0:00:05 > 0:00:08One aircraft transformed the world.
0:00:09 > 0:00:12Request permission to carry out a high-power ground run.
0:00:13 > 0:00:17With two decks carrying over 500 passengers...
0:00:20 > 0:00:22..and wings the width of a football pitch...
0:00:24 > 0:00:28..it was twice the size of any airliner before.
0:00:29 > 0:00:32The Boeing 747.
0:00:35 > 0:00:39Affectionately known as the jumbo jet.
0:00:39 > 0:00:41OK, going up on one on four.
0:00:41 > 0:00:45It's still an engineering marvel.
0:00:48 > 0:00:51It's just awesome, the power of these things.
0:00:55 > 0:01:01Now, as one 747, Victor X-ray, is stripped to its bare bones and given
0:01:01 > 0:01:05the biggest overhaul of its life, there's a rare opportunity
0:01:05 > 0:01:07to explore deep inside its hidden features.
0:01:08 > 0:01:13- Wow! This is pretty cramped. - HE LAUGHS
0:01:13 > 0:01:14That is massive!
0:01:14 > 0:01:18A 200-strong team of highly skilled engineers
0:01:18 > 0:01:22take on the challenge of checking over 20,000 parts
0:01:22 > 0:01:24of this mighty aircraft.
0:01:24 > 0:01:27If we don't take that out now, that crack will just run and run and run.
0:01:29 > 0:01:33Safety is paramount in this finely balanced machine.
0:01:33 > 0:01:35Every component, from its engines to its kettles,
0:01:35 > 0:01:38must be intricately examined for damage.
0:01:40 > 0:01:43The amount of knowledge and experience we need to learn is just incredible.
0:01:43 > 0:01:47I've got three children. They're very proud that Mummy works on aeroplanes.
0:01:47 > 0:01:51When you see it barrelling down the runway at 150 knots,
0:01:51 > 0:01:54you think, "I did them bolts up."
0:01:54 > 0:01:57And we reveal what happens to a jumbo
0:01:57 > 0:02:00when it reaches the end of its working life.
0:02:03 > 0:02:07This is Engineering Giants.
0:02:12 > 0:02:15I'm Rob Bell, I'm a mechanical engineer
0:02:15 > 0:02:19and I've always loved to get my hands on complex machines
0:02:19 > 0:02:20to discover how they work.
0:02:20 > 0:02:22I'm Tom Wrigglesworth,
0:02:22 > 0:02:26an electrical engineer with a passion for big machines.
0:02:28 > 0:02:35And this is Victor X-ray, the 747 that's about to let us in to all its engineering secrets
0:02:38 > 0:02:42This is the shortest flight this plane will no doubt ever do.
0:02:42 > 0:02:46'It's flying just 132 miles from Heathrow to Cardiff Airport.'
0:02:46 > 0:02:50And in a few moments' time, this is where the 747 will arrive.
0:02:50 > 0:02:52This enormous maintenance hangar.
0:02:57 > 0:02:59All planes are regularly maintained,
0:02:59 > 0:03:03but, every six years, 747s come here for a complete overhaul.
0:03:03 > 0:03:05That means that they're stripped right down,
0:03:05 > 0:03:08every part is meticulously checked before being reassembled
0:03:08 > 0:03:10and sent back out into service.
0:03:13 > 0:03:17This is the first time that British Airways have allowed cameras
0:03:17 > 0:03:19to film the complete overhaul of one of their aircraft.
0:03:19 > 0:03:25And we'll be there for every critical stage in the engineering process.
0:03:25 > 0:03:29This is a perfect opportunity for me and Rob to see deep within the Boeing 747
0:03:29 > 0:03:33and appreciate how amazing these enormous machines are.
0:03:40 > 0:03:42So there's the aircraft coming now.
0:03:45 > 0:03:51Victor X-ray is the 1,172nd jumbo to be manufactured by Boeing.
0:03:54 > 0:03:58It was delivered to the airline 14 years ago
0:03:58 > 0:04:04and has since flown 36 million miles, equivalent to 1,500 times around the world.
0:04:04 > 0:04:07Time for shut-down checks, please.
0:04:07 > 0:04:09As Captain Doug Brown shuts down the engines
0:04:09 > 0:04:13and hands the plane over to the Cardiff engineering team,
0:04:13 > 0:04:16I've been offered a rare glimpse inside the flight deck.
0:04:16 > 0:04:20Hey, Doug, thank you for letting me in here. This is, well, it's every boy's dream.
0:04:20 > 0:04:26- Absolutely.- Every boy's dream. What is the least used or pressed switch?
0:04:26 > 0:04:29To be honest, very few of them get used in flight.
0:04:29 > 0:04:33When the 747-400 was designed in 1989, it moved from being
0:04:33 > 0:04:36a three-crew aeroplane with a flight engineer's panel there,
0:04:36 > 0:04:39which had thousands of buttons, dials and gauges
0:04:39 > 0:04:42and a full-time flight engineer,
0:04:42 > 0:04:44to an automated two-crew aeroplane with just two pilots.
0:04:44 > 0:04:46So this is a simplified version?
0:04:46 > 0:04:50In some ways, yes, but what's going on behind the scenes is quite complex.
0:04:50 > 0:04:54The actual heart of the aeroplane is this flight-management computer.
0:04:54 > 0:04:58And what that allows us to do is to programme the aeroplane,
0:04:58 > 0:05:02and the autopilot of the aircraft, with a lot of the information before a flight
0:05:02 > 0:05:06and as we go through the flight, we're using the flight-management computer
0:05:06 > 0:05:09to control the aircraft as much as anything else on the aeroplane.
0:05:09 > 0:05:12In the case of raw flying, what is the minimum amount of controls you'd need?
0:05:12 > 0:05:13CAPTAIN LAUGHS
0:05:13 > 0:05:18In the absolute worst case, you can fly the aircraft using
0:05:18 > 0:05:20these three basic instruments.
0:05:20 > 0:05:24Artificial horizon, air-speed indicator and altimeter.
0:05:24 > 0:05:28I don't know of any case where a 747 has got down to flying on those instruments.
0:05:28 > 0:05:31There is a huge amount of redundancy built into the aeroplane.
0:05:37 > 0:05:44Now, it's time for the £200 million worth of 747 to be carefully towed into the maintenance hangar,
0:05:44 > 0:05:47where it will live for the next five weeks.
0:05:55 > 0:05:59I always wondered what it would be like to be part of the ground crew at Heathrow.
0:05:59 > 0:06:01I guess I'm getting a bit of a feel for it now.
0:06:06 > 0:06:09Handbrake on. Good to go.
0:06:10 > 0:06:13Now, I can finally climb aboard through what is currently
0:06:13 > 0:06:17'the only way in - a maintenance hatch in the belly of the plane.'
0:06:17 > 0:06:22- Welcome. Welcome aboard BA flight 319.- Thank you very much.
0:06:22 > 0:06:26- How was your flight?- Excellent, thank you.- Cheers, mate. - I'll give you a hand.
0:06:26 > 0:06:30- There we are. First class. - It's pretty spacious up here. - I've been sat in seat 1A.
0:06:30 > 0:06:33- How's the view from up there? - I'll show you.
0:06:35 > 0:06:40- Ooh, that's the stuff!- Absolutely, yeah, this is 1A.- Reserved for the creme de la creme.- Absolutely.
0:06:40 > 0:06:45- Which makes this seat what? - Mick Jagger's girlfriend. - ROB LAUGHS
0:06:45 > 0:06:46That'll do.
0:06:49 > 0:06:53Now that Victor X-ray is safely inside the hangar,
0:06:53 > 0:06:56the engineering team can begin the monumental task
0:06:56 > 0:06:59of stripping the jumbo back to its aluminium shell
0:06:59 > 0:07:05and forensically examining all of its critical parts for the smallest defect.
0:07:05 > 0:07:10Number one to us is safety. Safety, safety, safety.
0:07:10 > 0:07:14- We are looking after people's lives here.- You can't make any mistakes.
0:07:14 > 0:07:18You've got to be right all the time. There are no garages at 36,000 feet.
0:07:19 > 0:07:23Over the next five weeks, engineers will work in teams
0:07:23 > 0:07:26within different areas of the plane, methodically searching
0:07:26 > 0:07:28for any signs of damage
0:07:28 > 0:07:31amongst Victor X-ray's six million components.
0:07:31 > 0:07:35One day we'll come into work and we'll be doing the cabin,
0:07:35 > 0:07:36which is very involved.
0:07:36 > 0:07:39There's all sorts of different disciplines of engineering
0:07:39 > 0:07:43that the cabin holds and the next day we could be on the wing.
0:07:43 > 0:07:48Next day, we could be doing the engine runs at the end of the check, which is pretty exciting.
0:07:48 > 0:07:54This complex operation will take over 30,000 working hours,
0:07:54 > 0:07:58with the team having to complete 12,000 separate jobs.
0:07:58 > 0:08:00We pretty much run seven days, 24 hours.
0:08:00 > 0:08:06General manager Bill Kelly is in charge of the maintenance facility.
