0:00:06 > 0:00:09Air travel has transformed our lives.
0:00:10 > 0:00:13Fast, direct,
0:00:13 > 0:00:15and above all safe.
0:00:15 > 0:00:18And it keeps getting safer.
0:00:18 > 0:00:22In 2012, the global accident rate for Western-built jets
0:00:22 > 0:00:24was the lowest in aviation history.
0:00:24 > 0:00:28But the carefree flying that we enjoy today
0:00:28 > 0:00:30has been bought at a deadly cost...
0:00:33 > 0:00:36Because improvements in aviation safety
0:00:36 > 0:00:39have been driven by the stuff of nightmares...
0:00:42 > 0:00:46Air crashes.
0:00:51 > 0:00:54Every crash has its causes,
0:00:54 > 0:00:57and this information is used by scientists
0:00:57 > 0:01:00to prevent the same failures from happening again.
0:01:06 > 0:01:10For more than 60 years, Horizon and the BBC have reported
0:01:10 > 0:01:14on the accidents that have revolutionised aviation safety.
0:01:16 > 0:01:20In this programme, we'll chart the most significant improvements
0:01:20 > 0:01:22through the stories of the most deadly disasters.
0:01:37 > 0:01:40Tenerife Airport,
0:01:40 > 0:01:42March 27th, 1977.
0:01:46 > 0:01:50Debris is strewn far and wide.
0:01:50 > 0:01:52Thick plumes of smoke fill the sky.
0:01:54 > 0:01:58This is the wreckage from the deadliest air crash in history,
0:01:58 > 0:02:01a crash that happened not in the sky
0:02:01 > 0:02:03but on the runway.
0:02:03 > 0:02:06The control tower just 700 metres away
0:02:06 > 0:02:08didn't even see it happen.
0:02:14 > 0:02:16Just ten minutes earlier,
0:02:16 > 0:02:19the airport had been busy but running smoothly.
0:02:21 > 0:02:23Two Boeing 747s,
0:02:23 > 0:02:26one KLM, the other Pan Am,
0:02:26 > 0:02:30were a mile apart at opposite ends of the runway.
0:02:31 > 0:02:36They'd been instructed to position themselves ready for take-off.
0:02:36 > 0:02:39The KLM was to wait at one end of the runway
0:02:39 > 0:02:42while Pan Am was to turn off it
0:02:42 > 0:02:45and allow KLM to depart first.
0:02:45 > 0:02:46As they were manoeuvring,
0:02:46 > 0:02:49a thick fog came over the mountains
0:02:49 > 0:02:51and enveloped the airport.
0:02:51 > 0:02:53With the runway now shrouded in fog
0:02:53 > 0:02:56neither plane could see each other.
0:02:56 > 0:03:00Crucially, neither could the air traffic controller in the tower.
0:03:01 > 0:03:05The Pan Am pilots taxiing down the runaway missed the turning.
0:03:05 > 0:03:06At six minutes past five
0:03:06 > 0:03:10the KLM pilot, believing the Pan Am was now off the runway,
0:03:10 > 0:03:14began his take-off with Pan Am still ahead of him.
0:03:14 > 0:03:18First time in my life I've ever had a situation occur
0:03:18 > 0:03:21that I couldn't believe was happening.
0:03:21 > 0:03:24I just could not believe this airplane was coming
0:03:24 > 0:03:25down the runaway at us.
0:03:25 > 0:03:28My comment was, "Get off!" to the captain,
0:03:28 > 0:03:31which he tried everything he possibly could.
0:03:31 > 0:03:32As we were turning,
0:03:32 > 0:03:35I looked back out of my right window
0:03:35 > 0:03:39and the KLM airplane had lifted off the runway.
0:03:39 > 0:03:42Basically, what I did was just close my eyes and duck.
0:03:43 > 0:03:47During lift-off, the KLM plane collided with Pan Am.
0:03:53 > 0:03:57Although briefly airborne, it lost control,
0:03:57 > 0:04:00crashed and burst into a ball of flames...
0:04:02 > 0:04:07..while the Pan Am plane broke into several pieces and exploded.
0:04:12 > 0:04:15Almost 600 people died that day.
0:04:17 > 0:04:19The accident shocked the world.
0:04:21 > 0:04:26Everyone wanted to know what could have caused this devastating crash.
0:04:42 > 0:04:46Initially it seemed the obvious cause of the disaster was fog.
0:04:49 > 0:04:53562, turn tight, heading 070...
0:04:53 > 0:04:55But the crash investigation
0:04:55 > 0:04:57revealed that fog was only one factor.
0:04:57 > 0:05:00123 out of air...
0:05:00 > 0:05:03123, 29 miles over.
0:05:03 > 0:05:05Bad communication and poor crew dynamics
0:05:05 > 0:05:08also played a major role.
0:05:08 > 0:05:10Wind squall at 5524.
0:05:10 > 0:05:125524.
0:05:14 > 0:05:16The Tenerife disaster showed
0:05:16 > 0:05:21that the causes of plane crashes are rarely straightforward.
0:05:21 > 0:05:22And that's not surprising
0:05:22 > 0:05:26given that aviation is an incredibly complex business
0:05:26 > 0:05:29and there are so many things that can go wrong.
0:05:39 > 0:05:42If you stop and think about it for a second,
0:05:42 > 0:05:45travelling by plane is a pretty odd thing to do.
0:05:45 > 0:05:48Hundreds of us strapped into this narrow tube,
0:05:48 > 0:05:51hurtling through the air at upwards of 500 miles an hour,
0:05:51 > 0:05:56and separated from the freezing, oxygen-starved atmosphere
0:05:56 > 0:05:59by just a few centimetres of metal and plastic.
0:05:59 > 0:06:02Today we pretty much take it for granted
0:06:02 > 0:06:04that the aeroplane is up to the job.
0:06:04 > 0:06:07It's not going to fall apart around us.
0:06:07 > 0:06:09But in the early days of commercial aviation,
0:06:09 > 0:06:13even the structural integrity of the plane couldn't be guaranteed.
0:06:13 > 0:06:16Scientists realised the hard way
0:06:16 > 0:06:19that there were some significant gaps in their knowledge.
0:06:21 > 0:06:24There is arguably no single plane that's been more important
0:06:24 > 0:06:28in the story of aircraft engineering than the ill-fated Comet.
0:06:28 > 0:06:31- REPORTER:- When the 36-seater, jet-propelled De Havilland Comet
0:06:31 > 0:06:35opened the latest act in the drama of man's conquest of the heavens,
0:06:35 > 0:06:38the eyes of many nations were focused upon it.
0:06:40 > 0:06:43Built in Britain and launched in 1952,
0:06:43 > 0:06:46it was the first passenger jet to go into service.
0:06:48 > 0:06:50Cruising at 490 miles an hour,
0:06:50 > 0:06:53the Comet offered all the attractions
0:06:53 > 0:06:56of smooth, high-altitude travel.
0:06:59 > 0:07:02The Comet had grace and beauty.
0:07:03 > 0:07:06But unfortunately that's not what it's remembered for.
0:07:11 > 0:07:13Between May '52 and April '54,
0:07:13 > 0:07:17three of the nine Comets in service broke up in mid air.
0:07:17 > 0:07:19The Comet 1 never flew again.
0:07:19 > 0:07:21After the third disaster,
0:07:21 > 0:07:22bits of the aircraft were recovered
0:07:22 > 0:07:24from the bottom of the Mediterranean.
0:07:24 > 0:07:28In all, 67 people died in the crashes.
0:07:28 > 0:07:31It was a disaster for the British aircraft industry,
0:07:31 > 0:07:34particularly because no-one knew why the planes
0:07:34 > 0:07:37had apparently just fallen out of the sky.
0:07:38 > 0:07:40So all the Comets were grounded,
0:07:40 > 0:07:43and scientists set to work on one of the greatest
0:07:43 > 0:07:46aircraft detective stories in aviation history.
0:07:48 > 0:07:50As in any investigation,
0:07:50 > 0:07:54scientists started by painstakingly sieving through the crash wreckage.
0:07:54 > 0:07:57Their first clue came in the form of a curious anomaly
0:07:57 > 0:07:59found in fragments of the fuselage.
0:08:01 > 0:08:06There were unexplained rips through the aluminium shell.
