April 6, 2004
Narrator: This plane is
about to take part in a dangerous experiment. The pilot
will attempt to crash it into the ground. He sets his
course and then releases the controls.
Plane: Pull up, pull up.
Narrator: As danger approaches, the plane sounds
an urgent alarm. The pilot does nothing.
Plane: Pull up, pull up.
Narrator: Seconds to impact. The plane is about
to strike the ridge. With the pilot still doing nothing,
the plane decides to act. Disaster is averted at the
last second, thanks to a new invention called the
Assisted Recovery System. For the moment, it is
controlled from a laptop in the back of the plane. But
when installed, the device will automatically help
prevent the most common cause of air accidents --
Controlled Flight into Terrain. In other words, a pilot
crashing a plane into the ground.
This technology has been put on the development fast
track. For if it can prevent planes from crashing into
the ground, it could also stop terrorists from flying
them into buildings ...
Markus A. Johnson: What I have in the computer here
is a digital map of the whole world. That map contains
terrain information -- mountains -- and very tall
obstructions such as television towers, even the Eiffel
tower, are all in this computer. We know exactly where
we are by use of Global Positioning System. If the
system predicts that we're going to have a potential
collision with a mountain, or a potential penetration of
restricted airspace, then it will first sound an alert
to the pilot. If the pilot does nothing for the next few
seconds then the computer will take over and control the
airplane. It will make a climb and a turn away from the
obstruction or the airspace.
Narrator: The Assisted Recovery System was
introduced days after 9/11. In the new world of aviation
undermined by fears of terrorism, it has become a high
priority technology. It's a typical example of the way
the aviation industry often works. For cold as it may
sound, disaster can be the lifeblood of change.
Every year, some 800 people will die in air crashes.
This plane came in for landing much too fast and shot
off the end of the runway. The passengers and crew
survived, but many others are not so lucky. Sadly, it is
often the most terrifying crashes that lead to the
biggest and quickest advances. Cynics call this
"tombstone technology" -- when major disasters focus our
attention and force us to make changes.
Christine Negroni: I think you can argue that making
air safety changes dependent on how many people die, is
a cold and calculating and generally unseemly way to
make decisions. But it is what it is, it is the way
industry does things, and I think it's, it flies in the
face of everything we know about human nature and
reality, to suggest it could be done any other way.
Narrator: When it comes to air safety, the higher
profile an accident is, the more likely it is to cause
public outcry for investigation and change. And what
could be more high profile than a daytime crash in the
skies above a major city like Los Angeles?
In August 1986, a middle aged man filed a flight plan at
his local airfield in Torrance, California. He was
taking some friends to a resort in the mountains east of
LA. Like many light aircraft pilots at the time, he
would navigate by following the freeways. But what seems
simple enough to negotiate down here, can be much more
confusing from the sky. Even for experienced pilots.
Crash investigator Greg Feith has traced the Piper's
route. It seems the pilot followed the wrong freeway.
Instead of heading South to Long Beach on the 405, as
his flight plan dictated, he went east on 91 -- a
freeway that runs directly under the approach lanes to
LAX.
Greg Feith: He didn't tell the controllers he was
there ‘cause he didn't know he was there.
Narrator: The first air traffic controllers knew
of his presence, was when a small blip appeared on their
screens. The blip came from the Piper's transponder, a
device that radios a plane's position to Air Traffic
Control. But the transponder was a basic model, and did
not give the plane's altitude. The controller had no way
of knowing that the Piper was climbing directly into the
approach path of incoming commercial jets.
Flying in from Tijuana that day was an AeroMexico DC-9.
As the Piper continued to climb, the DC-9 descended on a
collision course at a hundred and ninety miles an hour
...
Greg Feith: As the Piper flew up in front of the
DC-9, the AeroMexico pilot only had time to say "No this
can't be" before the tail-plane struck the Piper Archer,
decapitating both the pilot and his passengers.
Narrator: A press photographer happened to look
up when the planes collided, and fired off a shot as the
DC-9 plummeted to the ground. The debris tore into the
Los Angeles neighborhood of Cerritos. All 64 people on
the DC-9, three aboard the Piper, and fifteen on the
ground perished. The final death toll was 82.
After the accident, investigators determined that the
AeroMexico pilots should have had the small plane in
view for almost two minutes. It was a clear day with 14
miles visibility. So why didn't the pilots see the
Piper?
Greg Feith: Well, this is what it's like as we
approach a big city, looking down from the cockpit. In
fact it's even more difficult for an airline pilot
because he can't get as close to the windscreen as I
can. It's just very, very difficult to see anything
against the background of a big city.