0:08:06 > 0:08:08How many years would that be flying for?
0:08:08 > 0:08:11This aircraft could fly upwards of 25 years.
0:08:11 > 0:08:13- Really?- Absolutely.
0:08:13 > 0:08:17A very robust, very reliable, strong aircraft.
0:08:17 > 0:08:22When well maintained, as we do, they will go on for many, many years yet.
0:08:22 > 0:08:25Bill and his team are under massive pressure
0:08:25 > 0:08:28to finish Victor X-ray's overhaul on time.
0:08:28 > 0:08:31On the same day it's due for completion,
0:08:31 > 0:08:35the jumbo is scheduled to fly passengers to South America.
0:08:35 > 0:08:38Delays can cost millions of pounds.
0:08:38 > 0:08:41You get something wrong in maintenance where it delays you
0:08:41 > 0:08:42by a day or two days, it can really impact
0:08:42 > 0:08:45the rest of the operation, so you need to be on the ball.
0:08:47 > 0:08:52Much of the work on Victor X-ray's fuselage needs to be carried out at height.
0:08:52 > 0:08:57The tip of its tailfin is 20 metres above the ground,
0:08:57 > 0:09:00so the aircraft will be surrounded by this rig,
0:09:00 > 0:09:04designed by these engineers specifically to fit a 747.
0:09:04 > 0:09:08It's not until you get up close to the tailfin that you get
0:09:08 > 0:09:10a sheer sense of scale for the whole thing.
0:09:10 > 0:09:14From the tip to the ground is almost 70ft.
0:09:14 > 0:09:16Looking back along to the front of the aircraft
0:09:16 > 0:09:19is a perspective I've never seen before.
0:09:20 > 0:09:22It's seriously impressive.
0:09:24 > 0:09:26The first big engineering challenge
0:09:26 > 0:09:30is to test one of the plane's heftiest components -
0:09:30 > 0:09:32the 18-wheeled landing gear.
0:09:32 > 0:09:35Locked into the scaffolding rig,
0:09:35 > 0:09:38the plane can't be propped up like a car,
0:09:38 > 0:09:43so its 180-tonne weight is supported on three jumbo-sized jacks,
0:09:43 > 0:09:44as the floor is lowered.
0:09:50 > 0:09:55I can see clear ground, now, between the wheels and the floor.
0:09:55 > 0:10:00A failure of the mechanical systems that lower the landing gear
0:10:00 > 0:10:02could be disastrous.
0:10:02 > 0:10:07So this is the only occasion when engineers have the opportunity to check that the wheels
0:10:07 > 0:10:10can drop safely if the pilot has to rely on gravity.
0:10:12 > 0:10:14Whoa, Jeez!
0:10:16 > 0:10:18And here they come.
0:10:18 > 0:10:22The landing gear weighs as much as a double-decker bus,
0:10:22 > 0:10:27so if it was simply allowed to fall down, it could potentially cause serious damage.
0:10:28 > 0:10:30Just getting the front one done.
0:10:30 > 0:10:33So its mechanisms are designed to offer enough resistance
0:10:33 > 0:10:35to control the speed of deployment.
0:10:38 > 0:10:41Now they've dropped, the guys are giving them a push
0:10:41 > 0:10:43to get them finally locked into place.
0:10:43 > 0:10:47If you're in the air and you have to do that, the pilot would just kind of swing the plane a bit
0:10:47 > 0:10:50and get them to swing out and lock. And for the back gears there,
0:10:50 > 0:10:53the air pressure that's flowing past it would lock them back into place.
0:10:53 > 0:10:56What are these two plates at the top here?
0:10:56 > 0:10:58On the nose wheel, you've got no brakes,
0:10:58 > 0:11:03so when the aircraft takes off, the wheels are spinning pretty fast.
0:11:03 > 0:11:04so those are, basically, big scuff plates.
0:11:04 > 0:11:08The tyres will hit them and it just slows them down and stops them.
0:11:08 > 0:11:10OK, OK.
0:11:13 > 0:11:15Inside Victor X-ray,
0:11:15 > 0:11:19the cabin team are preparing to strip out all the seats.
0:11:19 > 0:11:22Melanie Geddes and Janice Nash are among a growing number of female engineers
0:11:22 > 0:11:25working at the facility.
0:11:27 > 0:11:29You say you work for British Airways.
0:11:29 > 0:11:32Everybody knows the brand, and they assume you are cabin crew.
0:11:32 > 0:11:36They don't naturally assume that you work in engineering.
0:11:36 > 0:11:39So it's something to be proud of. I've got three children.
0:11:39 > 0:11:42They're very proud that Mummy works on aeroplanes and fixes aeroplanes.
0:11:42 > 0:11:46So it's definitely one to tell the kids.
0:11:46 > 0:11:49You go home from work one day, your boyfriend saying, "I've been stuck in the office."
0:11:49 > 0:11:53You say, "I've been walking the wing today." They're like, "Wow!" It's great.
0:11:53 > 0:11:55Through rigorous training,
0:11:55 > 0:11:59engineers must learn every facet of the 747.
0:12:00 > 0:12:04Stan Williams first worked on the jumbo 19 years ago
0:12:04 > 0:12:08and flying on one has never been the same since.
0:12:08 > 0:12:11I'm listening for everything! You can't help it. I wish I didn't.
0:12:11 > 0:12:14Sometimes I put headphones on, because you don't want to hear.
0:12:14 > 0:12:18There's lots of noises, different noises, that go on on an aircraft when its in flight.
0:12:18 > 0:12:21You can't help it. It's in our blood, if you like.
0:12:24 > 0:12:28- 'Before everything disappears from the cabin...' - This is the CSD's office.
0:12:28 > 0:12:34'..cabin-crew member Becky Wadsworth has agreed to reveal some aspects of working on a 747.'
0:12:34 > 0:12:38'She's spent over 10,000 hours in the air
0:12:38 > 0:12:41'on planes like Victor X-ray, where space is extremely tight.'
0:12:41 > 0:12:44- These are the ovens. - These are the ovens. OK.
0:12:46 > 0:12:51On an average flight, Becky and her team will serve 300 passengers
0:12:51 > 0:12:53over a tonne of food and drinks.
0:12:54 > 0:12:59Is it true that when there are two pilots on board, they have to have a different meal?
0:12:59 > 0:13:00That's... Absolutely.
0:13:00 > 0:13:04So should there be something wrong with the chicken, for example,
0:13:04 > 0:13:07you don't want them both coming down ill with the same thing.
0:13:07 > 0:13:11- It's those little flashpoints. Who decides first? - It's normally the captain.
0:13:11 > 0:13:14- Captain first, co-pilot gets what's left.- That's it.
0:13:14 > 0:13:16The captain will often say, "You choose first."
0:13:16 > 0:13:18Oh, what a lovely English tradition.
0:13:20 > 0:13:23'A 14-hour flight in cramped conditions is hard work.
0:13:23 > 0:13:28'So today's 747 crews are able to use a secret compartment...
0:13:29 > 0:13:32'..above the passengers' heads.'
0:13:32 > 0:13:39- Up the stairs is the crew rest area. - Space is a premium up here! - Absolutely!
0:13:39 > 0:13:40Cosy.
0:13:40 > 0:13:43Oh, wow. What's the longest flight you do?
0:13:43 > 0:13:46It's about 14 hours, from Singapore.
0:13:46 > 0:13:49And in that time, how long would you get to spend enjoying this luxury?
0:13:49 > 0:13:52You'd get about three-and-a-half-hours' rest.
0:13:52 > 0:13:55I think what you also should have is a little button
0:13:55 > 0:13:57- to call a member of the public up to help! - SHE LAUGHS
0:13:59 > 0:14:03Back down in the cabin, the next test is on a critical safety component
0:14:03 > 0:14:06that airlines hope their passengers will never see.
0:14:07 > 0:14:09Go on.
0:14:09 > 0:14:11HE LAUGHS
0:14:13 > 0:14:15Whoa!
0:14:17 > 0:14:19That was impressive.
0:14:19 > 0:14:22Failure of the chutes is not an option.
0:14:22 > 0:14:25With lives depending on them,
0:14:25 > 0:14:28they must inflate within seconds and stay inflated.
0:14:28 > 0:14:32So all 12 chutes are sent to the interiors workshop for rigorous testing.
0:14:32 > 0:14:35Wow. It's huge.
0:14:36 > 0:14:39Here, specially trained engineers, like Michael Wake,
0:14:39 > 0:14:42ensure that the slides are leak-free
0:14:42 > 0:14:45and inflate at incredibly high speeds.
0:14:45 > 0:14:48- Basically, they've got to open up within a certain time limit...- OK.
0:14:48 > 0:14:51- ..which on this unit is three seconds.- OK.
0:14:51 > 0:14:54So what's the process behind inflating one of these?
0:14:54 > 0:14:55The door will open
0:14:55 > 0:14:59and then the cylinder charges at 300 psi.
0:14:59 > 0:15:01- That's this here?- Yeah.
0:15:02 > 0:15:07There's a huge technical challenge with the inflation of such a large device.