0:08:06 > 0:08:08The scientists next had to work out
0:08:08 > 0:08:11what could have caused these tears,
0:08:11 > 0:08:13and the only way to do that
0:08:13 > 0:08:16was to try to recreate the damage.
0:08:16 > 0:08:20An entire fuselage was immersed in a high pressure tank
0:08:20 > 0:08:24and subjected to cycles of increasing and decreasing pressure
0:08:24 > 0:08:26to simulate an aircraft in service
0:08:26 > 0:08:28constantly climbing and descending.
0:08:28 > 0:08:31The fatal weakness suddenly revealed itself.
0:08:31 > 0:08:35A weakness that would change aircraft design forever.
0:08:37 > 0:08:40It was metal fatigue, a type of weakness that starts
0:08:40 > 0:08:42as a small crack somewhere in the fuselage
0:08:42 > 0:08:46and spreads catastrophically across the plane
0:08:46 > 0:08:48when it undergoes pressure changes in flight.
0:08:48 > 0:08:51It would have quickly and suddenly
0:08:51 > 0:08:53caused the plane to completely break up.
0:08:53 > 0:08:56Metal fatigue wasn't seen as a major problem
0:08:56 > 0:08:58prior to the Comet crashes,
0:08:58 > 0:09:01because aviation experts didn't fully understand
0:09:01 > 0:09:04the destructive effects of pressurisation
0:09:04 > 0:09:07and had been performing the wrong types of tests.
0:09:08 > 0:09:11The challenge for engineers was to find a way
0:09:11 > 0:09:15to protect the plane against the repetitive stresses of flight.
0:09:15 > 0:09:18How are you going to tackle the weakness in the fuselage?
0:09:18 > 0:09:20Well, it will be largely a question of a thicker skin
0:09:20 > 0:09:22and much improved detail design.
0:09:22 > 0:09:24Here's your skin.
0:09:24 > 0:09:26When you talk of a skin, what do you really mean?
0:09:26 > 0:09:29It isn't what we think of as a skin?
0:09:29 > 0:09:31Is it double thickness?
0:09:31 > 0:09:33Is it like a sort of insulated window, or...?
0:09:33 > 0:09:36- No, no, no, it's a single skin... - It is single?
0:09:36 > 0:09:38Oh, yes, high strength, light alloy,
0:09:38 > 0:09:40just single,
0:09:40 > 0:09:43and made thick enough to withstand the pressures and the loads
0:09:43 > 0:09:45that come on it from structural loads.
0:09:48 > 0:09:53Scientists also learnt that square cabin windows were problematic.
0:09:53 > 0:09:57The corners would often be where cracks in the fuselage started,
0:09:57 > 0:10:00so engineers simply got rid of the corners.
0:10:03 > 0:10:06The British civil aircraft industry never fully recovered
0:10:06 > 0:10:08from the Comet disasters.
0:10:08 > 0:10:11But what was learnt about metal fatigue
0:10:11 > 0:10:15and how to properly test for it was shared with airlines
0:10:15 > 0:10:17and engineers across the world.
0:10:17 > 0:10:22The emphasis was now on full-scale aircraft testing,
0:10:22 > 0:10:24because aviation experts realised
0:10:24 > 0:10:28that testing the structural integrity of individual plane parts
0:10:28 > 0:10:30can't be done in isolation.
0:10:35 > 0:10:4040 years after the Comet crashes, full-scale testing had become
0:10:40 > 0:10:44mandatory and a bit of a spectator sport for engineers.
0:10:45 > 0:10:48It's 1995, at the Boeing factory.
0:10:48 > 0:10:51Cables are pulling hard on a Triple 7 wing
0:10:51 > 0:10:53to test whether it can survive
0:10:53 > 0:10:57the strongest forces turbulence or bad handling could produce.
0:10:57 > 0:11:00REPORTER: As the test progresses, the forces on the wings
0:11:00 > 0:11:04are so strong that they cause ripples in the fuselage.
0:11:04 > 0:11:07The engineers hope that the wing will withstand
0:11:07 > 0:11:10150% of the strongest forces it will meet in flight.
0:11:10 > 0:11:14They're predicting a wing deflection of about 24 feet before it breaks.
0:11:15 > 0:11:17- ENGINEER:- Can I have your attention?
0:11:17 > 0:11:20We're now holding at 120% design limit load.
0:11:20 > 0:11:22We will make a loads check.
0:11:22 > 0:11:24It should be a short hold here.
0:11:31 > 0:11:33As the tension in the wing increases,
0:11:33 > 0:11:35the crowd of observers,
0:11:35 > 0:11:36including many of the people
0:11:36 > 0:11:40who have lived with the plane for four years or more, falls quiet.
0:11:41 > 0:11:45At 150% loading, it's the moment of truth.
0:11:45 > 0:11:47Will the wing remain intact?
0:11:55 > 0:11:59To the engineers' delight, the wing survives.
0:12:02 > 0:12:03151.
0:12:03 > 0:12:06They've got a safe, strong wing ready for service.
0:12:06 > 0:12:08156.
0:12:08 > 0:12:11If you've ever worried about wobbly wings,
0:12:11 > 0:12:13just see how much bending they can take.
0:12:15 > 0:12:17153.
0:12:17 > 0:12:20Now the engineers are going to push their creation
0:12:20 > 0:12:22to its absolute limit.
0:12:22 > 0:12:24154.
0:12:24 > 0:12:27It finally breaks at 154%...
0:12:29 > 0:12:33Way beyond the strongest forces any plane should experience.
0:12:35 > 0:12:37154.
0:12:40 > 0:12:43This is just one of the many tests a plane must pass
0:12:43 > 0:12:46before it's let anywhere near the runway.
0:12:46 > 0:12:50They're devised to weed out any weaknesses in the design
0:12:50 > 0:12:52or materials.
0:12:52 > 0:12:55So today it's very rare that a plane's strength
0:12:55 > 0:12:58is ever called into question.
0:13:02 > 0:13:06By the 1960s, the days of aircraft breaking up in mid air
0:13:06 > 0:13:08for no apparent reason were largely gone.
0:13:08 > 0:13:11But in terms of aircraft safety,
0:13:11 > 0:13:15fixing structural integrity actually turned out to be the easy bit.
0:13:15 > 0:13:18Much trickier was another major cause of crashes.
0:13:18 > 0:13:22What in the aviation world is called bad operational conditions,
0:13:22 > 0:13:24we would call bad weather,
0:13:24 > 0:13:27and the potentially lethal effects were highlighted
0:13:27 > 0:13:29by the investigation into
0:13:29 > 0:13:32one of the most mysterious crashes in history.
0:13:39 > 0:13:41On August 2nd, 1947,
0:13:41 > 0:13:45a British Lancastrian airliner called Star Dust
0:13:45 > 0:13:48took off on a routine passenger flight across South America.
0:13:51 > 0:13:55Although scheduled to fly from Buenos Aires to Santiago,
0:13:55 > 0:13:59the plane never reached its final destination.
0:13:59 > 0:14:01Instead it completely vanished
0:14:01 > 0:14:03just moments before touchdown.
0:14:07 > 0:14:11Despite an extensive search of the Andes mountains,
0:14:11 > 0:14:14no trace of the plane was ever found.
0:14:15 > 0:14:18But in 2000, 53 years after the crash,
0:14:18 > 0:14:22parts of the plane suddenly reappeared...
0:14:24 > 0:14:27..on a glacier high up in the Andes.
0:14:29 > 0:14:33Crash investigators examined the site in a bid to work out
0:14:33 > 0:14:35what had happened to the ill-fated plane.
0:14:40 > 0:14:43There was no explanation for why Star Dust had crashed
0:14:43 > 0:14:46when there was apparently nothing wrong with the plane.
0:14:47 > 0:14:51The plane had crashed 50 miles away from Santiago,
0:14:51 > 0:14:54even though the crew thought they were close to landing.
0:14:56 > 0:15:00So they focused on one key factor that could have caused the crash...
0:15:00 > 0:15:02navigation error.
0:15:04 > 0:15:08The investigators already knew that shortly before the crash
0:15:08 > 0:15:12the crew had decided to avoid bad weather by climbing
0:15:12 > 0:15:16above the clouds and flying over the top of the mountains.
