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00:00:02,620 --> 00:00:05,413
Every passenger jet
is a travelling
life-support system,
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00:00:05,517 --> 00:00:10,827
carrying inside it
the highly pressurized oxygen
that keeps us alive.
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00:00:10,931 --> 00:00:14,965
If it ever escapes,
a simple flight
becomes a living nightmare.
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00:00:17,551 --> 00:00:19,172
United 811.
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00:00:19,275 --> 00:00:21,517
There was nothing in front
of us, or to the side of us.
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00:00:21,620 --> 00:00:23,206
The whole side
of the plane was gone.
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00:00:24,862 --> 00:00:26,379
Aloha 243...
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00:00:28,827 --> 00:00:31,896
Everything was going,
was being sucked out
of the plane.
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00:00:32,000 --> 00:00:34,034
British Airways 5390...
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00:00:35,551 --> 00:00:38,448
I'll never forget.
His face was hitting
the side screen,
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00:00:39,655 --> 00:00:40,689
but he didn't blink.
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Mayday!
Mayday! Mayday!
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00:00:43,482 --> 00:00:46,551
Declaring an emergency!
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00:00:46,655 --> 00:00:50,965
Sometimes it takes
a terrible accident
to expose hidden dangers,
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00:00:51,068 --> 00:00:53,655
and change the way
airplanes are built.
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Unfortunately, we wait
until we have enough bodies.
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00:00:56,931 --> 00:00:59,689
Too many of the changes
have been, in effect,
written in blood.
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00:01:02,931 --> 00:01:03,965
Mayday, mayday!
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This is the assembly plant
for the Airbus A320.
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After the Boeing 737,
it's the most popular
jet plane ever built.
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Almost 2000 of them are flying
for airlines around the globe.
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It's safe and dependable,
the airline equivalent
of a minivan.
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The aluminum skin on the top
of an A320 is less
than two millimeters thick,
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about as thick as a coin.
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But this slender piece of metal
helps keep passengers alive...
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00:02:04,827 --> 00:02:08,034
because the skies aren't nearly
as friendly as they seem.
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Most people
take aviation absolutely
for granted.
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The difference between being
on a commercial airliner
at 35,000 feet
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and being in a space capsule
in orbit is really not all that
different.
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They're both life support
systems.
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The reality is,
it's a hostile environment.
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The reality is, it's 50 degrees
below zero outside.
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The reality is that jet stream
or air stream out there,
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it would kill you
almost immediately.
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It's not natural
for people to travel
through this killer atmosphere.
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But, every day,
millions of us fly easily
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00:02:49,413 --> 00:02:52,517
some 3,000 meters higher than
the top of Mount Everest.
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All our life support
that's natural for us
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is down here, at the bottom
of this sea of air.
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And if we swim up too high,
however we get there,
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if we're not protected,
we can't live.
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00:03:11,482 --> 00:03:14,379
But taking oxygen with us up
to 11,000 meters
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is potentially dangerous.
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00:03:20,241 --> 00:03:25,655
The air inside an airplane
is pressurized, so passengers
can breathe easily.
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00:03:25,758 --> 00:03:29,862
As planes climb,
the pressure outside decreases.
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00:03:29,965 --> 00:03:32,068
The tightly packed air
in the cabin begins
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00:03:32,172 --> 00:03:34,551
exerting tremendous pressure
on the fuselage.
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On an average jetliner,
it means that every square
meter of the fuselage
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must support more than
5,000 kilograms of force.
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00:03:51,379 --> 00:03:55,068
And, on almost every flight,
the fuselage wins the battle.
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00:03:58,655 --> 00:04:02,344
But only because
airplane designers have learned
tragic lessons.
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We have concentrated,
in the past,
on changing things.
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But, unfortunately, we wait
until we have enough bodies.
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00:04:13,551 --> 00:04:16,896
In the 1950s,
a series of shocking accidents
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triggered changes
that are still seen today.
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The Comet has blazed new trails,
achieving new speeds,
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00:04:23,482 --> 00:04:25,344
setting a new standard.
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The passenger jet era began
in the 1950s,
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with the introduction
of the De Havilland Comet.
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For the first time,
jet engines were being used
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00:04:37,896 --> 00:04:40,482
to push commercial planes
higher than ever before.
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00:04:42,827 --> 00:04:46,206
What Great Britain had at stake
with the comet was enormous.
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They wanted to really declare
their place in civil aviation
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00:04:54,586 --> 00:04:59,344
by having the first successful
jet transport aircraft.
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But less than two years
after its maiden flight,
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the glittering jewel
of British aviation
disintegrated in mid-air.
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00:05:14,965 --> 00:05:16,310
It would have been
horrible.
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00:05:16,413 --> 00:05:17,931
It would have been
a horrible situation,
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00:05:18,034 --> 00:05:20,000
but mercifully,
it would have been quick.
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What they had found
with the bodies
that they had recovered,
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was the massive decompression,
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of course, caused the air
inside your lungs
to burst your lungs.
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At the same time, the out rush
of air would tear you
from your seat,
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and that many of these people
actually smashed
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their heads
against the structure.
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Three months later,
another Comet ripped apart
in flight.
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Officials feared
that every single Comet
could be a flying time bomb.
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The entire fleet is grounded.
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The design of The Comet
was actually
a very sound design.
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There was only one thing
that they didn't do,
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and it's because nobody knew.
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00:06:03,482 --> 00:06:04,931
Unknown to engineers,
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00:06:05,034 --> 00:06:07,896
there was a deadly flaw
in The Comet's basic design.
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00:06:10,724 --> 00:06:12,758
To find the jet's
fatal weakness,
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00:06:12,862 --> 00:06:15,896
investigators built
a massive water tank.
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They immersed
a stripped-down Comet.
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The pressure in the tank
was increased and decreased,
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simulating the strains
of flights
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The experiment ran
24 hours a day,
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00:06:29,413 --> 00:06:30,655
seven days a week.
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00:06:33,241 --> 00:06:36,827
After the equivalent
of some 3,000 flights,
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The Comet's Achilles' heel
revealed itself.
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00:06:40,103 --> 00:06:41,448
Its square windows.
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00:06:43,517 --> 00:06:45,724
You have
a rapid change
of direction in the shape,
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essentially a corner,
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00:06:48,413 --> 00:06:50,379
you have
a high stress concentration.
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It gave rise
to a fatigue crack,
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which then travelled rapidly
through
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00:06:54,758 --> 00:06:58,689
the rest of the structure,
causing a massive decompression.
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The most advanced passenger jet
in the world had succumbed
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00:07:02,137 --> 00:07:03,827
to metal fatigue.
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00:07:03,931 --> 00:07:08,344
The fuselage simply could not
handle the force
of the air inside pressing out.
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The airplane, with all that
force behind it,
suddenly unzipped itself.
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Every plane that's built today
is safer
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because of the disaster
that struck The Comet.
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Like other passenger planes,
the windows
on the A-320 are rounded,
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so that pressure doesn't
build up around the corners.
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Perhaps even more importantly,
extra rivets reinforce the skin
of today's planes
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to contain cracks
that might start anywhere
on the fuselage.
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It's designed to go
to that first row of rivets
and absolutely be stopped.
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It's a healthy structure.
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It can never unzip itself.
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But 34 years
after The Comet crash,
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00:08:01,241 --> 00:08:04,896
aircraft manufacturers
were faced
with another tragic disaster.
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00:08:08,758 --> 00:08:11,517
The extra rivets that were
supposed to save lives
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00:08:11,620 --> 00:08:15,137
failed to withstand
the relentless power
of air pressure on metal.
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One of the fellows
that I knew at the FAA,
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he said, "You know,
the day after this accident,
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I had to throw away most of what
I knew about metallurgy
and start over."
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At this Airbus factory
in Toulouse, France,
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00:08:37,931 --> 00:08:41,793
A320s roll out
at about the rate
of one every working day.
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00:08:43,620 --> 00:08:47,068
Titanium rivets, lightweight
and extremely tough,
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hold the fuselage together.
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Three thousand are used
to join the separate sections.
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Another 3,000 can be found
on each wing.
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Without them,
the fuselage couldn't contain
the pressurized air
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00:09:01,551 --> 00:09:03,517
that's forced
inside during flight.
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00:09:05,103 --> 00:09:07,241
But even
these rivets aren't foolproof.
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00:09:12,000 --> 00:09:14,482
April the 28th, 1988.
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00:09:14,586 --> 00:09:18,448
Aloha Airlines Flight 243
is traveling
from Hilo Airport
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00:09:18,551 --> 00:09:20,172
on the Big Island to Honolulu.