0:15:07 > 0:15:10To inflate something the size of an aircraft lifejacket,
0:15:10 > 0:15:12a small canister can provide enough air.
0:15:16 > 0:15:21But the same system would require a three-metre-long canister on an escape chute.
0:15:23 > 0:15:29So, instead, when triggered, the canister of compressed carbon dioxide and nitrogen
0:15:29 > 0:15:31delivers only an initial boost.
0:15:32 > 0:15:35The clever technique is that these gases are forced through
0:15:35 > 0:15:39a narrow gap, which causes them to accelerate rapidly.
0:15:39 > 0:15:44This acceleration creates a vacuum that then sucks in enough ambient air
0:15:44 > 0:15:48to inflate the entire slide in three seconds.
0:15:55 > 0:15:57Woo-hoo-hoo!
0:16:01 > 0:16:02That was pretty quick.
0:16:02 > 0:16:06- Three seconds. We happy with that? - Yeah.- Wow.
0:16:06 > 0:16:10And look at it, I mean, it's absolutely solid.
0:16:13 > 0:16:16Testing the escape chute is the easy part.
0:16:16 > 0:16:20Now, like a parachute, the 30 square metres of material must be folded
0:16:20 > 0:16:24precisely back into its container, measuring just half a square metre.
0:16:26 > 0:16:30- And, typically, that would take how long?- Six hours of hard labour.- Wow.
0:16:30 > 0:16:32It's as much an art as science.
0:16:39 > 0:16:42It's all too easy to take flying for granted.
0:16:42 > 0:16:49As passengers, we're oblivious to the fact that the enormous metal tube we're travelling in
0:16:49 > 0:16:52is flying through the air at close to 600 miles an hour.
0:16:52 > 0:16:54And at a height similar to Everest -
0:16:54 > 0:16:57an atmosphere unable to support life.
0:16:59 > 0:17:01Engineer Gavin Beverstock is showing me
0:17:01 > 0:17:07how Victor X-ray pumps air from its engines into the cabin
0:17:07 > 0:17:11to create an atmospheric pressure similar to conditions on the ground.
0:17:11 > 0:17:15A rise in altitude means a decrease in pressure.
0:17:15 > 0:17:19But, also, due to comfort for passengers, it has to be maintained.
0:17:19 > 0:17:21When we're on the ground, we're at 14.7 psi
0:17:21 > 0:17:25and, as you're rising through the air, it reduces down.
0:17:25 > 0:17:29Once you get below 10 psi, it's not very comfortable,
0:17:29 > 0:17:33you start having breathing problems. The air's so thin, you will struggle.
0:17:34 > 0:17:37But the greater the pressure of air that these pipes pump into the cabin,
0:17:37 > 0:17:40the stronger the fuselage needs to be.
0:17:40 > 0:17:43That would add weight to the aircraft.
0:17:43 > 0:17:46So there's a compromise.
0:17:46 > 0:17:49Planes usually fly with the pressure equivalent to between 6,000
0:17:49 > 0:17:53and 8,000 feet, comparable to the world's highest cities.
0:17:54 > 0:17:57That means reduced oxygen
0:17:57 > 0:18:00and is one of the reasons we often feel tired on a flight.
0:18:00 > 0:18:04Pressurising the cabin can also cause metal fatigue,
0:18:04 > 0:18:06because, as air is pumped in and out of the aircraft,
0:18:06 > 0:18:10its fuselage expands and contracts.
0:18:10 > 0:18:12You can see the dimples along the skin of the plane
0:18:12 > 0:18:17which, when it's pressurised up in the air, all gets smoothed out.
0:18:17 > 0:18:20It's a pretty amazing bit of engineering,
0:18:20 > 0:18:24but this frequent flexing of the fuselage can cause cracks.
0:18:24 > 0:18:28It's one of the major reasons why Victor X-ray is undergoing
0:18:28 > 0:18:30this intensive operation.
0:18:32 > 0:18:37In order to thoroughly examine every inch of the airliner's internal shell,
0:18:37 > 0:18:41engineers have to remove almost every fixture and fitting inside the cabin.
0:18:41 > 0:18:45Some 747s can take over 500 passengers.
0:18:45 > 0:18:49But airlines can use tracks in the floor to choose their own seating plan.
0:18:50 > 0:18:56On Victor X-ray, Mick Gregg and his team must strip out 299 seats.
0:18:58 > 0:19:02With the right allen key, do you steal yourself a bit of extra leg room in-flight?
0:19:02 > 0:19:03- Would that...?- No, it wouldn't!
0:19:03 > 0:19:05Not unless you'd got a hammer and drift with you!
0:19:05 > 0:19:07- You'd never get past security! - No, you wouldn't.
0:19:09 > 0:19:13- They are light. They're lighter than a settee, aren't they?- Yeah.
0:19:13 > 0:19:16There you go, Tom, done.
0:19:17 > 0:19:22Once removed, Victor X-ray's seats are sent to the interiors workshop to be reupholstered
0:19:22 > 0:19:27and put through their paces by veteran seat tester Mark Jago.
0:19:27 > 0:19:31Is it your job to sit in this chair,
0:19:31 > 0:19:35watch films, play a few games and say, "Yeah, we're good"(?)
0:19:35 > 0:19:38- It's a terrible job, but somebody's- got- to do it!
0:19:40 > 0:19:43Back in the hangar, work continues in the cabin.
0:19:43 > 0:19:46All these side walls are yet to come out.
0:19:46 > 0:19:48All the dadoes on the bottom are all to come out.
0:19:48 > 0:19:52300 floor panels must be removed.
0:19:52 > 0:19:54All the centre trough area there gets reworked.
0:19:54 > 0:19:58180 window protectors and blinds taken out.
0:19:59 > 0:20:03And 140 side wall panels stripped off.
0:20:03 > 0:20:07- Here we go.- This is the skeleton of the plane, here. This is the...
0:20:07 > 0:20:09Behind here, that's the framework.
0:20:09 > 0:20:11Aluminium frame?
0:20:11 > 0:20:14Yeah, it's all aluminium. Wouldn't have steel, it's too heavy.
0:20:14 > 0:20:16We want an aircraft to be as light as possible.
0:20:16 > 0:20:18And that insulation is pretty vital, isn't it?
0:20:18 > 0:20:22- Because it is -50 degrees outside. - Yes, it is.
0:20:22 > 0:20:25It gets to about -56 degrees at around 30 to 35,000 feet.
0:20:25 > 0:20:28- And that's enough to protect you from that -50?- Yeah.
0:20:28 > 0:20:31It's two days into the overhaul
0:20:31 > 0:20:34and most of the first-class cabin fittings have been removed.
0:20:34 > 0:20:37The team can now begin the painstaking task of searching
0:20:37 > 0:20:41every inch of the internal frame for the smallest of defects.
0:20:41 > 0:20:44Lo and behold, we've found a little crack down in the corner,
0:20:44 > 0:20:47which we're going to put right. Yeah, your favourite seat, 1A.
0:20:47 > 0:20:51'Shift manager Paul Thomas has discovered a minor crack
0:20:51 > 0:20:53'in one of Victor X-ray's floor supports.'
0:20:53 > 0:20:56..which is right in the corner.
0:20:56 > 0:20:58You can see the telltale, and it runs right to the corner.
0:20:58 > 0:21:01They normally emanate from fastener holes or a rivet
0:21:01 > 0:21:04- and then run out. - Sharp edges, you know.
0:21:04 > 0:21:06Yeah, well, you can see the line, it's tracking.
0:21:06 > 0:21:08So, yeah, we pretty much got to replace that part now.
0:21:08 > 0:21:12- You visually inspect the whole structure?- Yeah, absolutely.
0:21:12 > 0:21:14If we don't take that out now, that crack will just run and run
0:21:14 > 0:21:16and run and run.
0:21:16 > 0:21:18So, we've found it now. So, the floorboards will come up.
0:21:18 > 0:21:23- We'll de-rivet all this area. - Just for that?
0:21:23 > 0:21:25- Just for that small, little crack. - Yeah.
0:21:25 > 0:21:27Reassuring, huh?
0:21:27 > 0:21:31It is reassuring, because, I mean, my car is, you know...
0:21:31 > 0:21:35Call that a crack? I'll show you cracks.
0:21:35 > 0:21:37No lay-bys at 38,000 feet, I'm afraid.
0:21:37 > 0:21:41- There are no lay-bys in the sky. - No, absolutely.
0:21:49 > 0:21:51It's day four of the overhaul.
0:21:51 > 0:21:55And work is beginning on Victor X-Ray's largest components,
0:21:55 > 0:21:57its wings.
0:21:57 > 0:22:01From wingtip to wingtip, we are looking at about 211 feet,
0:22:01 > 0:22:03so a huge, huge wingspan.
0:22:03 > 0:22:06- That's about a football pitch then? - About a football pitch, yeah.
0:22:06 > 0:22:10Overseeing the work on the aluminium and carbon fibre wings
0:22:10 > 0:22:12is shift manager Chris Morgan.