0:15:16 > 0:15:18Although they didn't know it, by trying to fly over
0:15:18 > 0:15:22the tops of the mountains, they were sealing their fate.
0:15:22 > 0:15:27They were about to encounter an invisible meteorological phenomenon
0:15:27 > 0:15:29which they knew nothing about.
0:15:30 > 0:15:33The jet stream.
0:15:34 > 0:15:37This powerful, high altitude wind
0:15:37 > 0:15:40only develops above the normal weather systems.
0:15:42 > 0:15:46It blows at speeds of well over 100mph.
0:15:51 > 0:15:55But in 1947, the phenomenon itself was still largely unknown.
0:15:59 > 0:16:02The crew of Star Dust would have had no idea
0:16:02 > 0:16:04what they were flying into,
0:16:04 > 0:16:07and now that the plane was flying above the clouds
0:16:07 > 0:16:09the crew could no longer see the ground.
0:16:09 > 0:16:14As Star Dust climbed, it began to enter the jet stream
0:16:14 > 0:16:16and slow down dramatically.
0:16:16 > 0:16:18But the crew had no knowledge of this.
0:16:18 > 0:16:22They believed that they were making much faster progress.
0:16:22 > 0:16:25At 24,000 feet, Star Dust was flying
0:16:25 > 0:16:31almost directly into the jet stream, which was blowing at around 100mph.
0:16:39 > 0:16:42The Jet Stream's effect was devastating.
0:16:42 > 0:16:45At 5.33, the crew was convinced they were crossing
0:16:45 > 0:16:47the mountains into Chile.
0:16:47 > 0:16:49But they weren't.
0:16:49 > 0:16:53They radioed their time of arrival as 5.45.
0:16:58 > 0:17:01In fact, the plane was still on the wrong side of the mountains.
0:17:05 > 0:17:09The plane descended towards what the crew thought would be
0:17:09 > 0:17:10Santiago Airport.
0:17:10 > 0:17:12But in fact they were flying
0:17:12 > 0:17:16straight into the cloud-covered glacier of Mount Tupangato.
0:17:18 > 0:17:21All 11 lives were lost in the crash,
0:17:21 > 0:17:25and the plane was buried within seconds, vanishing from sight.
0:17:28 > 0:17:30The Star Dust tragedy was the direct result
0:17:30 > 0:17:33of the unknown effects of the jet stream.
0:17:33 > 0:17:37Today, thankfully, high-altitude weather is no longer a mystery
0:17:37 > 0:17:40and sophisticated weather forecasting makes sure
0:17:40 > 0:17:43crews are prepared whatever the conditions.
0:17:45 > 0:17:49One of the paradoxes of aircraft safety is that every major leap
0:17:49 > 0:17:53in aircraft capability creates its own new set of problems,
0:17:53 > 0:17:56and many of those are connected with the weather.
0:17:56 > 0:17:59So, for Star Dust, it was its ability to climb high.
0:17:59 > 0:18:03In the 1960s, the industry was grappling with the problems
0:18:03 > 0:18:04of flying fast,
0:18:04 > 0:18:08as jet engines like this one were taking over from piston engines.
0:18:08 > 0:18:11Now, that extra speed may have been good news for passengers
0:18:11 > 0:18:14but it meant that common forms of weather suddenly became
0:18:14 > 0:18:16very real safety concerns.
0:18:16 > 0:18:19Fighter pilots were the first to find out
0:18:19 > 0:18:22about the danger of rain damage at near supersonic speeds.
0:18:22 > 0:18:25After only ten minutes in a rain storm, a Hunter jet fighter
0:18:25 > 0:18:29landed with its radar cone damaged like this.
0:18:29 > 0:18:31The nose cone is made of bonded layers of toughened glass fibre
0:18:31 > 0:18:33and rubber.
0:18:33 > 0:18:35This was one of the first recorded cases of rain drop damage
0:18:35 > 0:18:38so massive that the aircraft had been in critical danger.
0:18:38 > 0:18:40The outer cover had been torn off.
0:18:40 > 0:18:43The inner rubber shell was deeply pitted.
0:18:43 > 0:18:45To understand what was happening,
0:18:45 > 0:18:48scientists at the Royal Aircraft Establishment, Farnborough,
0:18:48 > 0:18:50constructed this gas-powered gun
0:18:50 > 0:18:53to try to recreate the hazard of dangerous rain.
0:18:53 > 0:18:55A magnesium bullet tipped with Perspex
0:18:55 > 0:18:57is loaded into the firing chamber.
0:18:57 > 0:19:00When the bullet is fired at over 1,000 feet a second,
0:19:00 > 0:19:04it will collide with a raindrop suspended directly in its path.
0:19:06 > 0:19:09Surface tension holds the raindrop in place on a web
0:19:09 > 0:19:12of artificial fibres specially created for each test.
0:19:15 > 0:19:18A carefully measured drop of soft rain water is about to be
0:19:18 > 0:19:21given the destructive power of an explosive blast.
0:19:25 > 0:19:28The web is shattered before you have time to hear the explosion.
0:19:28 > 0:19:31The impact of the raindrop has been recorded
0:19:31 > 0:19:33on the Perspex head of the bullet.
0:19:36 > 0:19:37The Perspex,
0:19:37 > 0:19:42the kind that's used in aircraft windows, is studied for damage.
0:19:42 > 0:19:45The moment of impact, seen from a different angle.
0:19:46 > 0:19:49With camera shutter speed at a millionth of a second,
0:19:49 > 0:19:53the disintegration of each drop of water can be analysed in detail.
0:19:56 > 0:19:59Damage is caused when the pressure built up
0:19:59 > 0:20:02in the raindrop on impact is released when it shatters.
0:20:04 > 0:20:07Three clear areas show where pressure built up
0:20:07 > 0:20:10before the raindrops carved out their circles of damage.
0:20:10 > 0:20:13The effect of a torrential downpour on a high-speed aircraft
0:20:13 > 0:20:16would be many times more serious.
0:20:16 > 0:20:19Even raised rivets on the fuselage could be forced out
0:20:19 > 0:20:21by the impact of this kind of rain.
0:20:21 > 0:20:24To test the effects of a prolonged rainfall,
0:20:24 > 0:20:26they constructed this whirling arm.
0:20:26 > 0:20:29The blade tip revolves at 500 miles an hour,
0:20:29 > 0:20:31as water is spun off the disc mounted in front of it
0:20:31 > 0:20:33to form a fine rain cloud.
0:20:33 > 0:20:35Prototypes of metal, glass, paint and rubber can be fixed
0:20:35 > 0:20:38to the whirling arm to see how they stand up to rain storms.
0:20:38 > 0:20:40ALARM
0:20:40 > 0:20:44Within seconds the arm accelerates to 500 miles an hour.
0:20:49 > 0:20:52As rain drops strike the test surfaces one after another,
0:20:52 > 0:20:54materials simply disintegrate...
0:20:57 > 0:20:59Perspex after only 20 minutes.
0:21:04 > 0:21:07Aluminium is reduced to this after 15 hours.
0:21:10 > 0:21:13Metals and alloys used in the next generation of aircraft
0:21:13 > 0:21:16will have to stand up to longer flying hours at higher speeds.
0:21:16 > 0:21:20They prove themselves or fail dramatically on this test rig.
0:21:20 > 0:21:22Even paintwork has to be strengthened
0:21:22 > 0:21:26when only two minutes in rain does this.
0:21:26 > 0:21:30This research has shown that streamlining of aircraft is vital
0:21:30 > 0:21:33because it lessens the head-on impact of dangerous rain.
0:21:33 > 0:21:37Aircraft designers quickly applied these findings to modern jets.
0:21:39 > 0:21:40Raised rivets were lost,
0:21:40 > 0:21:42paint became protective,
0:21:42 > 0:21:46and the shape of aircrafts became increasingly tapered
0:21:46 > 0:21:48as their speeds increased.
0:21:48 > 0:21:52Rain at high speeds no longer caused any serious damage to the plane.
0:21:54 > 0:21:57Of all the problems caused by bad weather,
0:21:57 > 0:22:00one of the most potentially dangerous is losing visibility.
0:22:00 > 0:22:03It can seriously disorientate a pilot
0:22:03 > 0:22:07and make any manoeuvre that requires particular accuracy
0:22:07 > 0:22:10or precise judgment that much more difficult.
