Jumbo Jet Strip-Down Engineering Giants

One aircraft transformed the world.

Request permission to carry out a high-power ground run.

With two decks carrying over 500 passengers...

..and wings the width of a football pitch...

..it was twice the size of any airliner before.

The Boeing 747.

Affectionately known as the jumbo jet.

OK, going up on one on four.

It's still an engineering marvel.

It's just awesome, the power of these things.

Now, as one 747, Victor X-ray, is stripped to its bare bones and given

the biggest overhaul of its life, there's a rare opportunity

to explore deep inside its hidden features.

-Wow! This is pretty cramped.

-HE LAUGHS

That is massive!

A 200-strong team of highly skilled engineers

take on the challenge of checking over 20,000 parts

of this mighty aircraft.

If we don't take that out now, that crack will just run and run and run.

Safety is paramount in this finely balanced machine.

Every component, from its engines to its kettles,

must be intricately examined for damage.

The amount of knowledge and experience we need to learn is just incredible.

I've got three children. They're very proud that Mummy works on aeroplanes.

When you see it barrelling down the runway at 150 knots,

you think, "I did them bolts up."

And we reveal what happens to a jumbo

when it reaches the end of its working life.

This is Engineering Giants.

I'm Rob Bell, I'm a mechanical engineer

and I've always loved to get my hands on complex machines

to discover how they work.

I'm Tom Wrigglesworth,

an electrical engineer with a passion for big machines.

And this is Victor X-ray, the 747 that's about to let us in to all its engineering secrets

This is the shortest flight this plane will no doubt ever do.

'It's flying just 132 miles from Heathrow to Cardiff Airport.'

And in a few moments' time, this is where the 747 will arrive.

This enormous maintenance hangar.

All planes are regularly maintained,

but, every six years, 747s come here for a complete overhaul.

That means that they're stripped right down,

every part is meticulously checked before being reassembled

and sent back out into service.

This is the first time that British Airways have allowed cameras

to film the complete overhaul of one of their aircraft.

And we'll be there for every critical stage in the engineering process.

This is a perfect opportunity for me and Rob to see deep within the Boeing 747

and appreciate how amazing these enormous machines are.

So there's the aircraft coming now.

Victor X-ray is the 1,172nd jumbo to be manufactured by Boeing.

It was delivered to the airline 14 years ago

and has since flown 36 million miles, equivalent to 1,500 times around the world.

Time for shut-down checks, please.

As Captain Doug Brown shuts down the engines

and hands the plane over to the Cardiff engineering team,

I've been offered a rare glimpse inside the flight deck.

Hey, Doug, thank you for letting me in here. This is, well, it's every boy's dream.

-Absolutely.

-Every boy's dream. What is the least used or pressed switch?

To be honest, very few of them get used in flight.

When the 747-400 was designed in 1989, it moved from being

a three-crew aeroplane with a flight engineer's panel there,

which had thousands of buttons, dials and gauges

and a full-time flight engineer,

to an automated two-crew aeroplane with just two pilots.

So this is a simplified version?

In some ways, yes, but what's going on behind the scenes is quite complex.

The actual heart of the aeroplane is this flight-management computer.

And what that allows us to do is to programme the aeroplane,

and the autopilot of the aircraft, with a lot of the information before a flight

and as we go through the flight, we're using the flight-management computer

to control the aircraft as much as anything else on the aeroplane.

In the case of raw flying, what is the minimum amount of controls you'd need?

CAPTAIN LAUGHS

In the absolute worst case, you can fly the aircraft using

these three basic instruments.

Artificial horizon, air-speed indicator and altimeter.

I don't know of any case where a 747 has got down to flying on those instruments.

There is a huge amount of redundancy built into the aeroplane.

Now, it's time for the £200 million worth of 747 to be carefully towed into the maintenance hangar,

where it will live for the next five weeks.

I always wondered what it would be like to be part of the ground crew at Heathrow.

I guess I'm getting a bit of a feel for it now.

Handbrake on. Good to go.

Now, I can finally climb aboard through what is currently

'the only way in - a maintenance hatch in the belly of the plane.'

-Welcome. Welcome aboard BA flight 319.

-Thank you very much.

-How was your flight?

-Excellent, thank you.

-Cheers, mate.

-I'll give you a hand.

-There we are. First class.

-It's pretty spacious up here.

-I've been sat in seat 1A.

-How's the view from up there?

-I'll show you.

-Ooh, that's the stuff!

-Absolutely, yeah, this is 1A.

-Reserved for the creme de la creme.

-Absolutely.

-Which makes this seat what?

-Mick Jagger's girlfriend.

-ROB LAUGHS

That'll do.

Now that Victor X-ray is safely inside the hangar,

the engineering team can begin the monumental task

of stripping the jumbo back to its aluminium shell

and forensically examining all of its critical parts for the smallest defect.

Number one to us is safety. Safety, safety, safety.

-We are looking after people's lives here.

-You can't make any mistakes.

You've got to be right all the time. There are no garages at 36,000 feet.

Over the next five weeks, engineers will work in teams

within different areas of the plane, methodically searching

for any signs of damage

amongst Victor X-ray's six million components.

One day we'll come into work and we'll be doing the cabin,

which is very involved.

There's all sorts of different disciplines of engineering

that the cabin holds and the next day we could be on the wing.

