[Narrator] In a
high-rise building.
-There was no warning.
[Narrator] At sea.
-Innocent people died.
[Narrator] In a train.
-Everything was on fire.
Everything was burning.
[Narrator] Disasters can begin
with the smallest things.
-Changing the opening
hours of a restaurant.
-The bad glue job.
-A paperwork error.
[Narrator]
Now, combining the
latest research with every
available source of evidence,
experts will forensically
analyze three disasters
down to each tiny detail.
-You've really got to
think outside the box.
-You have to work your
way back and understand
each link in the chain.
[expl*si*n]
[Narrator] State-of-the-art
graphics reveal every critical
detail at every
critical moment.
-This whole disaster
could have been averted.
[Narrator]
We can dissect them.
Get inside.
Or underneath.
Freeze time.
And even reverse it.
To conduct a complete
Disaster autopsy.
Northeast Japan,
March 11th, 2011.
A massive magnitude
9.0 earthquake strikes
just 45 miles off the coast.
-This is the most powerful
earthquake ever to hit Japan.
It had actually shifted
the earth on its axis.
[Narrator] A giant tsunami
hits the coastline.
[Sascha Auerbach] The tsunami
is absolutely devastating.
Cars, boats, buildings,
people are swept away.
Over 18,000 people
lose their lives.
[Narrator But even then,
the disaster isn't over.
150 miles north of Tokyo is the
Fukushima Daiichi
Nuclear Power Plant.
-This earthquake is
an absolute disaster
for the nuclear
power plant.
[Narrator] Over the next
few days, huge explosions
erupt at Fukushima.
-Now, as the news
has come through
of another nuclear expl*si*n,
we're being moved indoors.
These are very
nervous times.
[Narrator] Four of the plant's
six nuclear reactors
are destroyed.
-Nuclear regulators give
the Fukushima disaster
a severity level of seven,
the highest possible rating,
and the same as the 1986
disaster at Chernobyl.
-Prime Minister Kan
calls for the immediate
evacuation of about 100,000
residents in the area.
They are left without
homes and deeply fearful.
[Narrator] Now, using
eyewitness testimony,
scientific analysis, and
photographic evidence
from inside the
devastated reactors,
we will recreate
the disaster.
What really happened
at Fukushima?
[helicopter whirring]
-It would be easy to point
the finger of blame here
at Mother Nature.
There was an earthquake.
But the thing is that Japan
has five nuclear power plants
located in roughly the
same stretch of coast.
And only Fukushima
became a disaster.
[Narrator] So there must be
more to this disaster
than just the earthquake.
What is so special
about Fukushima?
[Ada McVean] There
are ancillary buildings,
offices, workshops,
but the main structures at
the Fukushima plant are
six nuclear reactors spread
right along the coast.
[Narrator] Satellite images
taken three days after
the disaster show clear evidence
of expl*sive damage.
Two structures
are in ruins.
[Margaret Harris]
It's clear that these are
reactor buildings.
Reactor one is
clearly damaged.
Reactor three is
a smoking ruin.
[Narrator] This is the
core of the disaster.
So why do these reactor
buildings explode?
-Fukushima Daiichi has
boiling water reactors,
which basically means
that inside each unit,
there's a giant steel tank,
a pressure vessel.
And inside the
pressure vessel,
there is nuclear fuel.
And the nuclear
fuel heats water.
It becomes steam.
The steam spins turbines,
which generates electricity.
So the critical thing to
avoid is overheating.
Because the nuclear fuel
is constantly generating heat,
it actually has
to be cooled down.
And otherwise, if it gets
too hot, it will melt.
[Narrator] A core meltdown is
a nightmare scenario
that the plant is designed
to avoid at all costs.
-It's constantly having cold
water pumped around it
to remove the heat.
[Narrator] Plant data
records that after
the earthquake strikes,
automatic safety systems
shut down the reactors.
But pumping cooling
water remains essential
to remove the vast
amounts of residual heat
still being produced.
Data suggests this
is where things
begin to go wrong.
-When the earthquake happened,
Fukushima experienced
loss of power.
[Narrator] The crucial cooling
water is circulated
by electric pumps.
Without power,
they will stop.
-If the nuclear fuel
isn't constantly cooled,
you can get steam
building up and up and up
in the reaction vessel
until eventually it
becomes so pressurized
that it can literally burst,
releasing nuclear material
out into the atmosphere.