0:22:10 > 0:22:12So it makes sense that, out of all the conditions,
0:22:12 > 0:22:16the one that pilots have feared the most is fog.
0:22:18 > 0:22:22Fog is particularly dangerous when a pilot is attempting to land.
0:22:26 > 0:22:29That's because the plane needs to be perfectly aligned
0:22:29 > 0:22:32to hit the runway at the right spot at the right time.
0:22:36 > 0:22:39But in foggy conditions, pilots might not have any visual cues
0:22:39 > 0:22:42to help them.
0:22:42 > 0:22:44Without good visibility,
0:22:44 > 0:22:46the plane could clip something on the way down
0:22:46 > 0:22:48or even overshoot the runway.
0:22:48 > 0:22:51So, in the 1960s, some scientists thought
0:22:51 > 0:22:54the answer to the problem might be to find a way
0:22:54 > 0:22:57to simply get rid of fog at airports.
0:22:57 > 0:23:00In America, they attacked the problem
0:23:00 > 0:23:01with a rather unique approach.
0:23:02 > 0:23:05This equipment is the latest on the anti-fog scene.
0:23:05 > 0:23:08It's been developed by an American horticultural company
0:23:08 > 0:23:11from a standard crop spraying machine, and if it works
0:23:11 > 0:23:12it could do away with the need
0:23:12 > 0:23:15for special aircraft for spraying chemicals.
0:23:15 > 0:23:18Instead, with this machine, detergents or dry ice
0:23:18 > 0:23:21could be sprayed through an inflatable plastic tube
0:23:21 > 0:23:22from a height of 200 feet.
0:23:22 > 0:23:25A fan at the base of the machine inflates the tube.
0:23:25 > 0:23:28It also powers the spray which can pivot vertically
0:23:28 > 0:23:32or horizontally while being towed along a fog-covered runway.
0:23:32 > 0:23:35By the time these development tests are over, the researchers hope
0:23:35 > 0:23:38they'll have an effective fog killer that could be in operation
0:23:38 > 0:23:40by the end of next year.
0:23:40 > 0:23:43Perhaps not surprisingly, this particular fog killer
0:23:43 > 0:23:46wasn't very effective, and it was soon abandoned.
0:23:46 > 0:23:48A quarter of a mile from touchdown.
0:23:48 > 0:23:50You're on the glide path.
0:23:50 > 0:23:52On track, on the glide path.
0:23:52 > 0:23:56Once scientists realised completely eliminating fog at airports
0:23:56 > 0:23:57is no easy task,
0:23:57 > 0:24:00they concentrated on improving tools
0:24:00 > 0:24:02that pilots could use to work around it.
0:24:02 > 0:24:06It's called ILS, or Instrument Landing System.
0:24:06 > 0:24:09Instead of relying on a ground controller,
0:24:09 > 0:24:13a pilot watches two cross wires on an instrument in his cockpit.
0:24:13 > 0:24:16When they're centred, he knows he's on the glide path,
0:24:16 > 0:24:18flying down a fixed radio beam
0:24:18 > 0:24:22coming from a transmitter on the end of the runway itself.
0:24:23 > 0:24:26As ILS became more advanced,
0:24:26 > 0:24:29it, together with radar and radio technology,
0:24:29 > 0:24:32equipped pilots with the means to fly and land in fog
0:24:32 > 0:24:34with much more safety.
0:24:38 > 0:24:40Reducing the threats of bad weather
0:24:40 > 0:24:43and improving the structural integrity of planes
0:24:43 > 0:24:47meant that, during the 1960s and '70s,
0:24:47 > 0:24:49aircraft safety began to improve.
0:24:56 > 0:24:59By the 1980s, aircraft safety seemed to have become
0:24:59 > 0:25:00a good news story.
0:25:00 > 0:25:03Planes were far less likely to fall out of the sky
0:25:03 > 0:25:06and the rates of crashes had fallen.
0:25:06 > 0:25:10But there was one statistic that was worrying safety experts.
0:25:10 > 0:25:13Although the rate of crashes had fallen,
0:25:13 > 0:25:16the chances of actually surviving one had stayed the same.
0:25:16 > 0:25:20Engineers had been concentrating on preventing accidents
0:25:20 > 0:25:23rather than saving us if the worst was to happen.
0:25:35 > 0:25:39Fire is the greatest single threat to survival in any plane crash.
0:25:43 > 0:25:44That's because, as a passenger,
0:25:44 > 0:25:48you're sitting on top of up to 300,000 litres of fuel,
0:25:48 > 0:25:52and if it comes into contact with even the smallest of sparks,
0:25:52 > 0:25:55it's likely to explode into a deadly inferno.
0:25:59 > 0:26:03It seemed logical to scientists working in the early 1940s
0:26:03 > 0:26:05that the way to tackle the threat of fire
0:26:05 > 0:26:08was to prevent it happening in the first place.
0:26:08 > 0:26:11ARCHIVE REPORTER: The United States Air Force
0:26:11 > 0:26:13provided a group of service-weary aircraft
0:26:13 > 0:26:15with which to conduct their research.
0:26:15 > 0:26:18A landing or a take-off accident was chosen for study
0:26:18 > 0:26:21because the chance for passenger survival of crash impact
0:26:21 > 0:26:23is highest in this kind of crash.
0:26:25 > 0:26:28The US Air Force discovered that what was particularly dangerous
0:26:28 > 0:26:32about jet fuel was the way it dispersed on impact.
0:26:35 > 0:26:38Here, you can see test planes being deliberately crashed.
0:26:38 > 0:26:40The fuel has been coloured red.
0:26:41 > 0:26:45When the plane impacts, the fuel at first trails behind.
0:26:45 > 0:26:47Then, as the aircraft slows,
0:26:47 > 0:26:51it moves ahead in a fine mist.
0:26:51 > 0:26:54It's this mist that's particularly volatile.
0:26:58 > 0:27:00It was a major discovery.
0:27:00 > 0:27:03The task for the next 40 years would be to develop a fuel
0:27:03 > 0:27:05that didn't mist.
0:27:05 > 0:27:07And in the 1980s, it was us Brits
0:27:07 > 0:27:10that looked like we may have figured it out.
0:27:10 > 0:27:13The answer, then, is to make the fuel thicker so it doesn't mist,
0:27:13 > 0:27:16and the thickening ingredient that the scientists have come up with
0:27:16 > 0:27:18is an additive called FM-9.
0:27:18 > 0:27:21Now, the molecular structure of FM-9 is like a long chain.
0:27:21 > 0:27:23It's called a polymer, which,
0:27:23 > 0:27:26if you dissolve it in kerosene, floats freely.
0:27:26 > 0:27:29But if you shake the kerosene around,
0:27:29 > 0:27:31as would happen in a violent accident,
0:27:31 > 0:27:33the chains of the polymer will tangle together
0:27:33 > 0:27:36and make the kerosene behave like a jelly.
0:27:36 > 0:27:38Well, here's the real stuff.
0:27:38 > 0:27:41Aviation fuel with FM-9 on this side
0:27:41 > 0:27:44and fuel that doesn't have it, here.
0:27:44 > 0:27:46Now, side by side they look exactly the same,
0:27:46 > 0:27:47but if you shake them both,
0:27:47 > 0:27:50you can see that the fuel with the additive over here
0:27:50 > 0:27:53goes like jelly, and jelly can't mist.
0:27:53 > 0:27:56But hold on. It can't ignite either,
0:27:56 > 0:27:59so it's not going to be much use in an engine.
0:27:59 > 0:28:02So any engine using this stuff would have to be modified
0:28:02 > 0:28:05to break down the polymer chains to make the fuel behave normally.
0:28:08 > 0:28:10The Federal Aviation Authority in America
0:28:10 > 0:28:14was so taken by the research that they organised a test crash
0:28:14 > 0:28:18using a plane carrying the new anti-misting fuel
0:28:18 > 0:28:20and the scientists were optimistic
0:28:20 > 0:28:23that the test was going to be a success.
0:28:23 > 0:28:28I've got a great deal of confidence that we're not going to see a fire.
0:28:28 > 0:28:32The crash date was set for December 1st 1984.
0:28:32 > 0:28:34All hopes for a new, safe jet fuel
0:28:34 > 0:28:37were pinned onto this 9 million experiment.
