Mayday (2013) s07e01 Episode Script

639 pieces of wreckage are recovered from the sea.
639 pieces that only deepen the mystery of a deadly plane crash.
A bit more to the right.
There! But when investigators bring up the 640th piece of China Airlines Flight 611, they get their answer.
There was definitely a 'Eureka!' moment on the dock.
It would be scrutinised more closely than any other piece of debris.
On this single piece of wreckage, investigators would find the one clue that would tell them why a modern jetliner with 225 people on board shattered in midair.
- (BANG!) - (ALL SCREAM) 30 feet.
The speed is low so watch it.
Did you feel that? WOMAN: (OVER RADIO) Taipei Control, serve and maintain, Echo Foxtrot 126.
May 25, 2002.
Gears up.
A China Airlines 747 lifts off from Taiwan's capital, Taipei.
Taipei approach, Dynasty 611.
Airborne, passing 1,600.
MAN: (OVER RADIO) Dynasty 611, Taipei approach radar.
Contact climb and maintain flight level 260.
Today's flight is a short one - 1 hour and 40 minutes across the Taiwan Strait to Hong Kong.
This route is one of the most widely travelled on the planet.
It makes so much money, it's called the 'Golden Route'.
MAN: (OVER PA) Ladies and gentlemen, the 'fasten seatbelts' sign has been turned off.
For your safety, we do recommend that you keep your seatbelt fastened at all times while seated.
Minutes after taking off, Flight 611 climbs steadily above the Taiwan Strait.
The plane's autopilot controls the ascent.
And then, 20 minutes after taking off, at an altitude of almost 35,000ft (RUMBLING, CREAKING) .
.
at Taipei Area Control, the flight vanishes from radar.
WOMAN: Dynasty 611, Taipei.
Dynasty 611, Taipei! I've got a plane off radar.
China Airlines 611.
Its last known return was east 119, decimal, 67.
North 23, decimal, 98.
Taiwanese authorities quickly launch one of the largest rescue missions in that country's aviation history.
(ALARM BEEPS) (SPEAKS CHINESE RAPIDLY) (SPEAKS CHINESE) TRANSLATION: I gave a clear order that the priority would be searching for whoever was still alive, then bodies, and then - only then - wreckage.
More than 1,000 people take part.
Fishing boats, the Coast Guard and Taiwan's military race out to sea.
Flight 611 was 55km from the Taiwanese shore, just north of the Penghu Islands, when it disappeared.
Rescuers find debris floating in the Taiwan Strait.
(SPEAKS CHINESE) TRANSLATION: The first thing we saw was a great amount of wreckage, including landing-gear wheels, napkins, knives, forks.
Wreckage from the plane is spread far and wide.
Some items are found on land more than 100km away in central Taiwan.
As the rescue effort continues, Taiwan's Aviation Safety Council begins its investigation into the crash of the 22-year-old plane.
747 200 delivered August 2, 1979.
Kay Young is the managing director of the ASC.
He'll be leading the investigation.
We're setting up a command post in Penghu Islands.
Let's go.
China Airlines have had a very, very poor safety record.
As a matter of fact, it was considered one of the worst in the world.
Typically it had, like, one major accident every four years.
This particular investigation was by far the most difficult one and one of the reasons why was it's on the ocean floor.
The search for survivors goes on around the clock.
There were 225 people on the airplane.
Nobody is found alive.
The bodies are taken to the Penghu Islands to be identified and examined.
Since the accident involved an American-made plane, the NTSB joins the investigation.
A team of investigators is dispatched to Taiwan.
They'll be led by John Delisi in Washington.
We have a very good working relationship with the ASC - the Aviation Safety Council of Taiwan - so we knew that they would ask for and welcome our assistance in the investigation.
Wreckage that's found floating is also brought to the Penghu Islands.
Investigators need to know how one of the world's most successful planes on one of the world's most travelled routes simply fell out of the sky.
Good morning.
I'm anxious to see what you have.
Sophisticated ground-based radar tracked Flight 611 throughout its short journey.
It should provide investigators with a much clearer picture of the flight than the radar at air traffic control.
Kay Young gets the first major clue in this case.
The radar tracked the plane as it climbed on course to 35,000ft.
Then suddenly Flight 611's signal split apart.
