Original subtitles

Helios 522, do you read?

High above Athens, Greece,

fighter jets track a 737 as it circles the city.

522, do you read?

Over.

There's no answer from the passenger plane,

but there is someone at the controls.

More than 100 people are on board.

Everybody's mind was going to hijack or terrorist.

There is one person moving in the cockpit.

Repeat, there is one person.

What happened to the crew and passengers?

522, do you read?

Over?

And who is flying the plane?

Helios 522, do you read?

Over.

Ladies and gentlemen,

we are starting our approach.

We lost both engines.

Keep your mask

over your nose and

- Mayday, mayday. - Brace for impact!

It's the lost one.

Investigations started in the tragedy.

He's going to crack.

Early morning, August 14, 2005.

The cabin crew of Helios Airways flight 522

are preparing for their trip from the island of Cyprus

to Athens, Greece.

Sure it is a beautiful day.

Maybe I shouldn't have come in.

Andreas Prodromou is 25.

He isn't supposed to be working today,

but he's taking the flight to spend

some time with his girlfriend, who also works for Helios.

It's the sort of day I'd like to be on flying.

Oh, you will, Andreas.

Prodromou is a flight attendant now,

but he has bigger plans.

One day he wants to fly for Helios.

His dream was to become

a professional pilot.

Personally, I wanted him to stay in the family business.

We often talked about this.

We've got company.

Stay warm at the back.

I will.

See you in Greece.

In the cockpit, the flight crew

is occupied with a daily routine of preparing

their jet for takeoff

Bright today.

Captain Hans Merton is an East German,

a contract pilot hired by Helios

for the busy holiday season.

Are you almost through?

Pardon?

Are you almost done?

Nearly.

So the overhead lights are extinguished.

His co-pilot is from Cyprus.

Pambous Paralambous has been working exclusively for Helios

for the last five years.

Before beginning any flight, crews

are required to perform dozens of checks

on various pieces of onboard equipment.

Oxygen masks.

It's a routine but necessary procedure.

Doors closed.

Sorry, could you store trays, pull your seat back.

Helios is a charter airline

with low-cost fares to Greece.

It's a summer weekend, and the plane is filled with families.

In all, there are 115 passengers

on the morning flight.

If you need any more help, let me know.

We're just about to take off.

They are low-fare, no frills.

They don't even serve you refreshments

during small sorts of flights, but

they offer another possibility for

the budget-minded traveler.

Paros Dimitrio and Maria Riccu

are traveling to the Greek Island of Patros.

They've just gotten engaged.

They booked... they booked this holiday a month

or more than a month ago.

It was like a honeymoon for them.

Flight attendants, please take your seats.

Prepare for takeoff.

Safe flight.

Just a few minutes after 9:00

in the morning, Helios Airways flight 522

lifts off into the bright sunshine.

area controls, this is Helios 522.

Request cruising at 340.

Helios 522, you are clear to climb to 340.

Have a good day.

He said 340?

340.

Minutes into the flight,

the plane is still climbing towards its cruising altitude.

Suddenly, an alarm blares in the cockpit.

What is it?

The takeoff config warning?

The flight crew is confused.

The takeoff configuration alarm normally

only sounds on the ground.

It tells pilots their jet isn't ready for takeoff.

The crew doesn't know why it's sounding now.

Uncertain what the problem is, the captain

radios the Helios operations center at Larnaca Airport

back in Cyprus.

Operations, this is flight 522.

Over.

Flight 522, what can I do for you?

We have a takeoff config warning on.

Pardon?

Our takeoff config warning is on.

I'm sure it's nothing.

I'll let you know when we level off.

With the first alarm still beeping in the cockpit,

things become even more confusing.

Their master caution alarm goes off.

It could indicate that some systems on board

are overheating.

We now have a master caution.

We'll get you an engineer, 255.

Just a minute.

I find him very hard to understand.

His accent is quite thick.