Next day, we could be doing the engine runs at the end of the check, which is pretty exciting.

This complex operation will take over 30,000 working hours,

with the team having to complete 12,000 separate jobs.

We pretty much run seven days, 24 hours.

General manager Bill Kelly is in charge of the maintenance facility.

How many years would that be flying for?

This aircraft could fly upwards of 25 years.

-Really?

-Absolutely.

A very robust, very reliable, strong aircraft.

When well maintained, as we do, they will go on for many, many years yet.

Bill and his team are under massive pressure

to finish Victor X-ray's overhaul on time.

On the same day it's due for completion,

the jumbo is scheduled to fly passengers to South America.

Delays can cost millions of pounds.

You get something wrong in maintenance where it delays you

by a day or two days, it can really impact

the rest of the operation, so you need to be on the ball.

Much of the work on Victor X-ray's fuselage needs to be carried out at height.

The tip of its tailfin is 20 metres above the ground,

so the aircraft will be surrounded by this rig,

designed by these engineers specifically to fit a 747.

It's not until you get up close to the tailfin that you get

a sheer sense of scale for the whole thing.

From the tip to the ground is almost 70ft.

Looking back along to the front of the aircraft

is a perspective I've never seen before.

It's seriously impressive.

The first big engineering challenge

is to test one of the plane's heftiest components -

the 18-wheeled landing gear.

Locked into the scaffolding rig,

the plane can't be propped up like a car,

so its 180-tonne weight is supported on three jumbo-sized jacks,

as the floor is lowered.

I can see clear ground, now, between the wheels and the floor.

A failure of the mechanical systems that lower the landing gear

could be disastrous.

So this is the only occasion when engineers have the opportunity to check that the wheels

can drop safely if the pilot has to rely on gravity.

Whoa, Jeez!

And here they come.

The landing gear weighs as much as a double-decker bus,

so if it was simply allowed to fall down, it could potentially cause serious damage.

Just getting the front one done.

So its mechanisms are designed to offer enough resistance

to control the speed of deployment.

Now they've dropped, the guys are giving them a push

to get them finally locked into place.

If you're in the air and you have to do that, the pilot would just kind of swing the plane a bit

and get them to swing out and lock. And for the back gears there,

the air pressure that's flowing past it would lock them back into place.

What are these two plates at the top here?

On the nose wheel, you've got no brakes,

so when the aircraft takes off, the wheels are spinning pretty fast.

so those are, basically, big scuff plates.

The tyres will hit them and it just slows them down and stops them.

OK, OK.

Inside Victor X-ray,

the cabin team are preparing to strip out all the seats.

Melanie Geddes and Janice Nash are among a growing number of female engineers

working at the facility.

You say you work for British Airways.

Everybody knows the brand, and they assume you are cabin crew.

They don't naturally assume that you work in engineering.

So it's something to be proud of. I've got three children.

They're very proud that Mummy works on aeroplanes and fixes aeroplanes.

So it's definitely one to tell the kids.

You go home from work one day, your boyfriend saying, "I've been stuck in the office."

You say, "I've been walking the wing today." They're like, "Wow!" It's great.

Through rigorous training,

engineers must learn every facet of the 747.

Stan Williams first worked on the jumbo 19 years ago

and flying on one has never been the same since.

I'm listening for everything! You can't help it. I wish I didn't.

Sometimes I put headphones on, because you don't want to hear.

There's lots of noises, different noises, that go on on an aircraft when its in flight.

You can't help it. It's in our blood, if you like.

-'Before everything disappears from the cabin...'

-This is the CSD's office.

'..cabin-crew member Becky Wadsworth has agreed to reveal some aspects of working on a 747.'

'She's spent over 10,000 hours in the air

'on planes like Victor X-ray, where space is extremely tight.'

-These are the ovens.

-These are the ovens. OK.

On an average flight, Becky and her team will serve 300 passengers

over a tonne of food and drinks.

Is it true that when there are two pilots on board, they have to have a different meal?

That's... Absolutely.

So should there be something wrong with the chicken, for example,

you don't want them both coming down ill with the same thing.

-It's those little flashpoints. Who decides first?

-It's normally the captain.

-Captain first, co-pilot gets what's left.

-That's it.

The captain will often say, "You choose first."

Oh, what a lovely English tradition.

'A 14-hour flight in cramped conditions is hard work.

'So today's 747 crews are able to use a secret compartment...

'..above the passengers' heads.'

-Up the stairs is the crew rest area.

-Space is a premium up here!

-Absolutely!

Cosy.

Oh, wow. What's the longest flight you do?

It's about 14 hours, from Singapore.

And in that time, how long would you get to spend enjoying this luxury?

You'd get about three-and-a-half-hours' rest.

I think what you also should have is a little button

-to call a member of the public up to help!

-SHE LAUGHS

Back down in the cabin, the next test is on a critical safety component

that airlines hope their passengers will never see.

Go on.

HE LAUGHS

Whoa!

That was impressive.

Failure of the chutes is not an option.

With lives depending on them,

they must inflate within seconds and stay inflated.

So all 12 chutes are sent to the interiors workshop for rigorous testing.

Wow. It's huge.

Here, specially trained engineers, like Michael Wake,

ensure that the slides are leak-free

and inflate at incredibly high speeds.