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00:09:23,137 --> 00:09:28,379
With this island hop,
Aloha 243 is making
its ninth flight of the day,
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00:09:28,482 --> 00:09:31,965
a normal schedule
for the planes of Aloha.
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00:09:32,068 --> 00:09:35,551
Protected within the jet,
passengers give little thought
to the fact
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00:09:35,655 --> 00:09:37,793
that the cabin is filled
with pressurized oxygen.
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00:09:39,206 --> 00:09:41,758
It's constantly pushing
against the fuselage,
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trying to escape into
the surrounding atmosphere.
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In the cabin,
the pressure is kept
at a constant level,
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00:09:48,482 --> 00:09:51,758
so passengers feel
like they've never
left the ground.
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00:09:51,862 --> 00:09:54,413
But as a plane rises
to its cruising altitude,
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00:09:54,517 --> 00:09:57,241
the air pressure
outside the cabin
is dangerously low.
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00:09:58,586 --> 00:10:03,448
Well, what we do is,
extract air from the engines
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00:10:03,551 --> 00:10:05,931
and use that
to pressurize the airplane.
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00:10:06,034 --> 00:10:10,862
And what we can do then
is control the pressure inside
by a series of valves.
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00:10:13,034 --> 00:10:15,965
The air moving
through the cabin
creates constant pressure
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00:10:16,068 --> 00:10:20,103
on the jet's fuselage,
keeping it inflated
like a balloon.
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00:10:20,206 --> 00:10:22,758
Every modern jet is built
to withstand this pressure.
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00:10:24,896 --> 00:10:28,310
There's
an internal structure
to a modern all-metal airplane.
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00:10:28,413 --> 00:10:32,448
The skin, without the structure,
would collapse easily.
It would buckle easily.
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00:10:32,551 --> 00:10:35,413
It would be sort of like a,
you know, a paper bag
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00:10:35,517 --> 00:10:39,206
without any structure inside
to hold it.
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00:10:39,310 --> 00:10:41,551
If you remove the skin
of a passenger jet,
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00:10:41,655 --> 00:10:44,275
you'll find hoop-shaped
bulkheads and formers
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00:10:44,379 --> 00:10:46,034
supporting the width
of the aircraft.
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00:10:47,482 --> 00:10:49,827
Stringers run the length
of the plane.
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00:10:49,931 --> 00:10:51,655
They all help support
the fuselage.
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00:10:55,034 --> 00:10:57,103
And the cabin needs
all the help it can get,
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00:10:57,206 --> 00:10:59,275
because, as the plane
gains altitude,
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00:10:59,379 --> 00:11:01,724
that pressurized oxygen
inside the plane
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00:11:01,827 --> 00:11:04,000
is pushing against
every square centimeter.
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00:11:09,068 --> 00:11:11,827
On this day in April, 1988,
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00:11:11,931 --> 00:11:16,206
passengers are about to learn
what happens
when that air suddenly escapes.
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00:11:25,137 --> 00:11:29,586
I saw a brilliant flash
of light. And, boom.
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00:11:29,689 --> 00:11:33,172
Everything was going,
was being sucked out
of the plane.
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00:11:33,275 --> 00:11:36,344
Aloha Airlines 243
has just suffered what
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00:11:36,448 --> 00:11:39,379
experts call
an "explosive decompression."
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00:11:39,482 --> 00:11:42,379
he air inside the plane
that makes jet flight possible
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00:11:42,482 --> 00:11:45,586
escapes in a sudden,
horrifying moment,
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Thirty-five square meters
of the fuselage are gone.
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Just imagine
the scene up there. The top
of the airplane broken off.
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00:11:53,655 --> 00:11:56,586
You now have 300 mile
an hour winds
blowing in that cabin.
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00:11:56,689 --> 00:11:59,172
That's three times
hurricane-force winds.
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00:11:59,275 --> 00:12:01,724
Those people were dressed
for Hawaii in the springtime,
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00:12:01,827 --> 00:12:03,862
not minus fifty-degree
temperatures.
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00:12:03,965 --> 00:12:07,448
Any period of time
at 24,000 feet,
those people will die.
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00:12:07,551 --> 00:12:09,206
What was that?
We have to get down!
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00:12:09,310 --> 00:12:12,310
Captain Bob Schornstheimer begins
an emergency descent,
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00:12:12,413 --> 00:12:14,586
dropping 20 meters a second.
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00:12:14,689 --> 00:12:17,793
The stress on the damaged craft
threatens to tear it apart.
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00:12:20,068 --> 00:12:22,310
The woman
that was sitting next to me,
and her husband,
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00:12:22,413 --> 00:12:24,517
he was on the other side
in the next row.
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00:12:24,620 --> 00:12:27,172
And she was next to me,
and they were reaching
their hands out,
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00:12:27,275 --> 00:12:30,620
and they were trying
to touch fingers
to say goodbye.
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00:12:30,724 --> 00:12:33,586
Against incredible odds,
the flight crew land
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00:12:33,689 --> 00:12:35,586
their bruised
and battered airplane.
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00:12:42,206 --> 00:12:44,103
Even with this explosive
decompression,
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00:12:44,206 --> 00:12:48,034
there's only one death
on Aloha Flight 243,
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00:12:48,137 --> 00:12:50,241
a flight attendant
who was pulled out
of the plane.
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00:12:56,896 --> 00:13:00,931
Jim Wildey investigates
the crash for the National
Transportation Safety Board.
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00:13:04,241 --> 00:13:08,068
In his laboratory,
Wildey makes
a disturbing discovery.
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00:13:08,172 --> 00:13:11,137
Running through some
of the pieces
of the plane's fuselage,
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00:13:11,241 --> 00:13:14,137
he finds a series
of hairline cracks.
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00:13:14,241 --> 00:13:16,620
They're right beside the holes
created by rivets
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00:13:16,724 --> 00:13:19,413
and barely visible
to the naked eye.
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00:13:19,517 --> 00:13:22,586
But they're classic signs
of metal fatigue.
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00:13:22,689 --> 00:13:25,586
Metal fatigue is something
that sounds exotic,
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00:13:25,689 --> 00:13:27,034
but it really is easy
to understand.
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00:13:28,379 --> 00:13:31,413
Any piece of metal has
a certain breaking point.
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00:13:31,517 --> 00:13:33,517
All of us have tried
to open a tin can
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00:13:33,620 --> 00:13:36,413
and not quite gotten the opener
all the way around.
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00:13:36,517 --> 00:13:39,586
We work it back and forth
until that last portion breaks.
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00:13:39,689 --> 00:13:41,310
You just demonstrated
metal fatigue.
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00:13:43,931 --> 00:13:46,655
A plane isn't
a rock solid tube.
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00:13:46,758 --> 00:13:49,758
To maintain the pressure
passengers need to enjoy
a flight,
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00:13:49,862 --> 00:13:51,655
it's designed
to be much more flexible.
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00:13:52,965 --> 00:13:55,965
The fuselage of the airplane
is actually breathing.
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00:13:56,068 --> 00:13:59,034
It expands and contracts
depending on altitude.
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00:13:59,137 --> 00:14:01,724
When it's on the ground,
it's in a contracted status.
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00:14:01,827 --> 00:14:06,896
When it's at altitude,
24,000 feet,
the fuselage expands.
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00:14:07,000 --> 00:14:08,517
If you could stand
at the back
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00:14:08,620 --> 00:14:13,413
of a 250-foot-long jetliner
and just sight
along that fuselage,
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00:14:13,517 --> 00:14:16,344
you'd see it begin
to puff up a little bit.
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00:14:16,448 --> 00:14:19,000
And as a plane lands,
the pressure differential
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00:14:19,103 --> 00:14:22,724
between the inside
and the outside
of the plane disappears.
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00:14:22,827 --> 00:14:24,931
The fuselage returns to normal.
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00:14:25,034 --> 00:14:27,551
So the airplane
is constantly cycling.
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00:14:27,655 --> 00:14:31,620
That's pressurization.
That will weaken the structure
over a long period of time.
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00:14:34,206 --> 00:14:38,241
Records show
that the Aloha jet
was 19 years old.
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00:14:38,344 --> 00:14:41,586
Boeing 737s are designed
for a 20-year service life,
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00:14:41,689 --> 00:14:44,965
and a recommended
75,000 flights.
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00:14:45,068 --> 00:14:47,758
But as investigators take
a closer look,
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00:14:47,862 --> 00:14:53,000
they discover that the Aloha jet
had logged an astonishing
89,000 separate flights.
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00:14:54,413 --> 00:14:56,689
The short hops
between the Hawaiian Islands
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00:14:56,793 --> 00:14:58,551
meant that the planes
in the Aloha Fleet
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00:14:58,655 --> 00:15:02,000
went through
more pressurization cycles
than any other aircraft.
