Original subtitles

Narrator: Two months after 9-11...

Pilot: Get out of it! Get out of it!

Narrator: A passenger jet...

Man: The house started vibrating.

Narrator: Slams into Queens, New York.

Man: The whole street was covered in flames.

Narrator: 265 people are dead.

Man: What the hell happened?

Woman: I will never forget this.

It looked just like september 11th.

Rudy giuliani : We asked for air cover,

new york city has that.

Narrator: Many fear the crash is no accident.

Woman: Everybody thought it was a terrorist attack.

Man: This was probably the most complex investigation

that I had ever directed.

It came in fast and steep.

Let's hope it's not what we think.

Flight attendant: Ladies and gentlemen, we are starting our approach.

Pilot: We lost both engines!

Flight attendant: Put the mask over your nose.

Emergency descent.

Pilot: Mayday, mayday.

Flight attendant: Brace for impact!

Controller: I think I lost one.

Man: Investigation starting...

Man: He's gonna crash!

Narrator: November 12, 2001.

It's the veterans day holiday in the united states--

a day off for many.

But at new york's john f. Kennedy airport,

it's another busy day.

American airlines flight 587 is carrying 251 passengers

en route to the caribbean.

Woman: I always pack too much.

Narrator: The crew is preparing the plane for takeoff.

Pilot: Your leg. You check the rudders.

Pilot: Rudders, check. Ok.

Taxi checklist is complete.

Narrator: Captain ed states is a former military pilot

who joined american airlines sixteen years ago.

Ed states: Bleeds...on.

Pilot: Temperature check.

I'm just gonna double check the winds here.

Narrator: First officer sten molin

will be the pilot flying today.

Sten molin: 101.1.

Winds checked.

He and the captain had flown together quite a bit before

and liked flying together,

so in that aspect, this was a normal trip.

States: Takeoff data set.

Controller: American 587,

follow japan air boeing 747 ahead.

Molin: Follow japan air, american 587.

States: Well, ladies and gentlemen,

at long last we're number two for takeoff.

Immediately after takeoff,

we will be in a left-hand turn heading for the shoreline.

In about two or three minutes it'll be our turn to go.

Narrator: Flight 587's flight plan

takes it out over new york's jamaica bay

before heading south to the dominican republic.

Everyone on board

is looking forward to swapping the bleak november weather

for the heat of the caribbean.

One passenger has even more reason to be thankful.

Two months ago, on september 11th,

hilda mayor survived the attack

on new york's world trade center.

She was working on the ground floor

when terrorists flew two airliners into the twin towers,

killing more than 2,500 people.

Barry mawn: 9-11 was perhaps--

well, not perhaps-- was the biggest terrorism event

that had occurred in u.s. Territory.

Lois shorr: September 11th was a day

that I don't think anybody who lives in new york

will ever forget.

It was a day that changed not only the city,

but the whole world.

I think everybody was in a total state of shock,

and I think that shock lasted

for months and months and months.

Controller: American 587, kennedy tower.

Caution, wake turbulence runway 3-1 left.

Taxi into position and hold.

States: Flight attendants, prepare for takeoff, please.

You have the airplane.

Brenner: The captain indicated

the first officer would be the flying pilot on this leg.

The captain designated him to fly the flight.

That's routine.

It's the captain's choice.

Controller: American 587.

Runway 3-1 left, cleared for takeoff.

Narrator: The first officer asks about their distance

behind the plane that just took off.

Molin: You happy with that distance?

States: Ah, we'll be all right once we get rolling.

He's supposed to be five miles by the time we're airborne.

That's the idea.

Molin: So you're happy.

Lights?

States: Yeah. Lights are on.

Molin: Takeoff checks complete.

I'm on the roll.

Thank you, sir.

Brenner: They perform the takeoff.

It's all done professionally.

It's all done by standard procedures.

States: V-1.

Rotate.

Narrator: Flight 587 lifts off at 9:14 a.m.

Controller: American 587, heavy.

Climb and maintain 1-3,000.

Narrator: In the homes below, residents of queens, new york,

hear the familiar sound of jets overhead.