Narrator: An MIT study in the 1980's tested
pilots' abilities to spot another aircraft in flight.
Only 56 percent of the time did they see the other
plane, and when they did, it was usually at the last
minute. The human eye just isn't very good at judging
whether another plane is heading up, down, or straight
ahead. But there is a better way to avoid collisions,
although until the AeroMexico crash, its introduction
had been resisted.
Greg Feith: One of the issues that typically evolves
out of every accident investigation is the fact that
there was either technology or equipment that was
available that could have prevented the accident.
Unfortunately someone somewhere has determined, either
because it was too expensive or unnecessary, it wasn't
installed on the airplane.
Narrator: This equipment is called TCAS, which
stands for Traffic Collision Avoidance System.
Traditional transponders tell air traffic controllers
where planes are by radioing the aircraft's position to
the nearest tower. But what if other aircraft could also
hear these signals? Then they too would know who was
approaching their air space.
Ron Crotty: The TCAS system includes a radio
transmitter which periodically sends out a signal to all
of the other airplanes within 40 miles of our airplane,
and it causes their transponders to send a signal back
to us. Now the computer in the TCAS can figure out how
far away those airplanes are, based on how long it takes
for that signal to come back, and because it uses a
directional antennae, it knows what direction they are,
and their signal includes their altitude. So based on
that, the computer can then project forward their flight
path to see if it's going to conflict with our airplane,
and if it provides a threat, then it'll sound an alarm
for our pilot.
Narrator: TCAS depicts other aircraft as diamonds
on the pilot's radar screen. If one gets too close, the
system flashes a warning in both cockpits.
Plane: Traffic, traffic
Pilot: Ok, that's a traffic advisory. The simple
changes to a yellow circle, and that's telling us that
we have a threat, and he's very close to us, within 30
to 40 seconds, and we should be looking out the window,
and being prepared to avoid him.
Narrator: 25 seconds to impact. If the pilot
ignores the warning, TCAS gets more insistent.
Plane: Descend. Descend now. Descend. Descend now.
Narrator: The plane descends and the danger
passes narrowly overhead. TCAS has been described as
"the best traffic alert you ever got in your life."
Plane: Clear of conflict. Clear of conflict.
Narrator: The AeroMexico crash over L.A. provoked
an outcry about aviation safety. Within a year, Congress
ordered the use of TCAS on all civil airliners. Since
then, not a single mid-air collision of commercial
planes has occurred in the United States.
But why was a major crash required to force the adoption
of TCAS? Cost was an issue, and pilots said it was
unreliable. And there is always a concern about what new
problems, changes might cause.
Greg Feith: In 2002, a Russian airliner carrying kids
on holiday to Spain was entering into Swiss air space. A
controller all by himself in the Zurich center was
monitoring two radar screens. His colleague was on
break. The controller identified the Russian aircraft on
one radar screen, and an American freighter on a second.
He determined that there was an impending collision. He
warned the Russian pilot to descend.
Plane: Traffic, traffic.
Narrator: At that very moment, a TCAS alert
sounded in the Russian cockpit.
Plane: Climb, climb.
Narrator: The Russian pilots were thrown into
confusion. The machine said one thing, the controller
another. They didn't know which instructions to follow.
Greg Feith: The Captain got into a debate for about
30 seconds and decided to follow the controller's
instruction and descend.
Narrator: But what he didn't know is that the
American plane had received a TCAS warning as well.
Plane: Descend now. Descend. Descend now.
Greg Feith: 71 people died that day, most of them
kids. The point - the technology worked, the human
didn't.
Narrator: The accident was an illustration of the
challenges of change. Western pilots had been trained to
always follow TCAS, but in the rest of the world, the
decision was left up to the pilots. Now, all pilots are
given the same instructions: Obey TCAS at all times.
Almost every major advance in air safety has come as a
result of an accident. "Tombstone technology" was even
responsible for what has been called the greatest safety
invention of all time -- the Black Box, which records
the pilots communications and other crucial details from
the plane during flight.
The Black Box was invented in the 1950's, in response to
a number of unexplained crashes. But the pilots' unions
resisted it, claiming it was a "spy" in the cockpit. 12
years passed before it was finally adopted, with
dramatic results.
Pilot: We're going down ...
Narrator: To survive a crash, the Black Box must
be able to withstand impacts of thirty-four hundred G's.
It gets tested for collisions ... And in fires of up to
eleven hundred degrees Celsius. The data it records
comes from up to 300 different areas of the plane, and
in its 40 years of use, it has revealed the causes of
thousands of accidents.