0:28:37 > 0:28:41The aircraft will fly into cutters that will rip open the wings
0:28:41 > 0:28:43and the fuel tanks inside them.
0:28:46 > 0:28:48The world's press and television have been invited
0:28:48 > 0:28:50to observe from a safe distance.
0:28:56 > 0:28:57There's no pilot on board.
0:28:57 > 0:29:00He too is watching from a distance by television.
0:29:03 > 0:29:07Federal Aviation Agency engineers join NASA in Mission Control
0:29:07 > 0:29:11to monitor every detail as the Boeing 720 skims in over the Mojave Desert.
0:29:15 > 0:29:18Dozens of cameras follow the action.
0:29:19 > 0:29:21But it's falling short of the target.
0:29:22 > 0:29:25It spins to the left as it heads toward the cutters.
0:29:25 > 0:29:26This is not in the plan.
0:29:34 > 0:29:36The pictures that were flashed around the world that day
0:29:36 > 0:29:38made it look like a total disaster.
0:29:48 > 0:29:50The fire took more than an hour to extinguish.
0:29:50 > 0:29:53It was a PR disaster.
0:29:56 > 0:29:57Funding was withdrawn
0:29:57 > 0:30:01and the idea of preventing a fire was all but abandoned.
0:30:07 > 0:30:10And a disaster the following year led scientists
0:30:10 > 0:30:13to focus on simply surviving one instead.
0:30:17 > 0:30:22On August 22nd 1985, Flight 28M was taxiing down the runway
0:30:22 > 0:30:25at Manchester Airport heading for Corfu.
0:30:26 > 0:30:29But just minutes after leaving the gate,
0:30:29 > 0:30:32as the plane was attempting take-off, something went wrong.
0:30:36 > 0:30:39There was a loud bang on the left-hand side of the aircraft
0:30:39 > 0:30:42like the report from a shotgun
0:30:42 > 0:30:46and someone shouted, "A tyre has burst."
0:30:46 > 0:30:51And then, within about 1.5 seconds,
0:30:51 > 0:30:54the nose of the aircraft came down, bang,
0:30:54 > 0:30:56hit the floor, and all the bottles,
0:30:56 > 0:30:59the duty free, rattled in the bins at the top.
0:31:01 > 0:31:04The captain abandoned take-off within one second of hearing that bang,
0:31:04 > 0:31:07but he thought it's a tyre blow-out, so go easy on the brakes.
0:31:07 > 0:31:11Even when the fire bell rang he had no idea how bad this was,
0:31:11 > 0:31:13so he continued down the runway.
0:31:14 > 0:31:16People watching from the terminal building
0:31:16 > 0:31:20could see more clearly than the crew how burning fuel trailed behind
0:31:20 > 0:31:23until the aircraft turned off the runway and across the wind
0:31:23 > 0:31:26so fire and smoke enveloped the back of the plane.
0:31:28 > 0:31:33The flames came through the windows and up onto the ceiling
0:31:33 > 0:31:37and all the ceiling started to burn and then it rapidly spread.
0:31:37 > 0:31:40It was the heat of the cabin.
0:31:40 > 0:31:44It was so hot that you could feel your flesh creep,
0:31:44 > 0:31:46creeping like that.
0:31:46 > 0:31:50And I think myself that it was the seats,
0:31:50 > 0:31:53the foam had reached the flash point and they just went up
0:31:53 > 0:31:55and the thick, thick black smoke came down
0:31:55 > 0:31:58and that's all there was to breathe.
0:31:59 > 0:32:02People were on fire and people were burning, and some people,
0:32:02 > 0:32:05because of the visibility, were running the wrong way.
0:32:05 > 0:32:10I saw one, one lady who had her... just had her hair done
0:32:10 > 0:32:13and she, it must have been very heavily lacquered,
0:32:13 > 0:32:14because all of a sudden...
0:32:16 > 0:32:18And her hair went, the lot went,
0:32:18 > 0:32:22it had reached its flash point and she, in a panic, ran the wrong way.
0:32:24 > 0:32:28Roy Metcalf made it off the plane, but many didn't.
0:32:29 > 0:32:3255 people lost their lives.
0:32:36 > 0:32:39The pilot had thought the loud thump was a burst tyre,
0:32:39 > 0:32:43but the noise was in fact his left engine breaking apart
0:32:43 > 0:32:45and sparking a fire.
0:32:59 > 0:33:03It wasn't just the cause that was the concern in the Manchester crash.
0:33:03 > 0:33:07What troubled scientists was that it should have been survivable.
0:33:07 > 0:33:09After all, the plane didn't fall out of the sky,
0:33:09 > 0:33:11it didn't collide with anything,
0:33:11 > 0:33:14the pilot never lost control of the aircraft -
0:33:14 > 0:33:17so why did so many people die?
0:33:17 > 0:33:19Well, investigators began to focus
0:33:19 > 0:33:22on what had happened inside the cabin
0:33:22 > 0:33:24in the minutes after the engine failure.
0:33:28 > 0:33:30The seats at Manchester contained a plastic foam cushion
0:33:30 > 0:33:33that's commonly been used throughout the airline industry
0:33:33 > 0:33:34because it's very light.
0:33:39 > 0:33:43At Manchester the fire burned through the outer skin of the aircraft
0:33:43 > 0:33:44in perhaps half a minute,
0:33:44 > 0:33:47then up through ventilation ducts below the seats.
0:33:51 > 0:33:54This urethane plastic foam not only feeds the fire,
0:33:54 > 0:33:56it also gives off poison gas.
0:33:58 > 0:34:00Within minutes all that's left is cinders.
0:34:02 > 0:34:05But of the 55 that died, only nine of them
0:34:05 > 0:34:07were killed directly by the fire.
0:34:09 > 0:34:1146 were choked and poisoned by the smoke.
0:34:11 > 0:34:14The seats they were sitting on killed them.
0:34:20 > 0:34:23Prior to the Manchester crash, there were relatively few regulations
0:34:23 > 0:34:26about what the cabin must be made from.
0:34:28 > 0:34:32At the moment we have this number of specifications,
0:34:32 > 0:34:35all of which are used on buildings or ships
0:34:35 > 0:34:38or things used in buildings or ships.
0:34:38 > 0:34:42So all these are rules for fire testing and specifications?
0:34:42 > 0:34:45- All those are rules for fire testing.- Boxes and boxes of it.
0:34:45 > 0:34:48There's the building regulations of the governing document,
0:34:48 > 0:34:51and all these are specifications which are used at various times
0:34:51 > 0:34:55for things that go into buildings, ships or possibly cars.
0:34:55 > 0:34:57Whereas at the same time,
0:34:57 > 0:35:01we have one document which runs to about 11 pages,
0:35:01 > 0:35:05which covers the contents of aircraft cabins.
0:35:05 > 0:35:07- That's all there is? - That's all there is.
0:35:07 > 0:35:12After the Manchester disaster, the Civil Aviation Authority
0:35:12 > 0:35:14hurried through a requirement
0:35:14 > 0:35:17that airlines fit a new type of seat onto all aircraft.
0:35:17 > 0:35:21Between the cover and the foam there's now an extra layer.
0:35:21 > 0:35:24This would make the seats more fire resistant.
0:35:24 > 0:35:27Although the fumes could still be deadly, the new seats would at least
0:35:27 > 0:35:32give passengers more time to get out before being affected by the poison.
0:35:34 > 0:35:37The toxicity of cabin materials was not the only issue
0:35:37 > 0:35:41highlighted by the Manchester crash. Investigators were also concerned
0:35:41 > 0:35:44at how slow the passengers were to escape.
0:35:44 > 0:35:47They believed if the evacuation had been faster,
0:35:47 > 0:35:49there might have been more survivors.
0:35:51 > 0:35:53When the fire came in through the back of the cabin
0:35:53 > 0:35:57and people started to see the smoke and so on,
0:35:57 > 0:36:00many people rushed as rapidly as they could,
0:36:00 > 0:36:03some of them going over the seats to the front of the cabin,
0:36:03 > 0:36:06and when they came up against what we call the bulkheads,
0:36:06 > 0:36:09which are the solid sections which are just in front of the galleys,
0:36:09 > 0:36:13and there we have a quite narrow gap of actually 20 inches
0:36:13 > 0:36:17between those bulkheads, the passengers weren't all able
0:36:17 > 0:36:20to get through as fast as they arrived
0:36:20 > 0:36:23and we tragically finished up with a situation
0:36:23 > 0:36:27where some people just didn't manage to get through and fell,
0:36:27 > 0:36:30and others moved on in spite of them.