Jason shorr: Planes, you know, take off and land.

They fly right over the peninsula every 45 seconds.

It was just a normal thing.

Narrator: A patch of turbulence rocks the plane.

Hilda mayor: Oh, boy.

Molin: Max power.

States: You all right?

Molin: Yeah, I'm fine.

States: Hang on to it. Hang on to it.

Molin: Let's go for power, please.

Narrator: 2,300 feet above the ground,

disaster strikes.

Mayor: Oh, my god! Oh, my god!

Narrator: The plane is losing altitude

and falling out of the sky.

Molin: Holy crap!

Narrator: There are over 68,000 pounds

of flammable jet fuel on board.

States: What the hell are we into?

Narrator: And the plane is heading straight for the houses

of queens, new york.

Jason: The sound at first

was just a normal airplane flying above.

I was still in bed,

kind of half sleeping, half awake.

As it started to get louder,

that's when you felt a little vibration.

Mayor: Oh, my god!

Molin: We're stuck in it!

Pilot: Tower, look to the south.

There's an aircraft crashing.

Controller: Airplane going down.

States: Get out of it! Get out of it! Get out of it!

Jason: The house started vibrating very heavily.

You know, this all happened really quick.

Narrator: The fuel ignites a massive fireball,

engulfing several homes.

Jason: The plane crashed

pretty much like in the backyard and the street,

exploded.

My whole window was bright orange...

Really loud, really bright.

I just jumped up looking for my glasses

and pretty much, with my dad,

ran out to the front of the house.

Controller: Are you missing any flights?

American airlines flight 587.

Jason: We ran out the front door.

All I could see, 'cause I didn't have my glasses,

I couldn't find my glasses...

The whole street was covered in flames.

My whole side of my house was covered in flames,

and there was just black smoke billowing up like really high.

What the hell happened?

I remember looking back into my house,

and the whole kitchen area was just black.

It was all thick black smoke already.

Narrator: Fire rips through the quiet neighborhood,

and a city still in shock from the events of 9-11...

Man: It's a plane!

Narrator: Is plunged back into fear and chaos.

Man: I see my eyes and I scream, "everybody go out!"

Officer: Just back up.

Man: It looks like a war zone.

Narrator: Jason's mother, lois, is driving to work

when she gets the most terrifying call of her life.

Lois: My husband was screaming hysterically

into the phone, "the house is burning down!

The house is burning down! Come home!"

And in those moments, I went into a state of panic

thinking I didn't know where jason was.

I drove towards rockaway, and I will never forget this.

It looked just like september 11th.

All I saw was the black smoke and the flames

for what looked like a mile.

The whole area looked like it was on fire.

Then I realized that my house was like gone,

and I was just in...i can't...

I was in total shock.

Jason: We're over here!

Lois: I heard mark and jason scream, "we're over here,"

and I turned around and I saw them,

and I ran over and I almost fainted.

Then I remember screaming to them, "what happened?"

And they're telling me a plane crashed.

Narrator: The horrific scene

seems to echo the events of september 11th.

All 260 people on board the plane are dead,

as well as five people on the ground.

Lois: Everybody thought it was a terrorist attack.

Narrator: Many people fear the worst.

New york mayor rudy giuliani tries to reassure the public.

Rudy giuliani: Just talked to president bush

and we talked to his chief of staff.

We asked for air cover, new york city has that.

The airports have been closed for a while,

and I talked to the governor and just as a precaution,

we're gonna close the bridges and tunnels for an hour or two.

Lois: I thought it was a terrorist attack

'cause I couldn't imagine a plane

just falling out of the sky.

Why would anybody want to crash a plane into rockaway?

Narrator: For the second time in two months,

new york airports are closed.

All flights are grounded,

stranding thousands of terrified passengers.

Fearing the crash is another act of terrorism,

the fbi immediately sends a team of agents to investigate.

Mawn: Send anyone who saw what happened over to me, ok?

Narrator: Barry mawn is the assistant director

of the fbi's field office in new york city.

Eight weeks earlier, he was at the scene

when the world trade center collapsed.