-Basically, they've got to open up within a certain time limit...

-OK.

-..which on this unit is three seconds.

-OK.

So what's the process behind inflating one of these?

The door will open

and then the cylinder charges at 300 psi.

-That's this here?

-Yeah.

There's a huge technical challenge with the inflation of such a large device.

To inflate something the size of an aircraft lifejacket,

a small canister can provide enough air.

But the same system would require a three-metre-long canister on an escape chute.

So, instead, when triggered, the canister of compressed carbon dioxide and nitrogen

delivers only an initial boost.

The clever technique is that these gases are forced through

a narrow gap, which causes them to accelerate rapidly.

This acceleration creates a vacuum that then sucks in enough ambient air

to inflate the entire slide in three seconds.

Woo-hoo-hoo!

That was pretty quick.

-Three seconds. We happy with that?

-Yeah.

-Wow.

And look at it, I mean, it's absolutely solid.

Testing the escape chute is the easy part.

Now, like a parachute, the 30 square metres of material must be folded

precisely back into its container, measuring just half a square metre.

-And, typically, that would take how long?

-Six hours of hard labour.

-Wow.

It's as much an art as science.

It's all too easy to take flying for granted.

As passengers, we're oblivious to the fact that the enormous metal tube we're travelling in

is flying through the air at close to 600 miles an hour.

And at a height similar to Everest -

an atmosphere unable to support life.

Engineer Gavin Beverstock is showing me

how Victor X-ray pumps air from its engines into the cabin

to create an atmospheric pressure similar to conditions on the ground.

A rise in altitude means a decrease in pressure.

But, also, due to comfort for passengers, it has to be maintained.

When we're on the ground, we're at 14.7 psi

and, as you're rising through the air, it reduces down.

Once you get below 10 psi, it's not very comfortable,

you start having breathing problems. The air's so thin, you will struggle.

But the greater the pressure of air that these pipes pump into the cabin,

the stronger the fuselage needs to be.

That would add weight to the aircraft.

So there's a compromise.

Planes usually fly with the pressure equivalent to between 6,000

and 8,000 feet, comparable to the world's highest cities.

That means reduced oxygen

and is one of the reasons we often feel tired on a flight.

Pressurising the cabin can also cause metal fatigue,

because, as air is pumped in and out of the aircraft,

its fuselage expands and contracts.

You can see the dimples along the skin of the plane

which, when it's pressurised up in the air, all gets smoothed out.

It's a pretty amazing bit of engineering,

but this frequent flexing of the fuselage can cause cracks.

It's one of the major reasons why Victor X-ray is undergoing

this intensive operation.

In order to thoroughly examine every inch of the airliner's internal shell,

engineers have to remove almost every fixture and fitting inside the cabin.

Some 747s can take over 500 passengers.

But airlines can use tracks in the floor to choose their own seating plan.

On Victor X-ray, Mick Gregg and his team must strip out 299 seats.

With the right allen key, do you steal yourself a bit of extra leg room in-flight?

-Would that...?

-No, it wouldn't!

Not unless you'd got a hammer and drift with you!

-You'd never get past security!

-No, you wouldn't.

-They are light. They're lighter than a settee, aren't they?

-Yeah.

There you go, Tom, done.

Once removed, Victor X-ray's seats are sent to the interiors workshop to be reupholstered

and put through their paces by veteran seat tester Mark Jago.

Is it your job to sit in this chair,

watch films, play a few games and say, "Yeah, we're good"(?)

-It's a terrible job, but somebody's

-got

-to do it!

Back in the hangar, work continues in the cabin.

All these side walls are yet to come out.

All the dadoes on the bottom are all to come out.

300 floor panels must be removed.

All the centre trough area there gets reworked.

180 window protectors and blinds taken out.

And 140 side wall panels stripped off.

-Here we go.

-This is the skeleton of the plane, here. This is the...

Behind here, that's the framework.

Aluminium frame?

Yeah, it's all aluminium. Wouldn't have steel, it's too heavy.

We want an aircraft to be as light as possible.

And that insulation is pretty vital, isn't it?

-Because it is -50 degrees outside.

-Yes, it is.

It gets to about -56 degrees at around 30 to 35,000 feet.

-And that's enough to protect you from that -50?

-Yeah.

It's two days into the overhaul

and most of the first-class cabin fittings have been removed.

The team can now begin the painstaking task of searching

every inch of the internal frame for the smallest of defects.

Lo and behold, we've found a little crack down in the corner,

which we're going to put right. Yeah, your favourite seat, 1A.

'Shift manager Paul Thomas has discovered a minor crack

'in one of Victor X-ray's floor supports.'

..which is right in the corner.

You can see the telltale, and it runs right to the corner.

They normally emanate from fastener holes or a rivet

-and then run out.

-Sharp edges, you know.

Yeah, well, you can see the line, it's tracking.

So, yeah, we pretty much got to replace that part now.

-You visually inspect the whole structure?

-Yeah, absolutely.

If we don't take that out now, that crack will just run and run

and run and run.

So, we've found it now. So, the floorboards will come up.

-We'll de-rivet all this area.

-Just for that?

-Just for that small, little crack.

-Yeah.

Reassuring, huh?

It is reassuring, because, I mean, my car is, you know...

