Original subtitles

Just minutes after taking off from Lima...

We declare an emergency.

...the pilots of Aeroperú Flight 6-0-3

get mixed messages from their plane.

I cut the engines but the speed is increasing.

Having erroneous airspeed indications now puts

into your brain: "Am I climbing? Am I not climbing?"

They seek assistance from the ground.

Can you tell us our altitude, please?

You're at 9,700 feet according to my radar.

But nothing makes sense.

We're hitting the water. Pull up!

All 70 people on board are killed.

Investigators compare the cockpit voice recording...

We will maintain 10,000 feet.

Set it 10,000 feet.

...with the flight data recorder...

The Captain doesn't realize how close they are to the water.

... and suspect a single faulty sensor

prevented the crew from averting disaster.

It violates the laws of physics.

Airplanes just don't do that.

It's nearing 1 a.m. at Jorge Chavez International Airport in Lima, Peru.

Thick clouds blanket the sky

as Aeroperú 6-0-3 taxis to the runway.

The weather in Lima, in Peru, is a very, very stable

environment, especially this time of the year.

The captain is 58-year-old Eric Schreiber.

He's highly experienced, having logged almost

22,000 flight hours.

Aeroperú 6-0-3, authorized to Santiago,

initial level 29,000 feet and afterwards on course,

transponder 5-6-0-3.

42-year-old First Officer David Fernández

has flown nearly 8,000 hours.

Correct, Lima Tower.

He will be the pilot flying the aircraft tonight.

Roger.

He's doing double duty by also operating the radio.

Lima Tower, Aeroperú 6-0-3, runway 1-5, ready for takeoff.

Aeroperú 6-0-3, wind calm, cleared for takeoff runway 1-5.

There are 61 passengers

and 7 flight attendants on board.

Takeoff at 41 minutes past midnight, on the dot.

What precision. Like the Swiss. Let's go.

The crew is extremely professional.

They accomplished their checklists and procedures

as what would be expected, and they were basically

an on-time machine.

Flight 6-0-3 will fly out to the Pacific Ocean

before heading south to Santiago.

The aircraft is a four-year-old Boeing 757-200.

The Boeing 7-5-7 is a long, narrow-bodied

aircraft, twin engine.

It's simple in its design, simple in its instrumentation,

just a overall comfortable airplane to fly.

The passengers settle in

for the three-and-a-half-hour flight.

In the cockpit...

...the first officer spots a potential problem.

The altimeters are stuck.

Wind shear.

Wind shear. Wind shear. Wind shear.

The pilots also get a wind shear warning.

- Wind shear. - This is new.

The wind shear is an alert that we're entering into

an environment of undesirable winds that could be

highly critical in the safety of the aircraft.

Those types of winds are just very uncommon

in that area and were not forecasted that night at all.

Wind shear.

Flight 6-0-3 climbs into the thick clouds

above Lima. The pilots lose sight of the ground.

The speed.

They now discover another instrument

isn't working.

Yeah, right.

Flying in the clouds at night, without knowing

how fast they're going or their height above the ground,

the pilots face a potentially dangerous situation.

Am I climbing? Am I not climbing?

Am I near mountainous terrain, which is very close

to the coastal line of Peru.

Tower, Aeroperú 6-0-3.

Flight 6-0-3 updates the tower controller.

Aeroperú 6-0-3, Tower, go ahead.

We have no altimeter and no airspeed.

Declaring an emergency.

When a pilot declares an emergency

with air traffic control, the controller

is going to give that aircraft priority handling.

Roger. Change frequency to 1-19.7

for further instruction from radar control.

Switching to 1-19.7.

Before contacting of radar control,

the captain takes over from the first officer.

Okay, I have control.

The captain may decide to take over the flying role

and tell the first officer to talk on the radio

and work procedures.

Lima, 6-0-3, we request vectors for ILS,

runway one five.

The pilots request directions for a return

to the airport.

Roger, we suggest a right turn heading 3-3-0.

It was a good call to ask air traffic control,

give us vectors, we're so busy up here dealing with

everything else, you can certainly help us out

if you tell us which direction to turn and guide us back

towards the airport.

Turn right, heading 3-3-0.

A heading of 3-3-0 will take the plane north

to a position where it can then make the turn back to Lima.