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00:15:03,655 --> 00:15:05,827
You saw something
as you got on this airplane.
227
00:15:05,931 --> 00:15:08,724
- What did you see?
- Investigator
Jim Wildey gets a lead
228
00:15:08,827 --> 00:15:11,931
when he interviews
one of the Aloha passengers.
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00:15:12,034 --> 00:15:16,137
She says she saw a small crack
in the fuselage just
to the right of the door.
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00:15:17,241 --> 00:15:20,137
The witness saw cracking
in this area,
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00:15:20,241 --> 00:15:22,758
and we found fatigue cracking
back in here.
232
00:15:22,862 --> 00:15:26,137
So this is the line
where the fatigue cracking
joined up.
233
00:15:26,241 --> 00:15:28,586
One piece came down this way
and folded off,
234
00:15:28,689 --> 00:15:31,206
and the other piece went
across the top and came off
to the right side.
235
00:15:33,103 --> 00:15:35,482
But something doesn't
make sense.
236
00:15:35,586 --> 00:15:39,034
The Aloha jet lost
35 square meters
of its fuselage.
237
00:15:40,241 --> 00:15:42,344
In the years
after The Comet disaster,
238
00:15:42,448 --> 00:15:45,206
Boeing and other companies
had designed a safety feature
239
00:15:45,310 --> 00:15:47,724
that should have kept
any tearing
to an absolute minimum.
240
00:15:49,689 --> 00:15:52,413
Inside the fuselage
of every 737,
241
00:15:52,517 --> 00:15:55,620
Boeing has installed
a series of tear straps.
242
00:15:55,724 --> 00:15:58,310
If any kind of tear develops
in the fuselage,
243
00:15:58,413 --> 00:16:01,068
it should only run
as far as the next tear strap,
244
00:16:01,172 --> 00:16:03,517
never more
than 13 centimeters away,
245
00:16:03,620 --> 00:16:05,689
before shooting off
at a 90-degree angle.
246
00:16:07,137 --> 00:16:08,448
This would have prevented
the sort of
247
00:16:08,551 --> 00:16:11,103
catastrophic disintegration
that ripped apart The Comet.
248
00:16:13,172 --> 00:16:16,551
The purpose of the tear strip
is to confine any kind
of rip or tear
249
00:16:16,655 --> 00:16:20,448
in the fuselage skin
to a ten inch square basically.
250
00:16:20,551 --> 00:16:23,689
The ten-inch square
allows controlled decompression,
251
00:16:23,793 --> 00:16:27,000
and confines
any structural damage
to a very small area.
252
00:16:29,000 --> 00:16:31,034
But for Aloha 243,
253
00:16:31,137 --> 00:16:35,275
the tear straps did not contain
the rupture caused
by the metal fatigue.
254
00:16:35,379 --> 00:16:39,068
The NTSB believes there were
so many cracks
in the fuselage
255
00:16:39,172 --> 00:16:41,000
that they eventually
joined together,
256
00:16:41,103 --> 00:16:42,896
tearing an enormous hole
in the plane.
257
00:16:45,965 --> 00:16:48,896
But jets aren't held together
by rivets alone.
258
00:16:49,000 --> 00:16:54,206
The Comet disaster had
also highlighted the need
to reinforce the fuselage.
259
00:16:54,310 --> 00:16:58,827
The skin of an airplane is built
from separate panels,
which overlap.
260
00:16:58,931 --> 00:17:04,344
These panels are bonded together
by a powerful adhesive,
known as epoxy.
261
00:17:04,448 --> 00:17:08,793
As the epoxy hardens,
the panels are locked together
by rivets.
262
00:17:08,896 --> 00:17:12,068
And during his investigation
on the Aloha fuselage,
263
00:17:12,172 --> 00:17:15,965
Jim Wildey finds discoloration
inside some
of the overlapping joints.
264
00:17:18,103 --> 00:17:20,448
You can see now
where the dark material is
265
00:17:20,551 --> 00:17:25,655
the epoxy that was used
to bond the two layers
of the lap joint together.
266
00:17:25,758 --> 00:17:28,379
The white material you see here
is corrosion damage.
267
00:17:28,482 --> 00:17:31,413
of the aluminum fuselage skin.
268
00:17:31,517 --> 00:17:34,206
The Hawaiian climate
is great for tourists,
269
00:17:34,310 --> 00:17:36,689
but it's tough on airplanes.
270
00:17:36,793 --> 00:17:40,034
The ocean air is humid
and heavy with salt.
271
00:17:40,137 --> 00:17:43,206
It can corrode even
industrial epoxy.
272
00:17:43,310 --> 00:17:48,103
Investigators learned
that Boeing, the company
that built Aloha 243,
273
00:17:48,206 --> 00:17:51,724
had issued
numerous written warnings
about the epoxy.
274
00:17:51,827 --> 00:17:53,931
If it isn't applied
at the right temperature,
275
00:17:54,034 --> 00:17:57,793
if the panels have moisture
or dirt on them,
the bonding can fail.
276
00:17:59,206 --> 00:18:02,689
Boeing recommended
regular detailed inspections.
277
00:18:02,793 --> 00:18:07,482
But workers
at Aloha didn't report
any problems with the epoxy.
278
00:18:07,586 --> 00:18:12,931
They either never saw
the compromised epoxy or,
if they did, it wasn't repaired.
279
00:18:15,448 --> 00:18:19,482
The stress that's trying to pull
one skin away
from the other skin piece,
280
00:18:19,586 --> 00:18:22,275
the stresses would go
through the bonding
and not through the rivets.
281
00:18:22,379 --> 00:18:25,344
Of course, as this thing
becomes disbonded,
282
00:18:25,448 --> 00:18:27,793
now the rivets themselves
are loaded,
283
00:18:27,896 --> 00:18:30,551
and especially
this top row of rivets.
284
00:18:30,655 --> 00:18:33,758
And this is the row of rivets
we think that had
the fatigue cracking in it.
285
00:18:34,896 --> 00:18:37,241
These cracks
go un-repaired,
286
00:18:37,344 --> 00:18:41,172
and now you have an airplane
that is a ticking time bomb.
287
00:18:41,275 --> 00:18:44,827
The fuselage
on Aloha 243 was
seriously compromised
288
00:18:44,931 --> 00:18:46,517
by several factors.
289
00:18:46,620 --> 00:18:50,344
Poor maintenance,
the age of the aircraft
and by the heavy tours of duty.
290
00:18:52,034 --> 00:18:53,103
Since 1988,
291
00:18:53,206 --> 00:18:55,827
we have come light years
in understanding this.
292
00:18:55,931 --> 00:18:59,965
And we no longer leave ourselves
the tolerance that used
to be left
293
00:19:00,068 --> 00:19:03,241
to airlines to just go out
and take a look
at the airplane and sign it off.
294
00:19:09,482 --> 00:19:13,344
The Aloha accident was
another step towards
making passenger jets safer.
295
00:19:16,793 --> 00:19:20,000
It's important to always learn
from your mistakes.
296
00:19:20,103 --> 00:19:22,275
It's important to learn lessons
from that.
297
00:19:22,379 --> 00:19:24,931
And that has been the case
with aeronautical engineering.
298
00:19:26,896 --> 00:19:31,758
The Aloha story was
a brutal lesson
in the dangers of metal fatigue.
299
00:19:31,862 --> 00:19:35,137
But it wasn't the last example
of the power of cabin pressure.
300
00:19:40,793 --> 00:19:44,862
Two years later,
the industry would get
another terrifying reminder.
301
00:19:49,655 --> 00:19:51,724
Ladies and gentlemen,
this is your captain speaking.
302
00:19:51,827 --> 00:19:53,379
My name is Tim Lancaster.
303
00:19:53,482 --> 00:19:55,724
Welcome aboard this British
Airways Flight to Malaga.
304
00:19:56,689 --> 00:19:59,586
June the 10th, 1990.
305
00:19:59,689 --> 00:20:03,862
British Airways Flight 5390
is leaving Birmingham, England,
for Spain.
306
00:20:05,206 --> 00:20:06,931
Eighty-seven people are
on board.
307
00:20:08,413 --> 00:20:09,241
Eighty knots.
308
00:20:17,000 --> 00:20:18,551
Two minutes into the climb,
the flight crew switch
309
00:20:18,655 --> 00:20:21,517
the flight crew switch
on the autopilot,
310
00:20:21,620 --> 00:20:24,310
Captain Tim Lancaster takes off
his shoulder straps.
311
00:20:27,413 --> 00:20:29,275
I went into the flight deck
312
00:20:29,379 --> 00:20:35,000
to ask Tim and Alistair
what they would like to drink.