0:22:12 > 0:22:13Obviously, they're very sturdy,
0:22:13 > 0:22:15but there's quite a bit of movement.
0:22:15 > 0:22:18Yeah. You can see there's movement there now.
0:22:18 > 0:22:23You get a total displacement up and down of about 32 feet.
0:22:23 > 0:22:25That's because you don't want a wing to be rigid.
0:22:25 > 0:22:28They need to allow for turbulence, for air flow.
0:22:28 > 0:22:32How air flows around a wing is crucial to achieving flight
0:22:32 > 0:22:34and yet, incredibly, even among experts,
0:22:34 > 0:22:36there are different theories
0:22:36 > 0:22:39to answer the question - how does a plane fly?
0:22:41 > 0:22:44Most people have that question answered with Bernoulli's theory.
0:22:44 > 0:22:47Bernoulli's theory suggests that air going over the top of the wing
0:22:47 > 0:22:50has to travel further than the air going underneath.
0:22:50 > 0:22:53Because it has got to travel further, it speeds up.
0:22:53 > 0:22:56Because it speeds up, the air particles spread out and diffuse.
0:22:56 > 0:22:59This results in lower pressure above the wing
0:22:59 > 0:23:01than the pressure beneath.
0:23:01 > 0:23:04That pressure difference literally pushes the plane into the air.
0:23:06 > 0:23:10But this doesn't explain why planes can fly with symmetrical wings.
0:23:10 > 0:23:12In fact, it's the angle of the wing
0:23:12 > 0:23:16and the amount of air it deflects down that matters.
0:23:16 > 0:23:18Because according to Newton's third law,
0:23:18 > 0:23:21the air force downwards results in an equal
0:23:21 > 0:23:25and opposite force upwards, onto the underside of the wing.
0:23:25 > 0:23:27At the right speed and angle,
0:23:27 > 0:23:29this is enough to lift the plane into the air.
0:23:32 > 0:23:37In flight, Victor X-ray's wings are subjected to enormous forces.
0:23:39 > 0:23:41Apprentice Lewis Robinson Hoare has been scouring
0:23:41 > 0:23:46the surface of this wing to find any damage that may have occurred.
0:23:46 > 0:23:49We found some damage during inspections.
0:23:50 > 0:23:52Which... The damage is around there,
0:23:52 > 0:23:56where all that is pulled away from the structure below it.
0:23:56 > 0:23:59- OK. So, the composite is starting to come apart.- Yeah.
0:23:59 > 0:24:02'Defect spotted, it can now be repaired.
0:24:02 > 0:24:05'It turns out that Lewis's engineering passion
0:24:05 > 0:24:07'runs in the blood.'
0:24:07 > 0:24:10Three generations of my family have worked here.
0:24:10 > 0:24:13- So, it just runs in the family, I suppose.- Yeah.
0:24:13 > 0:24:16- Are they on shift with you sometimes?- No.
0:24:16 > 0:24:19- My dad's on the opposite shift to me.- OK.
0:24:19 > 0:24:20Which is OK.
0:24:20 > 0:24:23And my bampy is retired now.
0:24:23 > 0:24:25But he used to work in here, as well.
0:24:28 > 0:24:31Lewis's next job is on Victor X-ray's flaps,
0:24:31 > 0:24:34vital components which increase the surface area of the wings,
0:24:34 > 0:24:36allowing aircraft to fly at slow speeds.
0:24:38 > 0:24:40The only way
0:24:40 > 0:24:43the crucial hydraulic and backup electrical control systems
0:24:43 > 0:24:45can be thoroughly checked is to remove the flaps.
0:24:46 > 0:24:50Lewis has to control this crane with absolute precision.
0:24:52 > 0:24:54The crane has been set to 0.9 of a tonne,
0:24:54 > 0:24:56which is the exact weight of the flap they're removing.
0:24:56 > 0:24:59That's so when the last guy undoes the last bolt,
0:24:59 > 0:25:02the wing doesn't drop to the floor or fly to the ceiling.
0:25:02 > 0:25:07Is she off? OK.
0:25:07 > 0:25:10Slowly but surely, the flap is removed from the wing,
0:25:10 > 0:25:12with barely a millimetre of movement up or down.
0:25:12 > 0:25:13Let it go.
0:25:13 > 0:25:16It's all yours, all right?
0:25:16 > 0:25:18Look at his face, he's loving it.
0:25:22 > 0:25:26During flight, air passes over these flaps and wings
0:25:26 > 0:25:28at hundreds of miles an hour.
0:25:28 > 0:25:31That causes friction and the build-up of static electricity.
0:25:32 > 0:25:36To deal with that, there are small attachments known as static wicks.
0:25:36 > 0:25:40If you could see it, how would that static look coming off here?
0:25:40 > 0:25:42Does it just sort of fizzle out?
0:25:42 > 0:25:43Literally that.
0:25:43 > 0:25:46Visibility wise, it is often very hard to see.
0:25:46 > 0:25:51- But you will still get sparking that will occur.- Really?- Yes.
0:25:51 > 0:25:57Sometimes in electric storms and certainly in a lightning strike,
0:25:57 > 0:25:59we will get these, like, sacrificial...
0:25:59 > 0:26:01They will take a bit of a battering.
0:26:01 > 0:26:04On average, every aircraft is hit by lightning once a year.
0:26:04 > 0:26:08So, how does a plane deal with this phenomenon?
0:26:09 > 0:26:13This laboratory at the University of Cardiff holds the answer.
0:26:13 > 0:26:15Because this is one of the few places in the world
0:26:15 > 0:26:17where scientists, led by Phil Leichauer,
0:26:17 > 0:26:19have the technology to make lightning of their own.
0:26:23 > 0:26:26It might sound mad doing these lightning tests to planes
0:26:26 > 0:26:29and things, but absolutely everything on an aircraft has to be certified
0:26:29 > 0:26:31against all the threats that could be posed to it.
0:26:33 > 0:26:36The state of the art laboratory tests new materials,
0:26:36 > 0:26:41as aircraft manufacturers look to find lighter, more cost-effective alternatives
0:26:41 > 0:26:43to the aluminium currently used.
0:26:45 > 0:26:48So, why do planes get hit by lightning?
0:26:48 > 0:26:52The airplane, seeing as it's in the sky, it's a huge metal object,
0:26:52 > 0:26:55it induces the lightning strikes itself
0:26:55 > 0:26:57because it is the only thing there.
0:26:58 > 0:27:00So, how do planes survive?
0:27:00 > 0:27:03To find out, we're going to test this aluminium model,
0:27:03 > 0:27:06similar to our own 747.
0:27:06 > 0:27:09- Let's blow it.- OK.- You might have the best job in the world.
0:27:09 > 0:27:13Sometimes I think so. There's a lot of paperwork, too, though.
0:27:13 > 0:27:15Now, it is my chance to play God.
0:27:16 > 0:27:20Basically, when I say fire, it's very easy, just press fire.
0:27:22 > 0:27:25And...fire.
0:27:31 > 0:27:34So, you see? The model aeroplane survived.
0:27:34 > 0:27:37It did. It looks perfectly intact.
0:27:38 > 0:27:41Everything and everyone inside a plane is protected
0:27:41 > 0:27:44by the aluminium fuselage, which is a good conductor.
0:27:46 > 0:27:49It allows the electricity to take the path of least resistance,
0:27:49 > 0:27:52along the fuselage and out again.
0:27:53 > 0:27:55What would the passenger feel?
0:27:55 > 0:27:57They might hear a loud thump, but that is about it.
0:27:57 > 0:27:59They shouldn't feel anything at all.
0:27:59 > 0:28:01A graphic experiment illustrates the dangers of using
0:28:01 > 0:28:06- 'a non-conducting material, in this case - plastic.'- Fire.
0:28:10 > 0:28:13Which is why all new material combinations
0:28:13 > 0:28:15are so extensively tested.
0:28:23 > 0:28:26Back at the hangar, work to strip back the 747 continues.
0:28:29 > 0:28:32Today, engineers are about to reveal
0:28:32 > 0:28:35one of the parts of the plane that the public never sees.
0:28:37 > 0:28:39The nose cone, or ray dome as it is known,
0:28:39 > 0:28:41shields the aircraft's weather radar,
0:28:41 > 0:28:43which needs to be checked for corrosion.
0:28:43 > 0:28:49And it works on the radar principle, which is like a complicated eco.
0:28:49 > 0:28:52It fires out radio waves in a very, very fine focus.
0:28:52 > 0:28:54It fires a beam out and then listens to that beam coming back,
0:28:54 > 0:28:57which will bounce off any clouds or anything that is up ahead.
0:28:57 > 0:29:01And that information is fired out at different angles to allow
0:29:01 > 0:29:04a huge range of sight, which is fed back to the flight deck,
0:29:04 > 0:29:06so the pilot can take whatever action he needs to take.
0:29:07 > 0:29:11Victor X-ray is now a week into its overhaul.
0:29:11 > 0:29:14Next, its most valuable components are about to be removed
0:29:14 > 0:29:16for closer examination.
