Impact! A Horizon Guide to Plane Crashes (2013) - full transcript
Air travel has
transformed our lives.
Fast, direct,
and above all safe.
And it keeps getting safer.
In 2012, the global accident rate
for Western-built jets
was the lowest in aviation history.
But the carefree flying
that we enjoy today
has been bought at a deadly cost...
Because improvements
in aviation safety
have been driven by the stuff
of nightmares...
Air crashes.
Every crash has its causes,
and this information is used
by scientists
to prevent the same failures
from happening again.
For more than 60 years,
Horizon and the BBC have reported
on the accidents that have
revolutionised aviation safety.
In this programme, we'll chart
the most significant improvements
through the stories of
the most deadly disasters.
Tenerife Airport,
March 27th, 1977.
Debris is strewn far and wide.
Thick plumes of smoke fill the sky.
This is the wreckage from the
deadliest air crash in history,
a crash that happened
not in the sky
but on the runway.
The control tower
just 700 metres away
didn't even see it happen.
Just ten minutes earlier,
the airport had been busy
but running smoothly.
Two Boeing 747s,
one KLM, the other Pan Am,
were a mile apart
at opposite ends of the runway.
They'd been instructed to position
themselves ready for take-off.
The KLM was to wait
at one end of the runway
while Pan Am was to turn off it
and allow KLM to depart first.
As they were manoeuvring,
a thick fog came over the mountains
and enveloped the airport.
With the runway now shrouded in fog
neither plane could see each other.
Crucially, neither could the air
traffic controller in the tower.
The Pan Am pilots taxiing
down the runaway missed the turning.
At six minutes past five
the KLM pilot, believing
the Pan Am was now off the runway,
began his take-off
with Pan Am still ahead of him.
First time in my life I've ever had
a situation occur
that I couldn't believe
was happening.
I just could not believe
this airplane was coming
down the runaway at us.
My comment was, "Get off!"
to the captain,
which he tried everything
he possibly could.
As we were turning,
I looked back out of my right window
and the KLM airplane had lifted
off the runway.
Basically, what I did was
just close my eyes and duck.
During lift-off, the KLM plane
collided with Pan Am.
Although briefly airborne,
it lost control,
crashed and burst
into a ball of flames...
..while the Pan Am plane broke
into several pieces and exploded.
Almost 600 people died that day.
The accident shocked the world.
Everyone wanted to know what could
have caused this devastating crash.
Initially it seemed the obvious
cause of the disaster was fog.
562, turn tight, heading 070...
But the crash investigation
revealed that fog
was only one factor.
123 out of air...
123, 29 miles over.
Bad communication
and poor crew dynamics
also played a major role.
Wind squall at 5524.
5524.
The Tenerife disaster showed
that the causes of plane crashes
are rarely straightforward.
And that's not surprising
given that aviation
is an incredibly complex business
and there are so many things
that can go wrong.
If you stop and think about it
for a second,
travelling by plane is
a pretty odd thing to do.
Hundreds of us
strapped into this narrow tube,
hurtling through the air
at upwards of 500 miles an hour,
and separated from the freezing,
oxygen-starved atmosphere
by just a few centimetres
of metal and plastic.
Today we pretty much
take it for granted
that the aeroplane is up to the job.
It's not going
to fall apart around us.
But in the early days
of commercial aviation,
even the structural integrity
of the plane couldn't be guaranteed.
Scientists realised the hard way
that there were some
significant gaps in their knowledge.
There is arguably no single plane
that's been more important
in the story of aircraft engineering
than the ill-fated Comet.
REPORTER: When the 36-seater,
jet-propelled De Havilland Comet
opened the latest act in the drama
of man's conquest of the heavens,
the eyes of many nations
were focused upon it.
Built in Britain
and launched in 1952,
it was the first passenger jet
to go into service.
Cruising at 490 miles an hour,
the Comet offered
all the attractions
of smooth, high-altitude travel.
The Comet had grace and beauty.
But unfortunately that's not
what it's remembered for.
Between May '52 and April '54,
three of the nine Comets in service
broke up in mid air.
The Comet 1 never flew again.
After the third disaster,
bits of the aircraft were recovered
from the bottom
of the Mediterranean.
In all, 67 people died
in the crashes.
It was a disaster
for the British aircraft industry,
particularly because
no-one knew why the planes
had apparently
just fallen out of the sky.
So all the Comets were grounded,
and scientists set to work
on one of the greatest
aircraft detective stories
in aviation history.
As in any investigation,
scientists started by painstakingly
sieving through the crash wreckage.
Their first clue came in the form
of a curious anomaly
found in fragments of the fuselage.
There were unexplained rips
through the aluminium shell.
The scientists next had to work out
what could have caused
these tears,
and the only way to do that
was to try to recreate the damage.
An entire fuselage was immersed
in a high pressure tank
and subjected to cycles of
increasing and decreasing pressure
to simulate an aircraft in service
constantly climbing and descending.
The fatal weakness
suddenly revealed itself.
A weakness that would change
aircraft design forever.
It was metal fatigue,
a type of weakness that starts
as a small crack
somewhere in the fuselage
and spreads catastrophically
across the plane
when it undergoes
pressure changes in flight.
It would have quickly and suddenly
caused the plane
to completely break up.
Metal fatigue wasn't seen
as a major problem
prior to the Comet crashes,
because aviation experts
didn't fully understand
the destructive effects
of pressurisation
and had been performing
the wrong types of tests.
The challenge for engineers
was to find a way
to protect the plane against
the repetitive stresses of flight.
How are you going to tackle
the weakness in the fuselage?
Well, it will be largely
a question of a thicker skin
and much improved detail design.
Here's your skin.
When you talk of a skin,
what do you really mean?
It isn't what we think of as a skin?
Is it double thickness?
Is it like a sort of
insulated window, or...?
No, no, no, it's a single skin...
It is single?
Oh, yes, high strength, light alloy,
just single,
and made thick enough to withstand
the pressures and the loads
that come on it
from structural loads.
Scientists also learnt that square
cabin windows were problematic.
The corners would often be where
cracks in the fuselage started,
so engineers simply
got rid of the corners.
The British civil aircraft industry
never fully recovered
from the Comet disasters.
But what was learnt
about metal fatigue
and how to properly test for it
was shared with airlines
and engineers across the world.
The emphasis was now on
full-scale aircraft testing,
because aviation experts realised
that testing the structural
integrity of individual plane parts
can't be done in isolation.
40 years after the Comet crashes,
full-scale testing had become
mandatory and a bit of
a spectator sport for engineers.
It's 1995, at the Boeing factory.
Cables are pulling hard
on a Triple 7 wing
to test whether it can survive
the strongest forces turbulence
or bad handling could produce.
REPORTER: As the test progresses,
the forces on the wings
are so strong that they cause
ripples in the fuselage.
The engineers hope
that the wing will withstand
150% of the strongest forces
it will meet in flight.
They're predicting a wing deflection
of about 24 feet before it breaks.
ENGINEER: Can I have your attention?
We're now holding
at 120% design limit load.
We will make a loads check.
It should be a short hold here.
As the tension in the wing increases,
the crowd of observers,
including many of the people
who have lived with the plane
for four years or more, falls quiet.
At 150% loading,
it's the moment of truth.
Will the wing remain intact?
To the engineers' delight,
the wing survives.
151.
They've got a safe, strong wing
ready for service.
156.
If you've ever worried
about wobbly wings,
just see how much bending
they can take.
153.
Now the engineers are going
to push their creation
to its absolute limit.
154.
It finally breaks at 154%...
Way beyond the strongest forces
any plane should experience.
154.
This is just one of the many tests
a plane must pass
before it's let anywhere
near the runway.
They're devised to weed out
any weaknesses in the design
or materials.
So today it's very rare
that a plane's strength
is ever called into question.
By the 1960s, the days of aircraft
breaking up in mid air
for no apparent reason
were largely gone.
But in terms of aircraft safety,
fixing structural integrity actually
turned out to be the easy bit.
Much trickier was another
major cause of crashes.
What in the aviation world is called
bad operational conditions,
we would call bad weather,
and the potentially lethal effects
were highlighted
by the investigation into
one of the most mysterious
crashes in history.
On August 2nd, 1947,
a British Lancastrian airliner
called Star Dust
took off on a routine passenger
flight across South America.
Although scheduled to fly
from Buenos Aires to Santiago,
the plane never reached
its final destination.
Instead it completely vanished
just moments before touchdown.
Despite an extensive search
of the Andes mountains,
no trace of the plane
was ever found.
But in 2000,
53 years after the crash,
parts of the plane
suddenly reappeared...
..on a glacier high up in the Andes.
Crash investigators examined
the site in a bid to work out
what had happened
to the ill-fated plane.
There was no explanation
for why Star Dust had crashed
when there was apparently
nothing wrong with the plane.
The plane had crashed
50 miles away from Santiago,
even though the crew thought
they were close to landing.
So they focused on one key factor
that could have caused the crash...
navigation error.
The investigators already knew
that shortly before the crash
the crew had decided to avoid
bad weather by climbing
above the clouds and flying
over the top of the mountains.
Although they didn't know it,
by trying to fly over
the tops of the mountains,
they were sealing their fate.
They were about to encounter an
invisible meteorological phenomenon
which they knew nothing about.
The jet stream.
This powerful, high altitude wind
only develops above
the normal weather systems.
It blows at speeds
of well over 100mph.