But two-and-a-half minutes later...

Aeroperú 6-0-3, you're showing level 9,200,

uh, what is your heading now?

...the radar controller notices

that Flight 6-0-3 hasn't turned back towards the airport.

Heading 2-0-5, we're heading away from the shore.

Affirmative.

We will maintain 10,000 feet. Set it 10,000 feet.

The Captain decides to fly further out to sea

before returning to Lima.

They go out over the ocean, which is one of the best

decisions to possibly do.

They don't now have to worry about other aircraft

and the Andes Mountains.

In the cabin, passengers are unaware

of what's happening in the cockpit.

Safely away from shore...

According to the radar, you are crossing radial 2-3-0

from Lima, distance west- southwest is 37 miles...

Flight 6-0-3 finally starts turning north

to begin the approach to Lima and needs to begin its descent

to the airport.

I'll try to descend with the power cut.

He was going to descend at idle thrust,

which is a good way to descend. It's nice and steady

in a 757 and keeps the airspeed under good control.

I cut the engines but the speed is increasing.

Even with power to the engines cut,

the airspeed indicators show that the plane is accelerating.

Can you tell us the speed please?

I have 3-20.

We have 3-50.

They'll need to use a different strategy to descend.

Getting to the lower altitude, hopefully getting into

some clearer areas to see the coastal line,

could give them more comfort for a safe landing.

Take the speed brakes out.

That is another great way of slowing the aircraft

and getting better control of the airspeed.

But deploying the speed brakes

has the opposite effect.

Overspeed.

A new warning tells them

they're flying far too fast.

The airplane is above its maximum allowable airspeed.

It's in danger of breaking apart

if they don't do something right now.

But I have the speed brakes out and all power is cut.

This can't be right.

What more possibly can be confusing

and going wrong right now.

Seconds later, they get a contradictory warning

that the plane's flying far too slow.

The stick shaker indicates to pilots that if the airplane

gets any slower, it's going to be in a stall condition.

Are they going too fast or too slow?

The pilots must decide which alarm to react to.

We're stalling.

The Captain decides to increase the speed

by pitching the nose down, silencing the stall warning.

But they're not out of danger yet.

With conflicting warnings and no reliable airspeed

or altitude readings, the pilots of Flight 6-0-3

urgently need help.

Is there any plane that can take off to rescue us?

Yes, we'll coordinate immediately.

At this point, it was a totally out of the box thought

by the first officer to ask for this type of assistance,

which would have given them a visual reference right next

to them with altitude, airspeed, also communications.

And we have somebody alongside of us holding our hand

to the airport.

The plane is now 50 miles from Lima's airport.

Aeroperú 6-0-3, you are heading 2-7-0, 10,000 feet.

While they wait for a rescue plane,

the captain attempts to join the approach path to the runway.

I'll try to intercept the ILS

and then descend.

Lima, Aeroperú 6-0-3, we will try to intercept the ILS.

Roger Aeroperú 6-0-3.

They think they're flying at a nice safe altitude.

And they think that they pretty much have airspeed under control.

They probably thought they were in a pretty darn good position.

Soon after, the radar controller provides

an update on the escort flight.

Aeroperú 6-0-3.

There is a 7-0-7 about to take off.

It is starting to move now.

It seems to be flying well.

Can you tell us our altitude please?

You're at 9,700 feet according to my radar.

Terrain. Too low. Terrain.

9,700 feet?

But we're getting a terrain warning.

Pull up! Pull up if it's telling you to pull up.

We're hitting the water. Pull up!

We're rolling over!

Pull up.

29 minutes after taking off, Flight 6-0-3

crashes into the Pacific Ocean, 48 miles from Lima, Peru.

Within hours, a navy aircraft discovers debris

from Flight 6-0-3.

The accident occurred at night

and the wave conditions were very high.

So the first few ships that went out to look for the wreckage

really struggled to find it.

Heavy fog also hampers recovery efforts.

By the end of the first day,

the bodies of only 13 of the 70 people on board are recovered.

There are no signs of survivors.

Those who haven't been found are believed to be inside

the fuselage on the seabed.

It's up to air crash investigators from Peru's

Accident Investigation Board to find out why a plane,

last observed flying nearly 10,000 feet above the sea,

suddenly crashed into it.