313
00:20:35,103 --> 00:20:36,241
Would you gentlemen
like a tea?
314
00:20:36,344 --> 00:20:37,137
Please, the usual.
315
00:20:38,379 --> 00:20:41,172
Minutes later,
at 5,200 meters,
316
00:20:41,275 --> 00:20:44,827
the plane is very close
to its assigned altitude.
317
00:20:44,931 --> 00:20:47,655
And then, like a cork out
of a champagne bottle,
318
00:20:47,758 --> 00:20:49,724
the windshield bursts
from its frame.
319
00:20:58,413 --> 00:21:01,206
Captain Tim Lancaster
is sucked out of his seat
320
00:21:01,310 --> 00:21:04,413
and is pinned to the fuselage
by blistering winds roaring
321
00:21:04,517 --> 00:21:07,965
close to 550 kilometers an hour.
322
00:21:08,068 --> 00:21:12,275
The temperature
is minus 17 degrees centigrade
and there's very little oxygen.
323
00:21:14,034 --> 00:21:16,896
Co-pilot Alastair Atchison
is alone at the controls.
324
00:21:18,689 --> 00:21:22,482
Ordinarily, cockpit windows
cannot budge from their frames.
325
00:21:22,586 --> 00:21:25,206
The force of the air,
as the planes soars
through the sky,
326
00:21:25,310 --> 00:21:27,206
pushes the windshield
onto the plane.
327
00:21:30,379 --> 00:21:34,551
But on Flight 5390,
something has gone
terribly wrong.
328
00:21:34,655 --> 00:21:37,068
Flight attendant Nigel Ogden
rushes in to help.
329
00:21:39,413 --> 00:21:44,724
And I looked in.
The flight deck door
was resting on the controls,
330
00:21:44,827 --> 00:21:46,413
and all I could see
was Tim hanging out the window.
331
00:21:51,241 --> 00:21:53,551
I just grabbed him
before he went out completely.
332
00:21:55,689 --> 00:21:58,137
Other flight attendants do
what they can.
333
00:21:58,241 --> 00:22:01,793
Co-pilot Alastair Atchison
reduces speed
and descends quickly.
334
00:22:03,517 --> 00:22:06,586
But as he slows the plane down,
the drop in wind pressure
335
00:22:06,689 --> 00:22:09,310
lets the captain slide around
on the side of the plane.
336
00:22:14,931 --> 00:22:17,793
All I remember
is Tim's arms flailing out.
337
00:22:17,896 --> 00:22:19,827
His arms seemed
about six foot long.
338
00:22:21,137 --> 00:22:23,896
I'll never forget
that his eyes were wide open.
339
00:22:24,000 --> 00:22:28,344
I mean, his face was
hitting the side of the
side screen,
340
00:22:29,620 --> 00:22:31,965
but he didn't blink.
341
00:22:32,068 --> 00:22:37,931
And I thought to myself,
and I said to John,
"I think he's dead."
342
00:22:38,034 --> 00:22:40,103
- "I think he's dead."
-
343
00:22:42,482 --> 00:22:45,172
Just 35 minutes
after taking off,
344
00:22:45,275 --> 00:22:47,793
Atchison gets
his jet safely back
on the ground.
345
00:23:01,275 --> 00:23:04,724
But the most
unbelievable chapter
of this entire story
346
00:23:04,827 --> 00:23:08,724
is the fact
that captain Tim Lancaster
survives his incredible ordeal.
347
00:23:10,689 --> 00:23:12,448
But I remember watching
the windscreen
348
00:23:12,551 --> 00:23:15,965
move away from the aircraft.
And then it had gone,
like a bullet.
349
00:23:16,068 --> 00:23:17,655
It disappeared
into the distance.
350
00:23:20,413 --> 00:23:22,724
And I was very conscious
of going upwards.
351
00:23:22,827 --> 00:23:26,931
And, well, the whole thing
became completely surreal then,
as it would.
352
00:23:27,034 --> 00:23:30,172
And I was aware of being
outside of the airplane.
353
00:23:30,275 --> 00:23:31,827
I remember seeing
the tail of the aircraft.
354
00:23:31,931 --> 00:23:33,448
I can remember
the engines going around.
355
00:23:33,551 --> 00:23:35,965
And then I don't remember
much more.
356
00:23:38,206 --> 00:23:40,689
Tim Lancaster
was pinned to the outside
of the plane
357
00:23:40,793 --> 00:23:42,724
for over 20 minutes.
358
00:23:42,827 --> 00:23:45,310
His injuries were
surprisingly minor.
359
00:23:45,413 --> 00:23:47,655
Bone fractures
in his right arm
and wrist,
360
00:23:47,758 --> 00:23:49,068
frostbite, and shock.
361
00:23:51,482 --> 00:23:54,241
Within five months,
Tim Lancaster
was flying again.
362
00:24:00,379 --> 00:24:03,793
In the immediate aftermath,
investigators have very little
to go on.
363
00:24:05,655 --> 00:24:09,137
Windscreen was missing.
There was a certain
amount of blood around.
364
00:24:09,241 --> 00:24:12,413
There were some minor dents
and scrapes on the fuselage,
365
00:24:12,517 --> 00:24:14,758
as you'd expect,
if the window had gone past.
366
00:24:14,862 --> 00:24:16,206
And, really, that was about it,
367
00:24:16,310 --> 00:24:19,620
apart from a lot of papers
scattered around inside.
368
00:24:21,172 --> 00:24:24,275
The maintenance log
is recovered from the plane.
369
00:24:24,379 --> 00:24:27,344
Stuart Culling learns
the windscreen had been
replaced,
370
00:24:27,448 --> 00:24:28,896
just hours before takeoff.
371
00:24:31,068 --> 00:24:32,827
Everything okay?
- Fine.
372
00:24:32,931 --> 00:24:34,275
She's just come out
of maintenance,
by the look of it.
373
00:24:36,482 --> 00:24:39,586
Nothing much, though.
Just changed the windscreen.
374
00:24:39,689 --> 00:24:41,793
I wanted to find out
exactly what had happened
375
00:24:41,896 --> 00:24:44,310
to the aircraft
before it took off.
376
00:24:44,413 --> 00:24:48,103
Early in the investigation,
the missing windscreen is found.
377
00:24:48,206 --> 00:24:51,448
It contains a curious piece
of evidence.
378
00:24:51,551 --> 00:24:54,034
There was something
like 30 bolts found with it,
379
00:24:54,137 --> 00:24:58,965
most of which were
one size short in diameter,
one size too small in diameter.
380
00:24:59,068 --> 00:25:00,137
On many planes,
381
00:25:00,241 --> 00:25:03,241
windscreens are fitted
from inside the cockpit.
382
00:25:03,344 --> 00:25:07,586
Internal cabin pressure pushes
against them, keeping them
in place.
383
00:25:07,689 --> 00:25:12,379
But on the BAC 111,
the windscreen is bolted
from the outside.
384
00:25:12,482 --> 00:25:16,827
The pressurized oxygen
inside the jet pushes out
against the windscreen.
385
00:25:16,931 --> 00:25:20,206
The bolts must resist
this pressure.
386
00:25:20,310 --> 00:25:23,793
There are enough of them there
that they simply can't pull out
of the structure.
387
00:25:23,896 --> 00:25:26,724
But, of course,
if you then violate
the very premise of that
388
00:25:26,827 --> 00:25:29,034
by putting the wrong bolts
on, all bets are off.
389
00:25:29,137 --> 00:25:30,827
You're now a test pilot.
390
00:25:30,931 --> 00:25:34,034
During his interview
with the ground engineer
who repaired the plane,
391
00:25:34,137 --> 00:25:36,965
Culling gets a major break.
392
00:25:37,068 --> 00:25:39,551
One thing that came out
was that he said,
"Oh, the old bolts
393
00:25:39,655 --> 00:25:42,000
went into a waste bin
in the hangar
where he did the job.
394
00:25:43,103 --> 00:25:44,103
and they may still be there."
395
00:25:44,206 --> 00:25:45,862
So we rushed across
to the waste bin
396
00:25:45,965 --> 00:25:48,379
and found something
like 80 discarded bolts.
397
00:25:48,482 --> 00:25:50,758
The old bolts are
the proper size.
398
00:25:50,862 --> 00:25:53,827
Why were smaller bolts
used to replace them?
399
00:25:53,931 --> 00:25:56,724
And these are the ones
you checked
against the new ones?
400
00:25:56,827 --> 00:25:58,689
- That's right. Yeah.
I took those...
- From the carousel?
401
00:25:58,793 --> 00:26:00,793
It was
really excellent evidence.