He pulled his team out

just before the twin towers came down.

Mawn: We were still heavily involved

in the investigation of 9-11,

so when I heard about it,

I immediately got concerned

as to was this another terrorist attack?

Narrator: But the fbi isn't working alone.

This is first and foremost a plane crash.

President george bush: This investigation is being led

by the national transportation safety board

to make sure that the facts are fully known

to the american people.

Narrator: The ntsb sends its own team of experts to queens.

They face a daunting challenge:

A passenger plane and four houses demolished.

Man: Mawn.

Narrator: The two agencies are searching for clues

that are going to be very hard to find.

Robert benzon: This was probably the most complex investigation

that I had ever directed.

Narrator: Robert benzon is a 17-year veteran of the ntsb.

He's investigated 30 major accidents.

He's in charge of a team of 21 investigators.

Benzon: We like to think

we enter any investigation with an open mind,

but we're all human beings,

and this accident occurred so close to the tragedy of 9-11

that we naturally jumped to conclusions,

and we had to force ourselves to back up

and carefully study the evidence.

Make sure it's all in one place.

Murphy, how are ya?

Inspector murphy, agent mawn, fbi.

Narrator: Investigator brian murphy

is the ntsb's structures and materials expert.

He's a veteran of many crashes,

but this one hits close to home.

He has close ties to this neighborhood.

Brian murphy: I hadn't given it much thought

until i'd seen the church where we'd buried

both my grandfather and my grandmother--

st. Dennis's right there, so...

And it came back--when I walked over to 129th street,

I remembered, you know, being a kid,

and my cousins and I were all there.

Narrator: This neighborhood,

though far removed from lower manhattan,

has a deep connection to the 9-11 attacks.

Lois: There are a lot of firemen and policemen

who live in this community,

and a lot of the firemen did respond september 11th,

and a lot of the firemen were killed.

Benzon: It came in fast and steep.

Let's hope it's not what we think.

Narrator: The ntsb and the fbi

will work the crash site together

until one important question is answered.

Was this terrorism or was it an accident?

Murphy: Airplane parts go in the bins.

Everything else stays here for now.

Narrator: The crash site is a chaotic mixture

of household debris and plane wreckage.

Sorting one from the other is a difficult task.

Murphy: Sorting between home and airplane has to be done.

I don't want to take all of the five homes home with me

to sort through.

You want to try and do as best a job you can

while you're on site

to make sure you isolate airplane,

and you also don't want to leave any airplane behind.

Definitely not from our plane. Thanks.

Benzon: We've been doing this a long time, of course,

and we can recognize an airplane

by only looking at about 10% of it.

But to a layperson,

the destruction of the fuselage and the wings was so great

that I would venture to say

a layperson would have trouble recognizing it

as an airplane crash.

Narrator: Flight 587

crashed into a densely populated neighborhood.

Hundreds of people saw the plane come down

and are eager to tell their story.

Woman: I heard a noise, I looked up in the sky,

I saw a plane, I saw fire coming out of it.

Man: The plane blew up in half.

It blew in the air.

Jason: I was half asleep.

It's...it's the sound that got me up.

It was real loud.

Narrator: Witness reports fuel concerns

that this was a terrorist attack.

Mawn: Some of the witnesses were saying

they saw the plane explode in the air,

that they saw a huge fireball,

and it's sounding like it had been a bomb on board.

Narrator: If there was a bomb,

there should be evidence of it in the debris.

Mawn: Experts would be physically examining

all of the parts of the plane

to see if there was any indentations

or outward movement of the plane,

indicating that the explosion was inside

and pushed everything out.

Any chance this plane exploded from the inside out?

And they weren't finding any of that.

Narrator: The twisted metal reveals

no evidence of an explosion.

But there are other signs to look for.

Mawn: They would be looking for any explosive residue

in any parts of the plane,

which usually tells us that this occurred

because of an explosion.

Narrator: Investigators take swabs from the debris

and send them to be tested for explosive material.

Mawn: We did a number of other things, too.

We went over to the airport

and we talked to the baggage handlers,

we talked to the airline personnel.