We have the military radar.

With the underwater wreckage still beyond reach,

investigators get their first lead from the Peruvian military.

Any coastal nation will have military radar

that's constantly scanning for any approaching aircraft.

So by querying the Peruvian military radar,

we were able to get some data about the altitude

and position of the accident flight.

So after taking off, they follow the approved flight

plan over the ocean, and then they start heading north.

Yeah, they're, they're headed back towards Lima.

Um-hm.

The flight climbs to 13,000 feet, and then

it starts to descend.

And now, in the last seven minutes, the flight

has a series of erratic climbs and descents before it crashes.

It appears they lost control.

It becomes just a rollercoaster ride of altitudes

because they don't have control.

What could have caused the pilots

to lose control?

When you start putting an investigation together,

you start putting the what-ifs on the table.

What if this failed, what if that failed,

what if this went wrong, what if the crew made a mistake?

Pre-takeoff seems okay.

Investigators scrutinize the communications

between air traffic control and the pilots.

Look at this. The crew reported problems with airspeed

and altitude readings only two and-a-half minutes

into the flight.

Tower, Aeroperú 6-0-3.

Aeroperú 6-0-3, Tower, go ahead.

We have no altimeters and no airspeed.

Faulty air data.

It sounds like an issue with the pitot-static system.

The pitot-static system uses tubes and sensors

mounted on the plane which measure air pressure

to calculate airspeed and altitude.

Well, wasn't there a recent crash involving

the pitot-static system?

Yeah. Birgenair Flight 3-0-1.

Only eight months earlier, another Boeing 757

crashed soon after taking off from Puerto Plata

in the Dominican Republic.

The cause was a blocked pitot tube.

Some investigators were wondering if we had a similar

situation to what we had in Birgenair.

It wasn't entirely the same, but it still involved

blockage or covering parts of the pitot-static system.

Well, maybe that's what happened here.

Nearly two weeks since Aeroperú Flight 6-0-3

crashed into the ocean, a US Navy ship helps

the Peruvian Navy to track the pings from the Boeing 757's

two black boxes.

The wreckage is finally located at a depth of 680 feet.

Using remotely operated vehicles, investigators

finally get their first view of the wreckage site.

The wreckage looks very concentrated.

The plane was intact when it hit the water.

The fact that all the major pieces

of the airplane are in one concentrated area

really gives the investigators a much clearer picture

of how the airplane came down.

So they either came down in a flat spin

or it came down nose first

which is a very unusual accident.

There.

The black boxes are also located.

It's very, very critical to get both recorders.

First, you want to know how the airplane was behaving,

and then secondly what was going on in the cockpit

between the crew members of the airplane.

They are packed in sea water

and sent to Washington where the NTSB,

the National Transportation Safety Board, will process

their invaluable data.

That's it, keep moving that way.

The team also searches for evidence

of some kind of blockage of the pitot tubes

and static ports.

There! Keep going.

They focus on a section

of the left fuselage where the static ports are located.

Okay, now move in...

That's it.

The static ports were blocked.

They can see that the ports are covered.

When we saw that those static ports were covered,

it was case closed, drop the curtains.

We knew exactly what happened in this accident.

How did such a critical device

which determines airspeed and altitude get covered up

and blocked?

Make sure you tag everything.

Investigators survey the recovered wreckage

of Aeroperú Flight 6-0-3 to find out what is covering

the static ports.

Look at that.

It looks like silver tape.

Same colour as the fuselage...

Pliers.

Why were the ports covered with tape, and by whom?

It wasn't our job to assign blame or liability,

but we wanted to understand the procedure to make sure

that important step of removing the tape would never

get overlooked again.

So, let's check the last log entry.

Okay.

Investigators check maintenance records

to understand why the ports were taped over.

Interesting. Hey, a bird strike.

During the plane's last landing before

the accident, the right engine was struck by birds.

They replaced two turbine blades, the hydraulic pump

was repaired, and they polished the "lower front" of the 757.

Exactly where the static ports are located.

Did maintenance personnel follow

the correct procedures for polishing the 757?

When you're performing work on the airplane,

such as polishing it, or washing it, it's important

not to get any debris into the ports,

because when you takeoff, temperatures go down,

they may freeze in place, which could cause severe

instrument problems to the airplane.