But in 1947, the phenomenon itself
was still largely unknown.
The crew of Star Dust
would have had no idea
what they were flying into,
and now that the plane was flying
above the clouds
the crew could no longer
see the ground.
As Star Dust climbed,
it began to enter the jet stream
and slow down dramatically.
But the crew had
no knowledge of this.
They believed that they were
making much faster progress.
At 24,000 feet, Star Dust was flying
almost directly into the jet stream,
which was blowing at around 100mph.
The Jet Stream's effect
was devastating.
At 5.33, the crew was convinced
they were crossing
the mountains into Chile.
But they weren't.
They radioed their time
of arrival as 5.45.
In fact, the plane was still
on the wrong side of the mountains.
The plane descended towards
what the crew thought would be
Santiago Airport.
But in fact they were flying
straight into the cloud-covered
glacier of Mount Tupangato.
All 11 lives were lost
in the crash,
and the plane was buried within
seconds, vanishing from sight.
The Star Dust tragedy
was the direct result
of the unknown effects
of the jet stream.
Today, thankfully, high-altitude
weather is no longer a mystery
and sophisticated
weather forecasting makes sure
crews are prepared
whatever the conditions.
One of the paradoxes of aircraft
safety is that every major leap
in aircraft capability
creates its own new set of problems,
and many of those are connected
with the weather.
So, for Star Dust, it was
its ability to climb high.
In the 1960s, the industry was
grappling with the problems
of flying fast,
as jet engines like this one were
taking over from piston engines.
Now, that extra speed may have been
good news for passengers
but it meant that common forms
of weather suddenly became
very real safety concerns.
Fighter pilots were
the first to find out
about the danger of rain damage
at near supersonic speeds.
After only ten minutes in a rain
storm, a Hunter jet fighter
landed with its radar cone
damaged like this.
The nose cone is made of bonded
layers of toughened glass fibre
and rubber.
This was one of the first
recorded cases of rain drop damage
so massive that the aircraft
had been in critical danger.
The outer cover had been torn off.
The inner rubber shell
was deeply pitted.
To understand what was happening,
scientists at the Royal Aircraft
Establishment, Farnborough,
constructed this gas-powered gun
to try to recreate
the hazard of dangerous rain.
A magnesium bullet
tipped with Perspex
is loaded into the firing chamber.
When the bullet is fired
at over 1,000 feet a second,
it will collide with a raindrop
suspended directly in its path.
Surface tension holds the raindrop
in place on a web
of artificial fibres
specially created for each test.
A carefully measured drop
of soft rain water is about to be
given the destructive power
of an explosive blast.
The web is shattered before you have
time to hear the explosion.
The impact of the raindrop
has been recorded
on the Perspex head of the bullet.
The Perspex,
the kind that's used in aircraft
windows, is studied for damage.
The moment of impact,
seen from a different angle.
With camera shutter speed
at a millionth of a second,
the disintegration of each drop
of water can be analysed in detail.
Damage is caused
when the pressure built up
in the raindrop on impact
is released when it shatters.
Three clear areas show
where pressure built up
before the raindrops carved out
their circles of damage.
The effect of a torrential downpour
on a high-speed aircraft
would be many times
more serious.
Even raised rivets on the fuselage
could be forced out
by the impact of this kind of rain.
To test the effects
of a prolonged rainfall,
they constructed this whirling arm.
The blade tip revolves
at 500 miles an hour,
as water is spun off the disc
mounted in front of it
to form a fine rain cloud.
Prototypes of metal, glass,
paint and rubber can be fixed
to the whirling arm to see
how they stand up to rain storms.
ALARM
Within seconds the arm accelerates
to 500 miles an hour.
As rain drops strike
the test surfaces one after another,
materials simply disintegrate...
Perspex after only 20 minutes.
Aluminium is reduced to this
after 15 hours.
Metals and alloys used
in the next generation of aircraft
will have to stand up to longer
flying hours at higher speeds.
They prove themselves or fail
dramatically on this test rig.
Even paintwork has to be strengthened
when only two minutes in rain
does this.
This research has shown that
streamlining of aircraft is vital
because it lessens the head-on impact
of dangerous rain.
Aircraft designers quickly applied
these findings to modern jets.
Raised rivets were lost,
paint became protective,
and the shape of aircrafts
became increasingly tapered
as their speeds increased.
Rain at high speeds no longer caused
any serious damage to the plane.
Of all the problems
caused by bad weather,
one of the most potentially
dangerous is losing visibility.
It can seriously
disorientate a pilot
and make any manoeuvre
that requires particular accuracy
or precise judgment
that much more difficult.
So it makes sense that,
out of all the conditions,
the one that pilots
have feared the most is fog.
Fog is particularly dangerous
when a pilot is attempting to land.
That's because the plane needs
to be perfectly aligned
to hit the runway at the right spot
at the right time.
But in foggy conditions, pilots
might not have any visual cues
to help them.
Without good visibility,
the plane could clip something
on the way down
or even overshoot the runway.
So, in the 1960s,
some scientists thought
the answer to the problem might be
to find a way
to simply get rid of fog
at airports.
In America,
they attacked the problem
with a rather unique approach.
This equipment is
the latest on the anti-fog scene.
It's been developed by an American
horticultural company
from a standard crop spraying
machine, and if it works
it could do away with the need
for special aircraft
for spraying chemicals.
Instead, with this machine,
detergents or dry ice
could be sprayed through
an inflatable plastic tube
from a height of 200 feet.
A fan at the base of the machine
inflates the tube.
It also powers the spray
which can pivot vertically
or horizontally while being
towed along a fog-covered runway.
By the time these development tests
are over, the researchers hope
they'll have an effective fog killer
that could be in operation
by the end of next year.
Perhaps not surprisingly,
this particular fog killer
wasn't very effective,
and it was soon abandoned.
A quarter of a mile from touchdown.
You're on the glide path.
On track, on the glide path.
Once scientists realised completely
eliminating fog at airports
is no easy task,
they concentrated
on improving tools
that pilots could use
to work around it.
It's called ILS,
or Instrument Landing System.
Instead of relying on
a ground controller,
a pilot watches two cross wires
on an instrument in his cockpit.
When they're centred,
he knows he's on the glide path,
flying down a fixed radio beam
coming from a transmitter
on the end of the runway itself.
As ILS became more advanced,
it, together with radar
and radio technology,
equipped pilots with the means
to fly and land in fog
with much more safety.
Reducing the threats of bad weather
and improving the structural
integrity of planes
meant that,
during the 1960s and '70s,
aircraft safety began to improve.
By the 1980s, aircraft safety
seemed to have become
a good news story.
Planes were far less likely
to fall out of the sky
and the rates of crashes had fallen.
But there was one statistic
that was worrying safety experts.
Although the rate of crashes
had fallen,
the chances of actually surviving
one had stayed the same.
Engineers had been concentrating
on preventing accidents
rather than saving us
if the worst was to happen.
Fire is the greatest single threat
to survival in any plane crash.
That's because, as a passenger,
you're sitting on top of
up to 300,000 litres of fuel,
and if it comes into contact
with even the smallest of sparks,
it's likely to explode
into a deadly inferno.
It seemed logical to scientists
working in the early 1940s
that the way to tackle
the threat of fire
was to prevent it happening
in the first place.
ARCHIVE REPORTER:
The United States Air Force
provided a group
of service-weary aircraft
with which to conduct their research.
A landing or a take-off accident
was chosen for study
because the chance for passenger
survival of crash impact
is highest in this kind of crash.
The US Air Force discovered that
what was particularly dangerous
about jet fuel was the way
it dispersed on impact.
Here, you can see test planes
being deliberately crashed.
The fuel has been coloured red.
When the plane impacts,
the fuel at first trails behind.
Then, as the aircraft slows,
it moves ahead in a fine mist.
It's this mist
that's particularly volatile.
It was a major discovery.
The task for the next 40 years
would be to develop a fuel
that didn't mist.
And in the 1980s, it was us Brits
that looked like
we may have figured it out.
The answer, then, is to make
the fuel thicker so it doesn't mist,
and the thickening ingredient
that the scientists have come up with
is an additive called FM-9.
Now, the molecular structure of FM-9
is like a long chain.
It's called a polymer, which,
if you dissolve it in kerosene,
floats freely.
But if you shake the kerosene around,
as would happen
in a violent accident,
the chains of the polymer
will tangle together
and make the kerosene
behave like a jelly.
Well, here's the real stuff.
Aviation fuel with FM-9 on this side
and fuel that doesn't have it, here.
Now, side by side
they look exactly the same,
but if you shake them both,
you can see that the fuel
with the additive over here
goes like jelly,
and jelly can't mist.
But hold on. It can't ignite either,
so it's not going to be
much use in an engine.
So any engine using this stuff
would have to be modified
to break down the polymer chains
to make the fuel behave normally.
The Federal Aviation Authority
in America
was so taken by the research
that they organised a test crash
using a plane carrying
the new anti-misting fuel
and the scientists were optimistic
that the test was going to be
a success.
I've got a great deal of confidence
that we're not going to see a fire.
The crash date was set
for December 1st 1984.
All hopes for a new, safe jet fuel
were pinned onto this
$9 million experiment.
The aircraft will fly into cutters
that will rip open the wings
and the fuel tanks inside them.
The world's press and television
have been invited
to observe from a safe distance.
There's no pilot on board.
He too is watching
from a distance by television.