The break-up is quite graphic.
It doesn't take long for the media to consider a sinister possibility .
.
that Flight 611 was shot down.
On the day of the China Airlines crash, China was conducting military exercises in the Taiwan Strait.
But officials there insist no missile was launched towards Flight 611.
None of the wreckage recovered so far has any of the telltale signs of being hit.
And there's no evidence on radar that there was ever a missile heading for Flight 611.
Once the evidence began to come in, it very quickly ruled out a missile, much the same way that it ruled out it being a midair collision.
There were no other objects in the air near the airplane.
Few things would cause a plane to break up in midair.
One of the big ones is a bomb.
Medical examiners check the bodies that have been recovered for burn marks and shrapnel.
They find none.
The plane's metal skin would be torn and curled in a very particular way if there had been a bomb on board.
Investigators find no such damage on any of the pieces.
But to rule out a bomb, they'll have to find more wreckage.
I think that will be it for floating wreckage.
The team from the NTSB arrives in Taiwan.
Morning.
I'm Clint Crookshanks from the NTSB.
Hello.
Good to see you, gentlemen.
I'm afraid we still don't have much.
Clint Crookshanks is a structural engineer who knows the 747 intimately.
I didn't have any preconceived notions.
This was my first major accident working for the NTSB.
KAY: We are not getting much from the floating debris.
In-flight break-up - that's all we know.
Taiwan's civil aeronautics authority doesn't take any chances.
They ground all of China Airlines' 747 200-series planes until they can be inspected for mechanical flaws.
Thank you for bringing these.
To the NTSB, this accident seems to have a lot in common with one of the world's most-studied plane crashes .
.
that of TWA Flight 800, six years earlier.
Like the China Airlines flight, it broke into pieces while still climbing.
TWA Flight 800 was the biggest investigation the NTSB has ever done.
It lasted about four years.
The painstaking investigation uncovered a design flaw with the 747.
Wiring near one of the plane's fuel tanks could spark and ignite the fuel in the tank.
Investigators conclude that's what likely caused the crash.
Investigators are struck by similarities between the two flights.
Both were 747s.
Both disintegrated without warning while still climbing.
Both flights took off in very hot weather.
The heat may have caused Flight 800 to explode.
That plane sat on the tarmac with its air conditioning running.
Investigators believe hot air from the air conditioner overheated the plane's fuel.
So it looks really very, very similar so therefore our immediate focus was essentially the central fuel tank.
Three weeks after the crash, the 'Jan Steen', a sophisticated salvage vessel, arrives in the Taiwan Strait.
It's equipped with divers, a diving chamber and a remote-operated submarine complete with sonar and video cameras.
The NTSB were tasked with manning the recovery vessel and watching video screens from the ROV.
Using sonar, investigators have located the wreckage of Flight 611 deep underwater.
Alright - to the right a bit.
Clint Crookshanks knows all the pieces that make up a 747 but he's never seen them like this.
CLINT: It was really quite a shock when I first saw pieces on the floor of the ocean.
With only the lighting of the ROV to guide you, you would notice something that looked like an airplane part.
The ROV would then circle around the part looking at it from all angles.
I think it takes a different kind of mind to be able to look at a mangled part and kind of straighten it out in your head to really determine where it comes from on the airplane.
Alright - a little bit more to the right.
Alright.
Go back.
There! OK, that's definitely a piece of wing.
Let's mark it.
Once a piece is identified, its GPS coordinates get recorded.
The GPS mapping tells investigators that the debris is spread out over 325 square kilometres.
It will be difficult to track down specific pieces of the plane.
25 days after the crash of Flight 611, the plane's two black boxes have been found.
One contains voice recordings of conversations in the cockpit.
The other, data from the plane's flight computer.
Either could hold the clues that will reveal what happened during the final minutes of the flight.
If the answer is on the tape, investigators may not have to bring up more wreckage to the surface.
The data is critical.
Everybody ready? Investigators begin with the plane's cockpit voice recorder.
MAN: Welcome aboard China Airlines.
The recording begins about 10 minutes before the plane took off.
Dynasty 611.
Runway 0-6.
Wind 0-5-0 and clear for take-off.
Clear for take-off, Dynasty 611.
Take-off.
- 80.
- Check.
V1.
Rotate.
OK.