According to the maintenance manual, they're supposed to

cover the static ports.

But whoever polished the plane covered the static ports

with tape and didn't remove it.

So why wasn't the tape removed

after the area was polished?

If you look at the maintenance process

on an airplane, and cleaning or polishing

an airplane is maintenance

there's multiple steps, multiple people and multiple looks.

The whole purpose of that is to make sure

that nothing is missed.

Were the static ports inspected as part

of Flight 6-0-3's line check?

It was a crazy night.

Investigators interview the Line Mechanic

to determine if the static ports were inspected

after the work was done.

The line chief usually does it, but he was sick.

So I did it.

So, I guess you didn't see the tape then?

Aluminum tape is pretty common. And if you take it

and just spread it over those ports, it blends in perfectly.

And it makes it very easy for somebody to miss it.

Was he adequately trained?

I would say the answer to that is no.

Did you see either pilot do a pre-flight check?

Yes, the Captain.

Do you know if he checked them?

I couldn't tell you.

If I add a new person on my crew, I would tell them

to watch the captain, see what he's doing,

and it becomes routine for mechanics to watch

what the flight crew does.

Okay. Thank you for your time.

There's at least one, if not two, line checks

that are done by the supervisors of the line maintenance.

And then, one of the crew members would do a walk-around,

as they are obligated to do, always.

So there are several levels where things

should have been detected but weren't in this flight.

So, both the Line Mechanic and the pilot missed it.

Investigators now know that,

despite all the safety checks that were meant

to be performed, no one spotted the silver tape

covering the static ports.

So, we know what caused the faulty airspeeds

and altitudes. But faulty air data alone doesn't cause

a plane to crash.

So, what did?

arrator): Investigators turn to the cockpit voice recorder

from Aeroperú Flight 6-0-3...

- Here you go. - Thank you.

...to determine how the pilots dealt with

faulty airspeed and altitude data.

Pick it up from the take-off.

Gear up.

Right, V-two plus ten. - Mm-mmh.

The plane is barely off the ground

when the pilots identify the first problem.

The altimeters are stuck.

The captain's altimeter, the first officer's

altimeter, the standby altimeter, all three sources

were different and they were all wrong.

Keep V-two plus ten, v-two plus ten.

It's quickly followed by a second issue.

The speed.

The airspeed is also stuck.

Yeah, right.

Hold on.

They were only at 200 feet above the ground,

and they already knew that they had problems

with altitude and airspeed.

In three different places in the cockpit,

they're seeing unreliable airspeed and altitude.

According to the FDR, they're still climbing.

Let's see how they handle that faulty data.

What's going on?

We're not climbing.

I'm climbing.

Investigators hear the captain continue to rely

on the faulty data on his altimeter...

Climb. Climb. Climb.

I am climbing.

...despite what the first officer tells him.

The captain is looking at his altimeter and saying

what he sees right in front of him.

It's very hard to ignore this false data.

The airspeed and altitude readings are like a magnet

drawing your eye and attention again and again.

- Climb. Climb. - I am climbing.

So, in these initial moments of the climb,

it seems like the first officer was more in touch

with what the airplane was really doing.

What else do the pilots do to handle the situation?

Keep playing.

Let's go to basic instruments.

But within a minute, the captain stops focusing

on the faulty instruments.

He decides to use the pitch and power procedure

and that's good.

Very quickly on, the captain says,

"basic instruments", but I believe he means

the pitch and power procedure.

The "pitch and power" procedure requires

reducing the pitch angle of the aircraft

to two degrees nose up and the throttles to 55%.

This should result in level flight.

By flying with set pitch and power and ignoring

the unreliable airspeed and altitude gives the crew time

to sort out what's going on and think through

what might be causing the unreliable indications.

Then they declare the emergency.

Pick it up after that.

Let's see if they did the procedure properly.

(Captain: Switching to 1-19.7.

Auto-throttle has disconnected.

But instead of checking his attitude

indicator and engine gauges...

Let's see. Read that.

...the captain focuses on the Crew Alerting Screen

which is displaying more alerts.

Rudder ratio and Mach speed trim.

The rudder ratio and Mach speed trim warnings

were just the result of the unreliable airspeed

and altitude indications in the cockpit.

They shouldn't have been the primary focus of the crew.