Federal Aviation Agency engineers
join NASA in Mission Control
to monitor every detail as the Boeing
720 skims in over the Mojave Desert.
Dozens of cameras follow the action.
But it's falling short of the target.
It spins to the left
as it heads toward the cutters.
This is not in the plan.
The pictures that were flashed
around the world that day
made it look like a total disaster.
The fire took more than an hour
to extinguish.
It was a PR disaster.
Funding was withdrawn
and the idea of preventing a fire
was all but abandoned.
And a disaster the following year
led scientists
to focus on simply
surviving one instead.
On August 22nd 1985, Flight 28M
was taxiing down the runway
at Manchester Airport
heading for Corfu.
But just minutes
after leaving the gate,
as the plane was attempting
take-off, something went wrong.
There was a loud bang on
the left-hand side of the aircraft
like the report from a shotgun
and someone shouted,
"A tyre has burst."
And then, within about 1.5 seconds,
the nose of the aircraft
came down, bang,
hit the floor, and all the bottles,
the duty free, rattled in the bins
at the top.
The captain abandoned take-off within
one second of hearing that bang,
but he thought it's a tyre blow-out,
so go easy on the brakes.
Even when the fire bell rang
he had no idea how bad this was,
so he continued down the runway.
People watching from
the terminal building
could see more clearly than the crew
how burning fuel trailed behind
until the aircraft turned off
the runway and across the wind
so fire and smoke enveloped
the back of the plane.
The flames came through the windows
and up onto the ceiling
and all the ceiling started to burn
and then it rapidly spread.
It was the heat of the cabin.
It was so hot that you could
feel your flesh creep,
creeping like that.
And I think myself
that it was the seats,
the foam had reached the flash point
and they just went up
and the thick, thick black smoke
came down
and that's all there was to breathe.
People were on fire and people
were burning, and some people,
because of the visibility,
were running the wrong way.
I saw one, one lady who had her...
just had her hair done
and she, it must have been
very heavily lacquered,
because all of a sudden...
And her hair went,
the lot went,
it had reached its flash point and
she, in a panic, ran the wrong way.
Roy Metcalf made it off the plane,
but many didn't.
55 people lost their lives.
The pilot had thought
the loud thump was a burst tyre,
but the noise was in fact
his left engine breaking apart
and sparking a fire.
It wasn't just the cause that was
the concern in the Manchester crash.
What troubled scientists was that
it should have been survivable.
After all, the plane didn't
fall out of the sky,
it didn't collide with anything,
the pilot never lost control
of the aircraft -
so why did so many people die?
Well, investigators began to focus
on what had happened
inside the cabin
in the minutes after
the engine failure.
The seats at Manchester contained
a plastic foam cushion
that's commonly been used
throughout the airline industry
because it's very light.
At Manchester the fire burned through
the outer skin of the aircraft
in perhaps half a minute,
then up through ventilation ducts
below the seats.
This urethane plastic foam
not only feeds the fire,
it also gives off poison gas.
Within minutes
all that's left is cinders.
But of the 55 that died,
only nine of them
were killed directly by the fire.
46 were choked and poisoned
by the smoke.
The seats they were sitting on
killed them.
Prior to the Manchester crash, there
were relatively few regulations
about what the cabin
must be made from.
At the moment we have this number
of specifications,
all of which are used
on buildings or ships
or things used
in buildings or ships.
So all these are rules
for fire testing and specifications?
All those are rules for fire
testing. Boxes and boxes of it.
There's the building regulations
of the governing document,
and all these are specifications
which are used at various times
for things that go into buildings,
ships or possibly cars.
Whereas at the same time,
we have one document
which runs to about 11 pages,
which covers the contents
of aircraft cabins.
That's all there is?
That's all there is.
After the Manchester disaster,
the Civil Aviation Authority
hurried through a requirement
that airlines fit a new type of seat
onto all aircraft.
Between the cover and the foam
there's now an extra layer.
This would make the seats
more fire resistant.
Although the fumes could still be
deadly, the new seats would at least
give passengers more time to get out
before being affected by the poison.
The toxicity of cabin materials
was not the only issue
highlighted by the Manchester crash.
Investigators were also concerned
at how slow the passengers were
to escape.
They believed
if the evacuation had been faster,
there might have been
more survivors.
When the fire came in
through the back of the cabin
and people started to see
the smoke and so on,
many people rushed as rapidly
as they could,
some of them going over the seats
to the front of the cabin,
and when they came up against
what we call the bulkheads,
which are the solid sections which
are just in front of the galleys,
and there we have a quite narrow gap
of actually 20 inches
between those bulkheads,
the passengers weren't all able
to get through as fast
as they arrived
and we tragically finished up
with a situation
where some people just didn't
manage to get through and fell,
and others moved on
in spite of them.
The CAA commissioned Helen Muir
to investigate
why more people didn't escape.
She knew that standard evacuation
trials were too orderly,
so she created a more realistic
experience by offering her subjects
a financial incentive
to be first off the plane.
The first half out of
whichever exits are used
will receive a £5 bonus payment
immediately,
and we have found
that this does encourage people
to make their way fairly rapidly,
and very interestingly
we've had survivors from accidents
come and see videos of behaviour
in these experiments and said,
"Oh, yes,
you know, that is how it was."
'Undo your seat belt and get out.'
In 1987 she used a real airliner
with standard exits and bulkheads.
She studied how different
cabin layouts affected
the flow of passengers to exits.
FRENETIC SHOUTING
This research video shows how
bulkheads could cause blockages.
The researchers recommended that the
opening be increased to 30 inches.
They also experimented
with different seat layouts
and suggested widening the access
to over-wing exits.
After the Manchester crash, the
Civil Aviation Authority enforced
the introduction of
new seat layouts on planes.
Airlines had to make access
to mid-exit doors easier
by either removing a seat
or moving the entire row back.
And they were forced to move
all the emergency exit lighting
to floor level so it wouldn't
be obstructed by smoke.
to floor level so it wouldn't
be obstructed by smoke.
The Manchester disaster was
a pivotal moment in improving
the chance of surviving
a plane crash.
Buying passengers
a little bit more time
and speeding up evacuation has saved
countless lives in fires since.
The Manchester incident didn't mark
the end of the study
of survivability
because in a crash, fire isn't the
only serious threat to your life.
In 1989, in another accident
also in Britain, safety experts were
forced to investigate
the other major killer
in air crashes - impact.
On 8th January 1989
British Midland Flight 92
took off from Heathrow
bound for Belfast.
Just minutes after take-off
the left engine caught fire
and the crew were re-directed
to East Midlands Airport,
but they never made it.
The British Midland plane hit the
motorway embankment at about 100mph.
It came to a standstill
in just over a second.
The force of the impact was
staggering, yet 79 people survived,
though most were seriously injured.
Had there been a fire, only 14
would have been able to escape.
Scientists were shocked by
the severity of the injuries
suffered by the survivors
and so focused much of their efforts
on uncovering what happened to them
at the moment of impact.
A research team quickly embarked
on the most detailed study yet
of air crash survivors.
Every survivor was photographed
and interviewed.
Every injury, including minor cuts
and bruises, was logged.
Their seat number
and the position they adopted
when the plane crashed
was also recorded.
The seats were examined,
numbered and photographed
from the front and rear.
The information stored on computer
accurately identified survivors,
their injuries and other important
details relevant to their survival.
Although the forces in the accident
were very high
they alone couldn't account
for the types of injuries suffered.
Even those passengers who had
got into the brace position
which was supposed to protect
against impact had suffered badly.
The scientists were mystified,
but they felt sure the injuries had
something to do with how passengers
prepared for the accident.
For the first time ever
they used computer simulations
to investigate further.
Precise details of
the Kegworth crash were analysed
by the computer program.
The height and weight
of one passenger
from the centre of the plane
and the position he was sitting in
were added to recreate
his exact movements
during the split-second crash.
First they looked at what happened
to those passengers
who didn't prepare for the crash.
The computer program reproduced
an accurate picture of why
passengers who sat bolt upright
during the crash
incurred such devastating injuries.
These passengers
suffered broken arms, legs
and serious head injuries.
Some died.
The researchers then looked at
what happened to a passenger
who did manage to get
into the brace position.
He rested his head on the seat
in front in between his arms.
His legs were slightly forward.
As the plane plunged over the M1,
his face and arms are forced into the
seat back. His legs move forward.
On impact with the motorway
his face powered into the seat back,
his arms flailed and his legs
flailed under the seat in front.
Most limb fractures resulted
from this flailing.
When the plane stopped
he impacted again.
Shocked that the recommended
brace position could also cause
so many injuries, the scientists
started to work on developing
a new, safer position that would do
a better job of protecting the body.
Instead of the feet simply
resting on the floor in front,
the scientists tucked the legs
under the seat
and rather than the head
being between the arms,
they positioned the arms
over the head
and rested this directly
onto the seat in front.
The dummy in the front seat is there
to simulate
someone occupying that seat.
At 20G, roughly
the force of the Kegworth crash,
the legs on the rear dummy
move forward on impact,
but only slightly, and they don't
flail under the seat in front.
The head impact is greatly reduced,
suggesting that cuts and bruises
would be less serious,
and the flailing of the arms which
caused so many fractures in Kegworth
is much less.
There is, of course, no proof,
but the research team is convinced
that had passengers on the Kegworth
plane adopted their brace position,
the injury toll would have
been greatly reduced.
The Kegworth investigation
led to the introduction
of a new brace position
which would be adopted
by airlines around the world.