But the Black Box has its limitations, and crash
investigators often have to find other ways to determine
the cause of an accident. Greg Feith is a retired member
of America's ever-ready go-team, the National
Transportation Safety Board's elite group of air-crash
detectives. Two of their recent investigations required
more information than the Black Boxes could provide.
Greg Feith: Showtim.e
Narrator: In 1997, Greg was called to Indonesia
to assist local authorities with the investigation of a
SilkAir Boeing 737 that had plunged into a river,
killing all 104 people aboard.
Investigator: Welcome to SilkAir.
Narrator: The plane crashed with such force, it
shredded the debris into tiny pieces. The Black Box
survived, but it could not confirm the cause of the
accident.
Greg Feith: It was an intentional act of suicide. The
captain himself had personal problems, he had some
financial difficulties, his career situation had changed
at SilkAir -- we were able to determine that all of
these factors culminated in him making the decision to
intentionally crash this airplane.
Narrator: Greg believes the captain had
deliberately put the plane into a nosedive. But the
Indonesian authorities were not prepared to accept that
one of their pilots had knowingly killed so many people.
They said the evidence did not rule out a mechanical
malfunction. Then in 1999, a carbon copy -- this time
off the US coast. An EgyptAir 767 crashed into the ocean
near Nantucket, killing all 217 people aboard.
Greg Feith: There was a struggle or fight in the
cockpit for control of the aircraft. One pilot tried to
push forward on the control yoke while another pilot was
pulling back. We found that evidence on the flight data
recorder, so we knew basically what was occurring in the
cockpit. We didn't really understand why. In the long
run, we were able to rule that it was an intentional
act, rather than an accident. However, as in the SilkAir
investigation, the Egyptians didn't want to accept that
position.
Narrator: The NTSB felt sure that both of these
crashes were intentional. But without being able to see
into the cockpit, they had no definitive proof. Now, one
company is making such vision a reality. They have
embedded 50 tiny cameras into the most sensitive areas
of a plane, including the cockpit. The cameras were
originally designed for keyhole surgery, and can focus
on anything from a quarter of an inch away to infinity.
With these monitoring the cockpit, every action a pilot
makes would be stored in the Black Box. Most likely,
they would have revealed exactly what took place aboard
the SilkAir and EgyptAir flights. But will they ever be
fitted?
Greg Feith: There are groups out there, pilot unions
especially, that we saw with the cockpit voice recorder,
who are averse to putting cameras in the cockpit. One,
because of disciplinary issues, two, because of privacy
issues. But the fact is, it's a tool that can benefit
not only the investigator but aviation safety.
Narrator: Cameras aboard planes could have many
benefits, and could reveal potential problems before
they get out of hand. Take landing, for example. On
approach, pilots cannot actually see whether the landing
gear, brakes and flaps are working. They rely on warning
lights, which, like anything electric, can be faulty.
But what if the pilots could see for themselves whether
there is a real problem, or just a faulty light? The
flaps are ok. False Alarm.
Jim Neill: (Vision Technologies) It gives the pilots
the advantage to look at flight surfaces, wings, inside
the landing-gear location, so that they could verify
that their landing-gear was down, on the rudders so
they'd have an overview of the aircraft. At the same
time, we have the ability to transmit those images off
the aircraft to a ground location. In the event that
there is an incident with an aircraft they could have
some consultations from an engineering team on the
ground.
Narrator: The cameras are currently being tested
by the FAA. The process is slow -- approvals normally
take about two years. But there is one additional
benefit that may get them a special look.
Jim Neill: One of the primary functions is to
counteract terrorism and to deal with air rage, drunken
passengers. It gives the pilots the ability to monitor
at any time what's going on through the cabin.
Narrator: It seems certain that miniature cameras
will eventually be approved, despite pilots'
reservations. But there is another device currently
being tested, that pilots are welcoming with open arms.
It is already saving lives in some of the most dangerous
skies in the world.
Alaska is sometimes called the Last Frontier, and not
without reason. It's a beautiful but harsh landscape
that challenges human survival. In Bethel, West Alaska,
midwinter means darkness twenty hours out of every
twenty four. With hardly any roads or railways, towns
and villages are isolated by hundreds of miles of ice
and mountains.
But Alaskans have found a way to get around. While the
rest of us jump into cars, they hop into planes.
Aircraft take them everywhere. Alaska gives new meaning
to the term "fast food." This is truly ... pizza to go.
John Hallinan: Beans, bacon, shotgun shells,
shingles, everything moves in an airplane. If you live
in a place like Tuntatuliac or Quethloc, if you have a
toothache, you will end up getting on an airplane going
to Bethel to seek medical assistance. Down near King
Salmon there's actually two villages divided by a river.