[Narrator] Do the reactor
vessels at Fukushima burst?
-After the incident, TEPCO,
the Tokyo Electric
Power Company,
which owns the plant, sends
camera-equipped robots
into the site to try to get
a survey of the damage.
[Narrator] They provide
vital evidence
from inside the
containment vessel.
-So looking at
the footage,
we see that the
containment vessels
are actually still
largely intact.
There's no evidence
of a steam expl*si*n.
[Narrator] It is clear
the reactor vessels
have not ruptured.
So what does cause the
devastating explosions?
Video evidence from
the robots reveals
another vital clue.
The nuclear fuel in
reactors one and three
has actually melted.
-Without pumps to
replenish the water,
the temperature inside
the reactor starts
rapidly rising to as high
as 5,000 degrees Fahrenheit.
This is not only hot
enough to melt the fuel
like the robotic footage
suggests happened,
but as well hot
enough for a very
dangerous reaction
to start happening.
[Narrator] Without
cooling circulation,
the water surrounding
the rods will
boil into steam,
and that creates
a whole new risk.
-The fuel rods are
coated in zirconium,
and that's important
because in the presence
of very hot steam,
zirconium undergoes
chemical reactions
that produce hydrogen.
[Narrator] Could the
Fukushima disaster
result from a
hydrogen expl*si*n?
Hydrogen is
famously expl*sive,
but only in the
presence of oxygen.
And there's none inside
the reactor vessel.
But plant records from
the morning after
the earthquake might
help explain what happens.
The pressure in reactor one
has been climbing,
but at 4 a.m., this
suddenly changes.
[Ada McVean] When they measure
the pressure in the reactor,
the pressure has
actually fallen since
the last reading, but
nobody's done anything
to relieve the pressure,
meaning that there
must be a leak.
[Narrator] This means that
before the first expl*si*n
in reactor one,
a pipe is leaking
the contents of
the reactor vessel
into the building
surrounding it.
-These ruptured pipes, they're
not just releasing steam.
They're also
releasing hydrogen.
[Narrator] And in the
reactor building, there is
plenty of oxygen.
-The hydrogen explodes,
damaging the reactor buildings
and leaking radioactive material
into the atmosphere.
[Narrator] It is clear
this disaster begins
with the loss of
electrical power
to the cooling pumps.
This causes a
core meltdown,
resulting in
hydrogen explosions.
But according to the
design plans of Fukushima,
losing electrical power
shouldn't be possible.
-There were a variety
of backup systems,
including diesel
generators and batteries,
to ensure that the
electricity supply
could be maintained,
even in the event
of a power outage.
[Narrator] But plant records
show that less than one hour
after the earthquake,
nearly all this backup
electrical power
has failed.
How can these separate
safety systems
fail simultaneously?
-So the plans of the
Fukushima reactor complex
show that the majority
of the power systems
were located in the
basement of the plants.
And this is for
a good reason.
They're there to protect them
from earthquakes, ironically.
[Narrator] A lot of
thought has gone into
designing a plant that
is earthquake-proof.
-When they built
the power plant,
the engineers artificially
lowered the ground
about 80 feet,
such that it could be
anchored into bedrock.
This makes the plant more
earthquake-resistant.
[Narrator] So the safety
systems were effectively
bolted to bedrock.
But for coastal installations
like Fukushima,
earthquake damage is
not the only risk.
-At 3:36 p.m. on March 11th,
a 50-foot-high wave
hit Japan's coast.
And this is just minutes
before the backup generators
and the batteries
all go down.
[Narrator] Ground level
at Fukushima ends up
just over 30 feet
above sea level.
And the backup systems
are in the basement.
So when the tsunami hits,
the basement is submerged,
destroying the emergency
electricity supply.
But tsunamis are a
well-known risk on
the Japanese coast.
Why isn't the
site protected?
[Narrator] The Fukushima
Nuclear Power Plant is
built on the coast
because it requires
lots of water for
cooling its reactors.
-The problem with
putting a nuclear reactor
on the Japanese coast
is that that coast
suffers extraordinarily
from tsunami waves.
[Narrator] Images pre-disaster
show that Fukushima
is built with
protective seawalls for
exactly this reason.
[Ada McVean] When TEPCO
was building the plant,
they looked into
the historic record
to see how high they
should build the seawalls
to resist tsunamis.
And they found that they
would need to build it
about 10 feet high
in order to resist
the big waves.