So next time you're on a plane, it's
worth checking out the safety card,
because getting into the right
position could save your life.
In the 1980s the aviation industry
had made considerable progress
on aircraft design and was working
on crash survivability,
but they'd also turn their attention
to another factor
that remained stubbornly immune to
improvement. It was becoming clear
to safety experts that most crashes
were the result of something
rather less well understood
than either weather or engineering,
something notoriously unpredictable
and difficult to control -
humans.
Human error had been the cause
of the Kegworth disaster.
When the left engine caught fire,
the crew thought the problem was
with the right one, so shut it down.
By the time they realised
they'd turned off the wrong engine
it was too late to restart it,
and with no engine power, the plane
and its passengers were doomed.
Human error is the most common cause
of air crashes, and in the 1980s,
after a spate of accidents caused
not by the plane or weather,
but by the crew,
the entire industry started looking
at how best to tackle the problem.
They decided to turn to aviation
psychologists for help.
Since 1975, a highly confidential
reporting system
has collected over 50,000 reports
from worried pilots
about serious incidents involving
breakdowns in teamwork.
It's run by NASA
and at their research centre
in California
they're trying to recreate
those incidents in a laboratory.
At its heart is a simulator
containing a full flight crew.
We have an emergency, Sierra...
Their highly realistic flight
is complete with real
air traffic controllers.
Using video cameras they can now
find out how bad teamwork
leads to accidents
without killing anybody.
FIRE ALARM SOUNDS
Engine fire number three.
Charlie, you do the check list.
I'll fly the aeroplane.
I'll do the talking.
One of their three engines
has caught fire.
It will have to be shut down fast.
Power lever number three. Idle.
Start lever number three, cut off?
Check, number three. Number three.
Yeah, Tony, it looks like
we've lost one of the engines.
Everything else is good,
but we are going to have
to go back and land.
When NASA put over 20 airline flight
crews through an exercise like this
they were amazed by the variety
of performance they saw,
everything from good coordination
to almost complete mayhem.
I didn't want to go
to Chicago anyhow.
It's clear
that effective communication
in the cockpit is vital,
yet the researchers have found
that those skills
are often barely adequate
or even nonexistent.
The psychologists at NASA
are discovering that anything
that prevents a flight crew
behaving like a well-oiled team
is potentially dangerous
and one of the most disruptive
influences is a pilot's personality.
Many of them simply aren't fitted
for commercial cockpits at all.
Cracking the sound barrier
in level flight
will be more than
a spectacular feat.
It will also give the Air Force
valuable knowledge
of the resources
of new propulsive systems.
Captain Yeager gets aboard the XS-1.
It can't be a long flight he's going
to have in the little aircraft.
At full power, the flight
can't last more than 2.5 minutes,
but it's going to be a fast one.
In 1947 Chuck Yeager became
a model hero for military pilots
when he became the first man
to break through the sound barrier
in his experimental rocket plane
the X-1.
The really big moment.
Through the sound barrier!
The first time ever in level flight.
His relaxed laconic style
while in great peril
became dubbed "the right stuff".
"The right stuff" is, as we see it,
in test pilots and in the early,
but not the present astronauts,
is really this combination
of high technical competence,
a very rugged individualism and a
very high level of competitiveness.
The latter two are very destructive
when you're trying to function
as an effective team.
The trouble is, whole generations
of military flyers who venerated
those test pilots
and tried to emulate them,
went on to fly
for commercial airlines
taking "the right stuff" with them.
In many accidents the result is not
that the crew makes a major mistake,
but that the captain decides
in an emergency situation
that HE must fly the aircraft,
he must physically take control
of the airplane
because he has "the right stuff".
What he fails to do then
is to manage the situation
and to use the resources
that are available
from the other crew members.
So he has turned it
into a single-seat fighter
when in fact he needs
all the assistance he can get.
He refuses to see it
as a group problem
but as an individual problem.
I think it's a real potential
problem, because the factors
that would lead you to
an effective, smooth-working crew
are very different from those
that make you a fighter ace.
"The right stuff" is
in fact the wrong stuff.
In the early 1980s, psychologists
started advising airlines
on how they could reduce human error
and improve teamwork
in the cockpit.
United Airlines were the first
to apply their recommendations
by changing their approach
to pilot training.
Gentlemen, we've been discussing
this afternoon
elements in our cockpit resource
management programme,
which we call CRM.
They use a number of charts
which depict a wide range of
personality types
between the two extremes
of concern solely for the job
and concern solely
for getting along with people.
After getting the low-down
from the business manager,
pilots are then put through a highly
realistic flight in a simulator.
We've got two engines. Number two is
flaming out. The altimeter is OK.
It looks like loss
of all generators.
Checklist, loss of all generators.
When something goes wrong,
between them, the team have to come
up with a way to solve the problem.
Can either one of you think
of anything that we haven't done
or that we need to do?
The only thing that we haven't
tried, we could start the APU...
Vern has volunteered
a novel solution
which is not on his checklist.
He wants to try and link
an extra device called
the auxiliary power unit
into the defunct third generator.
OK. I got the APU running. You want
me to try it on number three, boss?
Try it. Five for six.
Four, not a five for four.
It took. Good.
It took, OK, you should
have everything now.
Yes, sir, sure do.
Everything's back to normal,
flaps are back to normal.
That's a good thought, Vern.
Vern's creativity has paid off.
Control is restored.
They can now land safely,
and by praising him, Mike has
reinforced Vern's behaviour.
This is what commercial airlines
call "the right stuff".
United are convinced
that the self-awareness
generated by that system
is leading to safer cockpits.
There's a quiet revolution taking
place among the world's airlines.
This kind of training proved to be
so successful
that today most airlines
have made it mandatory
not just for pilots,
but for all crew members.
And it's thought to have
significantly reduced the kind
of teamwork issues that were
responsible for so many crashes.
Relationships in the cockpit
are clearly critical to get right,
but it's not just human interaction
that needs to be monitored.
So does the partnership
between pilot and machine,
and since the 1970s,
that's often been a difficult,
complicated love/hate relationship
since computers became
more sophisticated
and much more involved
in the business of flying the plane.
Ground crew 080.
This demonstration in the American
DC-9 Super 80
shows just how powerful
that technology is.
Before take-off
the computer automatically works out
what the correct engine thrust
should be
and sets the speed bugs in place.
The throttles advance automatically
to the correct setting for take-off.
Game on, rotate!
About 400 feet into the air,
the captain engages the auto-pilot.
One last dab at the computer and it
will now control the rate of climb,
air speed and engine thrust right up
to the assigned cruising altitude.
The route has already been programmed
in, so the plane will take itself
to its destination. All the pilot
needs to do is to watch it.
And that was the mid-1980s.
Today, computers are even more
powerful and sophisticated, but
too much automation brings with it
another set of problems,
problems that played out
with disastrous effect in the
cockpit of Air France Flight 447.
On May 31st 2009, an Air France
Airbus took off from Rio
headed for Paris.
But just 350 miles
off the coast of Brazil,
the plane crashed
into the Atlantic...
..killing all 228 people on board.
The cause of the crash
remained a mystery for years
until investigators managed
to pull together enough evidence
to reconstruct the last few minutes
before impact.
3.5 hours after take-off,
just before 2am,
Flight 447 was heading into
a huge 250-mile-wide storm.
When the plane started to experience
turbulence, the pilot dialled
a lower speed into the computer
and prepared to ride it out.
But at just 2.10am at 35,000 feet...
..a series of alarms went off...
..and the auto-pilot disconnected.
ALARMS SOUND
In total darkness
and heavy turbulence
the crew are forced to re-take
manual control.
Pilots are the last line of defence,
so when things go very wrong,
the last line of defence
is the aviator.
After more than three hours
on auto-pilot
the pilots are suddenly faced
by information overload.
That crew faced an almost unheard-of
series of failures,
one right behind the other,
and for them to sort through it
would have been very difficult
that night.
Why is the aeroplane
doing what it's doing?
What are all these failures?
Why are they all coming at one time?
Bombarded by faults,
the pilot must cope with
the most serious problem of all -
he must maintain speed
or they will go out of control.
But after the pilot
took manual control,
the plane lost critical speed
and went into the catastrophic
condition known as a stall.
In a stall the wings
of the aircraft lose lift
and the plane becomes
almost impossible to control.
The pilot should have responded
by trying to increase speed,
but he didn't.
No-one could be sure why,
but it could be that he wasn't aware
he was stalling or maybe because
he was just so used to automation
his manual skills had been blunted.
Either way, the Air France pilot
couldn't maintain control and the
plane simply dropped out of the sky.
To avoid the same scenario
ever playing out again
the crash investigation recommended
that simulator training placed
more of an emphasis
on manual high-altitude flying
and aviation authorities have
encouraged all pilots
to try switching off auto-pilot
once in a while.
These changes should make pilots
less reliant on automation
and better prepared to take back
the controls in a crisis.
It is odd to think
that we have only been flying
for a fraction over 100 years
and, despite the bewildering
complexity, it is incredibly safe.
Crashes are very rare and something
like 90% of those are survivable,
which is an amazing statistic
and should give you SOME comfort
if you worry about the idea
of hurtling through the air
at close to the speed of sound
35,000 feet above the ground
in a pressurised metal tube.
For me personally,
ever since I was a kid,
I found air travel to be thrilling,
but the more I think about it,
the more I think
it's, well, it's mind-blowing.