0:36:32 > 0:36:35The CAA commissioned Helen Muir to investigate
0:36:35 > 0:36:37why more people didn't escape.
0:36:37 > 0:36:40She knew that standard evacuation trials were too orderly,
0:36:40 > 0:36:44so she created a more realistic experience by offering her subjects
0:36:44 > 0:36:46a financial incentive to be first off the plane.
0:36:46 > 0:36:49The first half out of whichever exits are used
0:36:49 > 0:36:52will receive a £5 bonus payment immediately,
0:36:52 > 0:36:55and we have found that this does encourage people
0:36:55 > 0:36:58to make their way fairly rapidly,
0:36:58 > 0:37:02and very interestingly we've had survivors from accidents
0:37:02 > 0:37:05come and see videos of behaviour in these experiments and said,
0:37:05 > 0:37:08"Oh, yes, you know, that is how it was."
0:37:08 > 0:37:11'Undo your seat belt and get out.'
0:37:11 > 0:37:15In 1987 she used a real airliner with standard exits and bulkheads.
0:37:15 > 0:37:18She studied how different cabin layouts affected
0:37:18 > 0:37:20the flow of passengers to exits.
0:37:20 > 0:37:23FRENETIC SHOUTING
0:37:23 > 0:37:27This research video shows how bulkheads could cause blockages.
0:37:27 > 0:37:31The researchers recommended that the opening be increased to 30 inches.
0:37:33 > 0:37:36They also experimented with different seat layouts
0:37:36 > 0:37:39and suggested widening the access to over-wing exits.
0:37:39 > 0:37:43After the Manchester crash, the Civil Aviation Authority enforced
0:37:43 > 0:37:46the introduction of new seat layouts on planes.
0:37:46 > 0:37:50Airlines had to make access to mid-exit doors easier
0:37:50 > 0:37:53by either removing a seat or moving the entire row back.
0:37:55 > 0:37:58And they were forced to move all the emergency exit lighting
0:37:58 > 0:38:01to floor level so it wouldn't be obstructed by smoke.
0:38:04 > 0:38:07The Manchester disaster was a pivotal moment in improving
0:38:07 > 0:38:10the chance of surviving a plane crash.
0:38:10 > 0:38:12Buying passengers a little bit more time
0:38:12 > 0:38:17and speeding up evacuation has saved countless lives in fires since.
0:38:28 > 0:38:32The Manchester incident didn't mark the end of the study of survivability
0:38:32 > 0:38:36because in a crash, fire isn't the only serious threat to your life.
0:38:36 > 0:38:41In 1989, in another accident also in Britain, safety experts were
0:38:41 > 0:38:45forced to investigate the other major killer in air crashes - impact.
0:38:49 > 0:38:53On 8th January 1989 British Midland Flight 92
0:38:53 > 0:38:56took off from Heathrow bound for Belfast.
0:38:59 > 0:39:02Just minutes after take-off the left engine caught fire
0:39:02 > 0:39:06and the crew were re-directed to East Midlands Airport,
0:39:06 > 0:39:07but they never made it.
0:39:10 > 0:39:14The British Midland plane hit the motorway embankment at about 100mph.
0:39:14 > 0:39:16It came to a standstill in just over a second.
0:39:16 > 0:39:20The force of the impact was staggering, yet 79 people survived,
0:39:20 > 0:39:23though most were seriously injured.
0:39:23 > 0:39:26Had there been a fire, only 14 would have been able to escape.
0:39:28 > 0:39:31Scientists were shocked by the severity of the injuries
0:39:31 > 0:39:34suffered by the survivors and so focused much of their efforts
0:39:34 > 0:39:38on uncovering what happened to them at the moment of impact.
0:39:39 > 0:39:42A research team quickly embarked on the most detailed study yet
0:39:42 > 0:39:44of air crash survivors.
0:39:46 > 0:39:49Every survivor was photographed and interviewed.
0:39:49 > 0:39:52Every injury, including minor cuts and bruises, was logged.
0:39:54 > 0:39:56Their seat number and the position they adopted
0:39:56 > 0:39:59when the plane crashed was also recorded.
0:40:00 > 0:40:03The seats were examined, numbered and photographed
0:40:03 > 0:40:05from the front and rear.
0:40:05 > 0:40:09The information stored on computer accurately identified survivors,
0:40:09 > 0:40:13their injuries and other important details relevant to their survival.
0:40:14 > 0:40:17Although the forces in the accident were very high
0:40:17 > 0:40:22they alone couldn't account for the types of injuries suffered.
0:40:22 > 0:40:25Even those passengers who had got into the brace position
0:40:25 > 0:40:29which was supposed to protect against impact had suffered badly.
0:40:29 > 0:40:33The scientists were mystified, but they felt sure the injuries had
0:40:33 > 0:40:37something to do with how passengers prepared for the accident.
0:40:37 > 0:40:40For the first time ever they used computer simulations
0:40:40 > 0:40:42to investigate further.
0:40:42 > 0:40:46Precise details of the Kegworth crash were analysed by the computer program.
0:40:46 > 0:40:48The height and weight of one passenger
0:40:48 > 0:40:52from the centre of the plane and the position he was sitting in
0:40:52 > 0:40:54were added to recreate his exact movements
0:40:54 > 0:40:56during the split-second crash.
0:40:56 > 0:40:59First they looked at what happened to those passengers
0:40:59 > 0:41:02who didn't prepare for the crash.
0:41:02 > 0:41:05The computer program reproduced an accurate picture of why
0:41:05 > 0:41:08passengers who sat bolt upright during the crash
0:41:08 > 0:41:10incurred such devastating injuries.
0:41:12 > 0:41:15These passengers suffered broken arms, legs
0:41:15 > 0:41:18and serious head injuries. Some died.
0:41:19 > 0:41:23The researchers then looked at what happened to a passenger
0:41:23 > 0:41:25who did manage to get into the brace position.
0:41:25 > 0:41:29He rested his head on the seat in front in between his arms.
0:41:29 > 0:41:34His legs were slightly forward. As the plane plunged over the M1,
0:41:34 > 0:41:39his face and arms are forced into the seat back. His legs move forward.
0:41:39 > 0:41:43On impact with the motorway his face powered into the seat back,
0:41:43 > 0:41:47his arms flailed and his legs flailed under the seat in front.
0:41:47 > 0:41:50Most limb fractures resulted from this flailing.
0:41:50 > 0:41:53When the plane stopped he impacted again.
0:41:53 > 0:41:57Shocked that the recommended brace position could also cause
0:41:57 > 0:42:01so many injuries, the scientists started to work on developing
0:42:01 > 0:42:06a new, safer position that would do a better job of protecting the body.
0:42:08 > 0:42:11Instead of the feet simply resting on the floor in front,
0:42:11 > 0:42:14the scientists tucked the legs under the seat
0:42:14 > 0:42:17and rather than the head being between the arms,
0:42:17 > 0:42:19they positioned the arms over the head
0:42:19 > 0:42:22and rested this directly onto the seat in front.
0:42:24 > 0:42:26The dummy in the front seat is there
0:42:26 > 0:42:28to simulate someone occupying that seat.
0:42:33 > 0:42:35At 20G, roughly the force of the Kegworth crash,
0:42:35 > 0:42:38the legs on the rear dummy move forward on impact,
0:42:38 > 0:42:42but only slightly, and they don't flail under the seat in front.
0:42:42 > 0:42:45The head impact is greatly reduced,
0:42:45 > 0:42:48suggesting that cuts and bruises would be less serious,
0:42:48 > 0:42:52and the flailing of the arms which caused so many fractures in Kegworth
0:42:52 > 0:42:53is much less.
0:42:53 > 0:42:57There is, of course, no proof, but the research team is convinced
0:42:57 > 0:43:00that had passengers on the Kegworth plane adopted their brace position,
0:43:00 > 0:43:03the injury toll would have been greatly reduced.