Call that a crack? I'll show you cracks.

No lay-bys at 38,000 feet, I'm afraid.

-There are no lay-bys in the sky.

-No, absolutely.

It's day four of the overhaul.

And work is beginning on Victor X-Ray's largest components,

its wings.

From wingtip to wingtip, we are looking at about 211 feet,

so a huge, huge wingspan.

-That's about a football pitch then?

-About a football pitch, yeah.

Overseeing the work on the aluminium and carbon fibre wings

is shift manager Chris Morgan.

Obviously, they're very sturdy,

but there's quite a bit of movement.

Yeah. You can see there's movement there now.

You get a total displacement up and down of about 32 feet.

That's because you don't want a wing to be rigid.

They need to allow for turbulence, for air flow.

How air flows around a wing is crucial to achieving flight

and yet, incredibly, even among experts,

there are different theories

to answer the question - how does a plane fly?

Most people have that question answered with Bernoulli's theory.

Bernoulli's theory suggests that air going over the top of the wing

has to travel further than the air going underneath.

Because it has got to travel further, it speeds up.

Because it speeds up, the air particles spread out and diffuse.

This results in lower pressure above the wing

than the pressure beneath.

That pressure difference literally pushes the plane into the air.

But this doesn't explain why planes can fly with symmetrical wings.

In fact, it's the angle of the wing

and the amount of air it deflects down that matters.

Because according to Newton's third law,

the air force downwards results in an equal

and opposite force upwards, onto the underside of the wing.

At the right speed and angle,

this is enough to lift the plane into the air.

In flight, Victor X-ray's wings are subjected to enormous forces.

Apprentice Lewis Robinson Hoare has been scouring

the surface of this wing to find any damage that may have occurred.

We found some damage during inspections.

Which... The damage is around there,

where all that is pulled away from the structure below it.

-OK. So, the composite is starting to come apart.

-Yeah.

'Defect spotted, it can now be repaired.

'It turns out that Lewis's engineering passion

'runs in the blood.'

Three generations of my family have worked here.

-So, it just runs in the family, I suppose.

-Yeah.

-Are they on shift with you sometimes?

-No.

-My dad's on the opposite shift to me.

-OK.

Which is OK.

And my bampy is retired now.

But he used to work in here, as well.

Lewis's next job is on Victor X-ray's flaps,

vital components which increase the surface area of the wings,

allowing aircraft to fly at slow speeds.

The only way

the crucial hydraulic and backup electrical control systems

can be thoroughly checked is to remove the flaps.

Lewis has to control this crane with absolute precision.

The crane has been set to 0.9 of a tonne,

which is the exact weight of the flap they're removing.

That's so when the last guy undoes the last bolt,

the wing doesn't drop to the floor or fly to the ceiling.

Is she off? OK.

Slowly but surely, the flap is removed from the wing,

with barely a millimetre of movement up or down.

Let it go.

It's all yours, all right?

Look at his face, he's loving it.

During flight, air passes over these flaps and wings

at hundreds of miles an hour.

That causes friction and the build-up of static electricity.

To deal with that, there are small attachments known as static wicks.

If you could see it, how would that static look coming off here?

Does it just sort of fizzle out?

Literally that.

Visibility wise, it is often very hard to see.

-But you will still get sparking that will occur.

-Really?

-Yes.

Sometimes in electric storms and certainly in a lightning strike,

we will get these, like, sacrificial...

They will take a bit of a battering.

On average, every aircraft is hit by lightning once a year.

So, how does a plane deal with this phenomenon?

This laboratory at the University of Cardiff holds the answer.

Because this is one of the few places in the world

where scientists, led by Phil Leichauer,

have the technology to make lightning of their own.

It might sound mad doing these lightning tests to planes

and things, but absolutely everything on an aircraft has to be certified

against all the threats that could be posed to it.

The state of the art laboratory tests new materials,

as aircraft manufacturers look to find lighter, more cost-effective alternatives

to the aluminium currently used.

So, why do planes get hit by lightning?

The airplane, seeing as it's in the sky, it's a huge metal object,

it induces the lightning strikes itself

because it is the only thing there.

So, how do planes survive?

To find out, we're going to test this aluminium model,

similar to our own 747.

-Let's blow it.

-OK.

-You might have the best job in the world.

Sometimes I think so. There's a lot of paperwork, too, though.

Now, it is my chance to play God.

Basically, when I say fire, it's very easy, just press fire.

And...fire.

So, you see? The model aeroplane survived.

It did. It looks perfectly intact.

Everything and everyone inside a plane is protected

by the aluminium fuselage, which is a good conductor.

It allows the electricity to take the path of least resistance,

along the fuselage and out again.

What would the passenger feel?

They might hear a loud thump, but that is about it.

They shouldn't feel anything at all.

A graphic experiment illustrates the dangers of using

-'a non-conducting material, in this case - plastic.'

-Fire.

Which is why all new material combinations

are so extensively tested.

Back at the hangar, work to strip back the 747 continues.

Today, engineers are about to reveal

one of the parts of the plane that the public never sees.

The nose cone, or ray dome as it is known,

shields the aircraft's weather radar,

which needs to be checked for corrosion.

And it works on the radar principle, which is like a complicated eco.

It fires out radio waves in a very, very fine focus.