402
00:26:00,896 --> 00:26:03,655
Gold, as far as I was concerned.
403
00:26:03,758 --> 00:26:07,000
Instead of using
the old bolts to put
the new window on,
404
00:26:07,103 --> 00:26:09,241
the ground engineer decided
to replace them.
405
00:26:10,793 --> 00:26:13,344
He did not check
the parts catalogue to verify
406
00:26:13,448 --> 00:26:15,000
which bolt he needed
for the job.
407
00:26:21,068 --> 00:26:21,931
Morning.
408
00:26:24,068 --> 00:26:26,241
The bolts he chose
seemed the same,
409
00:26:26,344 --> 00:26:29,827
but in fact, were just over
half a millimeter smaller.
410
00:26:29,931 --> 00:26:31,620
They were too thin
to do the job.
411
00:26:38,482 --> 00:26:41,931
Early in the morning,
working against the side
of a hanger,
412
00:26:42,034 --> 00:26:44,000
the engineer couldn't tell
the difference.
413
00:26:46,620 --> 00:26:49,137
Hours later,
the window gave way.
414
00:26:58,241 --> 00:27:00,793
Faced with a challenge
they weren't trained for,
415
00:27:00,896 --> 00:27:03,965
the crew still managed to pull
their plane back from the brink.
416
00:27:06,275 --> 00:27:08,206
But the massive pressure
inside an airplane
417
00:27:08,310 --> 00:27:10,896
doesn't need bad maintenance
to rip a jet apart.
418
00:27:15,517 --> 00:27:19,206
That pressure can also find
a tiny flaw somewhere
in the design
419
00:27:19,310 --> 00:27:21,034
and cause a nightmare
in the sky.
420
00:27:33,103 --> 00:27:38,862
The Airbus A320,
one of the most popular
passenger jets in the sky.
421
00:27:41,206 --> 00:27:42,862
Every day around the world,
422
00:27:42,965 --> 00:27:45,275
thousands of passengers
board this plane.
423
00:27:47,655 --> 00:27:51,620
When they do, they walk
through what would seem to be
an obvious weak spot
424
00:27:51,724 --> 00:27:52,551
in the fuselage,
425
00:27:53,344 --> 00:27:54,137
the door.
426
00:27:57,620 --> 00:28:01,344
Any hole in the fuselage
is a potential danger,
427
00:28:01,448 --> 00:28:05,206
so engineers designed
passenger doors
that can't be opened in flight.
428
00:28:09,172 --> 00:28:11,241
It is virtually impossible.
429
00:28:11,344 --> 00:28:12,793
I don't use
that word very easily,
430
00:28:12,896 --> 00:28:14,689
but it is impossible
for a passenger
431
00:28:14,793 --> 00:28:17,344
to open a plug type door
in flight.
432
00:28:17,448 --> 00:28:21,137
Passenger doors are
plug-type doors.
433
00:28:21,241 --> 00:28:23,689
They're built
to be slightly larger
than their frames.
434
00:28:25,000 --> 00:28:27,344
When a plane takes off
and pressurizes,
435
00:28:27,448 --> 00:28:31,448
the atmosphere
inside the aircraft seals
the door shut,
436
00:28:31,551 --> 00:28:35,517
That door probably has
10,000 or more pounds
of pressure holding it
437
00:28:35,620 --> 00:28:37,896
firmly in place
in that door frame.
438
00:28:38,000 --> 00:28:41,068
And you have to pull it out
of that door frame
to get it open.
439
00:28:41,172 --> 00:28:43,965
But not all doors
on an airplane
are built the same.
440
00:28:44,068 --> 00:28:48,034
Even designs that seem flawless
on paper can rip apart
in the real world.
441
00:28:51,758 --> 00:28:55,413
February the 24th, 1989.
Honolulu Airport.
442
00:28:57,000 --> 00:29:00,793
United Airlines 811 is bound
for Auckland, New Zealand.
443
00:29:02,517 --> 00:29:04,103
Expected flying time,
444
00:29:04,206 --> 00:29:06,206
nine-and-a-half hours.
445
00:29:06,310 --> 00:29:10,206
There are 355 people on board,
plus a full load of cargo.
446
00:29:12,586 --> 00:29:17,206
The doors close on time
and the plane leaves the gate
just after 1:30 in the morning.
447
00:29:22,482 --> 00:29:24,206
Tell them
we can handle 33,
448
00:29:24,310 --> 00:29:26,137
- if it's available.
- Okay.
449
00:29:26,241 --> 00:29:29,827
We did notice
that there were thunderstorms
a 100 miles south,
450
00:29:29,931 --> 00:29:31,344
right on course,
451
00:29:31,448 --> 00:29:34,655
which was rather unusual,
for that time of night.
452
00:29:34,758 --> 00:29:36,793
So I left the seat belt sign on.
453
00:29:38,448 --> 00:29:41,068
Captain Cronin's decision
to keep that sign on
454
00:29:41,172 --> 00:29:42,344
will save lives.
455
00:29:45,068 --> 00:29:50,344
As the 747 climbs
past 7,000 meters,
passengers sitting just above
456
00:29:50,448 --> 00:29:53,379
and behind the cargo door begin
to hear a strange noise.
457
00:29:55,000 --> 00:29:56,689
Kind of a grinding noise.
458
00:30:02,103 --> 00:30:03,724
I heard a, like a thud.
459
00:30:07,965 --> 00:30:10,275
- What the hell?
- And the next nanosecond,
460
00:30:10,379 --> 00:30:13,103
it was pure,
unadulterated pandemonium.
461
00:30:23,862 --> 00:30:25,896
The next thing I knew,
I found myself
462
00:30:26,000 --> 00:30:27,896
on the stairwell
463
00:30:28,000 --> 00:30:29,448
hanging onto the rungs.
464
00:30:29,551 --> 00:30:32,482
And, I immediately knew it was
an explosive decompression.
465
00:30:33,965 --> 00:30:36,758
Everything on the airplane
that wasn't fastened down,
466
00:30:36,862 --> 00:30:39,482
tied down
or secured, became airborne.
467
00:30:41,034 --> 00:30:42,551
The noise was incredible.
468
00:30:45,000 --> 00:30:48,000
The 747's cargo door
had torn off,
469
00:30:48,103 --> 00:30:50,620
ripping away a section
of the fuselage.
470
00:30:50,724 --> 00:30:54,344
The pressurized oxygen
in the cabin shot out
with explosive force.
471
00:30:56,517 --> 00:30:58,413
And, as I looked up,
that was the first time
472
00:30:58,517 --> 00:31:02,137
I saw this tremendous hole
on the side of the aircraft
473
00:31:02,241 --> 00:31:05,827
that was just a void.
And seats were missing.
474
00:31:05,931 --> 00:31:08,103
And I immediately knew
that we had lost passengers.
475
00:31:09,758 --> 00:31:11,413
Everything in front
of us was gone.
476
00:31:11,517 --> 00:31:15,068
Where we were sitting,
we were about 6 inches
from the hole.
477
00:31:15,172 --> 00:31:18,206
So, there was nothing in front
of us, or to the side of us.
478
00:31:18,310 --> 00:31:20,310
The whole side
of the plane was gone.
479
00:31:20,413 --> 00:31:22,344
Actually, our feet were
dangling out of the hole.
480
00:31:22,448 --> 00:31:25,724
And I first thought
we weren't going to make it,
481
00:31:25,827 --> 00:31:28,379
you know? I just didn't think
there was any hope.
482
00:31:28,482 --> 00:31:31,517
The situation is desperate,
but by itself,
483
00:31:31,620 --> 00:31:35,103
an explosive decompression
won't bring a plane down.
484
00:31:35,206 --> 00:31:38,068
In 811, there's a whole
as big as Tulsa on the side
of this thing.
485
00:31:38,172 --> 00:31:41,034
I mean,
it's an aerodynamic disruption
of massive proportions.
486
00:31:41,137 --> 00:31:44,482
But if it was designed the way
we had designed things
a long time ago,
487
00:31:44,586 --> 00:31:45,586
it would have unzipped.
488
00:31:46,965 --> 00:31:48,206
After the door came off,
489
00:31:48,310 --> 00:31:50,586
eventually,
a row of rivets held,
490
00:31:50,689 --> 00:31:52,586
keeping the plane
from pulling itself apart.
491
00:31:56,896 --> 00:32:00,206
But the gaping hole is putting
massive stress on the aircraft.
492
00:32:00,310 --> 00:32:03,034
The flight crew needs to descend
as fast as possible.
493
00:32:04,965 --> 00:32:06,827
CO-PILOT: Left right valves on.