Flight 522, what can I do for you?

The ventilation cooling fan lights are off.

Sorry. Could you repeat?

While the pilots and ground engineers try

to troubleshoot the two alarms, most passengers have no idea

there's a problem until...

Everyone, stay calm, but please remain seated.

Everyone, please put the oxygen masks on, completely

over your mouth and nose.

The protocol was immediately to secure

yourself, grab an oxygen mask, stay in your seat.

If you can help passengers without getting up,

you could help them and, you should help, them

but you would not risk the safety of any cabin crew

member to go and help a passenger which is

five or six rows further up.

Their procedure would be

to grab their mask,

don it, and wait for the aircraft

to level off

or commence with the descent.

No one in the cabin knows what the problem is.

They're waiting for information from the cockpit.

The pilots are unaware that the oxygen masks in the cabin

have dropped, and they still don't know why their takeoff

configuration warning is on or why

their systems are overheating.

Both of my equipment cooling lights are off.

This is normal.

Can you please confirm your problem?

But the engineer on the ground

is struggling to get a clear picture of what's

happening in the air.

They are not switched off.

Can you confirm that the pressurization

panel is set to auto?

Where are my equipment cooling circuit breakers?

Behind the captain's seat.

Can you see them?

What's going on?

There's something wrong with the electrics in 522.

I had something to pick up

from operations.

So I was there.

I figured, oh not again.

One of our problems, so I left.

Oh.

Good luck.

The problem doesn't seem serious,

but as the plane continues to climb,

passengers still haven't received any information

from the cockpit.

Helios 522, can you see the circuit breakers?

And now, the engineer on the ground

loses contact with the aircraft.

Helios 522, can you hear me?

It's less than 30 minutes after takeoff,

and flight 522 is still on course.

The flight to Greece normally takes an hour and a half,

but the passenger jet has been in the air for over two hours,

circling in a holding pattern.

We heard that there was an airplane which

was flying into the Greek territory

and had no communication.

Everybody's mind was going to a hijack or to terrorists.

More than 3 million people live in Athens.

A plane slamming into the city could cause

an incredible loss of life.

This is a runaway aircraft.

It's a possible hijacking or it's a possible terrorist act,

so let's involve the military.

The Greek Air Force scrambles

two of its most sophisticated fighter jets

to investigate the Helios plane.

Helios 522, do you read?

Over.

But the pilots aren't getting any response.

One of the jets flies closer to the 737.

Someone is in the co-pilot seat,

slumped over the controls, but there's

no sign of the captain at all.

The fighter pilot radios air traffic control in Athens.

Athena ACC, there is one figure

in the cockpit of Helios 522.

He appears nonresponsive.

Athena ACC, checking the cabin.

He can see passengers in their seats,

but none of them react to the presence of the jet.

Then the pilot sees someone moving in the cockpit.

Athena control, there is one person moving

in the cockpit of Helios 522.

Repeat.

There is one person inside the cockpit.

Helios 522, do you read?

Over.

Helios 522, over.

Flight HCY, 522, this is Athena radar control.

How do you hear?

The F-16s continue shadowing the jet,

but there's no response at all from the cockpit.

One of them was actually in a shooting position

behind the 737.

The other one was nearby the cockpit,

and he was trying to communicate visually

with the person in the cockpit.

Suddenly, the 737 turns left

and begins to quickly descend.

Athena ACC, Helios 522 turning sharply.

Following down.

From nearly 33,000 feet,

the plane drops towards the ground.

There is no structural failure.

There is no fire.

There is no problem, obvious problem from the external view

with the plane.

Helios 522, over.

Do you read?

Helios 522, do you read?

Over.

Then, nearly 6,900 feet above the ground,

the person in the captain's seat

acknowledges the fighter jet for the very first time,

but no words are exchanged.

Neither the fighter pilot nor local air traffic control

can make radio contact with the jet.

Just after 12:00, almost three hours after it took off

from the island of Cyprus, Helios flight 522

slams into the ground.