It fires a beam out and then listens to that beam coming back,

which will bounce off any clouds or anything that is up ahead.

And that information is fired out at different angles to allow

a huge range of sight, which is fed back to the flight deck,

so the pilot can take whatever action he needs to take.

Victor X-ray is now a week into its overhaul.

Next, its most valuable components are about to be removed

for closer examination.

This is a big moment. They're taking the engine off the wing.

These things cost about £8,000,000 each.

The last thing you want to have happen

is it come crashing to the floor.

As experienced as he is,

it's a nervous moment for team leader Scott Croll.

I started as an apprentice ten years ago

and I worked my way up to team leader.

Even as a team leader now, the amount of knowledge

and experience we need to learn is incredible.

I think that is what keeps me going.

Generating over 60,000 pounds of thrust, an engine exerts

enormous pressure on the mounts that hold them in place.

It is crucial that engineers remove the engines

so they can examine these fixtures for signs of wear.

The pylon is that big bracket, if you like, you can see,

which connects the engine to the wing.

-The engine to the pylon itself has got eight bolts.

-Eight bolts? Wow.

Yeah, just for at the front and four at the back.

And that's what the boys are undoing now. They're undoing the four...

The eight bolts are crucial in holding the engine in place,

so each one will be sent to a laboratory and tested

for weaknesses.

There it is, yeah.

These all get sent away now, NDT'd but we'll have a new set going on.

-NDT - non-destructively tested.

-Nice.

Maybe X-rays, ultrasound.

Of course, looking inside, yeah.

For the drop,

the seven-tonne engine is supported in a sling attached to the crane.

It is an impressive operation to make sure this is all rigged up

perfectly well, so nothing can go wrong.

Yeah, you'll just be pushing it.

I mean, it's heavy to push or once it's suspended it's quite free?

We're just supporting it. Obviously, we try not to...

All the work is done by the crane.

All right? So we let that do it. OK, clear, come down.

-It's all happening.

-Take it down.

Scott and his team slowly lower the engine,

making sure that all of its pipes are disconnected.

To be honest, it seems that the tension

has been transferred from the crane into the engineers here.

You can see them all getting more and more focused,

-as it slackens off.

-Going down again.

I don't think even steel toe caps would withstand the force of one of these coming down.

-Looking good, we're almost there.

-That's it.

-It's in?

-Yeah, we're good.

And that, ladies and gentlemen, is a wrap.

So, at the end of the day, Scott, when you go home, you've still got that job satisfaction with you?

Oh, definitely. Every day I go home

and I see my little girl and she says,

"Daddy, how did your day at work go today?"

And I say, "Honey, today Daddy fitted an engine,

"not just any engine, an RB211."

-Here we go. Full-on impression now.

-Yeah.

When turning, the big fan at the front sucks in air,

which is then compressed, mixed with a mist of fuel

and ignited in a combustion chamber.

This produces a huge, continuous blast of energy

in the form of hot gases.

These are directed out the back of the engine,

producing some of the engine's thrust.

The energy from the combustion is also used to spin the front fan

faster, sucking more air in.

This air is directed around the outside of the core and forced

out of the rear, producing the rest of the engine's thrust.

The 24 precious titanium fan blades,

which provide the lion's share of the aircraft's thrust can now be removed

and examined by Chris Thomas and his team for damage.

Is it heavy? Can I...?

I mean, yeah, it is not an inconsiderable weight,

but it's lighter than I thought it would be.

'The titanium blades are hollow to save weight.'

What exactly are you looking for when doing those inspections?

OK, when I inspect the blade,

I inspect the surface of the blade,

the leading and trailing edge of the blade for any erosion damage,

any chips or dents, any corners missing

or any impact damage you can get on the surface of the blade.

Blades can be damaged by hail or bird strikes.

All the blades I've got on the blade roots here.

-You see the markings on the blade roots.

-Yeah.

Each blade is serialized and they're put in a specific location

to balance the hub.

So much like on a car wheel

when you have something done with your car wheel,

it needs to be balanced so when it's going round

-at a high speed it's not causing vibration.

-Exactly.

So, if you had to do work on one blade, you might have to rebalance

-the whole thing, not just that blade.

-That's right.

-Wow.

Fully loaded, Victor X-ray needs

approximately 120,000 horse power from its four engines

to get into the air.

That is similar to the power of 1,000 family cars pulling

this plane off the ground.

-It's just in through this hole?

-Just in through that hole.

-This one here?

-That one.

And generating that level of thrust is thirsty work.

Wow, this is pretty cramped.

I am crawling up into the bowels of the 747 with engineer Phil Taylor.

He will spend over two weeks looking for leaks

inside the aircraft's labyrinth of fuel tanks.

-So, this is the main tank.

-We are in the centre wing tank,

which is situated between the two wing sections.

Above you, is the cabin area, with the cabin seating.

And you are in the forward midsection of the aircraft, basically.

-It holds 65,000 litres.

-65,000 litres?!

-Certainly.

And is that all in this bit here?

No, this is one compartment of six compartments going towards

the rear of the aircraft.

-But there's more than one tank on a plane.

-There's eight in all.

So how much fuel are you looking at, across all of it?

The fuel quantity for the whole aircraft is 216,000 litres.

That is massive! Your average-sized car is what? I don't know, 60 litres?

Something like that.