To be extra safe,
they actually added
another nine feet,
building the seawalls
up to 19 feet.
[Narrator] So why do
these seawalls fail?
[Andrew Steele] Oceanographic
data show two tsunamis
hitting the coast
on March the 11th.
The first at 3:27 p.m.
is 13 feet high and
is easily deflected
by the seawall.
[Narrator] This
photographic evidence
shows the second wave.
It is very different.
-10 minutes later,
the big one arrives.
It's three times higher
than Fukushima's seawalls.
And it overwhelms the
generators and the batteries.
[Narrator] Yet four other
nuclear plants along the
same coast avoid catastrophe.
[Sascha Auerbach] The
Onagawa Nuclear Power Plant,
which is about 75 miles
north of Fukushima,
was hit by a wave
of the same size,
but it survived
pretty much intact.
[Narrator] Why is it only
at Fukushima that
tsunami defenses fail?
-The designs for the
Fukushima seawall
were based on a
tsunami that hit Japan
in May 22nd, 1960,
about 10 years
before the plant
was built.
But that earthquake happened
off the coast of Chile,
and this is 10,000
miles from Japan.
So the tsunami wave,
by the time it arrived,
was only 10 feet high.
[Narrator] Unlike Fukushima,
the designers
of other plants,
like Onagawa,
read Japan's
centuries-long history
of tsunami records
in more detail.
[Sascha Auerbach] The designers
of Onagawa had looked
much farther back in
history for the design
basis of their seawalls.
Two tsunami that hit
the coast in 1611
and another one
that hit it in 869.
Both of those tsunami
waves were much larger
than the 1960 tsunami.
[Narrator] Because of that,
they build significantly
higher seawalls.
There is now enough
evidence to piece together
what happens in the
Fukushima Daiichi
nuclear disaster.
-At 2:46 p.m. on
March 11th, 2011,
a magnitude 9.0
earthquake hits Japan.
[Narrator] The earthquake
causes a loss of power
at Fukushima and triggers
an automatic shutdown.
Backup generators
kick in to keep
coolant circulating
around the reactor cores.
-At 3:36 p.m., a
50-foot-high tsunami
breaches the seawalls
around the plant,
which has been built
too low to protect it.
[Narrator] Seawater floods most
of the backup generators
and batteries located
in the basement
of the plant's buildings.
-Five of the six
reactors lose power.
[Narrator] Cooling water
stops circulating
around the active
reactor cores.
[Margaret Harris]
Without this cooling,
the cores continue
to heat and pressure grows
in the vessels
surrounding the cores.
[Narrator] Temperatures
rapidly climb,
melting the fuel rods.
Their zirconium coating
begins reacting
with the steam to
produce hydrogen.
-The highly flammable
and radioactively
contaminated hydrogen
gas leaks out of
reactors one and three.
[Narrator] The leaking
hydrogen explodes,
wrecking the
reactor buildings
and sh**ting
radioactive material
into the atmosphere.
It takes two weeks of hosing
seawater into the reactors
to stabilize them
after the meltdowns.
-The workers who stayed
behind risked their lives
to prevent an even
greater tragedy,
although a lot of damage
had already been done.
Over 100,000 people
were displaced
and giant swaths of
land were declared
uninhabitable
and unfarmable.
-In the months
following the disaster,
European leaders
decided on a new set
of safety standards
for nuclear power,
and several countries
decided to forego
nuclear power altogether.
[Narrator] The disaster may have
been triggered by
a natural event,
but it exposed
human errors in its design
that still haunt Japan.
-There are many parts
of the site that remain
inaccessible to humans.
It's simply too dangerous
for them to go.
[Narrator] Fukushima was
carefully designed
to avoid the explosions
that ultimately wreck it.
But some disasters
are caused by things
whose sole purpose
is to blow up.
North Vietnam,
Gulf of Tonkin,
July, 1967.
Anchored 100 miles
off the coast
is the American
super-carrier,
the USS Forrestal.
-We're talking about
an aircraft carrier
that is longer
than 1,000 feet.
[Narrator] It is designed
to project US power
anywhere in the world.
[Film Narrator] The vast hull
can accommodate 200 aircraft,
including an atom b*mber
capable of 700
miles an hour.
-The Forrestal was
making its first entry
into the Vietnam w*r.
Since arriving, she had
made her presence known
by launching wave after
wave of attack aircraft
from her four-acre
flight deck.