Athena ACC, Helios 522 is down.

Repeat, Helios 522 is down on Grammatiko Hill.

Over.

Fire and rescue workers

rush to the crash site.

There are no survivors.

Flight attendant Lazaros Temetzian

is stunned by what he hears at the company's

operations center.

It was the most chaotic scene I've ever seen.

When I went back, our operations controller

said that he lost the aircraft, and... his eyes

he was starting to cry.

Helios is a small company, with just three jets.

Members of the cabin crew have been

working together for years.

For Paul Symeonides, news of the crash

is particularly terrifying.

He's a flight attendant for the airline and so is his fiancee.

I think that must have been the worst 30 minutes

of my life, following that first image

because Victoria was flying that morning to Glasgow.

I had every one and his brother, every person

we knew was calling me up to find out

if I'm alive, if Victoria is alive, what happened,

why it happened.

Andreas Prodromou's father didn't know his son

had been called to fill in on flight 522.

I was told that Helios aircraft

was lost by radar, and air controllers

couldn't contact him.

I got worried.

I called Andreas' phone.

He always had it on.

And unfortunately, he wouldn't answer.

After that phone call, I felt as if the ground was

pulled out from under my feet.

It's the worst air crash

in the history of Greece.

Most of the 121 victims are from Cyprus.

The small island nation declares three days of

mourning following the crash.

It's an eerie disaster.

For over an hour, air traffic controllers

watched the passenger jet fly in radio silence, closer

and closer to Athens, with no idea what

was going on inside the jet.

Now, piece by piece, investigators

are trying to find out what happened.

So we climbed over to the hill,

and there we were, you know, facing this situation, which

was beyond any description.

I saw a great area in front of me, which was burning.

It was black, burning, people spread,

pieces of the airplane.

It is a truly nightmarish sight .

I hope that I never experience it again.

It was terrible, just terrible.

Investigators immediately

start looking for the cause.

In the first days after the crash,

their efforts take a frustrating turn.

They recover the box containing the cockpit voice recorder,

but the recorder itself had been

thrown clear of the plane.

Investigators need to know what happened to the pilots.

Without the cockpit voice recorder,

they have little to go on.

So keep looking.

Let's hope we can find it.

Bodies recovered from the wreckage

are brought to the offices of Athens' chief coroner.

Autopsies add even more mystery to the case.

Everyone on board the plane was alive at the time

of the crash.

There were scenarios at the time

that they had all died in midair,

but the truth,

they did not die from inhaling a toxic substance

in the airplane, but from an explosion.

These people died on impact.

But if the passengers were alive the entire flight,

why didn't the pilot of the fighter jet

see any activity inside the cabin?

And who was at the controls as the jet circled over Athens?

When investigators find tissue samples

in the remains of the cockpit, they

make a stunning discovery.

The person at the controls of the plane when it crashed

was flight attendant Andreas Prodromou,

a last-minute addition to the cabin crew.

But why was he in the cockpit?

Was he trying to save the plane or did he deliberately

fly it into the ground?

Several days after finding the outer case

of the cockpit voice recorder, investigators

find the recording itself.

When Chief Investigator Tsolakis

listens to the final moments of the flight,

it answers a vital question.

Mayday. Mayday.

This was no terrorist act.

Helios Airways, flight 5...

22.

Prodromou was calling for help.

Mayday.

Mayday.

Tsolakis hears five separate "maydays"

on the tape, even though none of them

were heard by the air traffic controllers.

In fact, Prodromou had his commercial pilot's license.

It was the first step towards his goal of becoming

a captain for Helios.

It's the sort of day I'd like to be on flying.

Oh.

You will, Andreas.

But all of his training wouldn't

have helped save the jet.

When he was seen at the controls,

flight 522 had been in the air for almost three hours.

And the reason the Helios plane seemed to veer away

from the F-16s following it was because its left engine

was out of fuel.