So, approximately 3,500 cars you could fill

with one jumbo-full of aviation fuel.

Victor X-ray is now two weeks into its five-week overhaul

and so far, it is on schedule.

Engineers have completed over 5,000 of the 12,000 jobs that need

to be done before the 747 can be classified as airworthy again.

In the cabin, the last remaining floor and wall panels

need to be stripped, along with the toilet module.

-I'm good to go, Mick.

-Right, OK.

'I'd been roped in to help.'

-It stinks, Mick.

-I did tell you that.

Woo!

Now, Mick, on a lot of old trains,

I know that anything that was produced

would just be dumped out onto the track. And from that,

I think this urban myth has developed that suggests

the same happens on planes. Has that ever been true?

No. It ends up in the aft freights,

-which is right down the back there.

-All right.

We've got four tanks.

I last met Mick removing all the seats

and I wondered if working on aircraft for 19 years made him

feel more or less comfortable about flying in one.

I love flying anyway, so it doesn't bother me in the slightest.

-I've always loved flying. The wife doesn't like flying at all.

-No?

So, I mean, we'll go on holiday to Lanzarote, something like that,

and we sit there and the flaps all go down.

-And she's gripping your hand.

-"That the flaps going down."

-And she'll go, "Shut up, I don't want to know."

-Really?

-Yeah.

In an industry where safety is paramount,

even a toilet is a highly engineered piece of kit.

As an electrical component that could cause a fire,

it has to undergo stringent tests before it is passed fit to fly.

The tests are carried out at the company's avionics facility outside Cardiff.

Here, the hundreds of electronic gadgets used on a plane -

from navigational aid and in-flight entertainment remotes

to toilet flushing systems - are stripped,

tested and calibrated by highly skilled engineers

like Martin Jenkins.

So, what happens when you go to the toilet on an airplane, Martin?

When you actually finish what you are doing,

you press your little button, which is on the side of the toilet in the cabin.

It is. There's a massive whooshing noise.

That is what we hear on the actual rig.

We get a spray of water from the top

and a vacuum gets created in the bowl and sucks it all away.

Above 16,000 feet,

air pressure outside the plane is considerably lower than inside.

By opening a small vent, the waste pipe

and tank are brought to the same low pressure as outside,

effectively creating a vacuum.

This means that when a seal on the toilet bowl is opened,

anything in the bowl is sucked away into the pipes and waste tanks.

When you are flying, Martin, when you go to the toilet in the air,

you must have any ear now for what is the perfect flush.

That is a good point, actually, because sometimes you might

get one that is working, but not to the full capacity.

As you just said, you can pick it up as you are listening to it, the actual flush.

You might not hear it, but I probably would. And the other guys who work here as well.

Although it might seem over the top, this level of testing

is not without good reason.

On a flight, electrical power is at a premium, so even

the kettles are tested to make sure they don't use too much electricity

and take it away from a more important system.

Engineer Simon Aucock is currently checking that these kettles

draw the correct current, while taking the exact time to reach

the precise temperature to make a perfect cup of tea.

We boil it 83 Celsius, plus or minus 2 Celsius.

The board of tea tasters have decided.

If you read a packet of, say, PG Tips or whatever,

it never says boil a kettle.

-It says hot but not boiling, doesn't it?

-Yeah.

-It's amazing, even the kettles are over tested.

-Yeah.

When the 747 flew for the first time over 40 years ago,

many of these devices being tested here hadn't even been invented.

As technology has evolved, manually controlled cables

and pulleys have been replaced by computer-controlled

electronic signals, transmitted by wires.

Beneath Victor X-ray's passenger compartment is the cargo bay,

surrounded by the 172 miles of wiring

that connect all the plane's complex systems.

Just looking around,

there are miles and miles of wiring here.

Many of these cables flow from the pilot's controls to these vital computers,

currently being examined by avionics engineer Nick Jordai.

The first 747s were designed back in the '60s.

I presume those would not have had any of this.

No. Their racks were built,

but it had totally different boxes.

They were much more primitive than they are now.

So, how would what these boxes do now have been done back then?

A lot of the functions done by these boxes used to be done

-by the flight engineer.

-That role is redundant because of these guys.

There's a thought, a machine taking over man's job.

It is now just three weeks until Victor X-ray is due to fly again.

As it's been stripped bare, I've been able to see

how the aircraft's intricate flight controls work,

delved inside its complex engines

and experienced the impressive mass of its landing gear

as it was tested.

But could the plane's computers I've just seen

control all of these without a pilot?

I'm really interested to see if it could actually fly itself.

I am heading down to London to see pilot Doug Brown,

who flew Victor X-ray to Cardiff.

He is going to demonstrate a 747's autopilot

in one of the airline's £8 million flight simulators.

Right, I'll give you a chance to fly the aeroplane manually for a little while.

-As it...

-As we are climbing away, yep.

Then what we'll do is put the autopilot in, bring it round and

-then we'll do an automatic approach and an auto-land onto this runway.

-OK.

So, essentially there are three planes to be thinking about.

-One is pulling back to be able to lift off vertically.

-Yep.

-You've got the steering and the pedals to keep yourself down the runway on that plane.

-Yep.

-But then you've also got this horizontal level.

-Indeed.

What does this control?

All four of the engines.

So, engines one to four, forward thrust on there.

