Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
Building to Extremes Human Body Shop SpyCatchers Hi-Tech War Crash Site Secrets Miracle Cell Light Speed Brain Fingerprinting Innovation - Life, Inspired
about the series
intro

feedback credits
back to about the episode transcript
Crash Site Secrets
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: 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: 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: 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: 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.

Be more inspired. Help bring programs like INNOVATION to your PBS station ... pledge online!
E-mail this page
ask the experts for teachers resources about the series sitemap
INNOVATION Online is a production of Thirteen WNET New York. Copyright 2004 Educational Broadcasting Corporation.