Subtitles by Red Bee Media Ltd
transformed our lives.
Fast, direct,
and above all safe.
And it keeps getting safer.
In 2012, the global accident rate
for Western-built jets
was the lowest in aviation history.
But the carefree flying
that we enjoy today
has been bought at a deadly cost...
Because improvements
in aviation safety
have been driven by the stuff
of nightmares...
Air crashes.
Every crash has its causes,
and this information is used
by scientists
to prevent the same failures
from happening again.
For more than 60 years,
Horizon and the BBC have reported
on the accidents that have
revolutionised aviation safety.
In this programme, we'll chart
the most significant improvements
through the stories of
the most deadly disasters.
Tenerife Airport,
March 27th, 1977.
Debris is strewn far and wide.
Thick plumes of smoke fill the sky.
This is the wreckage from the
deadliest air crash in history,
a crash that happened
not in the sky
but on the runway.
The control tower
just 700 metres away
didn't even see it happen.
Just ten minutes earlier,
the airport had been busy
but running smoothly.
Two Boeing 747s,
one KLM, the other Pan Am,
were a mile apart
at opposite ends of the runway.
They'd been instructed to position
themselves ready for take-off.
The KLM was to wait
at one end of the runway
while Pan Am was to turn off it
and allow KLM to depart first.
As they were manoeuvring,
a thick fog came over the mountains
and enveloped the airport.
With the runway now shrouded in fog
neither plane could see each other.
Crucially, neither could the air
traffic controller in the tower.
The Pan Am pilots taxiing
down the runaway missed the turning.
At six minutes past five
the KLM pilot, believing
the Pan Am was now off the runway,
began his take-off
with Pan Am still ahead of him.
First time in my life I've ever had
a situation occur
that I couldn't believe
was happening.
I just could not believe
this airplane was coming
down the runaway at us.
My comment was, "Get off!"
to the captain,
which he tried everything
he possibly could.
As we were turning,
I looked back out of my right window
and the KLM airplane had lifted
off the runway.
Basically, what I did was
just close my eyes and duck.
During lift-off, the KLM plane
collided with Pan Am.
Although briefly airborne,
it lost control,
crashed and burst
into a ball of flames...
..while the Pan Am plane broke
into several pieces and exploded.
Almost 600 people died that day.
The accident shocked the world.
Everyone wanted to know what could
have caused this devastating crash.
Initially it seemed the obvious
cause of the disaster was fog.
562, turn tight, heading 070...
But the crash investigation
revealed that fog
was only one factor.
123 out of air...
123, 29 miles over.
Bad communication
and poor crew dynamics
also played a major role.
Wind squall at 5524.
5524.
The Tenerife disaster showed
that the causes of plane crashes
are rarely straightforward.
And that's not surprising
given that aviation
is an incredibly complex business
and there are so many things
that can go wrong.
If you stop and think about it
for a second,
travelling by plane is
a pretty odd thing to do.
Hundreds of us
strapped into this narrow tube,
hurtling through the air
at upwards of 500 miles an hour,
and separated from the freezing,
oxygen-starved atmosphere
by just a few centimetres
of metal and plastic.
Today we pretty much
take it for granted
that the aeroplane is up to the job.
It's not going
to fall apart around us.
But in the early days
of commercial aviation,
even the structural integrity
of the plane couldn't be guaranteed.
Scientists realised the hard way
that there were some
significant gaps in their knowledge.
There is arguably no single plane
that's been more important
in the story of aircraft engineering
than the ill-fated Comet.
REPORTER: When the 36-seater,
jet-propelled De Havilland Comet
opened the latest act in the drama
of man's conquest of the heavens,
the eyes of many nations
were focused upon it.
Built in Britain
and launched in 1952,
it was the first passenger jet
to go into service.
Cruising at 490 miles an hour,
the Comet offered
all the attractions
of smooth, high-altitude travel.
The Comet had grace and beauty.
But unfortunately that's not
what it's remembered for.
Between May '52 and April '54,
three of the nine Comets in service
broke up in mid air.
The Comet 1 never flew again.
After the third disaster,
bits of the aircraft were recovered
from the bottom
of the Mediterranean.
In all, 67 people died
in the crashes.
It was a disaster
for the British aircraft industry,
particularly because
no-one knew why the planes
had apparently
just fallen out of the sky.
So all the Comets were grounded,
and scientists set to work
on one of the greatest
aircraft detective stories
in aviation history.
As in any investigation,
scientists started by painstakingly
sieving through the crash wreckage.
Their first clue came in the form
of a curious anomaly
found in fragments of the fuselage.
There were unexplained rips
through the aluminium shell.
The scientists next had to work out
what could have caused
these tears,
and the only way to do that
was to try to recreate the damage.
An entire fuselage was immersed
in a high pressure tank
and subjected to cycles of
increasing and decreasing pressure
to simulate an aircraft in service
constantly climbing and descending.
The fatal weakness
suddenly revealed itself.
A weakness that would change
aircraft design forever.
It was metal fatigue,
a type of weakness that starts
as a small crack
somewhere in the fuselage
and spreads catastrophically
across the plane
when it undergoes
pressure changes in flight.
It would have quickly and suddenly
caused the plane
to completely break up.
Metal fatigue wasn't seen
as a major problem
prior to the Comet crashes,
because aviation experts
didn't fully understand
the destructive effects
of pressurisation
and had been performing
the wrong types of tests.
The challenge for engineers
was to find a way
to protect the plane against
the repetitive stresses of flight.
How are you going to tackle
the weakness in the fuselage?
Well, it will be largely
a question of a thicker skin
and much improved detail design.
Here's your skin.
When you talk of a skin,
what do you really mean?
It isn't what we think of as a skin?
Is it double thickness?
Is it like a sort of
insulated window, or...?
No, no, no, it's a single skin...
It is single?
Oh, yes, high strength, light alloy,
just single,
and made thick enough to withstand
the pressures and the loads
that come on it
from structural loads.
Scientists also learnt that square
cabin windows were problematic.
The corners would often be where
cracks in the fuselage started,
so engineers simply
got rid of the corners.
The British civil aircraft industry
never fully recovered
from the Comet disasters.
But what was learnt
about metal fatigue
and how to properly test for it
was shared with airlines
and engineers across the world.
The emphasis was now on
full-scale aircraft testing,
because aviation experts realised
that testing the structural
integrity of individual plane parts
can't be done in isolation.
40 years after the Comet crashes,
full-scale testing had become
mandatory and a bit of
a spectator sport for engineers.
It's 1995, at the Boeing factory.
Cables are pulling hard
on a Triple 7 wing
to test whether it can survive
the strongest forces turbulence
or bad handling could produce.
REPORTER: As the test progresses,
the forces on the wings
are so strong that they cause
ripples in the fuselage.
The engineers hope
that the wing will withstand
150% of the strongest forces
it will meet in flight.
They're predicting a wing deflection
of about 24 feet before it breaks.
ENGINEER: Can I have your attention?
We're now holding
at 120% design limit load.
We will make a loads check.
It should be a short hold here.
As the tension in the wing increases,
the crowd of observers,
including many of the people
who have lived with the plane
for four years or more, falls quiet.
At 150% loading,
it's the moment of truth.
Will the wing remain intact?
To the engineers' delight,
the wing survives.
151.
They've got a safe, strong wing
ready for service.
156.
If you've ever worried
about wobbly wings,
just see how much bending
they can take.
153.
Now the engineers are going
to push their creation
to its absolute limit.
154.
It finally breaks at 154%...
Way beyond the strongest forces
any plane should experience.
154.
This is just one of the many tests
a plane must pass
before it's let anywhere
near the runway.
They're devised to weed out
any weaknesses in the design
or materials.
So today it's very rare
that a plane's strength
is ever called into question.
By the 1960s, the days of aircraft
breaking up in mid air
for no apparent reason
were largely gone.
But in terms of aircraft safety,
fixing structural integrity actually
turned out to be the easy bit.
Much trickier was another
major cause of crashes.
What in the aviation world is called
bad operational conditions,
we would call bad weather,
and the potentially lethal effects
were highlighted
by the investigation into
one of the most mysterious
crashes in history.
On August 2nd, 1947,
a British Lancastrian airliner
called Star Dust
took off on a routine passenger
flight across South America.
Although scheduled to fly
from Buenos Aires to Santiago,
the plane never reached
its final destination.
Instead it completely vanished
just moments before touchdown.
Despite an extensive search
of the Andes mountains,
no trace of the plane
was ever found.
But in 2000,
53 years after the crash,
parts of the plane
suddenly reappeared...
..on a glacier high up in the Andes.
Crash investigators examined
the site in a bid to work out
what had happened
to the ill-fated plane.
There was no explanation
for why Star Dust had crashed
when there was apparently
nothing wrong with the plane.
The plane had crashed
50 miles away from Santiago,
even though the crew thought
they were close to landing.
So they focused on one key factor
that could have caused the crash...
navigation error.
The investigators already knew
that shortly before the crash
the crew had decided to avoid
bad weather by climbing
above the clouds and flying
over the top of the mountains.
Although they didn't know it,
by trying to fly over
the tops of the mountains,
they were sealing their fate.
They were about to encounter an
invisible meteorological phenomenon
which they knew nothing about.
The jet stream.
This powerful, high altitude wind
only develops above
the normal weather systems.
It blows at speeds
of well over 100mph.
But in 1947, the phenomenon itself
was still largely unknown.
