunderstorm
at the end of a runway

is the kind of threat
they were designed
to identify.

But this deadly storm
managed to foil
those systems.

As Flight 191
was approaching the airport,

the weather at DFW
was changing very quickly.

Attention,
all aircraft listening.

There's a little rain shower
just north of the airport.

Captain Connors heard
that part of the message,

but then he switched
his radio frequency

for his final
landing instructions.

The Delta crew never heard
the last part of this message
about weather ahead.

There's a little
bitty thunderstorm
sitting right on the final.

There was an observation
two minutes before the accident

that there was a wall of water
at the threshold of the runway.

It's been my contention
that that information

would have been very important
to the flight crew.

Radar readouts from
the day of the crash indicate

that the storm cell
Connors and Price flew into

grew out of nothing
in a matter of minutes.

This is two minutes
before the accident.

The readout shows
the beginnings of a weather cell

at the foot of Runway 17 Left.

This is three minutes
after the accident,

that we have a new cell

right at the threshold
of the runway

that wasn't evident
in the previous picture.

This explains
why Rufus Lewis was able
to land his Lear jet.

The microburst was just
beginning to form when he was
approaching the runway.

Many people think that there was
a huge vertical development

that the pilots recognized,
and they just decided

to go fly through it anyway,

and I maintain,

and I think
the evidence proves it,

that that was not the case.

They didn't recognize this,

this new developing cell.

They did get into the storm
beneath the cell.

But it was heavy rain.
They weren't worried
about that.

Then the hammer fell.

It was too late.

It's small,
it's the length of a runway,
roughly,

and it doesn't last
very long.

So, it's something
that can happen so quickly

that many accidents
have occurred because nobody
knew it was there.

The storm arrived
at the foot of Runway 17 Left
virtually unannounced,

but once there,
it attracted
a lot of attention.

Pilots on the ground,
as well as trained
weather observers,

saw the worsening storm,

but they all saw it
too late to warn the crew
of Delta 191.

The storm did show up
on a radar screen

at the Fort Worth Air Traffic
Control Center.

But at the time of the crash,

the meteorologist on duty
was in the cafeteria,

on a meal break.

If the flight crew
had had any idea

that there would be
a severe event
in front of them,

they would have missed
the approach.

Investigators conclude
that the Delta crash

was caused
by the pilot's decision

to continue their approach
into the storm.

A decision that was made
because the crew wasn't warned
about the hazard.

In 1985, there were
basic systems at airports

that could detect
dangerous winds,

but they could not reliably
detect a microburst.

On the ground,
there were systems

called low level wind shear
learning systems,

that primarily looked
for differences of wind speed

around the airport,
on the airport.

Unfortunately, these sensors
tend to be spaced so far apart

that a microburst could
actually exist in between them

and escape detection,
or at least detection in time

to warn a pilot of a threat.

But a microburst
detection system

to overcome this problem
had been developed.

It was being tested in Denver
and working very well.

What we found out
is that Doppler radar,

which is on the ground,
is incredibly effective

in detecting microbursts,
and in fact, it can detect

about 98% of a microburst.

Conventional radar
uses radio waves to measure
precipitation inside a storm.

Doppler also sends out
radio waves.

But by measuring the frequency
of returning waves,

Doppler can also calculate
the movement of the winds
inside a storm.

And if you look
through the Doppler radar,

you see a part of it
that's going away
from the radar,

and a part
that's coming
towards the radar.

And if it's small,
It's absolutely
a microburst.

It can be nothing else.

So it has what we call

an unambiguous signature
of a microburst,

which means we got it.

Since Doppler radar
could see a microburst,

controllers could use it
to warn crews
of their presence.

The Denver research resulted
in an important new system
at airports.

Terminal Doppler Weather Radar.

When the system detects
dangerous conditions,

it relays a warning
to air traffic controllers...

who can then alert pilots.

Flight 236, microburst alert.

Five-zero knot loss,
one mile final. Say intentions.

After the crash
of Delta 191,

The Federal Aviation Authority,
the FAA,

hurried to install
Terminal Doppler Weather Radar
at high risk airports.

Dallas Fort Worth
was one of the first.

The domes containing
the specialized radar

are now a common fixture
at major airports
around the world.

But radar on the ground
can't get the warning
to the pilots fast enough.

We also have an issue
of ground-based systems
in that

it takes time to communicate
the threat to the crew.

The system has to detect it
on the ground.

It would typically go
to a control position

in the control tower,
and be relayed by voice
to the pilot,

which can introduce a delay
of 10, 15, 20 seconds,
which could be very critical.

Planes also needed
on-board microburst detection.

A team from NASA
began developing
such a system

by flying into
the most dangerous microbursts,
they could find.

LANGLEY CO-PILOT:
Here we go. Here we go.

By risking
their own lives,

they would eventually save
thousands of others.

Delta Airlines Flight 191

is the latest
in a string of crashes
attributed to a microburst.

Since 1964,

microbursts were shown
to be the cause of 26 accidents

claiming more than 500 lives.

The public is unnerved.

Politicians are demanding answers.