No matter what caused the alarms to sound,

the ultimate reason for the crash was simple.

The DFTR and CVR gave us absolute proof.

The plane ran out of fuel.

And this was the cause of the crash.

Scheduled as a 90 minute flight,

the plane didn't have enough fuel to stay in the air

for over three hours.

But why had the plane flown so much longer

than it was supposed to?

Chief Investigator Tsolakis now knows

who was in the cockpit of Helios flight 522

and why it crashed, but to fully understand the mystery

he needs more information.

Mayday.

Helios...

His investigators uncover a suspicious history

of maintenance issues with the jet, issues that could

help explain what happened.

Less than a year before the crash, the same aircraft

had suffered a rapid decompression.

Lazarus Temetzian worked on that flight.

I was in the back of the aircraft

at the time.

There was a loud, metallic bang, a clanging sound.

And the oxygen masks dropped in the cabin.

Every step I was taking was difficult.

It was hard to move, hard to breathe.

In fact, I was starting to pant.

I was panting for air.

As the plane began an immediate descent

to 10,000 feet, all Temetzian could do was

remain strapped in and wait.

Once the plane reached a safe altitude,

Temetzian inspected the rear door

and was shocked by what he found.

I noticed that the aft service

door was not fully locked.

The hinges on the top and the bottom of the door

were kind of displaced.

I could pass my hands right through.

There were no injuries,

and the plane made an emergency landing.

And the door was inspected, but this wasn't the only problem

crews had with this plane.

There were more recent problems as well.

A Helios ground engineer tells Tsolakis

that on the very day of flight 522,

the 737 had another problem with its back door.

When we checked the flight log for the trip,

we saw that we'd have to do some unscheduled maintenance.

The plane had arrived in Cyprus just

after midnight on August 14.

The cabin crew had heard loud banging noises

and saw ice on the rear service door during the flight.

It was scheduled to take off again just hours later.

Soon after it landed, engineers began checking the problem.

To make sure there's nothing wrong with the seal

on the door, the engineers run a pressurization test.

During normal flight, a plane's engines

force air into the cabin.

To ensure oxygen circulates during the trip,

small valves in the rear allow some of it to leak out.

The pressurized airplane,

essentially, is sort of like a pressurized can.

Well, we pressurize the airplane

so that the people inside can survive

the environment that the airplane likes to operate in.

Switching digital pressure control unit from auto

to manual.

Without the jet's engines running,

the engineer uses the plane's auxiliary power unit to force

air into the aircraft.

And the cabin is pressurized for several minutes,

but there's no indication any air is escaping

through the back door.

The entire jet seems to be in good working order.

After performing a series of additional routine maintenance

procedures, the engineers signed

off on their technical log.

Investigators are faced with a dead end.

So explain again how you tested the pressure.

An explosive decompression

could have explained the tragic events of flight 522.

If the oxygen had been suddenly sucked out of the jet,

everyone on board could have been overcome,

but not only did engineers check the problem, when

the F-16s approached the plane near Athens,

no damage was seen.

There was no indication that the fuselage was punctured.

All investigators know for sure is that shortly after takeoff,

the crew stopped communicating with air traffic controllers.

Helios 522, over.

Mayday.

Then, after 2 and 1/2 hours

in the air, one of the plane's flight attendants

was seen at the controls.

522, Athens.

But investigators still

don't know what happened to the plane's captain

or the rest of the crew.

Tell me about what happened the day of the flight.

They concentrate on the conversation

between the pilot and the Helios engineer

shortly after takeoff.

As the plane passed through 10,000 feet,

an alarm sounded in the cockpit.

Operations, this is flight 522.

Over.

Flight 522, what can I do for you?

We have a takeoff config warning on.

Pardon?

Our takeoff config warning is on.

Usually, the takeoff config warning is only

triggered on the runway, but wreckage recovered

at the crash site reveals no problems with the plane's

flaps, landing gear, or anything else

that could trigger the alarm.

