March the 3rd, 1974. A perfect spring-like day in Paris. It's been almost two years since a DC-10 came close to crashing near Windsor, Ontario. Now more than 50 of the new planes are flying around the world. One of them, plane 29, is owned by Turkish Airlines. Normally the last leg of this trip from Turkey to England wouldn't be very crowded. But today the DC-10 is filling up fast. People are squeezing into seats throughout the plane.

A strike at a British airline has passengers scrambling for any flight back to London. Wendy Wheel is one of many last-minute additions to the flight. A model, she's returning home after a shoot in Spain. We'd been married for 18 months and we were about to start a family. I believe the secret of her success for modelling was not just that she was a very attractive girl and good model material, but she was generally liked by all the photographers

because she had such a pleasing, lovely, light personality. With all the new passengers boarding, the flight is a little behind schedule. And it's not only the crew who are waiting. At the back of the plane is baggage handler Mohamed Mahmoudi. With all the new passengers, he's not sure if there are any more bags to load. Not expecting any other luggage, Mahmoudi locks the rear cargo door. The DC-10 is set to go.

Just after 12.30 in the afternoon, THY flight 981 lifts off into the skies above Paris. London is less than an hour away. Paris Control, this is Tango Hotel Yankee 981. We're at 6-0, requesting clearance to flight level 2-3-0. Tango Hotel Yankee 981, you have cleared to flight level 2-3-0. 981, roger. As it flies away from the airport, the DC-10 continues to gain altitude. 2,700 metres. 2,700 metres. 3,000 metres.

3,300 metres. The huge jet shudders and banks to the left. What happened? The captain flew out. Are you sure? Just 16 seconds after the start of the crisis, the crew struggles to save their crippled jet. The nose is pitching down, the plane picking up speed. Bring it up! I can't bring it up! She doesn't respond! Passengers at the back of the plane witness a horrifying scene. Two rows of seats have simply disappeared.

Through a huge hole in the floor, passengers can see the sky over France. 7,000 feet! Hydraulics! We've lost it! The crew discovers that they have no hydraulic power with which to control the plane. Without it, they can't move their rudder or elevators. Even without its most basic controls, the plane begins to level out. But it's fallen too far. It looks like we're going to hit the ground! Speed! The DC-10 is travelling almost 800 kilometres an hour.

The flight from Paris to London never even makes it to the English Channel. Just nine minutes after taking off, Turkish Airways Flight 981 becomes the worst plane crash of all time. In London, the flight is late. In London, the flight is listed as delayed. The news of the crash comes out slowly. I went to the ticket office kiosk and I asked what has happened to the flight. And instantly, the look on the gentleman's face behind the counter told me something was wrong.

Instantly. There's barely anything left here that's recognisable as being a part of an aircraft. I looked on the television and I just thought, well, I just hope she's dead. Because I just saw the carnage of the forest in Saint-Denis and it was like looking at the first World War trench movie. Flight 981 carrying 346 passengers, virtually destroyed. Flight 981 carrying 346 passengers, virtually disintegrates on impact.

There are no survivors. It was just a scene of absolute, utter devastation. And the litter of personal possessions, electric wires, bits of metal, bits of bodies, just strewn everywhere. I mean, you couldn't walk. You couldn't walk anywhere without the danger you were going to stand on a part of a human being. I still have nightmares about this, even though it's 33 years ago. Investigators for the French Accident Investigation Bureau are quickly on the scene.

My first job was to evaluate the scope of the wreckage and to begin the first investigation on the spot. At first I was unable to know what has happened. I was just seeing that a terrible crash has occurred and that it will be a very hard work for the investigators. Despite the enormous force of the crash, the black boxes, made of three layers of hardened steel and insulation, survived. Their contents could provide valuable clues about the crash.

Most of the speculation was that it must have been a bomb. Because, you know, you've got an almost brand new, very powerful aeroplane flying in clear blue sky and it gets to 12,000 feet and falls out of it. Investigators are called to a field 15 kilometers from the crash site. They find a piece of fuselage and two rows of seats from the DC-10. Somehow they fell free of the airliner before the rest of the plane smashed into the forest.

When investigators arrive, the bodies of the passengers who were in the seats have already been removed. When relatives of those who died in the crash arrive in France, they're directed to a small church in the town of Saint-Lys. One of the saddest sights I've ever seen is in this church. They laid out on tables everything they'd found. You know, clothing, possessions, teddy bears, rings, watches. And then relatives who wanted to were allowed to come and walk around these trestle tables

with all this stuff laid out. They produced a little packet with my wife's wedding ring and engagement ring. It was all pretty battered up, so you could imagine the thoughts that went through my mind. Since the accident involves an American plane, the NTSB's Chuck Miller joins the investigation. For the second time in two years, he's dealing with a problem with the DC-10. I don't believe that Miller suspected for one moment that the door hadn't been fixed after Windsor.