0:43:04 > 0:43:06The Kegworth investigation
0:43:06 > 0:43:08led to the introduction of a new brace position
0:43:08 > 0:43:11which would be adopted by airlines around the world.
0:43:12 > 0:43:16So next time you're on a plane, it's worth checking out the safety card,
0:43:16 > 0:43:20because getting into the right position could save your life.
0:43:24 > 0:43:29In the 1980s the aviation industry had made considerable progress
0:43:29 > 0:43:33on aircraft design and was working on crash survivability,
0:43:33 > 0:43:36but they'd also turn their attention to another factor
0:43:36 > 0:43:40that remained stubbornly immune to improvement. It was becoming clear
0:43:40 > 0:43:45to safety experts that most crashes were the result of something
0:43:45 > 0:43:49rather less well understood than either weather or engineering,
0:43:49 > 0:43:53something notoriously unpredictable and difficult to control -
0:43:53 > 0:43:54humans.
0:43:55 > 0:43:58Human error had been the cause of the Kegworth disaster.
0:43:58 > 0:44:02When the left engine caught fire, the crew thought the problem was
0:44:02 > 0:44:05with the right one, so shut it down.
0:44:05 > 0:44:08By the time they realised they'd turned off the wrong engine
0:44:08 > 0:44:10it was too late to restart it,
0:44:10 > 0:44:15and with no engine power, the plane and its passengers were doomed.
0:44:21 > 0:44:26Human error is the most common cause of air crashes, and in the 1980s,
0:44:26 > 0:44:30after a spate of accidents caused not by the plane or weather,
0:44:30 > 0:44:32but by the crew,
0:44:32 > 0:44:36the entire industry started looking at how best to tackle the problem.
0:44:36 > 0:44:40They decided to turn to aviation psychologists for help.
0:44:45 > 0:44:48Since 1975, a highly confidential reporting system
0:44:48 > 0:44:52has collected over 50,000 reports from worried pilots
0:44:52 > 0:44:55about serious incidents involving breakdowns in teamwork.
0:44:55 > 0:44:58It's run by NASA
0:44:58 > 0:45:00and at their research centre in California
0:45:00 > 0:45:03they're trying to recreate those incidents in a laboratory.
0:45:06 > 0:45:10At its heart is a simulator containing a full flight crew.
0:45:10 > 0:45:12We have an emergency, Sierra...
0:45:12 > 0:45:14Their highly realistic flight
0:45:14 > 0:45:17is complete with real air traffic controllers.
0:45:17 > 0:45:20Using video cameras they can now find out how bad teamwork
0:45:20 > 0:45:23leads to accidents without killing anybody.
0:45:23 > 0:45:26FIRE ALARM SOUNDS
0:45:26 > 0:45:28Engine fire number three.
0:45:31 > 0:45:33Charlie, you do the check list.
0:45:33 > 0:45:36I'll fly the aeroplane. I'll do the talking.
0:45:36 > 0:45:39One of their three engines has caught fire.
0:45:39 > 0:45:40It will have to be shut down fast.
0:45:40 > 0:45:43- Power lever number three.- Idle.
0:45:43 > 0:45:48- Start lever number three, cut off? - Check, number three.- Number three.
0:45:50 > 0:45:53Yeah, Tony, it looks like we've lost one of the engines.
0:45:53 > 0:45:54Everything else is good,
0:45:54 > 0:45:57but we are going to have to go back and land.
0:45:59 > 0:46:02When NASA put over 20 airline flight crews through an exercise like this
0:46:02 > 0:46:05they were amazed by the variety of performance they saw,
0:46:05 > 0:46:09everything from good coordination to almost complete mayhem.
0:46:12 > 0:46:14I didn't want to go to Chicago anyhow.
0:46:15 > 0:46:19It's clear that effective communication in the cockpit is vital,
0:46:19 > 0:46:21yet the researchers have found that those skills
0:46:21 > 0:46:24are often barely adequate or even nonexistent.
0:46:25 > 0:46:28The psychologists at NASA are discovering that anything
0:46:28 > 0:46:32that prevents a flight crew behaving like a well-oiled team
0:46:32 > 0:46:33is potentially dangerous
0:46:33 > 0:46:37and one of the most disruptive influences is a pilot's personality.
0:46:37 > 0:46:41Many of them simply aren't fitted for commercial cockpits at all.
0:46:43 > 0:46:46Cracking the sound barrier in level flight
0:46:46 > 0:46:48will be more than a spectacular feat.
0:46:48 > 0:46:51It will also give the Air Force valuable knowledge
0:46:51 > 0:46:53of the resources of new propulsive systems.
0:46:54 > 0:46:57Captain Yeager gets aboard the XS-1.
0:46:57 > 0:47:01It can't be a long flight he's going to have in the little aircraft.
0:47:01 > 0:47:04At full power, the flight can't last more than 2.5 minutes,
0:47:04 > 0:47:06but it's going to be a fast one.
0:47:08 > 0:47:12In 1947 Chuck Yeager became a model hero for military pilots
0:47:12 > 0:47:15when he became the first man to break through the sound barrier
0:47:15 > 0:47:17in his experimental rocket plane the X-1.
0:47:21 > 0:47:24The really big moment. Through the sound barrier!
0:47:24 > 0:47:27The first time ever in level flight.
0:47:28 > 0:47:31His relaxed laconic style while in great peril
0:47:31 > 0:47:33became dubbed "the right stuff".
0:47:36 > 0:47:38"The right stuff" is, as we see it,
0:47:38 > 0:47:43in test pilots and in the early, but not the present astronauts,
0:47:43 > 0:47:47is really this combination of high technical competence,
0:47:47 > 0:47:51a very rugged individualism and a very high level of competitiveness.
0:47:53 > 0:47:55The latter two are very destructive
0:47:55 > 0:47:58when you're trying to function as an effective team.
0:48:00 > 0:48:03The trouble is, whole generations of military flyers who venerated
0:48:03 > 0:48:06those test pilots and tried to emulate them,
0:48:06 > 0:48:09went on to fly for commercial airlines
0:48:09 > 0:48:11taking "the right stuff" with them.
0:48:11 > 0:48:17In many accidents the result is not that the crew makes a major mistake,
0:48:17 > 0:48:21but that the captain decides in an emergency situation
0:48:21 > 0:48:23that HE must fly the aircraft,
0:48:23 > 0:48:26he must physically take control of the airplane
0:48:26 > 0:48:28because he has "the right stuff".
0:48:28 > 0:48:31What he fails to do then is to manage the situation
0:48:31 > 0:48:34and to use the resources that are available
0:48:34 > 0:48:35from the other crew members.
0:48:35 > 0:48:40So he has turned it into a single-seat fighter
0:48:40 > 0:48:43when in fact he needs all the assistance he can get.
0:48:43 > 0:48:46He refuses to see it as a group problem
0:48:46 > 0:48:47but as an individual problem.
0:48:47 > 0:48:51I think it's a real potential problem, because the factors
0:48:51 > 0:48:55that would lead you to an effective, smooth-working crew
0:48:55 > 0:48:58are very different from those that make you a fighter ace.
0:48:58 > 0:49:02"The right stuff" is in fact the wrong stuff.
0:49:02 > 0:49:07In the early 1980s, psychologists started advising airlines
0:49:07 > 0:49:09on how they could reduce human error
0:49:09 > 0:49:11and improve teamwork in the cockpit.
0:49:11 > 0:49:15United Airlines were the first to apply their recommendations
0:49:15 > 0:49:18by changing their approach to pilot training.
0:49:18 > 0:49:21Gentlemen, we've been discussing this afternoon
0:49:21 > 0:49:24elements in our cockpit resource management programme,
0:49:24 > 0:49:25which we call CRM.
0:49:25 > 0:49:29They use a number of charts which depict a wide range of
0:49:29 > 0:49:32personality types between the two extremes
0:49:32 > 0:49:33of concern solely for the job
0:49:33 > 0:49:36and concern solely for getting along with people.
0:49:37 > 0:49:40After getting the low-down from the business manager,
0:49:40 > 0:49:44pilots are then put through a highly realistic flight in a simulator.
0:49:44 > 0:49:49We've got two engines. Number two is flaming out. The altimeter is OK.
0:49:49 > 0:49:51It looks like loss of all generators.