[Narrator] But on July the 29th
at 10:51 in the morning,
the rear of the flight
deck bursts into flames.
[expl*si*n]
Explosions rock
the giant ship.
Fires rage out
of control.
21 aircraft
are destroyed.
161 crew are injured.
134 are k*lled.
-This is an
unprecedented event.
The most powerful
military in the world
has just lost its most
effective weapons platform.
[Narrator] Now, combining
detailed photographic
and film evidence,
with eyewitness accounts
and naval reports,
[expl*si*n]
we will digitally
dissect the disaster.
What wrecks one of
the most powerful
warships ever built?
[Narrator] Using the
available evidence,
we can construct a
timeline of the disaster
on the USS Forrestal.
-The crew were preparing
for their second launch
of attack aircraft that day.
And the flight deck
was absolutely packed
with fully fueled aircraft,
two of which had
just taken off.
[Narrator] Surviving crew
members placed the start
of the fire at the rear
of the flight deck,
beneath two Skyhawk bombers,
flown by Lieutenant
Commander Fred White
and the future Senator and
Republican presidential
candidate, John McCain.
-Eyewitness accounts
suggest that
the fire started
after one of the
fuel tanks on the
two planes ruptured.
[Narrator] Survivor testimony
confirms that both planes
are about to start a
new bombing mission,
meaning they are armed
and their fuel tanks are full.
-Each Skyhawk can hold
400 gallons of fuel.
That means there are
now gallons and gallons
of burning jet fuel
on the flight deck.
And the flight deck
is crowded with
expl*sives and missiles,
and other fully fueled jets.
[Narrator] One of the most
vital sources of evidence
comes from the
ship's plat camera,
a manned camera
system used to record
landings and takeoffs.
It captures the entire
disaster on film.
-The operator misses
the start of the fire,
but does manage to
capture the crew
grabbing their gear and
racing off to fight
the conflagration.
[Narrator] 94 seconds
after fire breaks out,
there is an expl*si*n underneath
one of the Skyhawks.
Nine seconds later, a second,
more powerful expl*si*n
rocks the ship.
[expl*si*n]
-The expl*si*n
k*lled or maimed
several crew members,
including White,
who couldn't escape
his burning plane.
[Narrator] But the pattern
of fatalities recorded
in Naval records reveals
something striking.
Despite the ferocity
of the blasts,
only 28 of the 134 crew k*lled
are up on the flight deck.
Why are so many
k*lled below decks?
Photographic
evidence shows that
exploding bombs
create large holes
in the inch-and-three-quarter
thick steel flight deck.
And the deck has
hundreds of gallons
of burning jet fuel
from the crippled
Skyhawks running
across it.
-The gash in the
flight deck allows
the burning jet fuel
to flow down and
penetrate into
other decks,
causing new fires
and creating huge
volumes of toxic smoke
in confined spaces,
which is going to make
it very difficult
for people to escape.
[Narrator] Because the ship
operates 24 hours a day,
many crew are
not even awake.
-50 sailors died
whilst they were
sleeping in their beds.
[Narrator] In total,
106 people died below deck.
But the Forrestal
carries well-trained
and experienced
fire crews.
Why don't they get the
situation under control
before fire pours down
into the lower decks?
Magnifying the
flight deck footage
at the start of the fire
reveals a vital clue.
[Sascha Auerbach] The man
running towards the fire
carrying an extinguisher is
Chief Aviation Boatswain's mate,
Gerald Farrier.
He was head of the
damage control team
on the Forrestal.
[Rory Hadden] We can see
Farrier and his team
rushing towards the fire,
grabbing the foam
hoses as they go
in order to put the fire out.
[Sascha Auerbach] The footage
shows Farrier clearly
focusing his efforts
with the extinguisher
on one of the
1,000-pound bombs
that's fallen off
of the Skyhawk.
So he had identified what
the main threat was.
[Rory Hadden] Experts have
estimated it should
have taken Farrier
and his team around
three minutes to
extinguish the fire.
[Narrator] That would get
the situation rapidly
under control.
But just 94 seconds
after the fire starts,
the b*mb Farrier
is spraying explodes.
- The expl*si*n kills
Farrier and most of the
other experienced
firefighting crew.
[expl*si*n]
[Narrator] In an instant,
the Forrestal has lost
almost all its
trained firefighters.
The burning fuel now
pours down below decks
with fatal consequences.