So why had it sounded?

Chief Investigator Akrivos Tsolakis

focuses on a small control panel found in the wreckage

of the ravaged jet.

Are you sure this is the way it was found?

It hasn't been moved at all?

We were lucky.

Finding this panel which had the switch

on the manual position was a major one.

The P5 pressurization panel

ensures that passengers have enough air to breathe,

even at high altitudes.

Normally, pressurization takes place automatically.

As the jet climbs, its engines force air

into the plane as they power it to the sky,

but when the pressurization switch is set to manual,

both the captain and co-pilot are

responsible for maintaining the cabin

atmosphere using a controller.

So explain again how you tested the pressure.

I went into the cockpit.

I turned the pressurization switch to manual.

Tsolakis learns that during the early-morning

maintenance check on Helios 522,

ground engineers had turned the P5 switch to manual.

That allowed them to use the onboard generators to test

the pressure seals on the plane's rear door

without starting the engines.

When the test was over, they didn't turn

the switch back to automatic.

The lights

Several hours later, when the flight crew entered

the cockpit, the pressurization switch

was still set to manual.

Air switches.

Bright today.

Are you almost through?

Pardon?

But neither the pilot nor co-pilot saw it.

As a result, after takeoff, the cabin would

not pressurize automatically.

And the higher flight 522 climbed,

the thinner the atmosphere became.

Not turning the switch back to automatic

was a deadly hidden danger.

Are you sure this is the way it was found?

It hasn't been moved at all?

Chief investigator Tsolakis

believes this panel could be the key to the mysterious

crash of Helios flight 522.

Leaving one switch on manual could

have led to all the other problems the plane faced.

To prove he's right, he takes an unusual step.

Four months after the disaster, he

takes an Olympic Airlines 737 on the same route

flown by the Helios jet.

If he's right about what caused the crash,

this plane should react exactly like the doomed airliner did.

Are we ready to go?

When there is a complicated accident like this,

I think a reenactment should be performed.

Of course, it's expensive to have a jetliner flying

for three or four hours, but it is worth

it if you have to come with some results which benefit

to the overall investigation.

Make sure the P5 is set to manual.

It's hard to see.

In the cockpit, Tsolakis

has the crew turn the pressurization

switch to manual.

A green light indicates it's no longer on automatic,

but in the bright glare of an early-morning departure,

the light is hard to see.

As the re-enactment flight climbs,

oxygen is thinning quickly in the aircraft.

The same thing happened on the Helios flight,

triggering an alarm.

What is it?

The takeoff config warning?

The alarm sounded,

and that alarm was misinterpreted.

Most of the flight crew,

they will never face an alarm

with no pressurization in all their flight career

because it's a rare event.

Tsolakis confirms that the alarm went off

because of the dangerously low air pressure in the aircraft,

but he also discovers that the sound itself

is identical to the takeoff config warning.

We have a take off config warning on.

But even if the flight crew did misinterpret

the first alarm, they still had another chance to determine

what the real problem was.

At over 16,000 feet, the plane's

master caution light flashed on and stayed on

for almost a minute.

We now have a master caution.

But once again, the pilots misinterpreted

the cause of the alarm.

The master caution light can indicate that the plane's

systems are overheating, but it can also tell pilots

the oxygen masks are down.

In this case, it was doing both at the same time.

But since the crew didn't think they were having

pressurization problems, they focused on the plane's

cooling systems.

On the recreation flight, investigators

monitor instruments recording the same events occurring

on board their aircraft.

At the same time, they also begin to feel the effects

of a lack of oxygen.

The first feelings you'd start to have

where your ears would pop.

You'd start feeling pressure in your sinuses.

As you climb higher, you begin to feel almost giddy.

It's almost like having a couple of drinks of alcohol.

The dwindling oxygen levels could also help explain

some of the crew's bizarre behavior,

such as when the ground engineer

asked about pressurization.