494
00:32:06,931 --> 00:32:08,206
Start dumping the fuel.
495
00:32:08,310 --> 00:32:10,103
I am dumping.
496
00:32:10,206 --> 00:32:12,448
Struggling to fly
their badly damaged jet,
497
00:32:12,551 --> 00:32:14,689
the crew turned back
to Honolulu airport.
498
00:32:22,379 --> 00:32:25,965
And all of a sudden,
we were slowing down,
slowing down.
499
00:32:26,068 --> 00:32:31,551
And I said,
"Oh, my God, we've landed.
We're on ground."
500
00:32:31,655 --> 00:32:33,344
Probably the best landing
I've ever made.
501
00:32:34,620 --> 00:32:37,034
When we finally stopped
on the runway,
502
00:32:38,103 --> 00:32:40,689
we deployed all ten chutes,
503
00:32:40,793 --> 00:32:44,275
and the flight attendants
evacuated all of the passengers.
504
00:32:46,103 --> 00:32:49,586
Thanks to
the experienced flight crew,
United Airlines 811
505
00:32:49,689 --> 00:32:52,000
landed with everyone
on board alive.
506
00:32:55,655 --> 00:32:57,965
But nine passengers
were missing,
507
00:32:58,068 --> 00:33:01,275
sucked out of the plane
when the fuselage tore open,
508
00:33:01,379 --> 00:33:04,413
taking with it five rows
of seats.
509
00:33:04,517 --> 00:33:07,655
One of those passengers
was a New Zealander
on his way home,
510
00:33:07,758 --> 00:33:09,517
Lee Campbell.
511
00:33:09,620 --> 00:33:11,275
We got a phone call
from Chicago,
512
00:33:12,551 --> 00:33:15,241
And they just said
that they regret to inform us
513
00:33:15,344 --> 00:33:17,103
that our son was missing,
presumed dead.
514
00:33:19,241 --> 00:33:21,793
In the wake
of their son's tragic death,
515
00:33:21,896 --> 00:33:25,000
Kevin and Susan Campbell embark
on an international mission
516
00:33:25,103 --> 00:33:27,931
to discover exactly why
the door had come off the plane.
517
00:33:29,724 --> 00:33:31,655
Lee can't have died for nothing.
518
00:33:31,758 --> 00:33:34,517
You know, you've got
to find out why he died.
519
00:33:34,620 --> 00:33:37,724
And you've just got to make sure
that it never happens again.
520
00:33:39,000 --> 00:33:40,655
Two months
after the accident,
521
00:33:40,758 --> 00:33:45,379
the National Transportation
Safety Board holds
preliminary hearings.
522
00:33:45,482 --> 00:33:49,655
During a break,
the Campbells take matters
into their own hands.
523
00:33:49,758 --> 00:33:52,172
They remove several boxes full
of files.
524
00:33:53,482 --> 00:33:55,379
So we quickly realized
we'd got
525
00:33:55,482 --> 00:33:58,034
a really good set of papers
with a lot of things
526
00:33:58,137 --> 00:34:00,758
that hadn't been released
to the public.
527
00:34:00,862 --> 00:34:04,586
We were able to really start our
investigation in earnest
at that stage.
528
00:34:06,793 --> 00:34:10,620
The unpublished documents reveal
a disturbing catalog of problems
529
00:34:10,724 --> 00:34:13,586
with the 747's
forward cargo door,
530
00:34:13,689 --> 00:34:15,758
going right back
to its original design.
531
00:34:17,896 --> 00:34:23,482
Passenger doors are plug doors,
but most cargo doors
on jets open outward.
532
00:34:23,586 --> 00:34:26,137
This increases the space
for luggage and other cargo.
533
00:34:30,068 --> 00:34:33,551
As the plane gains altitude,
the pressure inside the jet
534
00:34:33,655 --> 00:34:35,206
presses outwards
against the door.
535
00:34:36,517 --> 00:34:37,931
To prevent the door
from opening,
536
00:34:38,034 --> 00:34:41,379
Boeing had installed
what it believed
was a foolproof locking system.
537
00:34:42,724 --> 00:34:45,310
What they do is they build
in multiple redundancies
538
00:34:45,413 --> 00:34:47,965
to make sure the door
is properly latched
539
00:34:48,068 --> 00:34:52,655
and does not open.
And you build it
into a point of law
540
00:34:52,758 --> 00:34:56,275
that is extremely improbable
that the door would ever open.
541
00:34:58,655 --> 00:35:01,689
The Campbell's research uncovers
two major flaws
542
00:35:01,793 --> 00:35:04,275
with the 747 cargo doors.
543
00:35:04,379 --> 00:35:06,310
The first involved
the locking system,
544
00:35:07,758 --> 00:35:09,206
To lock the cargo doors,
545
00:35:09,310 --> 00:35:13,379
electric motors turn
C-shaped latches
around pins in the doorframe.
546
00:35:15,206 --> 00:35:17,896
A handle then moves arms
or locking sectors
547
00:35:18,000 --> 00:35:20,931
over the top of the C-latches
to prevent them from reopening.
548
00:35:24,137 --> 00:35:28,379
But on Flight 811,
the supposedly
foolproof system had failed.
549
00:35:31,000 --> 00:35:35,413
Kevin Campbell built a model
of the 747 cargo door latch.
550
00:35:35,517 --> 00:35:39,310
It showed the first deadly flaw
in the locking system.
551
00:35:39,413 --> 00:35:43,034
Aluminum locking sectors
could not hold the C-latch
in place
552
00:35:43,137 --> 00:35:45,310
if the latches started
to open on their own.
553
00:35:49,724 --> 00:35:52,310
With the aluminum
locking sectors,
554
00:35:52,413 --> 00:35:57,758
if the C-locks tried
to backwind open electrically,
555
00:35:57,862 --> 00:36:00,241
it would just push
the locking sector out
of the way.
556
00:36:02,103 --> 00:36:04,448
It just simply wasn't up
to the job
that it was designed for.
557
00:36:07,241 --> 00:36:10,310
But what would cause
the C-lock to backwind?
558
00:36:10,413 --> 00:36:12,379
The Campbells didn't have
the answer,
559
00:36:12,482 --> 00:36:14,068
but they knew they were
onto something.
560
00:36:16,827 --> 00:36:20,896
During their research,
they learned that two years
before Flight 811,
561
00:36:21,000 --> 00:36:24,965
a Pan Am 747 out of Heathrow
had pressurization problems
562
00:36:25,068 --> 00:36:26,620
as it climbed
to cruising altitude.
563
00:36:27,793 --> 00:36:30,413
The pilot was forced
to turn back.
564
00:36:30,517 --> 00:36:33,379
When they got back to Heathrow,
they found that
the door was hanging open
565
00:36:33,482 --> 00:36:38,551
an inch and a half at the bottom
and all of the locks were open.
566
00:36:38,655 --> 00:36:42,172
When it got
to the maintenance base,
they found that
567
00:36:42,275 --> 00:36:45,655
all of the locking sectors were
either bent or broken.
568
00:36:45,758 --> 00:36:48,206
The passengers
on this flight were lucky.
569
00:36:48,310 --> 00:36:51,206
They had survived
the faulty locking system.
570
00:36:51,310 --> 00:36:54,793
But why had the C-latches turned
and bent the locking sectors?
571
00:37:00,827 --> 00:37:04,310
As the Campbells continue
to search,
a Pan Am report surfaces
572
00:37:04,413 --> 00:37:07,724
that lays out a critical issue
with the cargo door's
electrical system.
573
00:37:09,413 --> 00:37:13,689
When the cargo door's
outer handle is placed
in the closed position,
574
00:37:13,793 --> 00:37:17,586
a master lock switch should
disconnect the power supply.
575
00:37:17,689 --> 00:37:19,551
This would stop
the C-latches from turning.
576
00:37:21,965 --> 00:37:23,793
But something was wrong
with the switch.
577
00:37:26,275 --> 00:37:29,620
There was power
to the door locks with the...
578
00:37:29,724 --> 00:37:33,827
with the outer handle closed.
And the locks started to move
579
00:37:33,931 --> 00:37:38,137
and it started to force
the locking sectors out
of the way.
580
00:37:38,241 --> 00:37:40,896
The faulty power switch
and weak locking sectors
581
00:37:41,000 --> 00:37:43,862
were no match
for the pressurized
oxygen inside the plane.
582
00:37:50,896 --> 00:37:53,965
After years of being pushed
by the Campbells,
583
00:37:54,068 --> 00:37:58,689
the NTSB produces a report
that agrees.
584
00:37:58,793 --> 00:38:04,275
There was an inadvertent failure
of either the switch
or the wiring
585
00:38:04,379 --> 00:38:07,103
that caused
an uncommanded opening
of the door.