Why didn't Farrier
realize the threat
from the bombs
and protect his
vital team by
pulling them back?
Any b*mb exposed to
fire or intense heat
has what is known
as a cook-off time.
This is the time it
takes for the heat
to cause an
unintended expl*si*n.
-Farrier and his team
had watched training footage
that demonstrated how
a 1,000-pound b*mb
could be directly exposed
to burning aviation fuel
for several minutes
before cooking off.
[Rory Hadden] The footage
Farrier and his team had watched
involved a Mark
83,000-pound b*mb.
It's quite a standard
b*mb for a Skyhawk.
These are bombs with
a relatively stable expl*sive
and a very thick
steel casing.
[Narrator] The training film
says that in a fire,
it will take at
least 10 minutes
for a Mark 83
to detonate.
So why does it explode
after just 94 seconds?
[Narrator] Clues to explain why
the 1,000-pound b*mb
on the USS Forrestal
blows up so quickly
with such lethal
consequences
can be found in the
ship's records.
-The day before, the
Forrestal had been
resupplied with
1,000-pound fat bombs,
so-called because of
their round shape.
[Narrator] According
to naval records,
some of these fat bombs
are over a decade old.
Their specifications
are quite different
to the bombs Farrier is
trained to deal with.
-So while the Mark 83
bombs had a cook-off time
of around 10 minutes,
these thinner-skinned fat bombs
had a much shorter
cook-off time of around
85 to 120 seconds.
[Narrator] It is one of these
fat bombs that kills Farrier
and much of his team.
It explodes 94 seconds
after the fire starts.
It takes the decimated
crew of the Forrestal
17 hours to finally
extinguish the Inferno.
This all explains
why the disaster
is ultimately
so devastating.
But what triggers this
lethal chain of events
in the first place?
Rewinding the plat
camera to the very start
provides a clue.
At this point, it
is filming in the
opposite direction
to the disaster.
[Sascha Auerbach]
Before the fire starts,
there's a flash on the film,
and this happens near
one of the planes
that is taking off.
[Narrator] At first glance,
it seems the plane
in the footage is firing,
but magnifying the footage
shows a curious anomaly.
-The figure in the
foreground actually
looks the other way.
[Narrator] What is
he looking at?
-Closer examination
reveals that this
flash on the film,
which is actually a
reflection on the window
that the camera is
filming through,
and that the origin
of that flash is
indeed the starboard
stern part of the ship.
[Narrator] The flash traces
back to an F-4B Phantom II
on the rear of
the flight deck.
It is pointing directly at
White and McCain's Skyhawks.
-The Phantom is armed,
amongst other things,
with LAU-10 underwing
rocket pods.
Each pod contains four
unguided five-inch
Zuni rockets.
[Narrator] The pilot,
Lieutenant Commander Bangert,
confirms it is one
of his Zuni rockets
that hits the
Skyhawks' fuel tanks.
-Bangert testified
that he had not fired
the m*ssile accidentally,
that all he had done
is powered up the plane's
electronic systems.
[Narrator] Launching a
m*ssile involves the pilot
pressing a button
on his joystick.
This sends an
electrical signal
to the underwing pod
to launch the Zuni.
But Bangert says
he never touches
the launch button.
All he does is switch
the electrical supply
from ship power
to plane power,
and the m*ssile
fires uncommanded.
Later investigation
of the F-4 Phantom
discovers a design flaw.
It can cause an
unintended power surge
during this switchover,
a power surge that
can activate the
m*ssile launch circuit.
[expl*si*n]
But an uncommanded
m*ssile launch
should still
be impossible.
-Power surges happen,
but there are several
safety measures in
place to ensure that
they don't result in
an accidental rocket launch.
[Narrator] A small pin inserted
into a triple ejector rack
under the wing physically
breaks the connection
to the m*ssile launching system.
With the pin in place,
a launch signal cannot
reach the m*ssile.
-According to
normal procedure,
that pin is only
supposed to be removed
when the plane is on
the launch catapult,
meaning if there was
an inadvertent rocket launch,
it would just fire
off into the ocean.
[Narrator] However,
Naval records reveal
that the Forrestal
has implemented
an unofficial procedure
to speed up takeoffs.
It involves removing
the pin earlier.
But even with
the pin removed,
a m*ssile launch should
still be impossible.
An electrical plug
called the pigtail
must be physically
inserted into the
m*ssile pod to arm it.