0:49:51 > 0:49:53Checklist, loss of all generators.
0:49:53 > 0:49:54When something goes wrong,
0:49:54 > 0:49:58between them, the team have to come up with a way to solve the problem.
0:49:58 > 0:50:01Can either one of you think of anything that we haven't done
0:50:01 > 0:50:03or that we need to do?
0:50:03 > 0:50:06The only thing that we haven't tried, we could start the APU...
0:50:08 > 0:50:12Vern has volunteered a novel solution which is not on his checklist.
0:50:12 > 0:50:14He wants to try and link
0:50:14 > 0:50:16an extra device called the auxiliary power unit
0:50:16 > 0:50:18into the defunct third generator.
0:50:20 > 0:50:23OK. I got the APU running. You want me to try it on number three, boss?
0:50:23 > 0:50:27- Try it.- Five for six.
0:50:27 > 0:50:28Four, not a five for four.
0:50:28 > 0:50:30- It took.- Good.
0:50:30 > 0:50:33It took, OK, you should have everything now.
0:50:33 > 0:50:34Yes, sir, sure do.
0:50:34 > 0:50:37Everything's back to normal, flaps are back to normal.
0:50:37 > 0:50:39That's a good thought, Vern.
0:50:39 > 0:50:43Vern's creativity has paid off. Control is restored.
0:50:43 > 0:50:45They can now land safely,
0:50:45 > 0:50:49and by praising him, Mike has reinforced Vern's behaviour.
0:50:49 > 0:50:53This is what commercial airlines call "the right stuff".
0:50:57 > 0:50:59United are convinced that the self-awareness
0:50:59 > 0:51:02generated by that system is leading to safer cockpits.
0:51:05 > 0:51:09There's a quiet revolution taking place among the world's airlines.
0:51:10 > 0:51:13This kind of training proved to be so successful
0:51:13 > 0:51:16that today most airlines have made it mandatory
0:51:16 > 0:51:20not just for pilots, but for all crew members.
0:51:24 > 0:51:27And it's thought to have significantly reduced the kind
0:51:27 > 0:51:31of teamwork issues that were responsible for so many crashes.
0:51:42 > 0:51:46Relationships in the cockpit are clearly critical to get right,
0:51:46 > 0:51:49but it's not just human interaction that needs to be monitored.
0:51:49 > 0:51:53So does the partnership between pilot and machine,
0:51:53 > 0:51:56and since the 1970s, that's often been a difficult,
0:51:56 > 0:51:59complicated love/hate relationship
0:51:59 > 0:52:01since computers became more sophisticated
0:52:01 > 0:52:05and much more involved in the business of flying the plane.
0:52:07 > 0:52:09Ground crew 080.
0:52:09 > 0:52:13This demonstration in the American DC-9 Super 80
0:52:13 > 0:52:16shows just how powerful that technology is.
0:52:16 > 0:52:19Before take-off the computer automatically works out
0:52:19 > 0:52:21what the correct engine thrust should be
0:52:21 > 0:52:23and sets the speed bugs in place.
0:52:25 > 0:52:29The throttles advance automatically to the correct setting for take-off.
0:52:33 > 0:52:35Game on, rotate!
0:52:41 > 0:52:45About 400 feet into the air, the captain engages the auto-pilot.
0:52:45 > 0:52:49One last dab at the computer and it will now control the rate of climb,
0:52:49 > 0:52:54air speed and engine thrust right up to the assigned cruising altitude.
0:52:54 > 0:52:58The route has already been programmed in, so the plane will take itself
0:52:58 > 0:53:01to its destination. All the pilot needs to do is to watch it.
0:53:03 > 0:53:07And that was the mid-1980s. Today, computers are even more
0:53:07 > 0:53:12powerful and sophisticated, but too much automation brings with it
0:53:12 > 0:53:16another set of problems, problems that played out
0:53:16 > 0:53:20with disastrous effect in the cockpit of Air France Flight 447.
0:53:24 > 0:53:28On May 31st 2009, an Air France Airbus took off from Rio
0:53:28 > 0:53:30headed for Paris.
0:53:31 > 0:53:35But just 350 miles off the coast of Brazil,
0:53:35 > 0:53:37the plane crashed into the Atlantic...
0:53:38 > 0:53:40..killing all 228 people on board.
0:53:55 > 0:53:58The cause of the crash remained a mystery for years
0:53:58 > 0:54:03until investigators managed to pull together enough evidence
0:54:03 > 0:54:06to reconstruct the last few minutes before impact.
0:54:09 > 0:54:123.5 hours after take-off, just before 2am,
0:54:12 > 0:54:17Flight 447 was heading into a huge 250-mile-wide storm.
0:54:20 > 0:54:24When the plane started to experience turbulence, the pilot dialled
0:54:24 > 0:54:28a lower speed into the computer and prepared to ride it out.
0:54:33 > 0:54:37But at just 2.10am at 35,000 feet...
0:54:39 > 0:54:41..a series of alarms went off...
0:54:43 > 0:54:45..and the auto-pilot disconnected.
0:54:45 > 0:54:47ALARMS SOUND
0:54:52 > 0:54:55In total darkness and heavy turbulence
0:54:55 > 0:54:58the crew are forced to re-take manual control.
0:55:00 > 0:55:05Pilots are the last line of defence, so when things go very wrong,
0:55:05 > 0:55:07the last line of defence is the aviator.
0:55:09 > 0:55:11After more than three hours on auto-pilot
0:55:11 > 0:55:14the pilots are suddenly faced by information overload.
0:55:16 > 0:55:20That crew faced an almost unheard-of series of failures,
0:55:20 > 0:55:22one right behind the other,
0:55:22 > 0:55:23and for them to sort through it
0:55:23 > 0:55:25would have been very difficult that night.
0:55:25 > 0:55:28Why is the aeroplane doing what it's doing?
0:55:28 > 0:55:31What are all these failures? Why are they all coming at one time?
0:55:32 > 0:55:37Bombarded by faults, the pilot must cope with the most serious problem of all -
0:55:37 > 0:55:42he must maintain speed or they will go out of control.
0:55:45 > 0:55:48But after the pilot took manual control,
0:55:48 > 0:55:50the plane lost critical speed
0:55:50 > 0:55:54and went into the catastrophic condition known as a stall.
0:55:55 > 0:55:58In a stall the wings of the aircraft lose lift
0:55:58 > 0:56:01and the plane becomes almost impossible to control.
0:56:03 > 0:56:05The pilot should have responded
0:56:05 > 0:56:08by trying to increase speed, but he didn't.
0:56:11 > 0:56:15No-one could be sure why, but it could be that he wasn't aware
0:56:15 > 0:56:20he was stalling or maybe because he was just so used to automation
0:56:20 > 0:56:24his manual skills had been blunted. Either way, the Air France pilot
0:56:24 > 0:56:29couldn't maintain control and the plane simply dropped out of the sky.
0:56:33 > 0:56:37To avoid the same scenario ever playing out again
0:56:37 > 0:56:41the crash investigation recommended that simulator training placed
0:56:41 > 0:56:44more of an emphasis on manual high-altitude flying
0:56:44 > 0:56:48and aviation authorities have encouraged all pilots
0:56:48 > 0:56:51to try switching off auto-pilot once in a while.
0:56:54 > 0:56:58These changes should make pilots less reliant on automation
0:56:58 > 0:57:02and better prepared to take back the controls in a crisis.
0:57:16 > 0:57:18It is odd to think that we have only been flying
0:57:18 > 0:57:21for a fraction over 100 years
0:57:21 > 0:57:25and, despite the bewildering complexity, it is incredibly safe.
0:57:25 > 0:57:29Crashes are very rare and something like 90% of those are survivable,
0:57:29 > 0:57:33which is an amazing statistic and should give you SOME comfort
0:57:33 > 0:57:36if you worry about the idea of hurtling through the air
0:57:36 > 0:57:40at close to the speed of sound 35,000 feet above the ground
0:57:40 > 0:57:42in a pressurised metal tube.
0:57:42 > 0:57:44For me personally, ever since I was a kid,
0:57:44 > 0:57:48I found air travel to be thrilling, but the more I think about it,
0:57:48 > 0:57:51the more I think it's, well, it's mind-blowing.
0:58:30 > 0:58:33Subtitles by Red Bee Media Ltd