Flap up.
Investigators listen to more than conversations.
They also want to hear if the plane itself was making any unusual sounds.
Noises on the cockpit voice recorder can either be audible spoken words that are recorded by a microphone, or they can be structural discrepancies that are picked up by the microphone.
If anything, though, this cockpit is unusually quiet.
WOMAN: (OVER RADIO) In the air, 608.
0-5-0.
In the moments before the disaster, nothing seems wrong.
There are no unusual sounds.
The final words spoken are from Captain Yi Ching-Fong.
2,000.
He calls out the distance to their cruising altitude.
That's followed by the sound of a chime (DING!) .
.
alerting the crew that they are nearing 35,000 feet.
And then the cockpit microphone picks up the sound of the plane breaking apart.
(LOUD TEARING) Half a second later, the recording stops.
The recorders told us that something happened but it wasn't enough to tell us exactly what it was yet.
Many things had been ruled out by then but we didn't have the golden nugget.
We didn't have the real piece of evidence that told us what initiated the break-up of this 747.
After the disappointment of the voice recorder, studying the wreckage becomes the only option for investigators.
They focus their efforts on items that can either prove or disprove the link to TWA Flight 800.
On July 12 - 48 days after the crash OK.
Whoa.
Whoa.
A little to the left, please.
.
.
success.
Alright.
That's definitely the central fuel tank.
OK, let's mark that.
Let's bring that up.
The tank joins the sea of wreckage piling up at the pier.
Investigators study it closely for any evidence that it exploded.
If it did explode, like the TWA tank, it would be curled and twisted .
.
and the metal would be bent outwards.
But this fuel tank is different.
We found the central fuel tank was relatively intact.
And it's crumpled inwards.
Unlike the tank from the TWA flight, there's no soot.
There would be if the jet fuel inside had ignited.
So, at that time, we pretty much ruled out it was the cause, the fuel tank.
The wreckage recovered so far has also forced investigators to abandon another theory - that a bomb brought down the plane.
None of the wreckage showed any evidence of sooting, any kind of explosive damage.
As more wreckage is identified and recovered, investigators find an intriguing clue.
It's discovered when they examine a series of small vents from Flight 611.
All commercial jetliners have dozens of these vents near the floor.
They're essentially pressure-release valves.
They're called dado panels.
And there's only one reason for them to open.
If the cargo area underneath the passengers were to suddenly decompress, the pressurised air above would exert so much force on the floor that it could collapse and damage vital flight controls.
That's precisely what happened to a Turkish Airlines flight in 1974.
(BANG!) (SCREAMING) The pilots couldn't control their plane after their cargo door blew out.
(SCREAMING) We've lost it! If the floor on that flight hadn't collapsed, the pilots may have been able to save the plane.
After that accident, the NTSB recommended that manufacturers install many more relief vents between a passenger plane's upper and lower levels.
If there is decompression in the cargo area, the dado panels open automatically and release the pressure on the floor.
There were 65 dado panels on the China Airlines flight.
19 of them were recovered from the ocean.
Four recovered panels were in the open position.
It tells investigators that there must have been a sudden loss of pressure beneath the passenger cabin.
But it doesn't tell them what caused it.
The dado panels lead investigators closer to solving the mystery of this crash.
But it's just a small piece of a much bigger puzzle.
There are hundreds of pieces of wreckage to be examined for clues.
Kay Young now wonders if a few of those pieces might be able to tell him where the decompression originated.
I've been reading about the trajectory analysis you did on Flight 800.
I'd like to try it.
Ballistic trajectory analysis is a technique that US investigators use to figure out how TWA Flight 800 disintegrated.
KAY: We figured that because it disintegrated in midair, the ballistic analysis from which NTSB did in TWA 800 could be very, very useful to us to help us to analyse the trajectory of the flying debris.
The analysis is based on a simple fact.
The pieces that came off the plane first would be the first to hit the water.
If investigators can figure out which pieces those were, they'll know where the trouble began.
The salvage workers have recorded the precise location of those same pieces of wreckage.
Investigators know the wind speed on the day of the crash and they can obtain precise information about ocean currents.
The last piece of the puzzle comes from the plane's flight data recorder - the plane's altitude, speed and direction at the time of the break-up.