They're getting distracted by false alerts.

They ignore their pitch and power procedure.

We're flying without speed.

Soon after...

The speed is zero.

All airspeed indicators at zero.

Investigators hear the pilots

turning their attention back to the erroneous airspeed

and altitude readings.

The tape on the static ports meant that the airspeed

and altitude were always wrong and they were always changing

as the airplane climbed and descended.

We will maintain 10,000 feet. Set it 10,000 feet.

But at no point did they disregard

the unreliable airspeed and altitude.

They looked at them constantly.

12,000 feet.

The crew never switched their mindset to just

using pitch and power.

They climb for seven more minutes.

But if they were climbing, how did the crew

end up hitting the ocean?

They can't keep climbing forever.

We have problems reading our instruments.

Investigators continue listening

to the cockpit voice recorder of Aeroperú Flight 6-0-3

to determine how the crew carried out

the return to Lima with faulty instrument data.

Set the approach please.

I did. I did.

Then let's go.

The captain, he knew he had to... to get down

to Lima airport.

I'll try to descend with the power cut.

And the way to do that

was to reduce the power.

No sooner do the pilots cut the power

than they face another problem.

The speed is increasing.

Why is the speed so high?

Is it the real speed?

That's what worries me. I don't think so.

They think they're speeding up when they can only

be slowing down.

The pilots don't know whether to believe

the faulty airspeed indicator that's showing

they're going too fast after having pulled

their thrust levers back to idle.

That'd be totally confusing for the captain.

He'd be saying, this can't be happening. It's impossible.

It violates the laws of physics of aircraft.

But the Captain's thought process is overtaken

by what happens next.

Overspeed.

The faulty airspeed data is now triggering

the overspeed warning.

An overspeed warning gets your attention very quickly.

And you want to react to it.

But this is the time when he should have been questioning

whether that was correct.

The First Officer makes a split-second decision.

Take the speed brakes out.

But now, with the power cut and the speed brakes out...

It slows the plane down to the point of stalling.

The erroneous overspeed data leads the pilots

to reduce their speed, which puts their plane into a stall.

The crew instinctively lowered

the nose and increased their actual airspeed.

Those are the steps that will keep you

from stalling the airplane.

Responding to the stall warning was the right move.

But after that...

...they head further out to sea instead of towards Lima.

Why would they do that?

Shortly after the stall warning ends...

Too low. Terrain.

...a new warning tells them they are dangerously close to terrain.

Too low. Terrain. Too low. Terrain.

The captain doesn't realize how close

they are to the water. Too low. Terrain.

On the 757, a radio altimeter measures the plane's

altitude when below 2,500 feet and sounds

the Ground Proximity Warning when the plane drops

too close to the terrain.

The ground proximity warning system is separate

from the pitot-static system. It was telling them the truth.

Too low. Terrain.

Too low, terrain.

And now we've induced a terrifying alert

of: "I'm about to hit a mountain."

The pilots thought they were near a mountain

when they were actually approaching the surface

of the ocean.

Too low, terrain.

Let's go left.

Too low, terrain.

Radar shows you're turning left, you are heading to the west.

Affirmative. We are heading 2-5-0.

We're heading out to sea because we have a low terrain warning.

Too low, terrain.

He knew that the water, the ocean, is to the left.

And that's going to be my safe environment.

Sink rate. Sink rate.

No sooner do they deal with

the terrain warning than the pilots are confronted

by an alert telling them they are descending too rapidly.

Sink rate. Sink rate.

Let's climb. Let's go up.

Too low. Terrain.

Now, going up was the right call. They were descending

at 3,000 feet per minute.

They climbed to 4,000 feet and they stay there for...

...approximately one minute.

So what led to the final plunge into the sea?

Let's go back to Lima.

I'll try to intercept the ILS and then descend.

After 25 harrowing minutes, the captain initiates

a turn back to Lima.

Lima, Aeroperú 6-0-3, we will try to intercept the ILS.

Can you tell us our altitude?

Is our altitude 9,700 feet?

Roger, Aeroperú 6-0-3, you're showing level at 9,700.

Too low. Terrain.

But when the terrain warning activates,

investigators know the plane was below 2,500 feet.

They both had the wrong altitude.

Investigators discover the controller

was also providing Flight 6-0-3

with incorrect altitude information.