You know, did they note anything suspicious

pertaining to the passengers on this flight?

Narrator: The two agencies could soon get the answers they need.

Within a day of the crash,

searchers find both the cockpit voice recorder

and the flight data recorder.

Benzon: Hallelujah.

Now let's see what secrets those boxes hold.

Narrator: While investigators wait

for the data to be downloaded,

they continue examining the wreckage for clues,

but not all of it is at the crash site in queens.

Benzon: We found the vertical stabilizer

miles and miles away.

Narrator: The vertical stabilizer

has been found in jamaica bay,

between the airport and the crash site.

The location tells investigators

it broke off while the plane was still in the air.

Benzon: So, that was a good first step for us.

Narrator: The vertical stabilizer

is part of the tail.

Along with the horizontal stabilizer,

it's critical for stable flight.

Benzon: The horizontal stabilizer

and the vertical stabilizer

are almost like feathers on a dart.

They keep the aircraft going in a straight direction.

Brenner: You can't fly without a tail.

I mean, you can't.

The airplane's gonna go down.

There's nothing you can do about it.

Benzon: Get that tail to the hangar

so we can get a good, close look.

Narrator: To seasoned air crash investigators,

the discovery hints

that terrorism did not cause the crash.

Benzon: The fact that we saw early on

the vertical stabilizer separated from the wreckage

by many miles,

led us to an initial hope that it wasn't a terrorist act

because it would be very difficult for a terrorist

to manage to blow the vertical stabilizer

off of an aircraft.

Narrator: Ntsb investigators

are under pressure to find answers.

If this wasn't an act of terrorism,

there could be a flaw with the a300,

one of the world's most popular planes.

It's a frightening prospect.

Benzon: That caused us, in our minds,

to accelerate the pace of the investigation a bit,

because the aircraft was not grounded.

We had reason to do the investigation

thoroughly but quickly.

Let me see rudder, airspeed,

and yaw in real time.

Narrator: Investigators pin their hopes

on the flight data recorder.

They immediately notice something unusual.

Benzon: Look at these rudder inputs.

Narrator: The rudder helps pilots turn the plane

by deflecting the oncoming air.

The more it pivots, the more the air is deflected

and the sharper the turn.

Benzon: What is going on?

From the flight data recorder, we discovered that the rudder

had been moved back and forth rapidly several times.

We didn't know why.

Could have been caused by the pilots--

one or both, perhaps, reacting to something.

We had to keep an open mind until we had more evidence.

Narrator: Investigators are intrigued.

It looks like the pilots

were having trouble controlling the plane

during the last 30 seconds of the flight.

A few seconds later,

the plane pitches down suddenly and accelerates.

The dramatic motion can only mean one thing:

This is the moment the tail came off the plane.

Benzon: Here they go with the rudder,

and then seven seconds later, the stabilizer snaps off.

I don't get it.

Narrator: Investigators hope

the plane's cockpit voice recorder

will tell them why the pilots were having so much trouble

controlling their plane...

Benzon: We ready to go?

Narrator: And why the plane's tail came off in midair.

Benzon: The cvr is an amazing device.

It's a digital tape recorder

that records all noises in the cockpit

and noises, even some outside the cockpit.

Narrator: They listen to the last few moments of the flight.

If a bomb brought down the plane,

they should hear the sound of the explosion.

States: A little wake turbulence, huh?

Molin: Yeah.

Narrator: Investigators listen

as the pilots discuss hitting the wake from another plane.

It seems molin wants more speed to help them fly through it.

Molin: 250 knots. Thank you.

Max power.

States: You all right?

Molin: Yeah, I'm fine.

States: Hang on to it.

Narrator: The investigators listen

for the sound of an explosion.

Benzon: We heard loud pops and snaps,

an especially loud noise.

Benzon: 15:58. That's the tail coming off.

Narrator: They match the timing of that sound to the fdr data.

Benzon: And we could pinpoint exactly to the second

when the vertical stabilizer came off.

Molin: Holy crap!

What the hell are we into?

We're stuck in it!

States: Get out of it! Get out of it! Get out of it!