As they're brought to the dock, every single piece of wreckage has been logged and numbered for identification.
Kay Young selects 18 pieces of wreckage for the computer analysis.
Some from the front, some from the middle and some from the back of the plane.
Along with all the other data, he'll feed information about each item's weight and shape into the computer.
Based on where the pieces fell, the computer should be able to calculate which of those 18 pieces was the first to come off the plane.
Can we see when each one of those items separated from the aircraft? All of the data paints a telling picture of what happened at 35,000ft.
The tail came off first.
Along with the dado panels, it's a very important clue.
That's pretty much indicating that something happened in the back of the aircraft rather than something happened in the forward part.
Investigators are now keen to recover items from the rear of the plane.
Hundreds of pieces of wreckage are piling up at the pier on the Penghu Islands.
The NTSB sends metallurgist Frank Zakar to Taiwan to examine the wreckage.
I was walking along the yard where the wreckage was placed and at that time I walked up to item 640.
I noticed that there were some peculiar areas of interest that I wanted to look at a little bit further.
With this battered piece of metal, investigators have struck gold.
(WHISTLES) Hey.
It's Frank.
I think we've found your golden nugget.
Item number 640 would give investigators a revealing glimpse into the past and lead them to conclude that the crash of Flight 611 actually began 22 years earlier.
Let's get as many pictures as we can.
The massive piece of fuselage that has caught Frank Zakar's attention is exactly what investigators have been searching for.
It includes a piece of the belly, the side wall and the rear cargo door.
It's from the back of the plane - precisely where the analysis told them the break-up had begun.
This piece of wreckage was highly unusual.
It wasn't what we were seeing on all the other pieces and it immediately drew our attention and drew the focus of the investigation.
The way most of the metal is torn suggests it ripped apart violently in midair.
Aerodynamically, as an airplane's moving through the air, if it were to break apart, just the force of the incoming air at over 500mph will just break up perfectly good structure.
That's what call an overload fracture.
So, most of the pieces that came up early were just indicative of that kind of overload.
When metal breaks due to overload or overstress, it comes apart at an angle.
But the fractured edges of piece number 640 aren't angled.
They're flat.
- What do you think? - It's definitely not overstress.
It's metal fatigue.
Fatigue fractures happen when metal is stressed repeatedly over time until it breaks.
It looks very different from a stress fracture.
Typically, a metal fatigue crack will have a flat appearance.
It'll be very smooth.
That's exactly the kind of crack that investigators observe on piece number 640.
That tells them it didn't break off the plane suddenly as it fell from the sky.
This piece separated from the plane over time.
There's something else about this piece that stands out.
It has a metal patch on it.
It's called a doubler plate.
It's the equivalent of a patch on a punctured tyre.
It's not unusual to find numerous doubler plates on older planes like this one.
A doubler plate is like a patch that you put over fuselage skin.
If there were to be a tear or a blemish, a crack identified, you'd want to repair the fuselage back to its original strength and one way to do that is to put a doubler plate or a patch right over the existing structure.
At some point, this section of the 747 had been repaired.
Investigators need to know why it was fixed and how that was done.
KAY: We're looking for repair to the outer lower lobe.
Whatever it was, it was big.
There's something about this particular doubler that catches Frank Zakar's attention.
The outside of the fuselage contained large altitudinal streaks that appeared to emanate from between the doubler plate and the skin.
Something is leaking from underneath the metal patch.
Was there a possibility that the skin had broken, cracked, and was there any fuel or air coming out from between the doubler and the fuselage? And that warranted further examination.
Let's cut it from hereto here and send this piece to Chung-Shan.
In order to see what's underneath the doubler, a large section of piece 640 is sent to a lab.
The Chung-Shan Institute of Science and Technology is a military research facility.
It's at the forefront of Taiwan's space program.
This is where investigators take a section of piece number 640 for a closer examination.
The NTSB's Frank Zakar finds a telling clue on the crack itself.
When I looked at the fracture surface, I found that this one specific area was covered with aluminum oxide, pretty much similar to rust on a car.
Years of exposure to oxygen changes the colour of metal.
The discoloration tells investigators that this particular crack at the rear of the airplane has been there for a very long time.
Then, when the doubler is finally removed, investigators get a look at the aluminium skin underneath.
They're intrigued by what they see.