The assumption was the controllers can tell us

our altitude but the flaw in that is that that altitude

is actually being sent to the controller from

the aircraft itself.

If the information on board the aircraft is incorrect

then the information that's being sent to the radar

is also going to be incorrect.

Investigators speak to the controller to understand

why he relayed the faulty readings back to Flight 6-0-3.

So it looks like you were providing the crew

with altitude data.

Yes. They said they didn't have any altimeters,

so I told them what I was seeing on my radar screen.

Were you using SSR in Mode C?

Yes. That's right.

Your radar's altitude

is coming from the plane's transponder.

When the controller confirmed

the altitudes for the pilots,

I think it gave them a false sense of hope that at least

one of our problems has been solved, the altitude problem,

when, in fact, that was tragically incorrect.

But even with the faulty altitude readings,

could the pilots still have landed their plane safely?

Pick it up during their final descent.

To determine if the pilots had any other

options to save their plane, investigators listen

to the final moments of Aeroperú Flight 6-0-3.

It seems to be flying well.

Can you tell us our altitude?

You're at 9,700 feet, according to my radar.

Too low. Terrain.

9,700 feet? But we're getting a terrain warning.

Too low, terrain.

The crew can't understand the conflicting information.

But there was a way for the pilots to determine

their actual altitude and save the plane.

If they had checked their radio altimeter,

they would have realized how close they are to crashing.

Too low, terrain. Too low. Terrain.

When the ground proximity warning system activated

in the cockpit, the crew could have referred to

the radio altimeter and that would have given them

the truth data about how high they were above the ground.

Too low. Terrain. Too low. Terrain.

But they never check their radio altimeter.

Pull up. Too low. Terrain. Pull up.

Pull up, pull up if it's telling you to pull up!

Terrain.

We're hitting the water!

When an aircraft has its wing touch the water

in a bank attitude, the situation is hopeless.

- Pull up! - I am.

Pull up. Terrain. Terrain. Pull up. Terrain.

Terrain. Terrain. Pull up. Terrain.

The pilots try to get the plane back in the air

but the plane banks left and falls back towards the sea.

We're rolling over!

Pull up. Terrain. Pull up.

They really had no idea how low they were.

And all those alarms false or real,

just made matters worse.

The situation in the cockpit was so confusing.

It was hard for either crew member

to understand which cautions and warnings were true and important

and there didn't seem to be a good balance

between the two crew members in sorting that out.

For investigators,

there's one final unanswered question.

Were the pilots properly prepared to handle

an emergency like this?

They examine the Quick Reference Handbook

which provides guidance in emergency situations,

as well as Aeroperú's training procedures.

Well, there's nothing here.

Anything in the training procedures?

Not one single word on how to handle erroneous air data.

The lack of training worked against them.

A big takeaway from this accident was that

flight crews need to be better trained to get to pitch

and power in the event of unreliable airspeed

and altitude.

Investigators needed only two months to solve

the mystery of Flight 6-0-3.

They now know that blocked static ports...

The altimeters are stuck.

...created faulty air data readings...

Overspeed.

And those faulty readings created

so much confusion in the cockpit...

But I have the speed brakes out and all the power is cut.

That can't be right.

... that the overwhelmed crew was unable

to separate the false alarms from the true ones.

They really needed to develop a laser focus

on just flying the airplane but they never got there.

Terrain. Terrain. Pull up.

The captain's failure to react

to the ground proximity warnings in time...

Pull up!

Pull up if it's telling you to pull up!

- Terrain. Terrain. - We're hitting the water.

Pull up. Pull up!

Terrain. Terrain. Pull up.

...contributed to the death of 70 people.

There's nothing highly technical about tape,

but boy did it start a chain of events.

The investigation's report outlines

a number of recommendations. But chief among them

is for more training to ensure crews know how to deal

with inaccurate air data and implementing the use

of "eye-catching" static port covers while a plane

is being maintained.

Remember, it's the simple things that cause

problems, and we need to keep that in everybody's mind.

Attention to detail, if you perform that detail,

whatever it is, you're not going to get problems.

This accident was one of the pillars

of safety procedures. Our training changed.

Our preflight procedures changed. Our attention

to details changed. And it still lives to this day.

Subtitling: difuze