Benzon: Onboard explosions also have a distinct sound pulse.

I didn't hear anything that sounded like a bomb.

And we didn't hear that on the cvr.

Narrator: There's nothing on the recording

to indicate a bomb exploded on the plane.

Not only that,

but lab results confirm

there's no trace of explosives on any of the debris.

Mawn: No signs of an incendiary device being on board,

no claims of credit,

no suspicious activity either at the airport

or even with the passengers themselves.

Benzon: Nothing on the flight recorder.

No explosions.

Mawn: This was in all likelihood

either a mechanical error or a pilot error.

I'm not surprised.

It seems consistent with what we're finding.

Once determination is made that it's not a criminal matter...

Let's wrap it up, guys. We're done here.

Then we totally go away, actually.

Narrator: The fbi leaves the investigation

in the hands of the ntsb.

Benzon: Once we could eliminate a terrorist act,

then the investigation took on a different focus.

We were sure now it was an aircraft accident.

Benzon: Alright, back to the wreckage.

Let's figure this thing out.

Narrator: Investigators are faced with a puzzling question.

Benzon: How does a vertical stabilizer just fall off?

I'd been investigator in charge with the ntsb

for, at that time... Oh, gosh, 20 years or so,

and I had never seen anything quite like this.

Narrator: Investigators study the vertical stabilizer

recovered from jamaica bay.

They look for any clues that might explain why it broke off.

Brenner: Here's a case where the vertical stabilizer failed

during a routine flight.

And it's a very rare event,

and we're trying to understand

what are the factors involved in it.

Narrator: As they take a closer look

at the edge that broke away from the rest of the plane,

they make a surprising discovery.

Murphy: The fitting just ripped apart.

Narrator: The vertical stabilizer

is attached to the plane mainly by three pairs of fittings.

For some reason, they all failed.

It's a confounding discovery.

The stabilizer is made of a modern composite material

that's designed to be stronger than steel.

Perhaps its strength has been overestimated.

Benzon: It was actually the first accident

that we had investigated

where a large composite component had failed,

so that became a question in our minds.

Narrator: Composites are made

by fusing more than a hundred layers

of carbon and glass fiber.

Because they're both strong and lightweight,

they're increasingly common in aircraft designs.

Murphy: On almost all aircraft

you're gonna find some type of composite material

on that airplane somewhere.

Narrator: Industry manufacturers

plan to increase the use of composite materials

for new aircraft.

But if composites can fail so easily,

it could jeopardize the lives of thousands of people

and cripple the airline industry.

Benzon: If it was a structural failure,

it would affect not only the accident aircraft,

but the entire airbus a300 fleet,

so if there was a design flaw in the aircraft,

we needed to know that very, very quickly.

Narrator: Investigators comb through

the manufacturing records of the downed a300.

They discover some disturbing information

about the stabilizer mounts.

Murphy: An investigation

of the early manufacturing build records

from this vertical stabilizer

did reveal that after it went through its inspection,

it actually was noted and determined

that there was a large delamination.

Narrator: Delamination

is the separation of the hundreds of layers

which make up the composite.

In other words, the material literally begins to peel apart.

Murphy: You would see a reduction

in the strength of the overall piece of structure,

quite possibly due to that delamination.

Narrator: Airbus had to repair the part

before the plane was delivered to american airlines.

If the laminate failed before, perhaps it failed again.

Murphy: What you're worried about

in your composite structure

is barely visible impact damage...

Cut it here. Send it to the lab.

Damage that's not able to be seen by the naked eye.

Narrator: Investigators study

microscopic scans of the composite material,

looking for evidence of delamination.

Murphy: It looks fine to me.

Narrator: They come up empty.

There's no sign that the composite is peeling apart.

If the material wasn't the problem,

then perhaps it's the design of the mounts that's faulty.

Murphy: Now that we know the material system is ok

and that there are no manufacturing defects,

you know, now we have to make sure,

well, did they miss it?

Did airbus drop the ball,

and the tail was just under-designed from day one?

Narrator: The vertical stabilizer

must withstand huge forces

when the rudder deflects fast-moving air in flight.