The crew of Star Dust
would have had no idea
what they were flying into,
and now that the plane was flying
above the clouds
the crew could no longer
see the ground.
As Star Dust climbed,
it began to enter the jet stream
and slow down dramatically.
But the crew had
no knowledge of this.
They believed that they were
making much faster progress.
At 24,000 feet, Star Dust was flying
almost directly into the jet stream,
which was blowing at around 100mph.
The Jet Stream's effect
was devastating.
At 5.33, the crew was convinced
they were crossing
the mountains into Chile.
But they weren't.
They radioed their time
of arrival as 5.45.
In fact, the plane was still
on the wrong side of the mountains.
The plane descended towards
what the crew thought would be
Santiago Airport.
But in fact they were flying
straight into the cloud-covered
glacier of Mount Tupangato.
All 11 lives were lost
in the crash,
and the plane was buried within
seconds, vanishing from sight.
The Star Dust tragedy
was the direct result
of the unknown effects
of the jet stream.
Today, thankfully, high-altitude
weather is no longer a mystery
and sophisticated
weather forecasting makes sure
crews are prepared
whatever the conditions.
One of the paradoxes of aircraft
safety is that every major leap
in aircraft capability
creates its own new set of problems,
and many of those are connected
with the weather.
So, for Star Dust, it was
its ability to climb high.
In the 1960s, the industry was
grappling with the problems
of flying fast,
as jet engines like this one were
taking over from piston engines.
Now, that extra speed may have been
good news for passengers
but it meant that common forms
of weather suddenly became
very real safety concerns.
Fighter pilots were
the first to find out
about the danger of rain damage
at near supersonic speeds.
After only ten minutes in a rain
storm, a Hunter jet fighter
landed with its radar cone
damaged like this.
The nose cone is made of bonded
layers of toughened glass fibre
and rubber.
This was one of the first
recorded cases of rain drop damage
so massive that the aircraft
had been in critical danger.
The outer cover had been torn off.
The inner rubber shell
was deeply pitted.
To understand what was happening,
scientists at the Royal Aircraft
Establishment, Farnborough,
constructed this gas-powered gun
to try to recreate
the hazard of dangerous rain.
A magnesium bullet
tipped with Perspex
is loaded into the firing chamber.
When the bullet is fired
at over 1,000 feet a second,
it will collide with a raindrop
suspended directly in its path.
Surface tension holds the raindrop
in place on a web
of artificial fibres
specially created for each test.
A carefully measured drop
of soft rain water is about to be
given the destructive power
of an explosive blast.
The web is shattered before you have
time to hear the explosion.
The impact of the raindrop
has been recorded
on the Perspex head of the bullet.
The Perspex,
the kind that's used in aircraft
windows, is studied for damage.
The moment of impact,
seen from a different angle.
With camera shutter speed
at a millionth of a second,
the disintegration of each drop
of water can be analysed in detail.
Damage is caused
when the pressure built up
in the raindrop on impact
is released when it shatters.
Three clear areas show
where pressure built up
before the raindrops carved out
their circles of damage.
The effect of a torrential downpour
on a high-speed aircraft
would be many times
more serious.
Even raised rivets on the fuselage
could be forced out
by the impact of this kind of rain.
To test the effects
of a prolonged rainfall,
they constructed this whirling arm.
The blade tip revolves
at 500 miles an hour,
as water is spun off the disc
mounted in front of it
to form a fine rain cloud.
Prototypes of metal, glass,
paint and rubber can be fixed
to the whirling arm to see
how they stand up to rain storms.
ALARM
Within seconds the arm accelerates
to 500 miles an hour.
As rain drops strike
the test surfaces one after another,
materials simply disintegrate...
Perspex after only 20 minutes.
Aluminium is reduced to this
after 15 hours.
Metals and alloys used
in the next generation of aircraft
will have to stand up to longer
flying hours at higher speeds.
They prove themselves or fail
dramatically on this test rig.
Even paintwork has to be strengthened
when only two minutes in rain
does this.
This research has shown that
streamlining of aircraft is vital
because it lessens the head-on impact
of dangerous rain.
Aircraft designers quickly applied
these findings to modern jets.
Raised rivets were lost,
paint became protective,
and the shape of aircrafts
became increasingly tapered
as their speeds increased.
Rain at high speeds no longer caused
any serious damage to the plane.
Of all the problems
caused by bad weather,
one of the most potentially
dangerous is losing visibility.
It can seriously
disorientate a pilot
and make any manoeuvre
that requires particular accuracy
or precise judgment
that much more difficult.
So it makes sense that,
out of all the conditions,
the one that pilots
have feared the most is fog.
Fog is particularly dangerous
when a pilot is attempting to land.
That's because the plane needs
to be perfectly aligned
to hit the runway at the right spot
at the right time.
But in foggy conditions, pilots
might not have any visual cues
to help them.
Without good visibility,
the plane could clip something
on the way down
or even overshoot the runway.
So, in the 1960s,
some scientists thought
the answer to the problem might be
to find a way
to simply get rid of fog
at airports.
In America,
they attacked the problem
with a rather unique approach.
This equipment is
the latest on the anti-fog scene.
It's been developed by an American
horticultural company
from a standard crop spraying
machine, and if it works
it could do away with the need
for special aircraft
for spraying chemicals.
Instead, with this machine,
detergents or dry ice
could be sprayed through
an inflatable plastic tube
from a height of 200 feet.
A fan at the base of the machine
inflates the tube.
It also powers the spray
which can pivot vertically
or horizontally while being
towed along a fog-covered runway.
By the time these development tests
are over, the researchers hope
they'll have an effective fog killer
that could be in operation
by the end of next year.
Perhaps not surprisingly,
this particular fog killer
wasn't very effective,
and it was soon abandoned.
A quarter of a mile from touchdown.
You're on the glide path.
On track, on the glide path.
Once scientists realised completely
eliminating fog at airports
is no easy task,
they concentrated
on improving tools
that pilots could use
to work around it.
It's called ILS,
or Instrument Landing System.
Instead of relying on
a ground controller,
a pilot watches two cross wires
on an instrument in his cockpit.
When they're centred,
he knows he's on the glide path,
flying down a fixed radio beam
coming from a transmitter
on the end of the runway itself.
As ILS became more advanced,
it, together with radar
and radio technology,
equipped pilots with the means
to fly and land in fog
with much more safety.
Reducing the threats of bad weather
and improving the structural
integrity of planes
meant that,
during the 1960s and '70s,
aircraft safety began to improve.
By the 1980s, aircraft safety
seemed to have become
a good news story.
Planes were far less likely
to fall out of the sky
and the rates of crashes had fallen.
But there was one statistic
that was worrying safety experts.
Although the rate of crashes
had fallen,
the chances of actually surviving
one had stayed the same.
Engineers had been concentrating
on preventing accidents
rather than saving us
if the worst was to happen.
Fire is the greatest single threat
to survival in any plane crash.
That's because, as a passenger,
you're sitting on top of
up to 300,000 litres of fuel,
and if it comes into contact
with even the smallest of sparks,
it's likely to explode
into a deadly inferno.
It seemed logical to scientists
working in the early 1940s
that the way to tackle
the threat of fire
was to prevent it happening
in the first place.
ARCHIVE REPORTER:
The United States Air Force
provided a group
of service-weary aircraft
with which to conduct their research.
A landing or a take-off accident
was chosen for study
because the chance for passenger
survival of crash impact
is highest in this kind of crash.
The US Air Force discovered that
what was particularly dangerous
about jet fuel was the way
it dispersed on impact.
Here, you can see test planes
being deliberately crashed.
The fuel has been coloured red.
When the plane impacts,
the fuel at first trails behind.
Then, as the aircraft slows,
it moves ahead in a fine mist.
It's this mist
that's particularly volatile.
It was a major discovery.
The task for the next 40 years
would be to develop a fuel
that didn't mist.
And in the 1980s, it was us Brits
that looked like
we may have figured it out.
The answer, then, is to make
the fuel thicker so it doesn't mist,
and the thickening ingredient
that the scientists have come up with
is an additive called FM-9.
Now, the molecular structure of FM-9
is like a long chain.
It's called a polymer, which,
if you dissolve it in kerosene,
floats freely.
But if you shake the kerosene around,
as would happen
in a violent accident,
the chains of the polymer
will tangle together
and make the kerosene
behave like a jelly.
Well, here's the real stuff.
Aviation fuel with FM-9 on this side
and fuel that doesn't have it, here.
Now, side by side
they look exactly the same,
but if you shake them both,
you can see that the fuel
with the additive over here
goes like jelly,
and jelly can't mist.
But hold on. It can't ignite either,
so it's not going to be
much use in an engine.
So any engine using this stuff
would have to be modified
to break down the polymer chains
to make the fuel behave normally.
The Federal Aviation Authority
in America
was so taken by the research
that they organised a test crash
using a plane carrying
the new anti-misting fuel
and the scientists were optimistic
that the test was going to be
a success.
I've got a great deal of confidence
that we're not going to see a fire.
The crash date was set
for December 1st 1984.
All hopes for a new, safe jet fuel
were pinned onto this
$9 million experiment.
The aircraft will fly into cutters
that will rip open the wings
and the fuel tanks inside them.
The world's press and television
have been invited
to observe from a safe distance.
There's no pilot on board.
He too is watching
from a distance by television.