But it becomes clear that the piece of fuselage found in France is in fact the plane's rear cargo door. It seems like a repeat of the Windsor accident. Miller is left with a haunting question. Why hadn't the problem been fixed? When he saw the door, of course, he saw that it hadn't been done. The fix hadn't been made. That's when I think his anger became very, very strong indeed. Miller takes an unusual step.

Although the official investigation is just beginning, he gives journalist Paul Eddy an important tip. I said, have you got any ideas what made the door come off? He said, yeah. If I were you, I'd go and look at a place called Windsor, Ontario. Hello. I'm Chuck Miller. Miller shares his suspicions with the French investigators. Could you please pass these around? These were taken on June 12th, 1972, right after the incident.

We have asked for the report on the Windsor accident, and our American colleagues were also volunteers to give us a lot of details. Now, we had an American Airlines flight from Detroit to Buffalo have its cargo door blow off. And he has been very frank, and had explained what he was thinking of the Windsor accident. After all the work done during the American Airlines investigation, had something been overlooked?

Was there another problem with McDonnell Douglas' enormous plane? With the information from Chuck Miller, French investigators take a closer look at the plane's cargo door. They make a shocking discovery. There is no new problem. It's just like the American Airlines case all over again. The plane's cargo door was blown off. There is no new problem. It's just like the American Airlines case all over again. The latches that are supposed to hold the cargo door closed aren't locked.

And since two rows of seats were sucked out of the DC-10 over Paris, it's clear that the floor on the plane collapsed, just as it had in Windsor. It looks like we're going to hit the ground! In fact, when investigators listen to the cockpit voice recorder, they find that the Turkish flight crew had even less control of their plane than the crew of American Airlines flight 96. We need to get down and make an approach.

I think it's going to fly. Over Windsor, Bryce McCormick was able to recover his plane and land it. But in Paris, all the hydraulic systems were destroyed. We've lost it! The hydraulic fluid helps crews move the rudder and elevators on the tail. Not being able to control them meant the crew couldn't keep their plane in the sky. The basic problem was the Paris flight was much heavier in terms of the number of people on board.

The floor, when it collapsed, collapsed with such a tremendous amount of pressure that it literally severed all the cables and controlled the back. They had no hope after that point. Shortly after the crash of Turkish Airlines flight 981, Chuck Miller is back in the United States. Our first witness this morning is Mr. C.O. Miller, Director of the Bureau of Aviation Safety of the NTSB. This time he's facing questions from American Senators.

A special hearing begins to find out how a problem that was identified in 1972 could bring another plane down two years later. What you've got to now discover is why wasn't that door fixed? Why would a major, venerable, mighty American corporation deliberately do something like this? Less than a month after the near crash over Windsor, the NTSB had made two very specific recommendations. Miller and his investigators recommended that a change be made to the locking mechanism.

Engage the lever. They wanted to make sure that it was physically impossible for baggage handlers to close the lever without the locking pins being in place. They also suggested that vents be put into the floors of all DC-10s. This would rapidly allow the pressurized cabin air to equalize without collapsing the floor. But in the two years since the accident, neither one of these recommendations was implemented.

There is a fundamental problem at the heart of aviation safety that has been in the United States for a very long time, and that is that it's the job of the NTSB to discover what's happened and to come up with recommendations as to how to prevent it happening again. But it has absolutely no authority to implement them. The NTSB does not have regulatory authority. They have to turn to the FAA, as they did, and say,

we want these things done. And that's where the system went wrong. If the FAA, the Federal Aviation Administration, issues an airworthiness directive, planes are pulled out of service until the proper fix is made. But as serious as the problems on the DC-10 were, no airworthiness directive was ever issued. A so-called gentleman's agreement between the head of the FAA and the head of McDonnell Douglas stopped it from happening.

The gentleman's agreement is the root cause of Paris. There is no question that if an airworthiness directive had been issued, as it should have been, after Windsor, Paris would not have happened. It was an entirely avoidable accident. McDonnell Douglas assured the FAA that it would fix the problem voluntarily. An airworthiness directive would cast a shadow on the still-fledgling DC-10. The last thing in the world you want is for the public

or any of the airlines that are going to be operating these airplanes to think, oh, maybe there's some flaws in this bird. And so an airworthiness directive, especially one that requires you to go back and re-engineer something, is a really horrific thought for an airline. McDonnell Douglas did make changes to the way the cargo door was built. A peephole was cut in the bottom of the door so baggage handlers could see if the locking pins had engaged.