-You can see the engines spool up.

-Here we go.

-That's actually there.

-OK. Now I'm going to put full power on.

Now, we are coming up towards the speed we ask you to pull back at.

-Really? Oh, there we go.

-And rotate.

So, back on the control.

Don't turn the stick while rotating, keep it in the middle.

That's nice. A bit further, I'm going to select the landing gear up.

This is amazing. This is amazing.

Once up,

it's a tight 360-degree turn

so that we can simulate an automatic landing.

-Can you see the airfield there?

-I can, straight ahead, yes.

We are going to let the autopilot run through

and we'll go right through to an auto-land.

Would autopilot be able to do that itself?

The aircraft will land itself if the pilot

-has set it up properly to do so.

-Fine.

The autopilot is now controlling the 747's approach to the runway,

altering the pitch and direction of the aircraft.

It can also control the level of trust.

But the autopilot cannot extend the wing flaps,

which slow the aircraft down, or deploy the crucial landing gear.

-Now it's going in, you see it?

-OK.

Only then can the 747 land itself.

Although the autopilot cannot apply the brakes.

-So, now you stick the reverse thrust on?

-You do.

-OK.

And a little bit of brake.

-That's it.

-Fantastic.

The 747 is a remarkably intelligent machine,

but it still requires skilled pilots to fly it.

And it is the high level of training which is one of the reasons

why flying statistically remains so safe.

Another reason is that the airline industry has learned

valuable lessons in rare accidents through an iconic component,

housed in the tail section of a plane.

Here they are, two black boxes.

This on the right, the data recorder,

records all the telemetry of the flight.

And on the left, is the voice recorder,

which records all the pilots' voices.

The two black boxes are regularly tested at BA's avionics lab,

where I met up with engineer John Davies.

This is a black box, but as you can see,

it is not actually black, it is orange.

And that's because it is clearly identified in any incident.

It is a big old tape recorder.

It is a big tape recorder. That's what basically it is.

As you can see, as well,

the tape is actually surrounded by two thermal packs, which are...

-Spring-loaded, as well.

-Spring-loaded, yeah.

With two thermal packs, which are chalk impregnated with water.

So, in the event of a fire, that water turns to steam,

keeps that tape at steam temperature.

-OK.

-So it won't destroy the tape.

And what sort of temperature range is it specified to?

Well, it should withstand 1,000 degrees C

over a 30-minute period of time.

That is where aviation fuel burns.

So the bit you're opening now, inside there,

that is the precious cargo.

This is the part we are interested in.

It will record the last 30 minutes of any flight.

It may look archaic and new airliners

have converted to digital, solid-state data storage,

but tape still does the trick.

That could contain the most precious of information

that will ultimately be fed back to make sure it never happens again.

-Exactly, yes. Which it has many times.

-Yeah.

To comply with comprehensive safety legislation,

all aircraft must work to strict maintenance schedules,

including detailed tests every year and a complete overhaul

every six years.

At 14 years of age,

Victor X-ray could still have another ten years of flying ahead,

but there comes a time

when a 747 is just too costly to keep maintaining.

Then, it is worth more as spare parts than a complete aircraft.

This is part of your flaps, part of the Krueger flaps.

Mark Gregory is the boss of Air Salvage International.

We are obviously the largest dismantling company in the UK,

in fact, in Europe.

'At Cotswold Airport, in Gloucestershire,

'Mark and his team salvage over 40 aircraft a year.'

These here, can we have a closer look at these?

They are 747 in-board landing gears

we removed from a 747-400.

If it has done a huge amount of landings,

then the value of that is kind of dropping.

But I think this has done quite a lot of landings. They're still not cheap.

-Roughly how much, then?

-You're probably looking at about 300,000

for a set of landing gears like this.

On a 747, Mark will salvage up to 1,200 parts,

which will eventually be sold to airlines around the world.

Precision electronics means a second-hand coffee maker

could fetch up to £3,000.

Even a simple bowl for the toilet could sell for as much as £500.

These are the front screens off the 747,

they've got a very high value. I would say probably around 30,000.

-What, each?

-For each screen, yeah.

These ones, obviously, are heated.

There are heated elements running through them.

I think they're gold heating elements that go through them.

-So, in here now, you've got...

-They are very, very thick.

They are really thick screens. They are laminated, as well.

-You can just see the elements in there.

-Yep.

A bit like your car heater front screen, as well.

That hits home, there.

The value of the whole industry.

Yeah, it's massive, absolutely massive.

80% of the salvage value of an aircraft comes from its engines.

This is a 737 engine.

-This probably has a resale value of about 1.2 million, I suppose.

-Wow.

And going back, the bigger engines at the back, are a bit more.

Once all the valuable parts of the 747 have been removed,

what's left of the aluminium shell will be tackled.

After almost 3 weeks,

Victor X-ray is now at a similar stage of its overhaul.

18 days ago this plane was flying passengers around the world

and today what it looks like inside is a far cry from what it would have been then.

In this skeletal state, there are signs of the 747's evolution.

We are right at the very front of the aircraft

and above us is the flight deck.

And just looking around, even in a plane as modern as the 747,

it is surprising to see how much mechanical equipment there is,

as well as all the electronics.