586
00:38:08,206 --> 00:38:09,758
It's nice
that other people know
587
00:38:09,862 --> 00:38:12,172
that you're right, and had been
all along.
588
00:38:12,275 --> 00:38:15,413
And the support
that they had given you was,
you know, was vindicated.
589
00:38:17,517 --> 00:38:22,068
I couldn't have lived
with myself if we had done
no investigating ourselves.
590
00:38:22,172 --> 00:38:24,586
It was just something
we both felt
591
00:38:24,689 --> 00:38:26,758
we needed to do.
We didn't even discuss it.
592
00:38:26,862 --> 00:38:28,310
We just knew
593
00:38:28,413 --> 00:38:29,344
that's what we would do.
594
00:38:35,413 --> 00:38:37,379
After United Flight 811,
595
00:38:37,482 --> 00:38:41,724
the locking system
on the Boeing 747 cargo doors
was changed.
596
00:38:41,827 --> 00:38:45,551
Inspections were increased.
Another potential cause
597
00:38:45,655 --> 00:38:49,379
of explosive decompression
had been found and eliminated.
598
00:38:49,482 --> 00:38:53,206
That is an amazing accolade
to what we've learned,
not just Boeing,
599
00:38:53,310 --> 00:38:54,758
but what we've learned
about maintenance,
600
00:38:54,862 --> 00:38:58,620
about structures,
maintaining them
and inspecting them.
601
00:38:58,724 --> 00:39:02,586
Since the first jet engines
pushed planes higher in the sky,
602
00:39:02,689 --> 00:39:05,103
the aviation industry
has struggled to harness
603
00:39:05,206 --> 00:39:08,965
and contain the deadly power
of pressurized oxygen.
604
00:39:09,068 --> 00:39:13,655
They know all too well
that a single flaw can lead
to a terrifying decompression.
605
00:39:20,448 --> 00:39:23,655
But more than 15 years
after United 811,
606
00:39:23,758 --> 00:39:26,310
another deadly lesson
is learned.
607
00:39:26,413 --> 00:39:29,137
Helios five-two-two,
do you read? Over.
608
00:39:29,241 --> 00:39:31,862
It's August the 14th, 2005.
609
00:39:34,379 --> 00:39:35,758
For almost an hour,
610
00:39:35,862 --> 00:39:40,034
Helios Flight 522 has been
circling the skies over Athens.
611
00:39:40,137 --> 00:39:41,931
Helios 522, over.
612
00:39:42,034 --> 00:39:45,137
Its flight crew
has stopped communicating
with air traffic control.
613
00:39:46,482 --> 00:39:48,793
Fearing a terrorist attack,
the Greek air force
614
00:39:48,896 --> 00:39:51,896
scrambles two fighter jets
to circle the mystery aircraft.
615
00:39:55,620 --> 00:39:56,724
One of them was
616
00:39:56,827 --> 00:39:59,965
actually in a shooting position
behind
617
00:40:00,068 --> 00:40:02,517
the 737.
The other one was
nearby the cockpit,
618
00:40:02,620 --> 00:40:06,689
and he was trying
to communicate visually
with the person in the cockpit.
619
00:40:06,793 --> 00:40:09,862
The fighter pilots
can't see any damage to the jet.
620
00:40:09,965 --> 00:40:12,103
No holes in the fuselage.
621
00:40:12,206 --> 00:40:15,241
There is no structural failure.
There is no fire.
622
00:40:15,344 --> 00:40:17,862
There is no problem,
obvious problem,
623
00:40:17,965 --> 00:40:19,724
from the external view
with the plane.
624
00:40:21,344 --> 00:40:24,413
Someone in the cockpit waves
at the fighter pilot.
625
00:40:24,517 --> 00:40:28,172
But all too soon,
the jet loses altitude
and falls towards the ground.
626
00:40:34,586 --> 00:40:37,310
All 121 people
on board are killed.
627
00:40:39,137 --> 00:40:41,413
It's the worst air crash
in the history of Greece.
628
00:40:47,137 --> 00:40:49,517
Within minutes,
investigators are on the scene.
629
00:40:55,241 --> 00:40:58,172
So we climbed over the hill,
and there we were. You know,
630
00:40:58,275 --> 00:41:03,137
facing this situation,
which was beyond
any description.
631
00:41:03,620 --> 00:41:05,206
I saw
632
00:41:05,310 --> 00:41:08,931
a great area in front of me,
which was burning.
It was black,
633
00:41:09,034 --> 00:41:15,137
burning, people spread,
pieces of the airplane.
634
00:41:15,241 --> 00:41:18,689
The autopsies add more mystery
to the case.
635
00:41:18,793 --> 00:41:22,551
Everyone on board
the Helios flight was alive
up to the moment of the crash.
636
00:41:25,482 --> 00:41:27,413
He did not die from inhaling
a toxic substance
637
00:41:27,517 --> 00:41:30,103
in the airplane
or from an explosion.
638
00:41:32,310 --> 00:41:33,586
These people died on impact.
639
00:41:35,137 --> 00:41:38,206
But if the passengers
were alive until impact,
640
00:41:38,310 --> 00:41:41,137
why didn't the fighter pilots
see more activity on the plane?
641
00:41:45,724 --> 00:41:48,862
Akrivos Tsolakis
is the lead investigator.
642
00:41:48,965 --> 00:41:51,965
He begins to dig
through maintenance records.
643
00:41:52,068 --> 00:41:53,896
He learns that
on the day of the crash,
644
00:41:54,000 --> 00:41:56,172
the rear door had been
inspected for leaks.
645
00:41:57,965 --> 00:42:00,034
Before it took off
on its last flight,
646
00:42:00,137 --> 00:42:03,827
the Helios jet arrived
in Cyprus with a problem.
647
00:42:03,931 --> 00:42:06,862
During the trip, the cabin crew
had heard loud banging
648
00:42:06,965 --> 00:42:08,965
and saw ice
on a rear service door.
649
00:42:15,758 --> 00:42:18,344
To make sure
there's nothing wrong
with the seal on the door,
650
00:42:18,448 --> 00:42:20,620
the engineer runs
a pressurization test.
651
00:42:21,413 --> 00:42:22,413
He's looking for a leak.
652
00:42:25,689 --> 00:42:27,862
So explain again
how you tested the pressure?
653
00:42:28,862 --> 00:42:30,724
I went into the cockpit,
654
00:42:30,827 --> 00:42:33,137
I turned
the pressurization switch
to manual.
655
00:42:33,241 --> 00:42:38,655
Switching digital pressure
control unit from auto
to manual.
656
00:42:38,758 --> 00:42:41,965
The jet's engines
are turned off,
so the engineer uses the plane's
657
00:42:42,068 --> 00:42:44,655
auxiliary power unit
to force air into the cabin.
658
00:42:46,413 --> 00:42:48,724
Just like looking for a leak
in a tire.
659
00:42:48,827 --> 00:42:52,551
In this case,
what you're having to do
is pressurize the aircraft,
660
00:42:52,655 --> 00:42:56,275
use a barometer, essentially,
to monitor the pressure inside.
661
00:42:57,517 --> 00:42:59,137
And look for leaks that way.
662
00:42:59,241 --> 00:43:02,482
A normally well-maintained
jetliner of any age
663
00:43:02,586 --> 00:43:06,793
is simply not going to be
completely airtight.
664
00:43:06,896 --> 00:43:08,724
You're going to have leaks.
As a matter of fact, as pilots,
665
00:43:08,827 --> 00:43:10,068
we know that
666
00:43:10,172 --> 00:43:11,827
certain airplanes are going
to leak more than others,
667
00:43:11,931 --> 00:43:13,655
and you've really got to
crank the pressurization up.
668
00:43:15,172 --> 00:43:17,551
After completing
the pressurization test,
669
00:43:17,655 --> 00:43:20,896
the ground engineer reports
that the jet is
in good working order.
670
00:43:24,931 --> 00:43:28,172
But the digital pressure control
is left in the manual position.
671
00:43:31,620 --> 00:43:38,689
They were supposed to return
the selector
to the auto position.
672
00:43:38,793 --> 00:43:42,551
If the flight crew fails to see
that the switch is on manual,
673
00:43:42,655 --> 00:43:45,310
their plane won't
properly pressurize.
674
00:43:45,413 --> 00:43:47,172
The oxygen available
inside the plane
675
00:43:47,275 --> 00:43:49,758
will be just as thin
as the outside atmosphere.
676
00:43:51,379 --> 00:43:53,551
The passengers will be
directly exposed
677
00:43:53,655 --> 00:43:56,862
to a deadly environment
in which they cannot survive.