The killer has to be stopped.

The body count is building,

and this ca...
this particular crash
tipped the scales

as far as
the federal government
was concerned.

The crash of Delta 191
showed that seconds count

when planes
encounter a microburst.

We're gonna lose it
all of a sudden.

There it is.

Increasing alert times...

Push it up!

...could save more lives,

especially if
a microburst detector
was mounted right on the plane.

If you can provide the airplane
with 10, 15, 20 seconds

of advanced warning,
pilots push the throttles up,

they build air speed,
they build altitude,
they build energy.

It's like money in the bank.

By the time
they get to the microburst

during a recovery,
they can survive.

Aviation experts
had to find a way
to give all pilots

those critical 20 seconds.

To develop that technology,

they would embark
on a high-risk,
unprecedented research project.

They would fly a 737
into the most severe microbursts
they could find.

We did a very careful
risk analysis

of all the possible dangers
that could occur.

And initially, you know,
the first reaction was,

"You want to do what
with an airplane?

"You want to fly it
through a microburst?"

In the summer of 1991,

NASA modified a Boeing 737

and went hunting
for microbursts.

The idea was to identify
onboard technology

that could warn pilots
of a microburst
in their path.

The airborne solution
brings detection
right into the cockpit,

so the pilot sees
exactly what's in front
of the aircraft,

and when the alert is given,
there's no time delay.

230...
Ground speed 234...

The NASA researchers
were testing
three separate systems

for detecting microbursts.

Modified Doppler Radar
housed in the 737's nose,

a laser radar
under its forward cargo bay.

and a side-mounted
infrared device

to measure changes
in air temperature.

Each of those systems
was wired to banks of computers
in the plane's cabin.

A spotter on the ground
could find a microburst

and quickly direct
the plane towards it.

Roger, Control, 515.

We're rolling.

Roger,
we understand your roll.

C-D-W-R NASA Control.

- Range.
- Range, 45 miles.

Ground speed, 240.

- Here we go.
- Take it straight ahead.

Take it up left about
10 degrees, 15 degrees.

Well, when you
spot a microburst,
it was all business.

It was, "How do we get there?
How do we get
to the right altitude,

"the right airspeed,
the right position?

"When to begin
data collection?"

So people were quite busy
during these flights.

Yeah, it was exciting.
We wanted to find them.

We wanted to
penetrate them.

With every microburst,

the three onboard
detection systems
were put to the test.

Researchers on the plane
could instantly see

which instrument was doing
the best job of picking up
the microburst ahead.

Behind the flight deck,

we had palettes
of equipment

where the radar engineers,

the laser engineers,
the data recording engineers

could sit and ensure
that each system was
performing as expected.

Ground speed, 234.

Dead ahead,
maybe one degree to the left.

- Let's go straight
through this one.
- Here we go.

Take it straight ahead.

We started with
very, very weak microbursts.

Again, we had
the ground-based radar

telling us
what we were about
to go into.

So we started
with very weak microbursts,
gained experience,

then gradually worked up
to stronger and stronger ones.

You would see the rain
begin to fall and you would feel
a sinking feeling.

It'd be a little settling,
a little like
an elevator starting down.

A few minutes here
before we touch down,
what you see...

So any apprehension that
the crew may have had initially
about going through them,

was actually replaced later
with joy at finding them.

LANGLEY CO-PILOT:
Here comes the center
of the target, right...

now.

Two hundred and forty-two
on the ground speed.

Wind's gone away.
Look for a tailwind.

I'm watching.

Lost some altitude
there, too.

There.
The wind's gone around
the tail at 10 knots.

Good, strong, downdraft
in the middle of it.

Just sucked 100 feet
in almost no time at all.

A good performance
decrease, too.

We were about 850
and we dropped to 750.
Beautiful.

The Langley
researchers flew
into dozens of microbursts

over the course
of their research.

The project proved

that the forward-looking
Doppler Radar
was the only system

that could consistently
give pilots advanced warnings
of a microburst ahead.

What we found was that
the Doppler radars

could detect
an extremely wide variety
of microbursts.

Lightning coming
out of that one.

If the crew
of Delta 191 had a system
to warn them of microbursts,

they could have boosted power
to their engines
and started climbing

before they encountered it.

That might have given them

the speed and the altitude
which they sorely lacked

when they began their battle
with the storm.

The Langley flight tests had,
in effect, tamed
the microburst menace.

After the NASA tests,

the FAA certified
a Doppler-based warning system
for planes.

Today, Forward Looking
Doppler Radar
is standard equipment

on commercial flights
around the world.

The good news out of all
of this tragedy is

so many things
have now happened,

from radar
to ground-based systems,
to airborne systems

and especially
to training for pilots,

we think
that microburst accidents

are a thing of the past.

If there is one crash
that we can look back on now

and say,
"This made things safer,
because we learned from it."

It was Delta 191.

The changes made
after the crash of Delta 191

have saved countless lives.

Captain Connors
and First Officer Price

lost their fight
against a microburst.

But their struggle did manage
to expose and disarm

an invisible killer.