Federal Aviation Agency engineers
join NASA in Mission Control
to monitor every detail as the Boeing
720 skims in over the Mojave Desert.
Dozens of cameras follow the action.
But it's falling short of the target.
It spins to the left
as it heads toward the cutters.
This is not in the plan.
The pictures that were flashed
around the world that day
made it look like a total disaster.
The fire took more than an hour
to extinguish.
It was a PR disaster.
Funding was withdrawn
and the idea of preventing a fire
was all but abandoned.
And a disaster the following year
led scientists
to focus on simply
surviving one instead.
On August 22nd 1985, Flight 28M
was taxiing down the runway
at Manchester Airport
heading for Corfu.
But just minutes
after leaving the gate,
as the plane was attempting
take-off, something went wrong.
There was a loud bang on
the left-hand side of the aircraft
like the report from a shotgun
and someone shouted,
"A tyre has burst."
And then, within about 1.5 seconds,
the nose of the aircraft
came down, bang,
hit the floor, and all the bottles,
the duty free, rattled in the bins
at the top.
The captain abandoned take-off within
one second of hearing that bang,
but he thought it's a tyre blow-out,
so go easy on the brakes.
Even when the fire bell rang
he had no idea how bad this was,
so he continued down the runway.
People watching from
the terminal building
could see more clearly than the crew
how burning fuel trailed behind
until the aircraft turned off
the runway and across the wind
so fire and smoke enveloped
the back of the plane.
The flames came through the windows
and up onto the ceiling
and all the ceiling started to burn
and then it rapidly spread.
It was the heat of the cabin.
It was so hot that you could
feel your flesh creep,
creeping like that.
And I think myself
that it was the seats,
the foam had reached the flash point
and they just went up
and the thick, thick black smoke
came down
and that's all there was to breathe.
People were on fire and people
were burning, and some people,
because of the visibility,
were running the wrong way.
I saw one, one lady who had her...
just had her hair done
and she, it must have been
very heavily lacquered,
because all of a sudden...
And her hair went,
the lot went,
it had reached its flash point and
she, in a panic, ran the wrong way.
Roy Metcalf made it off the plane,
but many didn't.
55 people lost their lives.
The pilot had thought
the loud thump was a burst tyre,
but the noise was in fact
his left engine breaking apart
and sparking a fire.
It wasn't just the cause that was
the concern in the Manchester crash.
What troubled scientists was that
it should have been survivable.
After all, the plane didn't
fall out of the sky,
it didn't collide with anything,
the pilot never lost control
of the aircraft -
so why did so many people die?
Well, investigators began to focus
on what had happened
inside the cabin
in the minutes after
the engine failure.
The seats at Manchester contained
a plastic foam cushion
that's commonly been used
throughout the airline industry
because it's very light.
At Manchester the fire burned through
the outer skin of the aircraft
in perhaps half a minute,
then up through ventilation ducts
below the seats.
This urethane plastic foam
not only feeds the fire,
it also gives off poison gas.
Within minutes
all that's left is cinders.
But of the 55 that died,
only nine of them
were killed directly by the fire.
46 were choked and poisoned
by the smoke.
The seats they were sitting on
killed them.
Prior to the Manchester crash, there
were relatively few regulations
about what the cabin
must be made from.
At the moment we have this number
of specifications,
all of which are used
on buildings or ships
or things used
in buildings or ships.
So all these are rules
for fire testing and specifications?
All those are rules for fire
testing. Boxes and boxes of it.
There's the building regulations
of the governing document,
and all these are specifications
which are used at various times
for things that go into buildings,
ships or possibly cars.
Whereas at the same time,
we have one document
which runs to about 11 pages,
which covers the contents
of aircraft cabins.
That's all there is?
That's all there is.
After the Manchester disaster,
the Civil Aviation Authority
hurried through a requirement
that airlines fit a new type of seat
onto all aircraft.
Between the cover and the foam
there's now an extra layer.
This would make the seats
more fire resistant.
Although the fumes could still be
deadly, the new seats would at least
give passengers more time to get out
before being affected by the poison.
The toxicity of cabin materials
was not the only issue
highlighted by the Manchester crash.
Investigators were also concerned
at how slow the passengers were
to escape.
They believed
if the evacuation had been faster,
there might have been
more survivors.
When the fire came in
through the back of the cabin
and people started to see
the smoke and so on,
many people rushed as rapidly
as they could,
some of them going over the seats
to the front of the cabin,
and when they came up against
what we call the bulkheads,
which are the solid sections which
are just in front of the galleys,
and there we have a quite narrow gap
of actually 20 inches
between those bulkheads,
the passengers weren't all able
to get through as fast
as they arrived
and we tragically finished up
with a situation
where some people just didn't
manage to get through and fell,
and others moved on
in spite of them.
The CAA commissioned Helen Muir
to investigate
why more people didn't escape.
She knew that standard evacuation
trials were too orderly,
so she created a more realistic
experience by offering her subjects
a financial incentive
to be first off the plane.
The first half out of
whichever exits are used
will receive a £5 bonus payment
immediately,
and we have found
that this does encourage people
to make their way fairly rapidly,
and very interestingly
we've had survivors from accidents
come and see videos of behaviour
in these experiments and said,
"Oh, yes,
you know, that is how it was."
'Undo your seat belt and get out.'
In 1987 she used a real airliner
with standard exits and bulkheads.
She studied how different
cabin layouts affected
the flow of passengers to exits.
FRENETIC SHOUTING
This research video shows how
bulkheads could cause blockages.
The researchers recommended that the
opening be increased to 30 inches.
They also experimented
with different seat layouts
and suggested widening the access
to over-wing exits.
After the Manchester crash, the
Civil Aviation Authority enforced
the introduction of
new seat layouts on planes.
Airlines had to make access
to mid-exit doors easier
by either removing a seat
or moving the entire row back.
And they were forced to move
all the emergency exit lighting
to floor level so it wouldn't
be obstructed by smoke.
to floor level so it wouldn't
be obstructed by smoke.
The Manchester disaster was
a pivotal moment in improving
the chance of surviving
a plane crash.
Buying passengers
a little bit more time
and speeding up evacuation has saved
countless lives in fires since.
The Manchester incident didn't mark
the end of the study
of survivability
because in a crash, fire isn't the
only serious threat to your life.
In 1989, in another accident
also in Britain, safety experts were
forced to investigate
the other major killer
in air crashes - impact.
On 8th January 1989
British Midland Flight 92
took off from Heathrow
bound for Belfast.
Just minutes after take-off
the left engine caught fire
and the crew were re-directed
to East Midlands Airport,
but they never made it.
The British Midland plane hit the
motorway embankment at about 100mph.
It came to a standstill
in just over a second.
The force of the impact was
staggering, yet 79 people survived,
though most were seriously injured.
Had there been a fire, only 14
would have been able to escape.
Scientists were shocked by
the severity of the injuries
suffered by the survivors
and so focused much of their efforts
on uncovering what happened to them
at the moment of impact.
A research team quickly embarked
on the most detailed study yet
of air crash survivors.
Every survivor was photographed
and interviewed.
Every injury, including minor cuts
and bruises, was logged.
Their seat number
and the position they adopted
when the plane crashed
was also recorded.
The seats were examined,
numbered and photographed
from the front and rear.
The information stored on computer
accurately identified survivors,
their injuries and other important
details relevant to their survival.
Although the forces in the accident
were very high
they alone couldn't account
for the types of injuries suffered.
Even those passengers who had
got into the brace position
which was supposed to protect
against impact had suffered badly.
The scientists were mystified,
but they felt sure the injuries had
something to do with how passengers
prepared for the accident.
For the first time ever
they used computer simulations
to investigate further.
Precise details of
the Kegworth crash were analysed
by the computer program.
The height and weight
of one passenger
from the centre of the plane
and the position he was sitting in
were added to recreate
his exact movements
during the split-second crash.
First they looked at what happened
to those passengers
who didn't prepare for the crash.
The computer program reproduced
an accurate picture of why
passengers who sat bolt upright
during the crash
incurred such devastating injuries.
These passengers
suffered broken arms, legs
and serious head injuries.
Some died.
The researchers then looked at
what happened to a passenger
who did manage to get
into the brace position.
He rested his head on the seat
in front in between his arms.
His legs were slightly forward.
As the plane plunged over the M1,
his face and arms are forced into the
seat back. His legs move forward.
On impact with the motorway
his face powered into the seat back,
his arms flailed and his legs
flailed under the seat in front.
Most limb fractures resulted
from this flailing.
When the plane stopped
he impacted again.
Shocked that the recommended
brace position could also cause
so many injuries, the scientists
started to work on developing
a new, safer position that would do
a better job of protecting the body.
Instead of the feet simply
resting on the floor in front,
the scientists tucked the legs
under the seat
and rather than the head
being between the arms,
they positioned the arms
over the head
and rested this directly
onto the seat in front.
The dummy in the front seat is there
to simulate
someone occupying that seat.
At 20G, roughly
the force of the Kegworth crash,
the legs on the rear dummy
move forward on impact,
but only slightly, and they don't
flail under the seat in front.
The head impact is greatly reduced,
suggesting that cuts and bruises
would be less serious,
and the flailing of the arms which
caused so many fractures in Kegworth
is much less.
There is, of course, no proof,
but the research team is convinced
that had passengers on the Kegworth
plane adopted their brace position,
the injury toll would have
been greatly reduced.
The Kegworth investigation
led to the introduction
of a new brace position
which would be adopted
by airlines around the world.