678
00:44:05,137 --> 00:44:08,068
August the 14th, 2005.
679
00:44:08,172 --> 00:44:12,482
The worst airline disaster
in Greek history has stunned
the nation.
680
00:44:12,586 --> 00:44:15,310
Investigators are sifting
through the gruesome wreckage.
681
00:44:19,310 --> 00:44:21,448
A few minutes after 9:00 a.m.
682
00:44:21,551 --> 00:44:26,551
Helios Flight 522 left
from Cyprus bound for Athens.
683
00:44:26,655 --> 00:44:31,275
The crew has no idea
that hours before takeoff
during a maintenance test,
684
00:44:31,379 --> 00:44:34,689
a flight engineer has left
a pressurization switch set
to manual.
685
00:44:36,344 --> 00:44:38,827
Both the captain
and co-pilot miss the fact
686
00:44:38,931 --> 00:44:41,517
that the plane is not set
to pressurize automatically.
687
00:44:44,862 --> 00:44:48,655
As Helios 522 climbs,
an alarm blares in the cockpit.
688
00:44:51,275 --> 00:44:52,655
What is it?
689
00:44:54,034 --> 00:44:55,448
A takeoff config warning?
690
00:44:55,551 --> 00:44:58,034
It's
a non-pressurization warning.
691
00:44:58,137 --> 00:45:00,517
but it sounds identical
to another alarm.
692
00:45:01,413 --> 00:45:03,655
The pilots confuse the two.
693
00:45:03,758 --> 00:45:04,965
It's a critical mistake.
694
00:45:06,310 --> 00:45:07,137
The alarm sounded.
695
00:45:08,379 --> 00:45:10,172
And that alarm
was misinterpreted.
696
00:45:10,896 --> 00:45:12,206
Most of
697
00:45:12,310 --> 00:45:14,034
the flight crew,
they will never
698
00:45:14,965 --> 00:45:17,724
face an alarm
699
00:45:17,827 --> 00:45:19,517
with non-pressurization
700
00:45:19,620 --> 00:45:23,344
in all their flight career
because it's a rare event.
701
00:45:23,448 --> 00:45:27,000
Operations,
this is Flight 522, over.
702
00:45:27,103 --> 00:45:29,586
Flight 522,
what can I do for you?
703
00:45:29,689 --> 00:45:31,931
We have a takeoff
config warning on.
704
00:45:32,620 --> 00:45:33,896
Sorry, can you repeat?
705
00:45:34,000 --> 00:45:37,000
As the pilots troubleshoot
with ground engineers,
706
00:45:37,103 --> 00:45:40,172
life-sustaining oxygen is slowly
seeping out of the plane.
707
00:45:41,586 --> 00:45:43,965
Eventually, oxygen masks
drop in the cabin.
708
00:45:44,827 --> 00:45:46,310
They do not fall in the cockpit.
709
00:45:48,000 --> 00:45:49,724
The reason that we don't
have automatically
710
00:45:49,827 --> 00:45:51,931
deploying oxygen masks
in a cockpit is
711
00:45:52,034 --> 00:45:53,482
there's simply
too much up there.
712
00:45:53,586 --> 00:45:54,862
And if you have things
popping out,
713
00:45:54,965 --> 00:45:56,793
they're going to hit switches
that they shouldn't hit.
714
00:45:58,689 --> 00:46:02,482
The crew don't realize they have
a pressurization problem.
715
00:46:02,586 --> 00:46:06,931
Eventually, both the captain
and the co-pilot
collapse, unconscious.
716
00:46:07,034 --> 00:46:08,724
The oxygen is too thin
to breathe.
717
00:46:10,896 --> 00:46:11,965
We're the ones that
718
00:46:12,068 --> 00:46:14,620
should be trained
consistently to understand
719
00:46:14,724 --> 00:46:18,344
that the ears popping, anything
that indicates pressurization,
720
00:46:18,448 --> 00:46:21,379
you don't even talk
to each other before you grab
that mask and put it on.
721
00:46:24,931 --> 00:46:27,034
The passengers are unaware
that the plane
722
00:46:27,137 --> 00:46:28,586
is now flying itself.
723
00:46:31,241 --> 00:46:32,689
In emergency situations,
724
00:46:32,793 --> 00:46:35,586
chemical generators
above the seats pump out oxygen.
725
00:46:36,620 --> 00:46:38,206
But there's a catch.
726
00:46:38,310 --> 00:46:42,758
These generators only produce
enough oxygen for
about 12 minutes.
727
00:46:42,862 --> 00:46:45,655
Well, the problem
with the passenger masks is,
728
00:46:45,758 --> 00:46:49,344
for one thing,
they're not designed
to keep you oxygenated
729
00:46:49,448 --> 00:46:52,275
at a high altitude.
What they're designed to do,
730
00:46:52,379 --> 00:46:53,862
is give you enough oxygen,
731
00:46:53,965 --> 00:46:56,551
so that you can survive
until the pilots
732
00:46:56,655 --> 00:46:58,137
get the airplane down
to a low altitude.
733
00:46:59,793 --> 00:47:02,620
But with both pilots
already unconscious,
734
00:47:02,724 --> 00:47:06,620
the Helios jet did not descend
so passengers could breathe
without assistance.
735
00:47:09,862 --> 00:47:13,448
Instead, the plane flew
on autopilot to Athens.
736
00:47:13,551 --> 00:47:17,103
When the oxygen supply stopped,
the passengers passed out.
737
00:47:26,482 --> 00:47:29,586
By the time the Greek Airforce
intercepted the Helios jet,
738
00:47:29,689 --> 00:47:31,620
only one person was
still moving.
739
00:47:33,724 --> 00:47:35,965
Likely surviving
with bottled oxygen,
740
00:47:36,068 --> 00:47:38,000
flight attendant
Andreas Prodromou
741
00:47:38,103 --> 00:47:40,551
was still conscious
when the fighters approached.
742
00:47:40,655 --> 00:47:43,482
He made it to the cockpit,
but he couldn't save the plane.
743
00:47:44,862 --> 00:47:46,068
Athinai control.
744
00:47:46,172 --> 00:47:49,448
There is one person moving
in the cockpit
of Helios 522.
745
00:47:50,655 --> 00:47:53,482
Eventually,
when its fuel ran out,
746
00:47:53,586 --> 00:47:55,482
Helios 522 crashed.
747
00:48:01,689 --> 00:48:05,068
Investigators eventually find
the panel
with the pressurization switch.
748
00:48:08,586 --> 00:48:10,689
Are you sure
this is the way it was found?
749
00:48:10,793 --> 00:48:11,896
It hasn't been moved at all?
750
00:48:16,103 --> 00:48:19,724
All 121 people
on the Helios flight died
751
00:48:19,827 --> 00:48:24,482
because their plane didn't carry
enough life sustaining oxygen
as it climbed into the sky.
752
00:48:31,103 --> 00:48:35,586
It's been more than 50 years
since the beginning
of the passenger jet era,
753
00:48:35,689 --> 00:48:39,793
fifty years in which the
industry has learned,
sometimes painfully,
754
00:48:39,896 --> 00:48:43,862
how to safely fly
more than ten kilometers
in the sky.
755
00:48:43,965 --> 00:48:47,000
When you look back
at all the other accidents
over the last 20 years,
756
00:48:47,103 --> 00:48:50,206
in most cases, we were pushing
the frontier of knowledge.
757
00:48:50,310 --> 00:48:52,724
Unfortunately, when you're
pushing the envelope,
758
00:48:52,827 --> 00:48:55,000
you're pushing the boundaries
of design.
759
00:48:55,103 --> 00:48:59,379
You're going
to encounter problems
that you hadn't anticipated.
760
00:49:00,827 --> 00:49:02,965
In search
of the safest plane imaginable.
761
00:49:03,068 --> 00:49:05,620
The history of aviation
traces a flight path
762
00:49:05,724 --> 00:49:08,965
through tragic accidents
to technological breakthroughs.
763
00:49:09,068 --> 00:49:11,965
Many of these accidents
display the incredible power
764
00:49:12,068 --> 00:49:13,379
of explosive decompression.
765
00:49:16,551 --> 00:49:20,344
The Airbus A320 and every other
passenger plane built today
766
00:49:20,448 --> 00:49:24,068
is infinitely safer
than the first jets
that flew in the 1950s.
767
00:49:29,344 --> 00:49:33,103
They have to remain safe
and get even safer,
768
00:49:33,206 --> 00:49:37,620
because we rely so heavily
on this incredible mode
of transportation
769
00:49:37,724 --> 00:49:40,034
that takes us somewhere
we were never meant to be.