Improper Repairs Prove Fatal To China Airlines Flight 611 | Mayday | On The Move

639 pieces of wreckage are recovered from the sea 639 pieces that only deepen the mystery of a deadly plane crash all right a little 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 scrutinized 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 hey [Music] 30 feet speed is mostly watching did you feel that [Music] one may the 25th 2002. yes up a china airlines 747 lifts off from taiwan's capital taipei taipei approach dynasty 611 airborne passing 1 600. 611 taipei approach radar contact climb and maintain flight level 260. 260 dynasty 611 autopiloty engaged china airlines is taiwan's national airline there are 225 people on board flight 611 today's flight is a short one one hour and 40 minutes across the taiwan strait to hong kong this route is one of the most widely traveled on the planet it makes so much money it's called the golden route ladies and gentlemen the fasten seat belt sign has been turned off for your safety we do recommend that you keep your seat belt fastened at all times while seated minutes after taking off flight 611 climbs steadily above the taiwan strait the plains autopilot controls the ascent and then 20 minutes after taking off at an altitude of almost 35 000 feet [Applause] at taipei area control the flight vanishes from radar dynasty 611 taipei dynasty 611 taipei i've got a plane off radar china airlines six one one its last known return was east 119 decimal six seven north two three decimal nine eight taiwanese authorities quickly launched one of the largest rescue missions in that country's aviation history [Music] [Music] 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 a thousand people take part fishing boats the coast guard and taiwan's military race out to sea flight 611 was 55 kilometers from the taiwanese shore just north of the pengu islands when it disappeared rescuers find debris floating in the taiwan strait first thing we saw was a great amount of wreckage including landing gear wheels napkins knives and forks wreckage from the plane is spread far and wide some items are found on land more than a hundred kilometers 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 2nd 1979. kaye young is the managing director of the asc he'll be leading the investigation command post go china and i have had very very poor safety record as a matter of fact it was considered one of the uh worst in the world typically it had like one major accident every four years this particular uh investigation was by far the most difficult one and uh one of the reason why was it's it's an ocean floor the search for survivors goes on around the [Music] clock there were 225 people on the airplane nobody is found alive the bodies are taken to the pengu islands to be identified and examined [Music] 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 delesi 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 assistants in the investigation wreckage that's found floating is also brought to the pengu islands investigators need to know how one of the world's most successful planes on one of the world's most traveled routes simply fell out of the sky well boeing 747 is the world's most popular jumbo jet and it's flown millions of people probably billions of miles so it we're very concerned [Music] 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 k young gets the first major clue in this case the radar tracked the plane as it climbed on course to 35 000 feet then suddenly flight 611 signal split apart the breakup is quite graphic right when the event happened it appeared as if there were three or four sizable pieces of wreckage that were getting radar returns that then began to drift and scatter as they fell to the earth so that told us that the airplane broke up in flight investigators now must turn their attention to finding out what caused that breakup there's all kind of theories about you know what seems to be happening of that particular aircraft we knew that something massive had happened happened suddenly without warning it doesn't take long for the media to consider a sinister possibility that flight 611 was shot down china and taiwan have a combative relationship china has fired missiles towards taiwan in the past there's suspicion in the media that china shot down flight 611. there were a lot of theories about you know the uh the it was shooting down by enemy fire only eight months earlier a siberia airlines flight with 78 people on board was shot down over the black sea it was accidentally hit by a missile fired from ukraine during a training exercise 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 [Music] 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 mid-air collision there were no other objects in the air near the airplane few things would cause a plane to break up in 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 they'll be it for floating wreckage the team from the ntsb arrives in taiwan good morning i'm playing correct thanks for me and tsp 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 we are not getting much from the floating debris in flight breakout 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 this puts added pressure on investigators to find out what happened 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 [Music] like the china airlines flight it broke into pieces while still climbing that plane crashed into the atlantic shortly after taking off from new york twa flight 800 was the biggest investigation the ntsb has ever done 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 the early evidence is pointing to a repeat of twa flight 800. so it looks really very very similar so therefore they our our immediate focus was essentially the central field tank three weeks after the crash the yan 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 [Music] using sonar investigators have located the wreckage of flight 611 deep underwater all right to the right of it clint crookshanks knows all the pieces that make up a 747 but he's never seen them like this it was really quite a shock when i first saw pieces on the on the floor of the ocean with only the lighting of the rov to guide you you would you would notice something that looked like an airplane part the rov would then circle around the part looking at it from all angles crookshank's job is to help the taiwanese identify specific airplane parts among the wreckage 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 all right a little bit more to the right all right go back there okay 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 kilometers 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 they hope that the pilots will have said something to each other about an emergency on board welcome aboard china airlines the recording begins about 10 minutes before the plane took off preparations for the flight sound normal okay i have to start checklist after start anti-ice the crew checks all their systems and runs through standard checklists it was very very experienced true both the captain and the fly and the first officers were quite seasoned dynasty 611 zero five zero at nine are cleared for takeoff clear for takeoff dynasty six one one take off [Music] 80 check e1 rotate 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 [Music] the captain seems relaxed roger nothing seems wrong there are no unusual sounds the final words spoken in the cockpit are from captain yee ching fung 2000 he calls out the distance to their cruising altitude that's followed by the sound of a chime alerting the crew that they're nearing 35 000 feet and then the cockpit microphone picks up the sound of the plane breaking apart half a second later the recording stops the copy voice recorder indicated that the the uh the conversation of the copy crew were totally normal and all of a sudden just just dying 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 breakup 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. we play a lot of focus on the wreckage observation examination of the central field tank on july the 12th 48 days after the crash okay whoa whoa then to the left please success all right that's definitely the central fuel tank okay let's mark that let's bring that up [Music] 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 and we found the central field 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 drew out it was the cause of the snow 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 the china airlines crash was neither a repeat of twa flight 800 nor a deliberate bombing investigators are running out of leads as more 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 pressurized 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 the pilots couldn't control their plane after their cargo door blew out if the floor on that flight hadn't collapsed the pilots may have been able to save the plane [Music] 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 [Music] 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 k 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 u.s investigators use to figure out how twa flight 800 disintegrated it's impossible to do without specialized computers we figured that because it disintegrated in the mid-air the ballistic analysis from which the ntsb did in tw 800 could be very very useful to us to help us to analyze the trajectory of the fine 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 radar that had been tracking the plane as it climbed also ended up tracking pieces of debris as they fell the salvage workers have recorded the precise location of those same pieces of wreckage their logs could match a specific piece to its radar track 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 breakup [Music] as they're brought to the dock every single piece of wreckage has been logged and numbered for identification three two seven k 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 199 along with all the other data he'll feed information about each item's weight and shape into the computer 526. 