So next time you're on a plane, it's
worth checking out the safety card,
because getting into the right
position could save your life.
In the 1980s the aviation industry
had made considerable progress
on aircraft design and was working
on crash survivability,
but they'd also turn their attention
to another factor
that remained stubbornly immune to
improvement. It was becoming clear
to safety experts that most crashes
were the result of something
rather less well understood
than either weather or engineering,
something notoriously unpredictable
and difficult to control -
humans.
Human error had been the cause
of the Kegworth disaster.
When the left engine caught fire,
the crew thought the problem was
with the right one, so shut it down.
By the time they realised
they'd turned off the wrong engine
it was too late to restart it,
and with no engine power, the plane
and its passengers were doomed.
Human error is the most common cause
of air crashes, and in the 1980s,
after a spate of accidents caused
not by the plane or weather,
but by the crew,
the entire industry started looking
at how best to tackle the problem.
They decided to turn to aviation
psychologists for help.
Since 1975, a highly confidential
reporting system
has collected over 50,000 reports
from worried pilots
about serious incidents involving
breakdowns in teamwork.
It's run by NASA
and at their research centre
in California
they're trying to recreate
those incidents in a laboratory.
At its heart is a simulator
containing a full flight crew.
We have an emergency, Sierra...
Their highly realistic flight
is complete with real
air traffic controllers.
Using video cameras they can now
find out how bad teamwork
leads to accidents
without killing anybody.
FIRE ALARM SOUNDS
Engine fire number three.
Charlie, you do the check list.
I'll fly the aeroplane.
I'll do the talking.
One of their three engines
has caught fire.
It will have to be shut down fast.
Power lever number three. Idle.
Start lever number three, cut off?
Check, number three. Number three.
Yeah, Tony, it looks like
we've lost one of the engines.
Everything else is good,
but we are going to have
to go back and land.
When NASA put over 20 airline flight
crews through an exercise like this
they were amazed by the variety
of performance they saw,
everything from good coordination
to almost complete mayhem.
I didn't want to go
to Chicago anyhow.
It's clear
that effective communication
in the cockpit is vital,
yet the researchers have found
that those skills
are often barely adequate
or even nonexistent.
The psychologists at NASA
are discovering that anything
that prevents a flight crew
behaving like a well-oiled team
is potentially dangerous
and one of the most disruptive
influences is a pilot's personality.
Many of them simply aren't fitted
for commercial cockpits at all.
Cracking the sound barrier
in level flight
will be more than
a spectacular feat.
It will also give the Air Force
valuable knowledge
of the resources
of new propulsive systems.
Captain Yeager gets aboard the XS-1.
It can't be a long flight he's going
to have in the little aircraft.
At full power, the flight
can't last more than 2.5 minutes,
but it's going to be a fast one.
In 1947 Chuck Yeager became
a model hero for military pilots
when he became the first man
to break through the sound barrier
in his experimental rocket plane
the X-1.
The really big moment.
Through the sound barrier!
The first time ever in level flight.
His relaxed laconic style
while in great peril
became dubbed "the right stuff".
"The right stuff" is, as we see it,
in test pilots and in the early,
but not the present astronauts,
is really this combination
of high technical competence,
a very rugged individualism and a
very high level of competitiveness.
The latter two are very destructive
when you're trying to function
as an effective team.
The trouble is, whole generations
of military flyers who venerated
those test pilots
and tried to emulate them,
went on to fly
for commercial airlines
taking "the right stuff" with them.
In many accidents the result is not
that the crew makes a major mistake,
but that the captain decides
in an emergency situation
that HE must fly the aircraft,
he must physically take control
of the airplane
because he has "the right stuff".
What he fails to do then
is to manage the situation
and to use the resources
that are available
from the other crew members.
So he has turned it
into a single-seat fighter
when in fact he needs
all the assistance he can get.
He refuses to see it
as a group problem
but as an individual problem.
I think it's a real potential
problem, because the factors
that would lead you to
an effective, smooth-working crew
are very different from those
that make you a fighter ace.
"The right stuff" is
in fact the wrong stuff.
In the early 1980s, psychologists
started advising airlines
on how they could reduce human error
and improve teamwork
in the cockpit.
United Airlines were the first
to apply their recommendations
by changing their approach
to pilot training.
Gentlemen, we've been discussing
this afternoon
elements in our cockpit resource
management programme,
which we call CRM.
They use a number of charts
which depict a wide range of
personality types
between the two extremes
of concern solely for the job
and concern solely
for getting along with people.
After getting the low-down
from the business manager,
pilots are then put through a highly
realistic flight in a simulator.
We've got two engines. Number two is
flaming out. The altimeter is OK.
It looks like loss
of all generators.
Checklist, loss of all generators.
When something goes wrong,
between them, the team have to come
up with a way to solve the problem.
Can either one of you think
of anything that we haven't done
or that we need to do?
The only thing that we haven't
tried, we could start the APU...
Vern has volunteered
a novel solution
which is not on his checklist.
He wants to try and link
an extra device called
the auxiliary power unit
into the defunct third generator.
OK. I got the APU running. You want
me to try it on number three, boss?
Try it. Five for six.
Four, not a five for four.
It took. Good.
It took, OK, you should
have everything now.
Yes, sir, sure do.
Everything's back to normal,
flaps are back to normal.
That's a good thought, Vern.
Vern's creativity has paid off.
Control is restored.
They can now land safely,
and by praising him, Mike has
reinforced Vern's behaviour.
This is what commercial airlines
call "the right stuff".
United are convinced
that the self-awareness
generated by that system
is leading to safer cockpits.
There's a quiet revolution taking
place among the world's airlines.
This kind of training proved to be
so successful
that today most airlines
have made it mandatory
not just for pilots,
but for all crew members.
And it's thought to have
significantly reduced the kind
of teamwork issues that were
responsible for so many crashes.
Relationships in the cockpit
are clearly critical to get right,
but it's not just human interaction
that needs to be monitored.
So does the partnership
between pilot and machine,
and since the 1970s,
that's often been a difficult,
complicated love/hate relationship
since computers became
more sophisticated
and much more involved
in the business of flying the plane.
Ground crew 080.
This demonstration in the American
DC-9 Super 80
shows just how powerful
that technology is.
Before take-off
the computer automatically works out
what the correct engine thrust
should be
and sets the speed bugs in place.
The throttles advance automatically
to the correct setting for take-off.
Game on, rotate!
About 400 feet into the air,
the captain engages the auto-pilot.
One last dab at the computer and it
will now control the rate of climb,
air speed and engine thrust right up
to the assigned cruising altitude.
The route has already been programmed
in, so the plane will take itself
to its destination. All the pilot
needs to do is to watch it.
And that was the mid-1980s.
Today, computers are even more
powerful and sophisticated, but
too much automation brings with it
another set of problems,
problems that played out
with disastrous effect in the
cockpit of Air France Flight 447.
On May 31st 2009, an Air France
Airbus took off from Rio
headed for Paris.
But just 350 miles
off the coast of Brazil,
the plane crashed
into the Atlantic...
..killing all 228 people on board.
The cause of the crash
remained a mystery for years
until investigators managed
to pull together enough evidence
to reconstruct the last few minutes
before impact.
3.5 hours after take-off,
just before 2am,
Flight 447 was heading into
a huge 250-mile-wide storm.
When the plane started to experience
turbulence, the pilot dialled
a lower speed into the computer
and prepared to ride it out.
But at just 2.10am at 35,000 feet...
..a series of alarms went off...
..and the auto-pilot disconnected.
ALARMS SOUND
In total darkness
and heavy turbulence
the crew are forced to re-take
manual control.
Pilots are the last line of defence,
so when things go very wrong,
the last line of defence
is the aviator.
After more than three hours
on auto-pilot
the pilots are suddenly faced
by information overload.
That crew faced an almost unheard-of
series of failures,
one right behind the other,
and for them to sort through it
would have been very difficult
that night.
Why is the aeroplane
doing what it's doing?
What are all these failures?
Why are they all coming at one time?
Bombarded by faults,
the pilot must cope with
the most serious problem of all -
he must maintain speed
or they will go out of control.
But after the pilot
took manual control,
the plane lost critical speed
and went into the catastrophic
condition known as a stall.
In a stall the wings
of the aircraft lose lift
and the plane becomes
almost impossible to control.
The pilot should have responded
by trying to increase speed,
but he didn't.
No-one could be sure why,
but it could be that he wasn't aware
he was stalling or maybe because
he was just so used to automation
his manual skills had been blunted.
Either way, the Air France pilot
couldn't maintain control and the
plane simply dropped out of the sky.
To avoid the same scenario
ever playing out again
the crash investigation recommended
that simulator training placed
more of an emphasis
on manual high-altitude flying
and aviation authorities have
encouraged all pilots
to try switching off auto-pilot
once in a while.
These changes should make pilots
less reliant on automation
and better prepared to take back
the controls in a crisis.
It is odd to think
that we have only been flying
for a fraction over 100 years
and, despite the bewildering
complexity, it is incredibly safe.
Crashes are very rare and something
like 90% of those are survivable,
which is an amazing statistic
and should give you SOME comfort
if you worry about the idea
of hurtling through the air
at close to the speed of sound
35,000 feet above the ground
in a pressurised metal tube.
For me personally,
ever since I was a kid,
I found air travel to be thrilling,
but the more I think about it,
the more I think
it's, well, it's mind-blowing.
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