It's maybe a mile and a half from one to another. Kids
will actually fly to school in the morning and fly
home in the evening.
Narrator: Each day, hundreds of planes take off
into the frigid mountain air. It is a recipe for
disaster, and until recently, thirteen percent of
Alaska's pilots were destined to die in crashes.
John Hallinan: If something didn't hit the ground
yesterday, it would today. Statistically on average
during the 90's, we would end up killing somebody every
nine days.
Narrator: Small planes crash here, because the
mountains are so high that pilots are forced to fly
between them. Radar, which sends radio waves from
control towers to aircraft, can't penetrate the
mountains. Controllers can't see the planes, so the
pilots are essentially flying blind.
Alarmed by the high death rate, the FAA stepped in with
a unique experiment called the Capstone Project. Two
hundred aircraft have been fitted with a device called
ADSB -- Automatic Dependant Surveillance Broadcast.
Skip Nelson: ADSB has been called the greatest
advance in air traffic control technology since the
introduction of radar more than fifty years ago.
Narrator: ADSB relies on satellites hovering
thousands of miles above the earth. Radio waves can now
bounce back and forth from the planes without being
blocked by the mountains. First the plane uses GPS to
establish its exact location. Then, it sends that
information, plus the call sign, speed, altitude,
heading, and even the number of people aboard, to the
ADSB satellite.
The data then gets relayed to all other ADSB equipped
planes within a 200 mile radius. The result is like an
advanced incarnation of TCAS. Pilots see other planes on
the screen, and can tell if they represent a threat. The
flip of a switch, calls up another display that shows
the whereabouts of nearby mountains and other
obstructions.
J.R. Ignatius: It's like a video game. It's so cool.
You're able to give your precise location, your air
speed, your altitude, and send it up to the satellite,
and everybody that's ADSB equipped can receive that
data, and know exactly where I'm at in relation to them,
or vice versa. When I flip through the terrain map,
green is obviously good, green is go, yellow is a
caution, and red terrain means if I continue towards red
terrain I won't be able to fly over that, and my
altitude is such that I'm too low.
Narrator: ADSB has already resulted in a 25
percent cut in Alaskan air accidents, even though it has
only been fitted to 200 light aircraft. But it has also
provided a glimpse into a future of Free Flight that
until now, pilots have only dreamed about. At the
moment, commercial planes must follow strict air lanes,
under supervision from air traffic controllers. But Free
Flight does away with the restrictions, and lets pilots
plot more direct routes that save time and fuel.
Skip Nelson: It'll be much like driving a car. You
can fly from A to B, joining other traffic, taking your
relative position from them, the car next to you, the
car ahead of you. And then exit the system all by itself
without the intervention of ground controllers.
Narrator: The tests at this tiny Alaskan airstrip
could one day be expanded to all the world's major
airports.
Skip Nelson: ADSB is the first step in that sort of
flying independence that we all hope to have some day.
Narrator: But first, it must meet the approval of
the FAA -- the world's most powerful regulator of
aviation technology and protocols. The FAA rigorously
tests all new safety devices before certifying or
rejecting them. It is a painstaking process that can
take many frustrating years, but it's designed to ensure
that the consequences of new technologies are clear
before they are installed.
Once an item is certified, it goes through more tests
before it can be made mandatory. Often, a major crash is
needed to force a final decision. At the heart of the
FAA's assessment is a mathematical equation called
Cost-Benefit -- whether the expense of an equipment
upgrade is greater or less than the cost of a crash.
Christine Negroni: The cost is how much it's going to
cost to install this device, how much it's going to cost
to do different maintenance, you know, whatever it is
it's going to cost the industry to do it.
Narrator: Increases are often passed on to
passengers as raised ticket prices, but there is also
another side to the coin. The Benefit -- the number of
people who will be saved if the new device is installed.
Christine Negroni: The benefit is how many people
have died from this problem, at the price per fatality
being somewhere in the neighborhood of two and a half
million dollars per person. And you do the math, how
many people died? Multiply that by two and a half
million dollars, and then you come up with the benefit.
If it's going to be more than two million dollars means
more than one person has to die, any twenty million
dollar change is going to mean ten people have to die.
That's Cost-Benefit analysis, how many people died, how
much is it going to cost to fix the problem?
Narrator: Calculating an average payout for a
death at $2.5 million, the industry must weigh whether
it makes economic sense to fix a problem. Take for
example, windshear -- a sudden and unexpected change in
wind direction. The shift can be deadly during take off
and landing. Many accidents originally blamed on pilot
error, are now thought to have been caused by this
potentially deadly phenomenon.