We noticed there were some fairly long gouge marks.
This is beyond the kind of damage a doubler is meant to patch.
That was an 'aha' moment, that we might have something here.
The search of the plane's documents also pays off.
The records contain a very short reference to a mishap 22 years earlier when this plane was only six months old.
Speed is low, sir.
Watch it.
Its tail scraped the runway while landing.
Did you feel that? It happens when a plane lands or takes off at too steep an angle.
It's called a 'tail strike'.
MAN: (OVER RADIO) 009, Hong Kong Tower.
We observed smoke and sparks from your tail on landing.
Roger, Hong Kong Tower.
We'll have that looked at.
It's tail strike, sir.
I'd better log that.
It is a relatively common occurrence.
It's not a good thing.
Some airplanes even have what's called a 'bumper' on that portion of the fuselage so that if the tail ever does get too close to the ground, instead of sacrificing skin from the fuselage you might have the sacrificial bumper that will take that wear.
Investigators want to know how China Airlines went about fixing the plane.
They can only find a brief mention of the repairs that were done in the plane's logbook.
- That's all there is? - That's all we could find.
There's not a lot of detail in China Airlines' records.
The documents that do exist show that the day after the tail strike, China Airlines did a temporary repair.
Workers attached a large aluminium plate over the damaged area.
What do we know about the permanent repair? It doesn't get much better.
A more permanent repair was to be carried out within four months.
Here's what we've got.
CLINT CROOKSHANKS: The maintenance records indicated that the permanent repair was done in accordance with Boeing recommendations in their structural repair manual.
Evidence that we uncovered indicate that the repair was NOT done per the Boeing repair manual.
According to the manual, many of the scratches on the plane were too deep to be repaired.
The entire damaged section should have been cut out and replaced.
KAY YOUNG: You have to follow certain procedures.
The Boeing structural repair manual indicates very clearly what you should do step by step.
22 years later, investigators can tell that for some reason the damaged piece was not replaced.
The scratches from the tail strike are still there.
China Airlines engineers tell investigators that the scratched area was too large to cut out, so they sanded the scratches down instead.
The scratches weren't sanded down or cut out.
They're still there.
Maintenance workers then made one final mistake.
JOHN DELISI: They put the doubler plate right over the scratched material.
The doubler plate that they put on was not 30% larger than the affected area.
In fact it was barely - maybe not even, in certain locations - larger than the area that was scratched.
Even though the repair wasn't done according to Boeing's instructions, the way it was logged made it seem like it was.
So for 22 years, anyone reading that entry would assume the damaged area had been cut out as it should have been.
Pieces were really starting to fall into place now.
Once we saw this piece of structure that had the fatigue cracks in it, we realised that it came from a structural repair that was not done properly .
.
that was left to fly for 20 years.
Airborne.
Passing 1,600.
What was so insidious about this improper repair was that the doubler plate hid all the damage.
So if you weren't there, watching them do this repair improperly, you wouldn't know.
And every time the plane took off over the next 20 years, the concealed problem got worse and worse.
The air inside a commercial airplane is pressurised.
As the plane climbs, air is forced into the cabin to keep the pressure inside the plane greater than the pressure outside.
It's like inflating a tyre.
The inside air pushes against the plane's skin.
Each time that the airplane pressurises, pressure builds up inside the fuselage of the airplane and that crack could open up a certain amount of inches or microns or millimetres.
The plane's skin expanded and contracted a little bit every time.
Because they weren't properly repaired, the cracks grew and spread.
Eventually the crack grew into a stunning 2.
3 metres.
If you were charting the crack, you would have seen very slow growth early but as time went on, the growth was getting bigger and bigger.
A small scratch had grown into an enormous problem.
Then in May 2002, as Flight 611 climbed, that problem killed 225 people.
As the airplane climbed in altitude and the fuselage was pressured, that put enough strain on this growing crack that reached its critical length.
From there, it just spread like a spider web.
It went in all directions and it probably looped all the way around the fuselage to the point where the entire aft section of the airplane just broke off from the rest of the structure.
The plane went into a steep dive.
The force of the air on what was left of the plane quickly ripped it to pieces.
Investigators know that an unseen crack caused Flight 611 to break apart.
They now discover that China Airlines came heartbreakingly close to finding that crack and saving 225 lives.