-The pigtail is only
supposed to be inserted
in the last moment before
the Phantom launches.
So between the
pin being removed
and the pigtail
being inserted,
it should be impossible
for the rocket
to launch accidentally.
[Narrator] But Naval records
show that the pigtail
procedure has also
been altered.
-It turns out that the
weapons coordination board
and the maintenance crew
on board the Forrestal
had changed the procedures
in order to save time.
They had been
inserting the pigtails
significantly before the
plane was ready to take off.
There are several
eyewitnesses who testified
that the pigtails
had been inserted
into Bangit's rocket pods
prior to the incident.
[Narrator] We are now
ready to bring all the pieces of
the disaster together
and reconstruct the entire
sequence of events.
[Narrator] The disaster
on the USS Forrestal
begins with a tiny
procedural change
to a m*ssile launch
system on a Phantom jet.
-The ship's committee
makes a decision
to insert the pigtails
significantly earlier
than the original safety
procedures dictated.
[Narrator] Evidence
strongly suggests
the pin on a
second safety system
has also been removed.
An electrical surge is
now able to trigger
the uncommanded launch
of a Zuni rocket.
The rocket hits two
Skyhawk bombers,
puncturing at least
one fuel tank.
-The ruptured fuel tank
spread gallons of fuel
onto the flight deck,
which is ignited by the
rocket's propellant.
[Narrator] The burning fuel
engulfs bombs dropped
by the Skyhawks.
[expl*si*n]
The bombs explode,
k*lling many of the
ship's firefighters
and blowing several large
holes in the flight deck.
Burning fuel floods
through the holes
into the lower
decks of the ship,
k*lling crew still
in their bunks.
It takes 17 hours
to fully bring the
fire under control.
134 people are k*lled.
-The Forrestal managed
to limp back to
safe harbor in Manila
before eventually
returning to the
United States,
where it's going to undergo
a $72 million refit.
-After the Forrestal disaster,
the safety procedures
around the Zuni
missiles were revised.
Old bombs were taken
out of service
and new bombs were
given more insulation
to protect them from
the heat of the fire.
[Narrator] The Forrestal
disaster begins with
not following the
designed procedures.
Procedural
errors can k*ll.
Even when they are far
from a b*ttlefield.
New York.
A city of soaring skyscrapers
and high-rises.
-Originally, you
have things like the
Empire State Building,
the Chrysler Building.
[Narrator] But New York is
a city of constant change.
[Sascha Auerbach] The skyline
is dominated by cranes,
which are constantly
renewing a city
that is ever-climbing upwards.
[Joshua Macabuag]
From the early 2000s,
there's a big boom
in residential buildings
being built by tower cranes.
[Narrator] On the corner of
East 51st and 2nd Avenue,
the construction of a
residential high-rise
is riding that boom.
But on March 15th, 2008,
the building's 179-ton
tower crane collapses.
[reporter] A crane
falling to the ground,
knocking down buildings,
crushing cars.
[Sascha Auerbach] The crane
crashes into an adjacent
building with the
giant boom and cabin
propelled across
another building
and landing on a house
on an adjacent street.
[Lester Holt] It crushed at
least one apartment building,
damaged others,
and sent people
running for their lives.
[Narrator] Heavy metalwork
plunges 200 feet
onto the New York streets.
[Sascha Auerbach] There were six
construction workers on the
crane mast when it fell.
Five were k*lled, and the sixth
was very seriously injured.
[Narrator] The operator and
a victim in the building
hit by the
crane also die.
24 people are
seriously injured.
-This was a huge crane,
and one eyewitness said
that when it landed,
it reminded him
of what happened when
the World Trade Centers
came down.
You know, dust and
debris everywhere.
[Narrator]
Using
eyewitness statements,
engineering reports,
and analysis of
the wreckage site,
we will digitally
dissect the disaster.
What causes this
lethal collapse?
The crane that
collapses is known as
a static tower crane.
[Joshua Macabuag]
A tower crane consists of
a single lattice mast,
a horizontal boom,
and the operator's cabin
just below that boom.
It's a static system,
meaning it doesn't move,
and it's actually
fixed to the building.
-The collars and
the tie beams
lock the crane
onto the building,
providing the lateral
support that it needs
to stay in place.
[Narrator] The bottom of the
crane is secured
to a concrete base.
-The crane legs sit on
two large steel beams.