When windshear conditions approach an airport, as they
often do here in Denver, controllers prepare to quickly
shut things down. But in August of 1985, aircraft were
still landing at the Dallas-Fort Worth Airport in Texas,
as the weather deteriorated. On approach was a Delta
Airlines Tristar -- Flight 191.
Pilot: There's lightning coming out of that one.
Narrator: This NASA animation shows what happened
as the plane tried to land.
Pilot: Push it up, push it way up. Way up, way up...
Narrator: The plane touched down briefly in a
field, engines screaming at full power. It then careened
across a freeway, bouncing down onto a small car,
killing the driver. Still traveling at high speed, it
entered the airfield and veered towards two
4-million-gallon water tanks.
The plane hit the tanks with such force, it lifted them
off their foundations. Including the driver of the car,
one hundred and thirty seven people died. Only thirty
one survived. When investigators looked into the crash,
they found that Delta 191 had been hit by a deadly form
of windshear, called a microburst.
Greg Feith: A microburst has been likened to a high
pressure air hose pointed at the ground. As the air
comes down it'll spread out near the ground.
Narrator: Initially, a microburst gives a plane
extra lift, causing pilots to decrease power as they
prepare to land. But as the plane flies farther in, the
situation reverses, and the plane needs more power to
stay aloft.
Greg Feith: By the time the power is increased by the
pilot it's usually too late because the airplane is so
low that it flies into the ground.
Charlie Phipps: We're losing some air speed.
The tailwind -- Yes, we got a tailwind now, a strong
tailwind. Oh yes.
Narrator: Charlie Phipps -- a Delta Airlines
training instructor -- flies the approach into
Dallas-Forth Worth. His simulator has been programmed
with the exact conditions Flight 191 had encountered
that day.
Charlie Phipps: Wow, look at the tailwind. We've got
a heck of a tailwind here. Oh my god. Come on, come on
airplane. Come on, come on... Come on, fly baby, come
on, come on baby, you can make it. You can make it. Come
on. Come on, come on...
Plane: Windshear, windshear.
Greg Feith: That was the worst windshear accident
ever. Microburst and windshear can happen anywhere in
the world. Here in Denver because of the climate and
those Rocky Mountains, it's become known as the
windshear capital of the world. We nearly lost five
airplanes in one afternoon.
Narrator: After the Dallas crash, urgent research
was carried out to enhance windshear detection. The
results can be seen in the form of giant golf balls
situated at all of America's vulnerable airports. It's
called Terminal Doppler Weather Radar.
This dish is sending out a pencil-thin beam of radar
that interacts with moisture and dust particles in the
air. It can measure changes in wind direction and speed
-- both signs of impending windshear. When dangerous
conditions are observed, the device relays a warning to
air traffic control.
Greg Feith: One of these costs about five million
dollars. We have 43 vulnerable airports here in the
United States. When you multiply that times five, it
works out to be about 215 million. You have to contrast
that against one accident. If we use for example, the
Dallas accident, where we lost 137 people, and you
multiply that times 2.5 million dollars, which the
insurance company would typically pay out, that of
course is well over 300 million dollars.
Narrator: The Dallas crash cost the industry more
than all 43 of these towers. And experts predicted that
without a warning system, similar accidents would occur
every few years. So the Doppler radar got installed.
Greg Feith: The Cost-Benefit is immense. Since 1990,
when the FAA started to install TDWR, we haven't had a
commercial aviation accident attributed to windshear
here in the United States. That in and of itself is the
best thing the FAA has done in the last century.
Narrator: But sometimes, the equation provides
different results. Cost-Benefit analysis can save lives,
but it can also allow disasters that could have been
prevented. One hot summer evening in July of 1996, a TWA
747 bound for Paris was waiting on the tarmac at Kennedy
Airport, in New York. On board were two hundred and
twelve passengers, many of them teenagers heading off to
France on a school trip.
A problem with missing luggage delayed the plane, and
the pilot had to run the air conditioning on high to
keep the passengers cool. TWA 800 eventually took off an
hour late, and headed northeast along the coast of Long
Island. As it climbed into the evening sky, the 747
approached another jet belonging to Eastwind Airlines.
Suddenly, the Eastwind pilot saw a flash out his cockpit
window.
Pilot: We just saw an explosion out here, Stinger Bee
507.
Controller: Stinger Bee 507, I'm sorry I missed it,
you're out of 18. Did you say something else?
Pilot: We just saw an explosion up ahead of us here,
somewhere about 16,000 feet or something like that, it
just went down in the water.