0:29:17 > 0:29:20This is a big moment. They're taking the engine off the wing.
0:29:22 > 0:29:24These things cost about £8,000,000 each.
0:29:24 > 0:29:25The last thing you want to have happen
0:29:25 > 0:29:27is it come crashing to the floor.
0:29:27 > 0:29:30As experienced as he is,
0:29:30 > 0:29:32it's a nervous moment for team leader Scott Croll.
0:29:32 > 0:29:35I started as an apprentice ten years ago
0:29:35 > 0:29:37and I worked my way up to team leader.
0:29:37 > 0:29:39Even as a team leader now, the amount of knowledge
0:29:39 > 0:29:42and experience we need to learn is incredible.
0:29:42 > 0:29:43I think that is what keeps me going.
0:29:45 > 0:29:49Generating over 60,000 pounds of thrust, an engine exerts
0:29:49 > 0:29:53enormous pressure on the mounts that hold them in place.
0:29:53 > 0:29:56It is crucial that engineers remove the engines
0:29:56 > 0:30:00so they can examine these fixtures for signs of wear.
0:30:00 > 0:30:03The pylon is that big bracket, if you like, you can see,
0:30:03 > 0:30:05which connects the engine to the wing.
0:30:05 > 0:30:08- The engine to the pylon itself has got eight bolts.- Eight bolts? Wow.
0:30:08 > 0:30:10Yeah, just for at the front and four at the back.
0:30:10 > 0:30:14And that's what the boys are undoing now. They're undoing the four...
0:30:14 > 0:30:17The eight bolts are crucial in holding the engine in place,
0:30:17 > 0:30:20so each one will be sent to a laboratory and tested
0:30:20 > 0:30:21for weaknesses.
0:30:21 > 0:30:23There it is, yeah.
0:30:23 > 0:30:26These all get sent away now, NDT'd but we'll have a new set going on.
0:30:26 > 0:30:28- NDT - non-destructively tested. - Nice.
0:30:28 > 0:30:31Maybe X-rays, ultrasound.
0:30:31 > 0:30:34Of course, looking inside, yeah.
0:30:34 > 0:30:35For the drop,
0:30:35 > 0:30:40the seven-tonne engine is supported in a sling attached to the crane.
0:30:41 > 0:30:44It is an impressive operation to make sure this is all rigged up
0:30:44 > 0:30:46perfectly well, so nothing can go wrong.
0:30:46 > 0:30:49Yeah, you'll just be pushing it.
0:30:49 > 0:30:52I mean, it's heavy to push or once it's suspended it's quite free?
0:30:52 > 0:30:55We're just supporting it. Obviously, we try not to...
0:30:55 > 0:30:57All the work is done by the crane.
0:30:57 > 0:31:01All right? So we let that do it. OK, clear, come down.
0:31:01 > 0:31:04- It's all happening.- Take it down.
0:31:04 > 0:31:08Scott and his team slowly lower the engine,
0:31:08 > 0:31:11making sure that all of its pipes are disconnected.
0:31:11 > 0:31:13To be honest, it seems that the tension
0:31:13 > 0:31:16has been transferred from the crane into the engineers here.
0:31:16 > 0:31:18You can see them all getting more and more focused,
0:31:18 > 0:31:21- as it slackens off. - Going down again.
0:31:33 > 0:31:39I don't think even steel toe caps would withstand the force of one of these coming down.
0:31:39 > 0:31:41- Looking good, we're almost there.- That's it.
0:31:41 > 0:31:42- It's in?- Yeah, we're good.
0:31:42 > 0:31:45And that, ladies and gentlemen, is a wrap.
0:31:45 > 0:31:49So, at the end of the day, Scott, when you go home, you've still got that job satisfaction with you?
0:31:49 > 0:31:51Oh, definitely. Every day I go home
0:31:51 > 0:31:53and I see my little girl and she says,
0:31:53 > 0:31:56"Daddy, how did your day at work go today?"
0:31:56 > 0:31:58And I say, "Honey, today Daddy fitted an engine,
0:31:58 > 0:32:01"not just any engine, an RB211."
0:32:01 > 0:32:05- Here we go. Full-on impression now.- Yeah.
0:32:07 > 0:32:12When turning, the big fan at the front sucks in air,
0:32:12 > 0:32:15which is then compressed, mixed with a mist of fuel
0:32:15 > 0:32:17and ignited in a combustion chamber.
0:32:19 > 0:32:22This produces a huge, continuous blast of energy
0:32:22 > 0:32:24in the form of hot gases.
0:32:26 > 0:32:28These are directed out the back of the engine,
0:32:28 > 0:32:30producing some of the engine's thrust.
0:32:31 > 0:32:35The energy from the combustion is also used to spin the front fan
0:32:35 > 0:32:37faster, sucking more air in.
0:32:39 > 0:32:42This air is directed around the outside of the core and forced
0:32:42 > 0:32:45out of the rear, producing the rest of the engine's thrust.
0:32:47 > 0:32:50The 24 precious titanium fan blades,
0:32:50 > 0:32:54which provide the lion's share of the aircraft's thrust can now be removed
0:32:54 > 0:32:57and examined by Chris Thomas and his team for damage.
0:32:58 > 0:33:00Is it heavy? Can I...?
0:33:01 > 0:33:03I mean, yeah, it is not an inconsiderable weight,
0:33:03 > 0:33:06but it's lighter than I thought it would be.
0:33:06 > 0:33:09'The titanium blades are hollow to save weight.'
0:33:09 > 0:33:12What exactly are you looking for when doing those inspections?
0:33:12 > 0:33:13OK, when I inspect the blade,
0:33:13 > 0:33:15I inspect the surface of the blade,
0:33:15 > 0:33:18the leading and trailing edge of the blade for any erosion damage,
0:33:18 > 0:33:20any chips or dents, any corners missing
0:33:20 > 0:33:24or any impact damage you can get on the surface of the blade.
0:33:24 > 0:33:30Blades can be damaged by hail or bird strikes.
0:33:30 > 0:33:33All the blades I've got on the blade roots here.
0:33:33 > 0:33:36- You see the markings on the blade roots.- Yeah.
0:33:36 > 0:33:40Each blade is serialized and they're put in a specific location
0:33:40 > 0:33:41to balance the hub.
0:33:41 > 0:33:42So much like on a car wheel
0:33:42 > 0:33:45when you have something done with your car wheel,
0:33:45 > 0:33:47it needs to be balanced so when it's going round
0:33:47 > 0:33:49- at a high speed it's not causing vibration.- Exactly.
0:33:49 > 0:33:53So, if you had to do work on one blade, you might have to rebalance
0:33:53 > 0:33:56- the whole thing, not just that blade.- That's right.- Wow.
0:34:03 > 0:34:05Fully loaded, Victor X-ray needs
0:34:05 > 0:34:09approximately 120,000 horse power from its four engines
0:34:09 > 0:34:11to get into the air.
0:34:11 > 0:34:15That is similar to the power of 1,000 family cars pulling
0:34:15 > 0:34:18this plane off the ground.
0:34:18 > 0:34:20- It's just in through this hole? - Just in through that hole.
0:34:20 > 0:34:22- This one here?- That one.
0:34:22 > 0:34:26And generating that level of thrust is thirsty work.
0:34:26 > 0:34:29Wow, this is pretty cramped.
0:34:29 > 0:34:36I am crawling up into the bowels of the 747 with engineer Phil Taylor.
0:34:36 > 0:34:39He will spend over two weeks looking for leaks
0:34:39 > 0:34:42inside the aircraft's labyrinth of fuel tanks.
0:34:42 > 0:34:45- So, this is the main tank. - We are in the centre wing tank,
0:34:45 > 0:34:48which is situated between the two wing sections.
0:34:48 > 0:34:51Above you, is the cabin area, with the cabin seating.
0:34:51 > 0:34:55And you are in the forward midsection of the aircraft, basically.
0:34:55 > 0:34:58- It holds 65,000 litres. - 65,000 litres?!- Certainly.
0:34:58 > 0:35:00And is that all in this bit here?
0:35:00 > 0:35:04No, this is one compartment of six compartments going towards
0:35:04 > 0:35:06the rear of the aircraft.
0:35:06 > 0:35:09- But there's more than one tank on a plane.- There's eight in all.
0:35:09 > 0:35:11So how much fuel are you looking at, across all of it?
0:35:11 > 0:35:15The fuel quantity for the whole aircraft is 216,000 litres.
0:35:15 > 0:35:19That is massive! Your average-sized car is what? I don't know, 60 litres?
0:35:19 > 0:35:21Something like that.
0:35:21 > 0:35:25So, approximately 3,500 cars you could fill
0:35:25 > 0:35:28with one jumbo-full of aviation fuel.
0:35:29 > 0:35:34Victor X-ray is now two weeks into its five-week overhaul
0:35:34 > 0:35:36and so far, it is on schedule.
0:35:38 > 0:35:42Engineers have completed over 5,000 of the 12,000 jobs that need
0:35:42 > 0:35:46to be done before the 747 can be classified as airworthy again.