Those beams spread the
weight of the crane
over two large reinforced
concrete walls.
So the base is
designed to take
the whole vertical
load of the crane.
[Narrator] But
photographic evidence
shows significant
damage to this base.
Could the entire disaster
be caused by a fault
in the crane's
foundations?
The feet of the
tower are displaced,
but the design of the base
is supposed to prevent this.
-The feet of the tower
are actually in pockets
on two steel beams,
which span between
reinforced
concrete walls.
[Narrator] These steel
pockets are designed
to stop the legs
moving sideways.
-When we look at the
foot of the tower
after the collapse, you
can see that the feet
have actually moved out
of those steel pockets,
and the foot of the
tower has actually moved
towards the building.
And that really
shouldn't happen.
[Narrator] Photographic
evidence suggests
the steel pockets
have not failed.
Instead, their edges
have been crushed.
One face is bent and
squashed inwards.
For this to happen,
the tower leg would
have to lean sideways
into the edge of
the stationary
pocket to crush it.
This means the pockets
and base don't fail.
The crush damage
is caused by the
tower above moving.
That should be impossible.
-The tower itself is
fixed to the building
with the connectors
at the third and ninth-floor.
[Narrator] Is there
something wrong
with the tower's ties
to the building?
To understand what
has happened,
we need to create a
timeline of the disaster.
Engineers confirm that
prior to the collapse,
the crane is bolted
to the building
at the third and ninth floors.
-The crane was involved
in the construction
of a 43-story
residential building
in Midtown East.
Construction had already
reached the 19th floor.
[Narrator] As the
building grows taller,
the crane has to
grow with it.
It is known as
jumping the crane.
-The jumping of the
crane is an incredible process
where you install a new
section of the tower.
[Narrator] We know from
survivors that at the
time of the collapse,
the six-man crane team
have just completed
raising the tower
by 54 feet.
They are working
up to 238 feet
above the
Manhattan streets.
-The latest segment
had extended the tower
as far as it could go
without fitting a new
tie to the building.
So the next job, once
they jumped the crane,
was to fit a new
collar and ties
on the 18th floor.
[Narrator] Evidence from
the crane operators
confirms the workers
are attaching this
18th floor collar at
the time of the collapse.
-The first sign that
anything was wrong
was when huge
pieces of metal
started crashing down
the side of the crane.
[Narrator] Photographic evidence
of the third-floor level
clearly identifies
what these huge
pieces of metal are.
The collars holding the
crane to the building.
-What we see there
is the collars
that belong to the
higher elevations
is sitting on top
of each other on
the third-floor.
[Joshua Macabuag] So you can
see that the ninth-floor collar
is sandwiched between
the third-floor
and the 18th floor collar,
which is what was
being installed
at the time of
the collapse.
[Narrator] How could both of
these massive collars fall?
[Narrator] Eyewitness
evidence confirms that
at the time of the 2008
New York crane collapse,
the collar on the
18th floor is being fitted.
-This is a huge
collar weighing
five-and-a-half-tons
in two pieces that
are connected
around the tower.
[Narrator] This key
photographic evidence
is taken just before
the collapse.
It shows heavy polyester
slings are temporarily
supporting the new
collar to the tower
until workers
connect it to the building
with steel beams.
-Before they could connect
the tie beams to the collar,
these slings snapped.
This meant that nothing
was really holding up
this five-and-a-half-ton
piece of metal.
[Narrator] Five-and-a-half-tons
of steel slides 100 feet
down the crane tower.
It slams into the
ninth-floor collar.
The force of the impact
rips the second collar
away from the building.
Both now plummet
down onto the
third-floor collar.
-The third-floor collar
doesn't completely
break away from its connections,
so that's why the third, ninth,
and 18th floor collars
remain at that point.
-There are now huge,
unbalanced loads
on the tower.
-There is a permanent
42-ton counterweight
on the back of the boom.
That allows it to lift
much heavier weights.
-The counterweight
creates a huge imbalance.
-And that's exactly why
the tower is connected
to the building to
counteract that.
[Narrator] After
the collars fall,
the crane is only
connected at one point,
the third-floor.
Above, 16 stories of
unsupported tower
are being pulled away
from the building
by the immense
counterweight
on the boom.
-The crane tower was
moved away from the building
by the weight that
is sitting on top.
And it pivoted on one
remaining connection
that is on the
third-floor collar.