To test the design of the stabilizer mounts,

investigators enlist the help of the manufacturer.

Murphy: Airbus was a great party to the investigation.

They were very eager to get an answer,

very eager to defend their product.

Benzon: Alright, ready to start the test?

Let's go.

Narrator: Investigators want to know

if the fittings can really withstand

100,000 pounds of force,

as they're meant to.

Benzon: Stop it there.

100,000 pounds and holding.

So far, so good.

Narrator: The fitting has met its design requirements.

Benzon: So this, in essence, confirmed the fact

that the design of the vertical stabilizer attach points

was good.

Narrator: But the test isn't over.

Benzon: Let's keep going.

Narrator: Investigators apply more pressure.

Benzon: That's 150,000.

Narrator: They want to know

exactly how much force it must have taken

to snap the tail on flight 587.

Benzon: Let's keep going.

Narrator: In dramatic fashion, they have their answer.

Murphy: At the time the vertical stabilizer failed,

the right rear lug was experiencing a load

of about 200,000 pounds of force.

Narrator: That's twice the force

that the mounts were designed to handle.

Benzon: So what would cause that kind of pressure?

Narrator: Somehow, more than 200,000 pounds of pressure

ripped the tail fin from the plane...

A force far stronger

than anything an a300 should normally encounter.

Benzon: We knew, of course,

from listening to the air traffic control tapes

that the accident aircraft took off

a minute and a half or two minutes

after a jal, japanese airline boeing 747.

States: A little bit of wake turbulence, huh?

Molin: Yeah.

Brenner: The captain says, "a little wake turbulence, huh?"

Molin: Holy crap!

Narrator: Could that turbulence have been strong enough

to tear the tail from the plane?

States: What the hell are we into?

Narrator: Wake turbulence

is caused by the movement of air over and under the wing.

When the two streams of air meet at the wing tips,

they combine to create a powerful vortex

that trails behind the plane.

Benzon: So you can almost imagine two tornados

coming off the wing tips of an airplane.

The effects of wake turbulence vary

upon the size of the aircraft encountering the turbulence.

Narrator: Small planes face the greatest risk,

especially when flying behind large airliners.

The powerful turbulence can be catastrophic.

Pilots are trained

to avoid the wakes coming off planes ahead of them

by staying back a safe distance.

Investigators wonder if the pilots of flight 587

miscalculated that distance

as they waited to take off behind a jumbo jet.

Controller: Japan airlines, 47 heavy,

runway 3-1 left, cleared for takeoff.

Narrator: The jal flight took off

at 11 minutes after 9:00.

Controller: American 587, kennedy tower.

Caution, wake turbulence runway 3-1 left.

Taxi into position and hold.

States: You have the airplane.

Brenner: They had been cautioned

about wake turbulence behind the 747 by air traffic,

so they would all have been aware of it.

Narrator: A minute and a half later,

flight 587 was cleared to take off in the same direction.

Controller: American 587,

runway 3-1 left, cleared for takeoff.

Narrator: Investigators know the first officer was concerned

about their distance from the 747.

Molin: You happy with that distance?

States: Uh, we'll be ok once we get rolling.

He's supposed to be five miles by the time we're airborne.

That's the idea.

Molin: So you're happy.

Lights.

Benzon: Maybe they got too close.

Narrator: If the pilots misjudged the distance

to the plane ahead...

Molin: I'm on the roll.

Narrator: Airport radar information

should reveal their mistake.

Investigators plot the paths and distance between the two planes.

Benzon: Never closer than five miles.

They should have been fine.

Narrator: Their calculations show that flight 587

was flying at a safe distance.

The wake should be too weak to be dangerous.

Benzon: The separation was entirely within

federal aviation administration regulations.

But after they hit the wake, the tail falls off.

Was this some kind of super wake?

Narrator: Something put more than 200,000 pounds of pressure

onto the tail to make it snap.

If the wake was unusually strong,

it might explain it.

Benzon: Our job then became to figure out

how strong the wakes were.