Controller: Virgin 009, I'm sorry your transmission
is broken up.
Controller: ... sardi kennedy 92 another handoff
please.
Controller: Center TWA 800, if you hear Center ident.
Controller: TWA 800, if you hear Center, ident.
Controller: TWA 800, Center.
Pilot: I think that was him.
Control: I think so.
Pilot: ... God Bless ‘em.
Narrator: TWA 800 had gone down with all two
hundred and thirty people on board. The crash happened
on the eve of the Atlanta Olympics. The FBI immediately
suspected an act of terrorism, and took over the
investigation. First reports indicated a possible
missile attack or a bomb.
But while the FBI searched fruitlessly for evidence of
terrorism, the NTSB patiently began putting TWA 800 back
together, as wreckage was recovered from the seabed. It
was a morbid million-piece puzzle.
Joe Lychner: For us as family members- we're looking
at each of those windows and we're thinking about our
loved one who was sitting on the opposite side of that
window and you roll through your mind what they must
have experienced when that plane fell apart ... it's
terrifying.
Narrator: Each piece of wreckage was analyzed as
it came ashore. On one piece, investigator Bob Swaim
noticed something unusual that would alter the course of
the entire investigation.
Bob Swaim: It was odd because airplanes are a
collection of curves and rounded shapes but this was
straight and it was quite long for an airplane, so we
started looking at it in greater depth and it turned out
that it had molten aluminum on the edges and it was
blackened all over, it was sooted.
Narrator: A part number stenciled on the twisted
metal revealed that it came from the center wing tank,
which sits right in the middle of the plane. It's a
large steel box, about as big as a two-car garage. The
part was one of the reinforcing beams that should have
been inside the tank. But the beam had been blown out,
and it was burned. To the NTSB, the evidence was
unmistakable. There had to have been an explosion inside
the fuel tank.
Greg Feith: The airplane had been sitting on the
tarmac for several hours with the air conditioner packs
running. The heat from those packs had to go somewhere,
so as it rose it heated up the fuel tank above it.
Narrator: The flight to Paris was short for a
747, so the fuel tanks had not been full. The center
wing tank, with a capacity of twelve thousand gallons,
was virtually empty -- it held only fifty. As the tank
grew hotter, the fuel turned to vapor.
Greg Feith: Now that in and of itself wasn't a
dangerous situation, because of the large volume of
fresh air that was in that tank. The fact that there was
enough fresh air to dissipate the fuel vapor didn't make
it an explosive situation. The danger really didn't come
until the airplane took off. As the airplane ascended
and the outside air pressure decreased, bleeder valves
in the fuel tank started to draw that fresh air out. So
now you had a decrease in fresh air and an increase in
fuel vapor. All you needed now was a spark to fire off
that explosive combination.
Narrator: But where could a spark come from?
Cables connected to the fuel gauges run into the tank,
but they only carry tiny voltages -- not enough to
generate a spark. Surrounding them outside the tank
however, are 170 miles of other wires. In a 25 year-old
plane like this one, some of these could have been
corroded, causing electricity to arc, or jump from one
wire to another.
Bob Swaim: We have, as we counted, close to four
hundred other power wires routed with the center tank
wires, giving the capability for a potential short
circuit, putting power into the center tank wires from
another system.
Narrator: Approximately 12 minutes into the
flight, power from a heavy-duty cable arced across to
the wires leading into the fuel tank. A vast surge of
electricity was now traveling down these low voltage
cables. The NTSB later discovered that inside the tank,
long exposure to fuel had coated the fuel-gauge
terminals in sulphide, which conducts electricity ...
The entire nose of the 747 forward of the fuel tank, was
blown off by the explosion. It plunged thirteen thousand
feet, with the pilots still at the controls. Without the
nose to keep it balanced, the rest of the plane tilted
up. Engines still running, it continued to climb for
close to 30 seconds before stalling ... and plummeting
to the sea.
Joe Lychner: We all have visions of what our family
members experienced when that plane fell apart at 17,500
feet and our greatest fears are that they didn't die
immediately, that they knew what was happening and that
they experienced pain and fear.
Narrator: Joe Lychner lost his wife and two young
daughters aboard TWA 800.
Joe Lychner: I have always hoped that I would be able
to find some indication that they died immediately, but
unfortunately everything that I see and all indications
are because they were sitting in the back of the plane
that they didn't die immediately, that they knew what
was happening. And the terror that they must have
experienced is something that I just can't get out of my
head.
Narrator: Both before and after the TWA 800
crash, industry specialists had argued that fuel tank
explosions were rare events, that did not warrant the
huge costs involved in preventing them. This decision
was a mistake ...