0:35:49 > 0:35:52In the cabin, the last remaining floor and wall panels
0:35:52 > 0:35:55need to be stripped, along with the toilet module.
0:35:55 > 0:35:58- I'm good to go, Mick.- Right, OK.
0:35:58 > 0:36:01'I'd been roped in to help.'
0:36:02 > 0:36:05- It stinks, Mick. - I did tell you that.
0:36:05 > 0:36:06Woo!
0:36:09 > 0:36:11Now, Mick, on a lot of old trains,
0:36:11 > 0:36:13I know that anything that was produced
0:36:13 > 0:36:15would just be dumped out onto the track. And from that,
0:36:15 > 0:36:18I think this urban myth has developed that suggests
0:36:18 > 0:36:20the same happens on planes. Has that ever been true?
0:36:20 > 0:36:22No. It ends up in the aft freights,
0:36:22 > 0:36:25- which is right down the back there. - All right.
0:36:25 > 0:36:26We've got four tanks.
0:36:26 > 0:36:29I last met Mick removing all the seats
0:36:29 > 0:36:32and I wondered if working on aircraft for 19 years made him
0:36:32 > 0:36:37feel more or less comfortable about flying in one.
0:36:37 > 0:36:39I love flying anyway, so it doesn't bother me in the slightest.
0:36:39 > 0:36:43- I've always loved flying. The wife doesn't like flying at all.- No?
0:36:43 > 0:36:46So, I mean, we'll go on holiday to Lanzarote, something like that,
0:36:46 > 0:36:49and we sit there and the flaps all go down.
0:36:49 > 0:36:52- And she's gripping your hand. - "That the flaps going down."
0:36:52 > 0:36:55- And she'll go, "Shut up, I don't want to know."- Really?- Yeah.
0:36:57 > 0:37:00In an industry where safety is paramount,
0:37:00 > 0:37:03even a toilet is a highly engineered piece of kit.
0:37:03 > 0:37:06As an electrical component that could cause a fire,
0:37:06 > 0:37:11it has to undergo stringent tests before it is passed fit to fly.
0:37:11 > 0:37:16The tests are carried out at the company's avionics facility outside Cardiff.
0:37:16 > 0:37:20Here, the hundreds of electronic gadgets used on a plane -
0:37:20 > 0:37:23from navigational aid and in-flight entertainment remotes
0:37:23 > 0:37:26to toilet flushing systems - are stripped,
0:37:26 > 0:37:29tested and calibrated by highly skilled engineers
0:37:29 > 0:37:31like Martin Jenkins.
0:37:32 > 0:37:36So, what happens when you go to the toilet on an airplane, Martin?
0:37:36 > 0:37:38When you actually finish what you are doing,
0:37:38 > 0:37:41you press your little button, which is on the side of the toilet in the cabin.
0:37:41 > 0:37:44It is. There's a massive whooshing noise.
0:37:44 > 0:37:47That is what we hear on the actual rig.
0:37:47 > 0:37:49We get a spray of water from the top
0:37:49 > 0:37:53and a vacuum gets created in the bowl and sucks it all away.
0:37:53 > 0:37:56Above 16,000 feet,
0:37:56 > 0:38:00air pressure outside the plane is considerably lower than inside.
0:38:00 > 0:38:02By opening a small vent, the waste pipe
0:38:02 > 0:38:06and tank are brought to the same low pressure as outside,
0:38:06 > 0:38:08effectively creating a vacuum.
0:38:08 > 0:38:11This means that when a seal on the toilet bowl is opened,
0:38:11 > 0:38:15anything in the bowl is sucked away into the pipes and waste tanks.
0:38:20 > 0:38:23When you are flying, Martin, when you go to the toilet in the air,
0:38:23 > 0:38:26you must have any ear now for what is the perfect flush.
0:38:26 > 0:38:29That is a good point, actually, because sometimes you might
0:38:29 > 0:38:31get one that is working, but not to the full capacity.
0:38:31 > 0:38:35As you just said, you can pick it up as you are listening to it, the actual flush.
0:38:35 > 0:38:39You might not hear it, but I probably would. And the other guys who work here as well.
0:38:44 > 0:38:47Although it might seem over the top, this level of testing
0:38:47 > 0:38:49is not without good reason.
0:38:50 > 0:38:54On a flight, electrical power is at a premium, so even
0:38:54 > 0:38:57the kettles are tested to make sure they don't use too much electricity
0:38:57 > 0:39:01and take it away from a more important system.
0:39:04 > 0:39:08Engineer Simon Aucock is currently checking that these kettles
0:39:08 > 0:39:12draw the correct current, while taking the exact time to reach
0:39:12 > 0:39:15the precise temperature to make a perfect cup of tea.
0:39:15 > 0:39:20We boil it 83 Celsius, plus or minus 2 Celsius.
0:39:20 > 0:39:21The board of tea tasters have decided.
0:39:21 > 0:39:24If you read a packet of, say, PG Tips or whatever,
0:39:24 > 0:39:26it never says boil a kettle.
0:39:26 > 0:39:29- It says hot but not boiling, doesn't it?- Yeah.
0:39:29 > 0:39:35- It's amazing, even the kettles are over tested.- Yeah.
0:39:38 > 0:39:42When the 747 flew for the first time over 40 years ago,
0:39:42 > 0:39:47many of these devices being tested here hadn't even been invented.
0:39:50 > 0:39:53As technology has evolved, manually controlled cables
0:39:53 > 0:39:56and pulleys have been replaced by computer-controlled
0:39:56 > 0:39:59electronic signals, transmitted by wires.
0:40:02 > 0:40:06Beneath Victor X-ray's passenger compartment is the cargo bay,
0:40:06 > 0:40:10surrounded by the 172 miles of wiring
0:40:10 > 0:40:13that connect all the plane's complex systems.
0:40:13 > 0:40:16Just looking around,
0:40:16 > 0:40:20there are miles and miles of wiring here.
0:40:21 > 0:40:25Many of these cables flow from the pilot's controls to these vital computers,
0:40:25 > 0:40:30currently being examined by avionics engineer Nick Jordai.
0:40:30 > 0:40:32The first 747s were designed back in the '60s.
0:40:32 > 0:40:35I presume those would not have had any of this.
0:40:35 > 0:40:37No. Their racks were built,
0:40:37 > 0:40:38but it had totally different boxes.
0:40:38 > 0:40:40They were much more primitive than they are now.
0:40:40 > 0:40:44So, how would what these boxes do now have been done back then?
0:40:44 > 0:40:47A lot of the functions done by these boxes used to be done
0:40:47 > 0:40:51- by the flight engineer.- That role is redundant because of these guys.
0:40:51 > 0:40:55There's a thought, a machine taking over man's job.
0:40:56 > 0:41:01It is now just three weeks until Victor X-ray is due to fly again.
0:41:01 > 0:41:04As it's been stripped bare, I've been able to see
0:41:04 > 0:41:07how the aircraft's intricate flight controls work,
0:41:07 > 0:41:10delved inside its complex engines
0:41:10 > 0:41:13and experienced the impressive mass of its landing gear
0:41:13 > 0:41:15as it was tested.
0:41:15 > 0:41:18But could the plane's computers I've just seen
0:41:18 > 0:41:21control all of these without a pilot?
0:41:21 > 0:41:24I'm really interested to see if it could actually fly itself.
0:41:24 > 0:41:28I am heading down to London to see pilot Doug Brown,
0:41:28 > 0:41:30who flew Victor X-ray to Cardiff.
0:41:31 > 0:41:34He is going to demonstrate a 747's autopilot
0:41:34 > 0:41:38in one of the airline's £8 million flight simulators.
0:41:38 > 0:41:43Right, I'll give you a chance to fly the aeroplane manually for a little while.
0:41:43 > 0:41:45- As it... - As we are climbing away, yep.
0:41:45 > 0:41:49Then what we'll do is put the autopilot in, bring it round and
0:41:49 > 0:41:52- then we'll do an automatic approach and an auto-land onto this runway. - OK.
0:41:52 > 0:41:55So, essentially there are three planes to be thinking about.
0:41:55 > 0:42:00- One is pulling back to be able to lift off vertically.- Yep.
0:42:00 > 0:42:04- You've got the steering and the pedals to keep yourself down the runway on that plane.- Yep.
0:42:04 > 0:42:07- But then you've also got this horizontal level.- Indeed.
0:42:07 > 0:42:09What does this control?
0:42:09 > 0:42:10All four of the engines.
0:42:10 > 0:42:13So, engines one to four, forward thrust on there.
0:42:13 > 0:42:16- You can see the engines spool up. - Here we go.
0:42:16 > 0:42:20- That's actually there.- OK. Now I'm going to put full power on.
0:42:25 > 0:42:28Now, we are coming up towards the speed we ask you to pull back at.
0:42:28 > 0:42:31- Really? Oh, there we go.- And rotate.
0:42:31 > 0:42:33So, back on the control.
0:42:33 > 0:42:36Don't turn the stick while rotating, keep it in the middle.
0:42:43 > 0:42:47That's nice. A bit further, I'm going to select the landing gear up.