Narrator: Many factors can influence

the intensity and direction of wake turbulence,

the strongest of which is weather.

Benzon: Weather and wake turbulence

go hand in hand, in a sense.

In fact, wake turbulence is almost a weather phenomenon.

I mean, it's air movement.

In a perfectly calm wind condition, for instance,

the wake turbulence off of an aircraft

goes straight back and affects anything straight behind it.

If you have a cross wind,

the wakes off the tips of the wings

actually blow with the wind.

They remain rotating, but they move.

Winds were just 11 knots.

Narrator: Investigators discover

that there was very little wind as flight 587 took off.

That may have made things worse.

There was no wind to help dissipate the vortex.

Nasa scientists conduct a study

to determine exactly how strong the wake would have been.

Benzon: They said at the time of the encounter

by the accident aircraft,

the wake from the 747 had dissipated 20 to 40% or so.

Narrator: The vertical stabilizer

can withstand almost 200,00 pounds of bending force.

Even at full strength, the wake from a 747

should not be strong enough to snap the tail off an a300.

At 80% of its strength,

it could not have done any damage at all.

Benzon: Not even close to what it would take

to rip the tail off an airbus.

The overall strength of the wake itself

was not capable of upsetting a large aircraft like an a300.

Narrator: Investigators return to the best clue they have--

the unusual rudder movements.

Benzon: 11 degrees left.

11 degrees right.

We saw the rudder go back and forth

to its maximum deflection

several times very, very rapidly.

As of this point, we still didn't know why,

but that was something that raised our eyebrows.

11 degrees left.

11 degrees right.

Could he have ripped the tail off his own plane?

We needed to determine whether that particular motion

would be violent enough to snap the vertical stabilizer off.

Narrator: Normally, pilots only move the rudder

a couple of degrees in either direction to steer the plane.

Investigators wonder

if the extreme rudder movements on flight 587

created the aerodynamic force

needed to tear the stabilizer off.

Benzon: You ready?

Narrator: To find out,

they create a computer simulation of an a300

and fly it the same way as first officer molin,

moving the rudder 11 degrees back and forth three times.

Murphy: With each rudder deflection,

the aerodynamic loads on the tail increase.

There.

Benzon: That would have done it.

Murphy: And it was those increasing loads

that caused this.

Brenner: They concluded that it was the inputs

that were being made on the controls

that led to the structural failure,

and no other factor.

Benzon: He was doing it to himself.

By way of analogy,

you stick your hand out a car window

going 60 miles an hour,

and you can feel it being pushed backwards.

Well, try sticking your hand out the window

when you're going 250 miles an hour.

Well, you'd probably lose your hand.

Benzon: What was he thinking?

Narrator: The discovery finally explains

what happened to american airlines flight 587,

but it doesn't explain why.

Benzon: So now...now we've eliminated several items,

and we're starting to look at the actions

of the flight crew very carefully.

Narrator: It's clear the pilots should have had no trouble

handling the amount of wake turbulence

they experienced on takeoff.

Benzon: Our studies through nasa indicated

that the strength of the wakes were not that severe.

They were easily manageable.

Brenner: Normally in wake turbulence,

an airplane, especially as large as an a300,

can respond itself to the wake turbulence.

There's a momentary discomfort.

Mayor: Oh, boy.

Brenner: And then the airplane resumes normal flight.

Narrator: But that's not what happened on flight 587.

States: A little wake turbulence, huh?

Brenner: The captain commented, "a little wake turbulence."

Molin: Yeah.

Brenner: He may have been questioning

the first officer's response,

and he was just saying, "it was not that big a thing, was it?"

States: You all right?

Molin: Yeah, I'm fine.

Brenner: What's surprising was the first officer's response.

There really should not be a call

to have that kind of aggressive actions to it.

Narrator: They don't understand why an experienced pilot

would move his rudder so violently

to fly out of the wake.

Investigators talk to pilots who flew with molin.

Benzon: You can take a seat.

Narrator: They make a surprising discovery.

Benzon: We began to suspect that the first officer overreacted.

Tell me what happened.