Several warning signs were also attached to the plane's door. The company also made other changes to the DC-10. These included increasing the length of the door and attaching a plate to the inside of the door. This plate would make it physically impossible to push down the lever if the door wasn't properly locked. But each of the proposed fixes had its own problem. Many baggage handlers didn't know what the small window in the door was for.

And the baggage handlers didn't know what the small window in the door was for. And the baggage handler in Paris read and spoke three languages, but not English, the only language in which the warning signs were written. The support plate that was supposed to be installed in the door was never attached to the jet that crashed in Paris. Papers confirming the completion of the work are also uncovered. But no matter what the paper trail says, the fix was never made.

Again, the problem is you don't have an independent FAA inspector coming along to look and see and then put his stamp on it, because it wasn't an airworthiness directive. In the years following the Turkish Airlines crash, an enormous flurry of lawsuits are filed in California. The tragic story of the DC-10 has one more surprise in store. It's 1974, and an unprecedented series of lawsuits are being filed against McDonnell Douglas.

The families of those who died near Paris want someone held responsible. As time went by, I learned more and more about what actually happened and realised that it was not an accident as we would call an accident. It was totally avoidable. My goal was to expose these people. In the weeks leading up to the trial, lawyers who were involved in the case have access to the entire history of the DC-10's development.

They're not the only ones who pour through the evidence. So does journalist Paul Eddy. We were determined to get to those documents and that testimony. Somebody gave us a key to the depository where the documents were, and so at night we would go in and then had a huge accumulated pile of documents to go through in order to find out what they'd been up to. Reading through the immense pile of paper, Eddy makes an incredible discovery.

A memo, written by Don Applegate, the director of product engineering for Convair, the company who'd built the cargo door for McDonnell Douglas. I think the point when we knew we'd got them was the Applegate memorandum that specifically pre-warned this would happen. The memo is a damning indictment of the cargo doors that were being made for the DC-10 and the lack of venting in the cargo doors. It's the first time in the history of the DC-10

that we've had a case like this. It's the first time in the history of the DC-10 that we've had a case like this. The memo is a damning indictment of the cargo doors that were being made for the DC-10 and the lack of venting in the cabin floors. It warns that it's only a matter of time before there's a major disaster involving the doors. The airplane demonstrated an inherent susceptibility to explosive decompression of the cargo compartment.

The memo, written just weeks after the near disaster in Windsor, recommends that immediate changes be made to the DC-10 cargo door. You know you've got them. You know you've got them because you know they knew. During the court case, another chilling find is made. Not only did McDonnell Douglas know about the problem after Windsor, they knew during the development of the DC-10. Four years before the Paris crash, two years before Windsor,

the cargo door failed during a pressure test. The company knew there was a problem, but the fundamental design of the door stayed the same. I could not believe a large corporation like McDonnell Douglas at the time could do such a thing, could risk our lives, ordinary people's lives, for the sake of money. Well, in aviation it's called tombstone technology. In other words, we always have the balance of money,

and unfortunately over the years it has been true more times than not that we have had to wait until we had enough people die in an accident to say, you know, we really are going to have to spend the money over here. The Applegate memo and other information that comes out during the court case leads to one of the biggest settlements in the history of aviation. McDonnell Douglas paid over $80 million in damages.

After the Paris crash, foolproof changes were finally made to the DC-10 cargo door. And this time nothing was left to chance. The FAA issued an airworthiness directive that ensured the doors would never again open in mid-air. And it worked. After Paris, there wasn't another serious incident involving the cargo doors on a DC-10. But the plane's history, and an intensely competitive industry, did have an impact.

McDonnell Douglas sold far fewer commercial DC-10s than it had once hoped for. Most of the pilots that I know who have flown the DC-10 over the years really love the old bird. She's probably a little more clunky than the 747 in terms of her heaviness of flight controls. But it's still a lovely bird to fly. That's fine, but you can't disassociate either the airplane or the company from the awful reputation that the crash left.

Eventually, McDonnell Douglas itself disappears. The company was bought by Boeing in 1996. In the forest outside Paris, a monument now stands honouring those who were killed on flight 981. A permanent reminder of one of the most disturbing crashes in the history of aviation. You never forget. And I've gone on to tell you, You never forget. And I've gone on to lead my life for 30 odd years, but I've never forgotten.

People, to this day, think it was an accident. And it wasn't.