Victor X-ray still uses the jumbo's original cable and pulley system

to control some of the aircraft's most important functions,

including the landing gear doors and the rudder.

And then finally, right at the back here, hopefully, I... Yep.

You see the cables heading off through the cabin

and off to the rudder.

Keeping it mechanical, keeping it simple.

Ah, the flight deck.

It looks a lot different without the seats

and all the flight instruments.

The Cardiff team now have a tight deadline to turn Victor X-ray

back into a fully working plane.

It is booked to go back into service in just over two weeks,

on the same day the complex process is due to finish.

But when a 747 has come to the end of its working life,

like this one at Cotswold Airport,

there is no turning back for Mark Gregory and his salvage team.

We've removed over 130 tonnes of equipment

and all we're left with now is 100 tonnes of aircraft,

which has got very little value because the only value that is there is the metal.

At this point, the final part of the demolition process can begin.

So, we'll start, we'll take the tail off first, chew the tail up.

And then we'll work forward.

Then the wings into the fuselage.

And then through the rest of the body.

It doesn't take very long. It's about three days to do a 747.

It really is all the guts and the veins and everything

just being pulled out of the whole machine.

Look at that.

Very soon, this 747 is nothing more than a heap of scrap metal.

So, this is £200 million worth of plane reduced to probably

the most expensive pile of scrap I've ever seen in my life.

Only a few recognizable fragments of the aircraft remain.

-So, this is a leading-edge and this is...

-Aluminium.

-Well, there you go, you can see it here.

-It's thin, but pretty...

It takes some battering there, doesn't it?

Yeah, that's pretty durable.

As the wing moves back, it doesn't need to be as strong,

-so they make it out of this lightweight stuff.

-There you go, yeah.

Engineering being led by nature, isn't it? Honeycomb.

Look at this, though. You can see the thickness.

It's so thin, it's like that.

Some 747 flight decks are spared demolition

to be used as the shell in the construction

of flight simulators.

Wow. This is a bit different.

It's like a relic, isn't it? Look at that.

This is proper aviation history here, how it all used to be.

These controls here are where a flight engineer would have sat.

When you needed one. Obviously, on Victor X-ray, that's gone now.

The remaining carcass of a 747 like this still has a recycling value

worth up to £35,000.

Although it is no longer pure enough to be used again in aircraft construction,

as recycled aluminium, it does get to live another day.

Once they've separated out the aluminium, it'll be sent away,

smelted down and recycled, meaning what was once a fuselage

of a 747 could be your next fizzy drink.

Or even the frame of a bicycle.

We're on our way back to Cardiff,

where Victor X-ray should now have been given a new lease on life.

-Last time.

-Last time, indeed.

-It's heading out.

Tomorrow evening it's due to head back into service.

There it is, Victor X-ray.

Completely different, it's all back in.

-It does smell new.

-It does smell new.

The last time I was here, this was all completely open.

-Yeah.

-It's all on again, the screens are running, good.

Since arriving five weeks ago,

engineers have replaced over 5,000 separate parts,

including 11 brand-new toilets.

386 square metres of new carpet has been fitted along with 285 refurbished seats.

And there are 14 brand-new first class seats

for passengers paying upwards of £5,000 a flight for the luxury.

Wow!

-Oh, wow!

-Hey!

Ooh!

Oh.

It's mad to think it does all this AND it flies.

In just over 24 hours' time, these seats should be occupied

by paying customers en route to South America.

So now, for the first time in five weeks,

Victor X-ray is towed from the hangar,

for the final critical tests that need to be carried out to ensure

all the parts of the aircraft, including its four engines, are working.

For Hugh Gibbs, this is the only occasion

when an engineer gets to power up a 747 for real.

So, will we be moving anywhere

when you put it up to almost maximum thrust?

No, we've got the brakes on.

We can't do more than one engine at full power at a time.

-We have to do them one at a time.

-Really?

So if you had all four, we'd be taking off...

-Well, taking off through the middle of Cardiff airport.

-Yeah.

Request permission to carry out a high-power ground run.

OK, going up on one and four.

The sensation of being here right now is kind of what you get

when you hit turbulence midflight, but, yeah,

we're here on the runway, outside Cardiff airport.

It is just awesome, the power of these things.

That was a brilliant, fun experience for me.

From a technical perspective, how did it go?

All went well, we had no problems at all.

We got to high power and it was lovely and smooth.

And it passed all the tests that we need it to do.

And does running those engines up to throttle like that

get any less exciting any time?

No, I've been doing it for five years now, I still love it.

The following day, and on time,

Victor X-ray is ready to bid farewell to Cardiff.

For the engineers, this is the moment

when all the hard work pays off.

You know, job ownership,

especially if you have been on it from start to finish

and you look back, "I've done that.

"It works."

When you see it barrelling down the runway at 150 knots, you think,

"I did them bolts there."

You know, I've been in the industry 20 years

and you'll never lose that pride and that feeling inside

that you have been part of producing that product and keeping it safe.

And, obviously, knowing that

when the aircraft returns to Heathrow,

the customers then sit on that aircraft

and you know you've done your job well.

After five weeks, over 30,000 working hours

and 12,000 separate jobs,

Victor X-ray is ready once again to take to the skies.

And for the engineering team

who have painstakingly stripped the aircraft down

and built it back up again,

there is the satisfaction of knowing it works.

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