Brenner: There was one unusual aspect

that was disturbing,

that he had a history of responding very aggressively

to wake turbulence.

Benzon: He did the same thing seven years ago.

Brenner: He moved the rudder pedal quickly back and forth.

The captain said that he was shocked by this.

Benzon: He was overworking the rudders.

Brenner: He said, "why did you do that?

Why did you respond like that?"

And according to the statement, the first officer said,

"they taught us to respond like that in the training."

Narrator: Is it possible

that the airline is teaching their pilots

such a dangerous maneuver?

Investigators have to find out

before another pilot makes the same mistake.

Investigators believe

the first officer was following his training

when he overreacted to wake turbulence.

They discover that one of the situations molin trained for

likely taught him a dangerous lesson.

American airlines pilots

are trained to recover from steep rolls

up to 90 degrees wing down--

an almost unheard-of occurrence.

Benzon: This isn't what happens in flight.

You recover much quicker.

You roll the airplane five degrees,

and then you put her back.

You never let it get to 90 degrees.

There's no history of this.

Simulator: Wait, wait. Wait for 90 degrees.

Brenner: To make the exercise more effective,

unfortunately the simulator was programmed not to respond

to any pilot inputs within the first few moments.

Simulator: Recover now. Recover now.

Narrator: The only way to recover

is with sustained rudder inputs.

Molin: That's a situation I never want to be in.

Narrator: Investigators wonder what trainees were told

about the cause of the sudden upset.

Benzon: Mm-hmm.

And what did they say would cause such a situation?

Well, that explains everything.

It was an example of training that did not equate to reality.

Narrator: They learn that some trainees

were presented with an impossible scenario.

Simulator: For this drill,

there's a boeing 747 just ahead of you.

When you encounter his wake, the upset will begin.

Narrator: They were told that wake turbulence

would induce the sudden roll.

Benzon: Wake turbulence rarely tilts you

more than 10 degrees in any direction,

and it's easily recoverable.

Brenner: Unfortunately, the exercise was exaggerated.

The airplane banked one direction a little bit

and then went very strongly to 90 degrees,

which is tremendous bank, in the opposite direction.

Benzon: We determined that they were actually providing,

inadvertently providing some negative training

to their pilots.

That led us to the conclusion that he overreacted,

and we had the reasons why.

States: A little wake turbulence, huh?

Molin: Yeah.

Narrator: First officer molin was trained to believe

that severe wake turbulence

could cause a catastrophic upset.

Molin: Max power.

States: You all right?

Brenner: The captain asks him, "are you all right?"

And it's noteworthy

that the captain does not add max power.

In the captain's opinion,

max power is not appropriate in this situation.

The first officer began responding

with wheel back and forth

and accompanied by rudder... Back and forth rudder.

States: Hang on to it. Hang on to it.

Brenner: He thought it was some outside turbulence

or something else that was happening,

and he was making opposite controls

and was fighting himself

and didn't know that it was actually his inputs

that were causing the problem.

Benzon: The first officer overreacted on the rudders.

He didn't let the aircraft stabilize

in one position or the other,

so it hits a stop and then whips itself back...

Back and forth, back and forth,

and this creates huge loads on the vertical part of the fin.

Narrator: The first officer's actions

stress the vertical stabilizer...

Until it breaks under the strain.

Molin: What the hell are we into?

States: Get out of it! Get out of it! Get out of it!

Narrator: After the accident,

american airlines changes its training procedures

dealing with wake turbulence.

Benzon: Once it became clear

that some negative training was going on,

american airlines, to their credit,

revamped the program to prevent this type of activity.

Narrator: The training simulator

has been modified to be more realistic.

Inputs have an immediate effect.

Pilots are now taught not to use the rudder at high speed.

A new warning light is also installed in the cockpit

to help prevent pilots from deflecting the rudder too far

during flight.

Benzon: When people ask me about the effects of 587,

I hark back on the incredible loss of life.

It's the second worst accident in u.s. History.

Brenner: Since this accident,

the industry made major changes in terms of pilot training

and made a big effort

to help pilots understand the situation

so that they will not be caught by surprise

so this will never happen again.