0:42:49 > 0:42:50This is amazing. This is amazing.
0:42:56 > 0:42:57Once up,
0:42:57 > 0:42:59it's a tight 360-degree turn
0:42:59 > 0:43:03so that we can simulate an automatic landing.
0:43:05 > 0:43:08- Can you see the airfield there? - I can, straight ahead, yes.
0:43:08 > 0:43:10We are going to let the autopilot run through
0:43:10 > 0:43:13and we'll go right through to an auto-land.
0:43:13 > 0:43:15Would autopilot be able to do that itself?
0:43:15 > 0:43:17The aircraft will land itself if the pilot
0:43:17 > 0:43:19- has set it up properly to do so.- Fine.
0:43:22 > 0:43:27The autopilot is now controlling the 747's approach to the runway,
0:43:27 > 0:43:31altering the pitch and direction of the aircraft.
0:43:31 > 0:43:35It can also control the level of trust.
0:43:35 > 0:43:37But the autopilot cannot extend the wing flaps,
0:43:37 > 0:43:42which slow the aircraft down, or deploy the crucial landing gear.
0:43:44 > 0:43:47- Now it's going in, you see it?- OK.
0:43:47 > 0:43:52Only then can the 747 land itself.
0:43:52 > 0:43:55Although the autopilot cannot apply the brakes.
0:43:56 > 0:44:00- So, now you stick the reverse thrust on?- You do.- OK.
0:44:00 > 0:44:02And a little bit of brake.
0:44:02 > 0:44:05- That's it.- Fantastic.
0:44:07 > 0:44:11The 747 is a remarkably intelligent machine,
0:44:11 > 0:44:15but it still requires skilled pilots to fly it.
0:44:15 > 0:44:19And it is the high level of training which is one of the reasons
0:44:19 > 0:44:22why flying statistically remains so safe.
0:44:22 > 0:44:26Another reason is that the airline industry has learned
0:44:26 > 0:44:30valuable lessons in rare accidents through an iconic component,
0:44:30 > 0:44:35housed in the tail section of a plane.
0:44:35 > 0:44:37Here they are, two black boxes.
0:44:37 > 0:44:40This on the right, the data recorder,
0:44:40 > 0:44:42records all the telemetry of the flight.
0:44:42 > 0:44:44And on the left, is the voice recorder,
0:44:44 > 0:44:47which records all the pilots' voices.
0:44:48 > 0:44:53The two black boxes are regularly tested at BA's avionics lab,
0:44:53 > 0:44:55where I met up with engineer John Davies.
0:44:57 > 0:44:59This is a black box, but as you can see,
0:44:59 > 0:45:02it is not actually black, it is orange.
0:45:02 > 0:45:06And that's because it is clearly identified in any incident.
0:45:06 > 0:45:08It is a big old tape recorder.
0:45:08 > 0:45:11It is a big tape recorder. That's what basically it is.
0:45:11 > 0:45:12As you can see, as well,
0:45:12 > 0:45:17the tape is actually surrounded by two thermal packs, which are...
0:45:17 > 0:45:21- Spring-loaded, as well. - Spring-loaded, yeah.
0:45:21 > 0:45:27With two thermal packs, which are chalk impregnated with water.
0:45:27 > 0:45:31So, in the event of a fire, that water turns to steam,
0:45:31 > 0:45:34keeps that tape at steam temperature.
0:45:34 > 0:45:37- OK.- So it won't destroy the tape.
0:45:37 > 0:45:40And what sort of temperature range is it specified to?
0:45:40 > 0:45:43Well, it should withstand 1,000 degrees C
0:45:43 > 0:45:46over a 30-minute period of time.
0:45:46 > 0:45:48That is where aviation fuel burns.
0:45:48 > 0:45:50So the bit you're opening now, inside there,
0:45:50 > 0:45:52that is the precious cargo.
0:45:52 > 0:45:54This is the part we are interested in.
0:45:54 > 0:45:57It will record the last 30 minutes of any flight.
0:45:57 > 0:46:00It may look archaic and new airliners
0:46:00 > 0:46:03have converted to digital, solid-state data storage,
0:46:03 > 0:46:05but tape still does the trick.
0:46:06 > 0:46:09That could contain the most precious of information
0:46:09 > 0:46:13that will ultimately be fed back to make sure it never happens again.
0:46:13 > 0:46:16- Exactly, yes. Which it has many times.- Yeah.
0:46:19 > 0:46:22To comply with comprehensive safety legislation,
0:46:22 > 0:46:26all aircraft must work to strict maintenance schedules,
0:46:26 > 0:46:30including detailed tests every year and a complete overhaul
0:46:30 > 0:46:33every six years.
0:46:33 > 0:46:35At 14 years of age,
0:46:35 > 0:46:38Victor X-ray could still have another ten years of flying ahead,
0:46:38 > 0:46:40but there comes a time
0:46:40 > 0:46:44when a 747 is just too costly to keep maintaining.
0:46:44 > 0:46:50Then, it is worth more as spare parts than a complete aircraft.
0:46:50 > 0:46:53This is part of your flaps, part of the Krueger flaps.
0:46:53 > 0:46:57Mark Gregory is the boss of Air Salvage International.
0:46:57 > 0:47:00We are obviously the largest dismantling company in the UK,
0:47:00 > 0:47:01in fact, in Europe.
0:47:01 > 0:47:04'At Cotswold Airport, in Gloucestershire,
0:47:04 > 0:47:07'Mark and his team salvage over 40 aircraft a year.'
0:47:07 > 0:47:09These here, can we have a closer look at these?
0:47:09 > 0:47:14They are 747 in-board landing gears
0:47:14 > 0:47:16we removed from a 747-400.
0:47:16 > 0:47:18If it has done a huge amount of landings,
0:47:18 > 0:47:21then the value of that is kind of dropping.
0:47:21 > 0:47:26But I think this has done quite a lot of landings. They're still not cheap.
0:47:26 > 0:47:29- Roughly how much, then?- You're probably looking at about 300,000
0:47:29 > 0:47:32for a set of landing gears like this.
0:47:34 > 0:47:38On a 747, Mark will salvage up to 1,200 parts,
0:47:38 > 0:47:42which will eventually be sold to airlines around the world.
0:47:42 > 0:47:45Precision electronics means a second-hand coffee maker
0:47:45 > 0:47:48could fetch up to £3,000.
0:47:48 > 0:47:52Even a simple bowl for the toilet could sell for as much as £500.
0:47:54 > 0:47:56These are the front screens off the 747,
0:47:56 > 0:47:59they've got a very high value. I would say probably around 30,000.
0:47:59 > 0:48:01- What, each?- For each screen, yeah.
0:48:01 > 0:48:03These ones, obviously, are heated.
0:48:03 > 0:48:05There are heated elements running through them.
0:48:05 > 0:48:08I think they're gold heating elements that go through them.
0:48:08 > 0:48:10- So, in here now, you've got... - They are very, very thick.
0:48:10 > 0:48:14They are really thick screens. They are laminated, as well.
0:48:14 > 0:48:16- You can just see the elements in there.- Yep.
0:48:16 > 0:48:20A bit like your car heater front screen, as well.
0:48:20 > 0:48:22That hits home, there.
0:48:22 > 0:48:24The value of the whole industry.
0:48:24 > 0:48:27Yeah, it's massive, absolutely massive.
0:48:27 > 0:48:3280% of the salvage value of an aircraft comes from its engines.
0:48:32 > 0:48:34This is a 737 engine.
0:48:34 > 0:48:37- This probably has a resale value of about 1.2 million, I suppose.- Wow.
0:48:37 > 0:48:41And going back, the bigger engines at the back, are a bit more.
0:48:41 > 0:48:43Once all the valuable parts of the 747 have been removed,
0:48:43 > 0:48:47what's left of the aluminium shell will be tackled.
0:48:50 > 0:48:52After almost 3 weeks,
0:48:52 > 0:48:57Victor X-ray is now at a similar stage of its overhaul.
0:48:57 > 0:49:0218 days ago this plane was flying passengers around the world
0:49:02 > 0:49:07and today what it looks like inside is a far cry from what it would have been then.
0:49:08 > 0:49:13In this skeletal state, there are signs of the 747's evolution.
0:49:14 > 0:49:17We are right at the very front of the aircraft
0:49:17 > 0:49:19and above us is the flight deck.
0:49:19 > 0:49:23And just looking around, even in a plane as modern as the 747,
0:49:23 > 0:49:26it is surprising to see how much mechanical equipment there is,
0:49:26 > 0:49:28as well as all the electronics.
0:49:28 > 0:49:32Victor X-ray still uses the jumbo's original cable and pulley system
0:49:32 > 0:49:36to control some of the aircraft's most important functions,
0:49:36 > 0:49:40including the landing gear doors and the rudder.
0:49:40 > 0:49:44And then finally, right at the back here, hopefully, I... Yep.
0:49:44 > 0:49:47You see the cables heading off through the cabin
0:49:47 > 0:49:49and off to the rudder.
0:49:49 > 0:49:51Keeping it mechanical, keeping it simple.