Can you confirm that the pressurization

panel is set to auto?

Captain Merton ignores the question

and responds with one of his own.

Where are my equipment cooling circuit breakers?

You really don't notice it at first.

It's amazing how subtle it can be in the early phases.

They start feeling dizzy.

They begin to lose the ability to think coherently.

In a way, it traps you into the situation.

You can't react to anything.

Eventually, you're going to lose consciousness.

Tsolakis believes that the captain may have been

checking on the circuit breakers behind his seat

when he and the co-pilot finally ran out of air.

And unlike in the cabin, the oxygen masks in the cockpit

do not automatically deploy if the atmosphere begins to thin.

Helios 522, can you hear me?

On the other side of the locked cockpit door,

no one in the cabin would have known that the plane

was now flying itself, nor were they have realized

that a limitation of the passenger oxygen system

had sealed the fate of everyone in the cabin.

Passenger masks are supplied by a chemical generator

above their seats, but the generators

only produce enough oxygen to last about 12 minutes.

Well, the problem with the passenger masks is,

for one thing, they're not designed to keep you

oxygenated at a high altitude.

What they're designed to do is give you enough oxygen

so that you can survive until the pilots get the airplane

down to a low altitude.

In almost every event where we've had a decompression,

that's been perfectly adequate.

For those who did put their masks on,

they would have remained conscious for several minutes

until their oxygen ran out.

Then they too would have passed out.

Once you get up to 34,000 feet,

you're talking useful consciousness

of 30 to 60 seconds.

Most of the people, once the hypoxia

begins to cause them to lose consciousness,

they're just going to go to sleep.

Without a flight crew,

Helios 522 would have continued to Athens on autopilot.

When the crew didn't take control,

the autopilot would have put the jet in a holding pattern

as it flew over the airport.

Exactly the same thing will happen

on the reconstruction flight if cabin pressure isn't restored.

Tsolakis asks the co-pilot to reset the P5 panel to auto

before the jet continues to climb to its cruising altitude

of almost 33,000 feet.

Then as it approaches Athens, Tsolakis

also has an F-16 shadow the jet performing at recreation.

He wants to confirm that it was Andreas

Prodromou at the controls of flight 522 when it went down.

We dressed one of our guys

with the uniform of the steward, and he came in.

He sat on the captain's chair, and the F-16

was looking at him.

He was confirming that it was exactly what

he saw on the accident plane.

The reconstruction also

answers another question about the tragic fate

of Helios flight 522.

The cockpit voice recorder picked

up several strange noises.

They're heard just before Prodromou enters the cockpit.

Tsolakis confirms that these sounds were made

by Prodromou, using the electronic keypad

to unlock the cockpit door.

We confirmed all those items.

And during the enactment flight,

it was very, very useful.

It filled a lot of gaps we had.

For Chief Investigator Tsolakis,

the re-enactment flight has been convincing.

There was no dramatic cabin failure, instead,

a series of small mistakes and misunderstandings

have led to the worst air disaster in Greek history.

15 months after the crash, Greek authorities

released the official report on Helios airways flight 522,

but mysteries remain.

What was happening in the cabin while the doomed airplane flew

towards Athens, and why was Andreas Prodromou the only one

conscious at the very end?

The crash of Helios flight 522 was

the worst disaster in the history of Greek aviation.

Like many crashes, it was a fatal combination

of mechanical problems and human error.

The final accident report details

a tragic series of oversights and false assumptions

made by the flight crew.

Problems that could have been easily prevented

turned deadly for all 121 people on board.

Where are my equipment cooling circuit breakers?

Behind the captain's seat.

Can you see them?

But what the final report does not do

is explain what happened in the cabin of the plane.

What actions did the flight attendants take?

And why was Andreas Prodromou still conscious after almost

three hours?

Mayday. Mayday.

Interviews with Helios safety instructors

and crew members painted tragic picture

of what may have occurred.