Christine Negroni: The big misconception with TWA
Flight 800 was that this fuel tank explosion was some
sort of rare phenomenon. It was an unprecedented event.
And after a while, investigators and statisticians said,
you know what, we've had over the course of the past
thirty years, thirteen fuel tank explosions on
commercial aircraft and we've had thirteen fuel tank
explosions on military aircraft. That's thirteen and
thirteen is twenty-six, we got TWA 800 is twenty-seven.
They started doing the numbers and they realized, that's
not rare and unprecedented at all, that's a scary
number.
Narrator: A solution had to be found. Inside this
room in Los Angeles, fifteen virtual planes take off
every 40 seconds. They do so on these laptops, which
simulate entire flights, second by second. The computers
are testing an invention, that designers hope will
prevent future crashes like TWA 800.
Called a fuel tank inerting system, the device reduces
the amount of oxygen inside the tanks. Since oxygen is
required for a fire to ignite, the system should prevent
an explosion. Before it enters the tank, air is forced
through bundles of fibers that filter out the oxygen.
Steve Zimmerman: These fibers are really in the
structure of very small straws the size of a human hair.
So there's millions of these fibers laid axially down
the length of the air separation module. So, air that's
24% oxygen enters these fibers and starts traveling down
their length. Now because of the nature of the fiber and
the structure of the molecules, oxygen's allowed to be
absorbed into the walls of the fiber, and then exits the
fiber and is collected and dumped overboard. Whereas the
balance of the air that continues traveling down these
fibers, becomes more and more nitrogen enriched as it
flows down the length.
Narrator: With nitrogen levels increased and
oxygen levels decreased, the fuel cannot ignite. The
system has been hailed as a breakthrough by the FAA,
which intends to make it mandatory by 2006. But the
technology was actually around long before the TWA
crash.
Greg Feith: Back in 1983 Boeing actually had a
superior system that inerted all the fuel tanks and put
out fires in the cargo hold. Unfortunately it weighed
eighteen hundred pounds and nobody wanted to install it.
The system today only inerts the center fuel tank but
weighs two hundred pounds, and that's acceptable. The
ironic thing is that those same people that were
concerned about eighteen hundred pounds, are now
installing three thousand pound in-flight entertainment
systems. Three thousand pounds for entertainment, two
hundred pounds for safety.
Narrator: From a marketing standpoint, this makes
sense, since amenities attract passengers. Safety is
more basic -- all planes are expected to be safe.
Christine Negroni: Safety devices have never been
used as marketing efforts on airplanes. The coffee, the
attractiveness of the flight attendants, the width of
the seats, the leg room, those are marketing devices.
But safety devices I don't think are considered the sort
of things you can get a competitive edge for. You can
get a safer airplane, but you can't get a competitive
edge.
Narrator: Ironically, the entertainment systems
that put people in seats, also add five extra miles of
wiring to aircraft that already have one hundred and
seventy miles of it. And as the TWA 800 accident
illustrated, wiring is loaded with potential problems
...
Christine Negroni: Great lengths of it are not
accessible to inspection or maintenance, and wiring is
subjected to a great hostile environment all of its
operating life. Heat, cold, humidity, dryness,
chemicals, vibration, pressurization, de-pressurization.
So there's great stress on the wiring.
Narrator: Aviation experts say that wiring faults
are almost certain, on any aircraft older than 20 years.
And the average age of the world's fleets is now 18.
Christine Negroni: The problem is you can't replace
wiring on airplanes. I mean you can replace pieces but
you can't re-wire an airplane, just can't do it, you
might as well scrap the aircraft.
Narrator: You can't rewire a plane, but a small
avionics company in England has come up with another way
to keep wires safe.
Smart connectors
-- designed to prevent this ...
Glenn Lacey:
(Phoenix
Aviation Technologies) This connector is
typical of the thousands of connectors that can be found
in both military and commercial aircraft.
Narrator: The smart connectors don't fix wiring
faults, but they can detect them before they prove
fatal. A thin wafer with a built-in microchip is placed
inside the connector. It bounces an electrical pulse
along the wires, checking for faults.
Glenn Lacey: We have two wires running from two pins
to an electric bulb which could be representative of any
system in any aircraft. And you see, it has a loose
connection, and the light bulb is starting to flicker.
This information is monitored and picked up by our
system immediately and it sends a signal to the captain
via a television screen that it has a problem. Where it
is and how critical it is.
Narrator: U.S. Special Forces are currently
testing the smart connectors before they get evaluated
by the FAA. But even if the FAA certification process
goes smoothly, approval will come 10 years after the
loss of TWA 800.