[Narrator] The leverage of the
42-ton counterweight
over 16 stories
above is immense.
-This created enough
force for the legs
to pop from
their pockets.
[Narrator] Once that happens,
the crane is doomed.
The disaster is
triggered by the failure
of the polyester slings
holding the collar
on the 18th floor.
How can these
have snapped?
-The crane manufacturer provides
very precise instructions
on how to lift the collars
to prevent any potential errors.
[Narrator] Each half of
the collar has six lugs.
Two are for
lifting the collar
and four are for securing
it to the tower.
It is critical that
the correct ones are
used for each job.
-What should happen is that
the two halves of the
collars should be lifted
by lifting lugs
specified at the
corners of the collars,
and then secured thereafter
using the lugs in the
center of the collars.
[Narrator] This allows
the securing slings
to be tied to smooth
supporting bars
on the tower,
designed for
that purpose,
while the collar is
secured to the building.
But according to the evidence,
this does not happen.
-You can see from a
photo taken an hour
before the collapse that
one of those halves
is actually being lifted
by the central connections,
not the lifting
lugs at the corners.
[Narrator] It sounds like
a trivial change,
but the consequence is
that the crane team
secure the collar
to the tower
on the available
lugs at the corners.
Now, the securing
slings cannot be fitted
around the correct
smooth bars.
-They improvised and
just connected the collar
to the tower at those
corner positions.
[Narrator] This improvisation
creates critical problems.
-The first is that
there's only positions
to fix the collar
with four slings,
as opposed to the eight
specified in the instructions.
[Narrator] The collar is now
held in place 180 feet
above the New York streets
by half the correct
number of slings.
And that's not
the only error.
-By connecting to the corners,
they're being forced into
sharp V-shaped grooves,
which brings them
into risk of cutting
at the sharp edge.
So you have fewer slings
under a lot of stress
being stressed
over a sharp edge
that gave them a
risk of being cut.
[Narrator] Not only are
there half the correct
number of slings,
but they are secured in
a way that makes them
vulnerable to failure.
We can now piece
together the evidence
of the 2008 Manhattan
crane disaster
to identify exactly
what happens.
[Joshua Macabuag] The first
in a series of errors
that led to the
disaster is the lifting
of those collars by
the wrong sets of fittings.
[Narrator] This prevents the
crane's five riggers
200 feet up in the air,
securing the collar correctly.
So they improvise.
They secure it using
half the correct number
of polyester slings.
They loop these
weakened slings
around V-shaped
grooves on the
corners of the crane.
These pinch the
slings and increase
the strain on them.
Before the riggers can attach
the collar to the building,
the polyester slings snap.
The five-and-a-half-ton collar
falls 100 feet down
the crane mast.
It smashes into the
collar on the ninth floor,
tearing it away
from the building.
The crane is now
attached to the building
by a single connection
at the third floor.
-At that point, we have
our 42-ton counterweight
at the top of the tower,
pulling the tower away.
[Narrator] The one remaining
connection on the
third-floor collar
acts as a pivot point.
The legs of the
tower dislodge
from their
supporting pockets.
The 238-foot crane
falls into the
adjacent building.
Seven people die
in the accident.
-The 2008 crane disaster
prompted New York
to change its regulations
with regards to
the safety of
crane operation.
Now, anyone
involved in that
has to take a 30-hour
training course
with refreshers
every three years.
[Narrator] The legislation
also limits the use
of the synthetic slings,
like the ones that snap.
So hopefully, no one
else will die again
in this kind of disaster.
Welcome to our World! Where we serve you cookies to ensure you get the best viewing experience on our site.
Did you know that you can remove censorship board-wide, use our advanced search functions, be notified when new content is posted, join our memberships, set episodes to show in any order you want & more if you are logged into your account?
Register or sign in here: ucp.php?mode=register
Did you know that you can remove censorship board-wide, use our advanced search functions, be notified when new content is posted, join our memberships, set episodes to show in any order you want & more if you are logged into your account?
Register or sign in here: ucp.php?mode=register
01x07 - Fukushima, Manhattan Crane, Forrestal
Watch/Buy Amazon
Expert analysis recreates real-world disasters in 3D graphics to uncover hidden causes like paperwork errors, bad glue jobs, or changed restaurant hours.
Expert analysis recreates real-world disasters in 3D graphics to uncover hidden causes like paperwork errors, bad glue jobs, or changed restaurant hours.