Everyone, please put your mask on.

We're not sure what the trouble is, but remain calm

and please remain seated.

Prodromou was sitting at the back of a cabin .

When the oxygen masks fell, he would

have waited for instructions from the cockpit.

The flight attendants sitting at the front of the plane

would have done the same, but none of them

would have waited forever.

We made it an issue at Helios

to emphasize that cabin crews should not entirely depend

on their procedures, but to think on their feet

and to adapt to any impending situation.

In most depressurizations,

the plane descends quickly.

But as minutes passed on the Helios flight,

the plane continued to climb.

Unsure of what was going on, Prodromou would have tried

to contact the flight crew.

Captain.

Captain Merton.

But he gets no response.

Can you give us an update, please?

Captain Merton.

With no word from the cockpit,

he would have soon realized that this was not

a typical depressurization.

When there was no call out from the cockpit

and the aircraft didn't start an emergency descent,

there was absolutely no protocol.

They would be winging it.

By now, Prodromou must have felt that something

was terribly wrong, but to find out what the problem was,

he had to leave his seat.

The oxygen available on the 737

is, of course, the dropout oxygen. 10% of those masks

are available for the crew in case of a

depressurization incident.

There are extra masks per every seat row.

Taking advantage of the extra passenger masks,

he could have made his way to the front of the plane,

a process cabin crew calls "monkey swinging."

But if more than 12 minutes had passed,

his girlfriend and the other flight attendant

may have still been in their seats

and, like the passengers, overcome by hypoxia.

But Prodromou was a scuba diver and a former soldier

in the Cypriot special forces.

His training may have helped him

to stay alert a little longer.

Andreas was not a coward.

He was a brave person.

Fearless, brave, and very calm.

But to survive after the passenger oxygen system

stopped working, he needed another solution.

The 737 had four portable oxygen bottles.

Each one could last more than an hour.

All four bottles were found at the crash site.

Three of them appeared to have been used.

While the F-16 pilot saw Prodromou in the cockpit

just before the crash, it may not have been

the first time he had gone in.

As he did at the end of the flight,

he could have used the security code

to unlock the door earlier.

During the accident investigation,

DNA was discovered on an oxygen mask in the cockpit

that matched the co-pilot's.

It's possible Prodromou used it to try and revive him.

You can still revitalize somebody,

and for quite an extended period of time,

if you get to them before major brain damage has set in.

And that's somewhat a variable situation,

depending on the person, depending on how long they're

exposed to a high altitude.

But if he was in the cockpit earlier,

why did he leave?

No one will ever know.

After three hours in the air, everyone

who didn't have bottled oxygen would have been unconscious.

As it approached Athens, flight 522 was now a ghost plane.

Most of the victims, they probably still

had heartbeats when the airplane

crashed, but almost certainly were in an irreversible coma.

Hypoxia is no more painful than falling asleep,

but for Andreas Prodromou, the flight

must have been a nightmare.

As the F-16s roared to meet the jet

and with his oxygen running out,

he must have known that he too was almost out of time.

Yet to the very end, he didn't give up.

Prodromou made one last attempt to save the plane.

When he returns to the cockpit, the young flight attendant

who dreamed of becoming a pilot calls for help,

but no one can hear him, probably because the radio was

still tuned to Larnaca, the airport on Cyprus

where the flight had taken off.

Fighting hypoxia and struggling to control an airplane larger

than any he had ever flown, Prodromou was

in an impossible situation.

Even if he could have landed the plane,

it was now too late.

Flight 522 was out of time and out of fuel.

There are pictures of Andreas in Cyprus,

in the cemetery where he and his girlfriend, Haris,

are buried side by side.

As his father,

my son is in front of me.

Wherever I go, he's always there.

He left a very big gap.

We will never get over it.

There are pictures in Greece, too.

On the hill north of Athens, where Helios flight 522

crashed, there are faded photographs

of many of those who died.