0:49:53 > 0:49:56Ah, the flight deck.
0:49:56 > 0:49:59It looks a lot different without the seats
0:49:59 > 0:50:01and all the flight instruments.
0:50:01 > 0:50:06The Cardiff team now have a tight deadline to turn Victor X-ray
0:50:06 > 0:50:09back into a fully working plane.
0:50:10 > 0:50:14It is booked to go back into service in just over two weeks,
0:50:14 > 0:50:18on the same day the complex process is due to finish.
0:50:21 > 0:50:25But when a 747 has come to the end of its working life,
0:50:25 > 0:50:26like this one at Cotswold Airport,
0:50:26 > 0:50:30there is no turning back for Mark Gregory and his salvage team.
0:50:30 > 0:50:34We've removed over 130 tonnes of equipment
0:50:34 > 0:50:37and all we're left with now is 100 tonnes of aircraft,
0:50:37 > 0:50:42which has got very little value because the only value that is there is the metal.
0:50:42 > 0:50:46At this point, the final part of the demolition process can begin.
0:50:49 > 0:50:53So, we'll start, we'll take the tail off first, chew the tail up.
0:50:58 > 0:50:59And then we'll work forward.
0:51:03 > 0:51:05Then the wings into the fuselage.
0:51:11 > 0:51:13And then through the rest of the body.
0:51:17 > 0:51:20It doesn't take very long. It's about three days to do a 747.
0:51:27 > 0:51:31It really is all the guts and the veins and everything
0:51:31 > 0:51:33just being pulled out of the whole machine.
0:51:35 > 0:51:36Look at that.
0:51:38 > 0:51:42Very soon, this 747 is nothing more than a heap of scrap metal.
0:51:45 > 0:51:51So, this is £200 million worth of plane reduced to probably
0:51:51 > 0:51:56the most expensive pile of scrap I've ever seen in my life.
0:51:56 > 0:52:00Only a few recognizable fragments of the aircraft remain.
0:52:00 > 0:52:03- So, this is a leading-edge and this is...- Aluminium.
0:52:03 > 0:52:07- Well, there you go, you can see it here.- It's thin, but pretty...
0:52:07 > 0:52:09It takes some battering there, doesn't it?
0:52:09 > 0:52:11Yeah, that's pretty durable.
0:52:11 > 0:52:14As the wing moves back, it doesn't need to be as strong,
0:52:14 > 0:52:17- so they make it out of this lightweight stuff. - There you go, yeah.
0:52:20 > 0:52:24Engineering being led by nature, isn't it? Honeycomb.
0:52:24 > 0:52:29Look at this, though. You can see the thickness.
0:52:29 > 0:52:31It's so thin, it's like that.
0:52:32 > 0:52:36Some 747 flight decks are spared demolition
0:52:36 > 0:52:39to be used as the shell in the construction
0:52:39 > 0:52:40of flight simulators.
0:52:42 > 0:52:43Wow. This is a bit different.
0:52:43 > 0:52:46It's like a relic, isn't it? Look at that.
0:52:46 > 0:52:50This is proper aviation history here, how it all used to be.
0:52:50 > 0:52:53These controls here are where a flight engineer would have sat.
0:52:53 > 0:52:56When you needed one. Obviously, on Victor X-ray, that's gone now.
0:52:58 > 0:53:02The remaining carcass of a 747 like this still has a recycling value
0:53:02 > 0:53:04worth up to £35,000.
0:53:07 > 0:53:11Although it is no longer pure enough to be used again in aircraft construction,
0:53:11 > 0:53:15as recycled aluminium, it does get to live another day.
0:53:15 > 0:53:18Once they've separated out the aluminium, it'll be sent away,
0:53:18 > 0:53:23smelted down and recycled, meaning what was once a fuselage
0:53:23 > 0:53:25of a 747 could be your next fizzy drink.
0:53:25 > 0:53:28Or even the frame of a bicycle.
0:53:32 > 0:53:34We're on our way back to Cardiff,
0:53:34 > 0:53:39where Victor X-ray should now have been given a new lease on life.
0:53:39 > 0:53:43- Last time.- Last time, indeed. - It's heading out.
0:53:43 > 0:53:47Tomorrow evening it's due to head back into service.
0:53:53 > 0:53:54There it is, Victor X-ray.
0:53:54 > 0:53:56Completely different, it's all back in.
0:54:01 > 0:54:03- It does smell new. - It does smell new.
0:54:04 > 0:54:08The last time I was here, this was all completely open.
0:54:08 > 0:54:11- Yeah.- It's all on again, the screens are running, good.
0:54:12 > 0:54:14Since arriving five weeks ago,
0:54:14 > 0:54:18engineers have replaced over 5,000 separate parts,
0:54:18 > 0:54:20including 11 brand-new toilets.
0:54:22 > 0:54:28386 square metres of new carpet has been fitted along with 285 refurbished seats.
0:54:35 > 0:54:38And there are 14 brand-new first class seats
0:54:38 > 0:54:42for passengers paying upwards of £5,000 a flight for the luxury.
0:54:44 > 0:54:45Wow!
0:54:45 > 0:54:48- Oh, wow!- Hey!
0:54:48 > 0:54:50Ooh!
0:54:50 > 0:54:51Oh.
0:54:51 > 0:54:55It's mad to think it does all this AND it flies.
0:54:55 > 0:54:59In just over 24 hours' time, these seats should be occupied
0:54:59 > 0:55:04by paying customers en route to South America.
0:55:04 > 0:55:06So now, for the first time in five weeks,
0:55:06 > 0:55:09Victor X-ray is towed from the hangar,
0:55:09 > 0:55:13for the final critical tests that need to be carried out to ensure
0:55:13 > 0:55:18all the parts of the aircraft, including its four engines, are working.
0:55:24 > 0:55:26For Hugh Gibbs, this is the only occasion
0:55:26 > 0:55:30when an engineer gets to power up a 747 for real.
0:55:31 > 0:55:32So, will we be moving anywhere
0:55:32 > 0:55:35when you put it up to almost maximum thrust?
0:55:35 > 0:55:37No, we've got the brakes on.
0:55:37 > 0:55:39We can't do more than one engine at full power at a time.
0:55:39 > 0:55:41- We have to do them one at a time. - Really?
0:55:41 > 0:55:44So if you had all four, we'd be taking off...
0:55:44 > 0:55:47- Well, taking off through the middle of Cardiff airport.- Yeah.
0:55:47 > 0:55:49Request permission to carry out a high-power ground run.
0:55:52 > 0:55:54OK, going up on one and four.
0:56:10 > 0:56:14The sensation of being here right now is kind of what you get
0:56:14 > 0:56:17when you hit turbulence midflight, but, yeah,
0:56:17 > 0:56:21we're here on the runway, outside Cardiff airport.
0:56:21 > 0:56:24It is just awesome, the power of these things.
0:56:26 > 0:56:28That was a brilliant, fun experience for me.
0:56:28 > 0:56:30From a technical perspective, how did it go?
0:56:30 > 0:56:32All went well, we had no problems at all.
0:56:32 > 0:56:35We got to high power and it was lovely and smooth.
0:56:35 > 0:56:37And it passed all the tests that we need it to do.
0:56:37 > 0:56:40And does running those engines up to throttle like that
0:56:40 > 0:56:42get any less exciting any time?
0:56:42 > 0:56:45No, I've been doing it for five years now, I still love it.
0:56:49 > 0:56:52The following day, and on time,
0:56:52 > 0:56:55Victor X-ray is ready to bid farewell to Cardiff.
0:56:59 > 0:57:02For the engineers, this is the moment
0:57:02 > 0:57:04when all the hard work pays off.
0:57:05 > 0:57:09You know, job ownership,
0:57:09 > 0:57:11especially if you have been on it from start to finish
0:57:11 > 0:57:13and you look back, "I've done that.
0:57:13 > 0:57:16"It works."
0:57:16 > 0:57:20When you see it barrelling down the runway at 150 knots, you think,
0:57:20 > 0:57:22"I did them bolts there."
0:57:25 > 0:57:28You know, I've been in the industry 20 years
0:57:28 > 0:57:30and you'll never lose that pride and that feeling inside
0:57:30 > 0:57:34that you have been part of producing that product and keeping it safe.
0:57:34 > 0:57:36And, obviously, knowing that
0:57:36 > 0:57:37when the aircraft returns to Heathrow,
0:57:37 > 0:57:40the customers then sit on that aircraft
0:57:40 > 0:57:42and you know you've done your job well.
0:57:44 > 0:57:47After five weeks, over 30,000 working hours
0:57:47 > 0:57:51and 12,000 separate jobs,
0:57:51 > 0:57:55Victor X-ray is ready once again to take to the skies.
0:58:01 > 0:58:04And for the engineering team
0:58:04 > 0:58:07who have painstakingly stripped the aircraft down
0:58:07 > 0:58:08and built it back up again,
0:58:08 > 0:58:13there is the satisfaction of knowing it works.
0:58:52 > 0:58:55Subtitles by Red Bee Media Ltd