The China Airlines 747 was in regular service for 22 years following the improper repair to its skin.
It took off and landed more than 20,000 times.
Over the years, mechanics would have scrutinised the plane.
There are regular inspections per the Boeing maintenance program that have to be performed on the airplane.
But the massive crack forming at the rear of the plane was never detected.
Another accident in another country almost led China Airlines to discover the hidden damage.
In 1988, the roof peeled off an ageing Boeing 737 owned by Aloha Airlines.
As a result of that incident, the Federal Aviation Administration laid out an inspection procedure for older planes.
Airlines around the world were forced to inspect their planes much more diligently for corrosion and cracks.
The regulation called for airlines to re-evaluate all existing repairs to a plane's structure.
CLINT CROOKSHANKS: Indications on this airplane were that if they had looked at the maintenance records and compared it to the repair they would have had to remove the repair and redo it.
China Airlines took the first steps of the new procedure in 2001, a year before the accident.
The airline identified and photographed 31 different doublers on the 747, including the one over the catastrophic crack.
Those pictures show investigators that China Airlines overlooked a vital clue that could have warned them of the looming danger.
We examined the photograph that China Airlines took of the repair and noticed that there were some issues that may have warranted further investigation.
Investigators see a dark brown stain on the outside of the plane.
It's the same mysterious staining that led Frank Zakar to suspect that there was a hole behind the doubler when he first saw it on the pier.
So why hadn't this stain raised alarms before the crash? For years, passengers on China Airlines' doomed 747 were allowed to smoke.
They filled the pressurised air with nicotine.
The smoke was being forced out through the crack at the rear of the plane.
Over time, that smoke left a nicotine stain on the outside of the plane.
It was very vivid.
Any experienced maintenance engineer would be able to spot it immediately.
Smoking hadn't been allowed on China Airlines for seven years before the crash.
It tells investigators that the crack in the plane had been there for at least that long.
But instead of investigating the source of the staining We need to conduct the new inspection when we do our next major check.
China Airlines scheduled the second part of the FAA's procedure - a detailed inspection of the repaired areas.
That would be the 7C check currently scheduled for November 2, 2002.
But the 747 never made it to November 2, 2002.
It came apart over the Taiwan Strait five months before the inspection that would have undoubtedly uncovered its hidden flaw.
Investigators want to prevent a similar accident from ever happening again.
They recommend that aviation agencies around the world immediately inspect repairs for any possible hidden damage.
JOHN DELISI: We were no longer going to accept just a quick write-up that the repair was done properly.
If the repair didn't have all the necessary documentation to allow us to know it was done properly, we were requiring operators to take doubler plates off and do a visual inspection of the structure underneath.
The National Transportation Safety Board issues its own recommendations.
The board asks that maintenance personnel be warned of the consequences of hiding the kind of damage that could lead to the structural failure of an airplane.
The moral of this story is that the repair has to be done properly.
As a mechanic, when you're doing work on an airplane, you're not thinking about the people who might be flying on that fuselage 20 years from now, but their safety depends on you doing the repair properly.
China Airlines has revised the way its fleet is inspected and maintained.
Its safety record has improved dramatically since the crash of Flight 611.
Investigators also propose the development of new tools that would allow mechanics to detect damage behind a doubler.
Such tools are being used today.
Boeing developed a non-destructive procedure that can find cracks in the fuselage underneath a doubler.
That device uses ultrasound - soundwaves that travel through metal.
It can reveal damage underneath a doubler.
It's the same technology that allows doctors to observe a foetus while it's still inside the womb.
The device would have been able to detect the crack behind Flight 611's doubler plate.
But the technology has some limitations.
A great number of hours are required just to do one specific area of the airplane, but the technology is getting better.
The problems that led to the China Airlines disaster are not going away.
Planes the world over are getting older.
And older planes need to be more thoroughly inspected for cracks.
Six years after the China Airlines crash, Southwest Airlines in the United States was hit with a record-breaking fine - 10.
2 million for missing inspections designed to find cracks.
The fining of Southwest brings back into focus how important it is to do maintenance properly on an airplane.
A proper program of maintenance and inspections can be costly, but as China Airlines showed, the price of not maintaining ageing planes is even costlier.
Supertext Captions by Red Bee Media Australia