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 35 000 feet kay young gets to see how flight 611 broke up from beginning to end the tail came off first along with the dado panels it's a very important clue that 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 pengu islands the ntsb sends metal urges 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 [Music] there was definitely eureka moment on the dock that was hey we might have something here hey it's frank i think we 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 breakup 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's if it were to break apart just the the force of the incoming air at over 500 miles per hour will just break up perfectly good structure that's what we 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 over stress 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 over stress 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 had it caused the deaths of 225 people there was much more work that needed to be done a detailed analysis of the piece had to be done in order to see if this in fact was the smoking gun 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 tire 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 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 we were looking for repair to the aft lower lobe whatever it was it was big investigators sift through 22 years of documents but the records are sketchy finding details on one particular repair could take time there's something about this particular doubler that catches frank zakar's attention the outside of the fuselage contained longitudinal streaks that appear to emanate from between the doppler plate and the skin something is leaking from underneath the metal patch [Music] 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 here to here and send this piece to chengchang in order to see what's underneath the doubler a large section of p640 is sent to a lab no evidence has been found of structural or mechanical problems with boeing's 747 200 airplanes taiwanese aviation officials have no reason to keep the planes on the ground the chungshan institute of science and technology is a military research facility it's at the forefront of taiwan's space programme [Music] 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 [Music] 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 color 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 when we disassembled the doubler plate from the skin we noticed that 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 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 it is closer 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 z009 hong kong tower we observe smoke and spark from your tail on landing your hong kong tower we'll have that looked at still strike sir i better log that it is a relatively common occurrence it's not a good thing some airplanes even have what's called a bumper in that portion of the air 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 tail strike damage is routinely repaired investigators want to know how china airlines went about fixing the plane they could 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 china indicating they could not find any those any of those any of those documents and when we start looking for it we could not find any and they said they probably got lost 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 [Music] is what we got [Music] 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 repairman 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 [Music] you have to follow certain procedures in the bowling structure repair manual indicating 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 [Music] in the event of scratching it depends on how deep the scratches are if they're not very deep they can be blended out but if the scratches are too deep the repair technique that's called for is to actually cut out all of the scratched material and then design a doubler patch that's larger by a big percentage of the structure that was originally removed the scratches weren't sanded down or cut out they're still there maintenance workers then made one final mistake they put the doubler plate right over the scratched material the doubler plate that they put on was not 30 percent 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 [Music] pieces were really starting to fall into place now once we saw this piece of structure that had the fatigue cracks in it and we realized that it came from a structural repair that was not done properly [Music] that was left to fly for 20 years airborne passing 1 hundred things began to make sense by covering an improper repair with a doubler and then documenting the repair as meeting boeing standards the workers made their mistake impossible to detect what was so insidious about this improper repair was that the doubler plate hid all of the damage so if you weren't there watching them do this repair improperly you wouldn't know that it was done improperly you would have assumed that the structure underneath had been cut out the way it was supposed to 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 pressurized 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 tire the inside air pushes against the plane's skin each time the airplane pressurizes pressure built up inside the fuselage of the airplane that crack could open up for a certain amount of inches or microns or millimeters 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 meters 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 it reached its critical length and 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 [Music] 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 the years mechanics would have scrutinized the plane there's 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 aging 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 [Music] the regulation called for airlines to re-evaluate all existing repairs to a plane structure 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 examined the photographs that china airlines took of the repair and and noticed that there was 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 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 pressurized air with nicotine 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 be able to spot it right 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 and that would be the 7c check currently scheduled for november the 2nd 2002. but the 747 never made it to november 2nd 2002 it came apart over the taiwan strait five months before the inspection that would have undoubtedly uncovered its hidden floor [Music] investigators want to prevent a similar accident from ever happening again [Music] they recommend that aviation agencies around the world immediately inspect repairs for any possible hidden damage [Music] 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 [Music] investigators also proposed 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 the doppler that device uses ultrasound sound waves that travel through metal it can reveal damage underneath the doubler [Music] it's the same technology that allows doctors to observe a fetus 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 dollars for missing inspections designed to find cracks the finding of southwest brings back into focus how important it is to do maintenance properly on an airplane [Music] a proper program of maintenance and inspections can be costly but as china airlines showed the price of not maintaining aging planes is even costlier [Music] you

Channel: On The Move

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Keywords: on the move, cars, planes, trains, documentary, documentaries, full length documentaries, plane documentary, mayday series, mayday, plane disasters, airport, runway, plane pilot, pilot, hd documentary, 2021 documentary, united airlines, plane crash, air accident, air crash, air disaster, plane accident, air emergency, plane disaster, plane emergency

Id: t2tyGMfXYAk

Length: 50min 3sec (3003 seconds)

Published: Tue Oct 19 2021