Despite all the emphasis on Cost-Benefit analysis, there
are times when mathematics is unceremoniously swept
aside. This was a day that changed forever the way
people think about flying. As the tragedy sank in, air
traffic fell by 34% in the United States, and by 15%
worldwide. Airlines faced bankruptcy. This heightened
fear of terrorism in the air, galvanized the industry.
The FAA had already begun a remarkable series of tests
after the Lockerbie terrorist attack, aimed at finding
out exactly what happened when a bomb went off in the
luggage compartment of a plane. They were trying to
develop ways to contain explosions. Many aircraft were
sacrificed in the trials.
But could the luggage containers themselves be made to
contain a blast? This is what happens to a normal
container when it's filled with a tiny amount of
explosives -- equal to that used on the Pan Am flight
over Lockerbie. Trying for a better result, scientists
in Holland have built containers out of a material
called GLARE, which contains alternating layers of
glass, metal and fiber. This is what happens when a bomb
explodes inside a GLARE container.
But GLARE is more expensive and heavier than normal
containers, although its makers claim its cost would add
a mere 87 cents to the price of a ticket. So far, only
El Al and a few other airlines are using it. Instead,
most have chosen to rely on airport scanners to detect
explosives before they get on the plane. The scanners
are paid for by the government, not the airlines.
So what will the airlines think of the Assisted Recovery
System, which prevents controlled flight into terrain?
Will it only be adopted if it's commercially viable? Or
will public concern about terrorism be the driving
force, no matter what the cost?
J. Howard Glover: (Honeywell Corp) If we made this
system robust enough that the terrorist could not turn
it off once it was engaged then the airplane would
simply refuse to fly into, not only a building
necessarily, but airspace where it shouldn't be.
Of-course the difficulty is making it robust enough that
the terrorist could never turn it off. Theoretically,
it's possible. And we're working on various techniques
for doing that.
Narrator: But in that case, pilots may argue that
it takes too much control away from them.
Markus A. Johnson: (Pilot Assisted Recovery System) A
lot of pilots are concerned about overly automating the
airplane. In other words, pilots are there for a reason
and they feel that they need to have the ultimate
decision-making in control capability. In essence, there
should be an off switch.
Narrator: Air safety is full of these kinds of
contradictions. Passengers want safety, but are more
likely to opt for cheaper seats and better amenities.
Pilots want safety, but are adamant about retaining
control of their aircraft. Airlines want safety, but
with margins so slim, they are forced to worry about
their bottom line. And the FAA wants safety, but needs
to weigh the Cost-Benefit of each new advance. So in the
end, it is often Tombstone Technology and accidents --
that drive the industry forward.
PRODUCTION CREDITS:
Narrated By
BILLY CRUDUP
Produced and Directed by
DAVID DARLOW
Series Producer
JARED LIPWORTH
Photography
ANDREW WEBB
REX BARKER
Sound
TOBY TRACKMAN
Editor
ANDREW WEBB
STUART GAZZARD
On-line Editor
SIMON COLDRICK
ED GIVNISH
Sound Editing
MIKE WOOD
BILL GARDNER
DOUG JOHNSON
Colorist
STEVE LUCAS
Graphics
ATOMIC ARTS LTD
Archive Producer
PAUL GARDNER
Archive
BOEING
CHANNEL 4 TELEVISION
CNN
DALLAS AIRPORT PUBLIC AFFAIRS
FAA
HONEYWELL
ITN/REUTERS
L3 COMMUNICATIONS
LECTROMEC
NASA
QINETIQ
STORMSTOCK
US NAVY
Special Thanks
IAN GUREKIAN
Series Open and Additional Graphics
Creative Consultant
JAY SLOT
Design
DAVID CHOMOWICZ
Series Open and Additional Graphics
Music
BANG MUSIC
Producer
MARA POSNER
Post-Production Supervisor
TARA THOMAS
Production Assistant
MARY TUCKER
Production Managers
KATE LEONARD-MORGAN
JULIE SCHAPIRO THORMAN
Production Coordinator
AMY GOSTLING
Science Editor
SHARON KAY
Associate Producer
ERIN CHAPMAN
Executive Producer, Darlow Smithson
TOM BRISLEY
Executive in Charge
WILLIAM R. GRANT
Executive Producer
BETH HOPPE
A Darlow Smithson production for Thirteen/WNET New York
in association with Carlton International
© 2004 Educational Broadcasting Corporation and Carlton
International
INNOVATION was produced by Thirteen/WNET New York, which
is solely responsible for its content.
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