Denmark's Deadliest Plane Crash Partnair Flight 394 | Mayday | Wonder

paper was light gold in medieval times [Music] oh no tobacco sugar [Music] that everything we thought we knew about the world might turn out to be completely wrong [Music] high above the north sea an aging propeller plane tumbles from the sky first headline was sabotage investigators consider a string of possibilities it takes two years to find the cause it's something that's never been seen in any previous investigation they looked at that and said man oh man how could that be it would lead to arrests half a world away and call into question the safety of one of the world's most important planes air force one it reached all the way to the aviation that flies around the present united states so 4 30 p.m september the 8th 1989 are flying a charter flight from oslo norway to the german city of hamburg radar the plane is about 100 kilometers from the danish coast one two four decimal five five by partner three nine four how was dinner delicious a little pricey but delicious the two friends have flown around the world together including remote areas of africa they're highly experienced and both are only months away from retirement copenhagen good afternoon partner 394 flight level partner 394 good afternoon radar contact copenhagen control 394 the plane is flying 22 000 feet above the north sea the aircraft they're flying is a twin prop convair 340-580 it's a popular plane for short routes like this one [Music] the plane has been chartered by the norwegian shipping company wilhelmsen all 50 passengers are winners of a company lottery sending them on a free trip to hamburg to name a new ship [Music] some had maybe been through naming sermons before but the naming ceremonies are quite exciting and the atmosphere was very very very good at the time of leaving one of the company's best employees is chosen to give a speech at the christening of the ship in hamburg you have to deliver a speech and it's not so very often that normal person within the company is giving the honor of naming a ship but just felt that that was right as the convair crosses the north sea a norwegian air force f-16 approaches the plane on its way home [Music] whoa look at that 11 o'clock f-16 [Music] suddenly the plane experiences a violent shock the crew is caught by surprise the plane begins rolling upside down [Music] air traffic control notices that partner 394 is off course and falling from the sky partner 394 copenhagen control please report new flight level the crew is struggling to save the plane and the lives of everyone on board please report new flight level then it disappears [Music] it seems as though the charter flight has crashed into the sea partner 394 on route to hamburg is off radar [Music] rescue teams race to the crash site nearly 20 kilometers north of the danish coast they find only wreckage and bodies all 55 people who were on the flight are dead i knew all the people and some were close friends some were less close but i knew them all and the pressure then felt double [Music] the shipping company is devastated by the news half the staff from its head office has been killed [Music] the nation is in shock [Music] jan ovind is a young reporter for norway's largest newspaper he's assigned to cover this story one of the inspectors in the norwegian faa jumped to the conclusion that it had to be sabotaged and it was also stated by one of the danish rescue team leaders who said that they had no distress call it just fell out of the sky which meant it had to be a bomb or something and somebody draw links to lucky b the year before in december 1988 pan am flight 103 exploded over lockerbie scotland the evidence in that case is pointing conclusively to a bomb [Music] norwegian journalists uncover an intriguing fact about the partner airplane our prime minister at the time guru holland and clancy used the plane on her campaign trip to the north of norway and i guess he used it for two or three days and that was just two or three days before he crashed the nation wonders could the tragedy have been a botched assassination attempt the first headline was sabotaging on the whole front page a bomb would explain the plane's sudden plunge from the sky had the 55 people on board been the innocent victims of a murderer investigators looking into the mysterious downing of a passenger jet over the north sea are facing a stunning possibility that the plane was deliberately sabotaged [Music] the norwegian accident investigation board recruits an air force investigator fein heimdall to join the team it will be a severe test of his investigative skills it's good to be here i started many many years ago with the air force and of course i saw some investigations mishandled terribly and i thought it can be done better than that investigators hear from several witnesses who lend support to the idea that the plane was sabotaged a young man claims to have heard a cannon-like sound coming from the crash site of the danish coast it may have been the explosion that brought down the partner plane searchers scour the surface of the sea for floating debris and for victims of the crash eventually all but five bodies are found they're taken to denmark for autopsies those examinations reveal that some of the victims have small puncture-like wounds this supports the notion that a bomb brought down partner flight 394 an autopsy on the first officer also uncovers something unusual a complete unbroken toothpick is discovered in his stomach now that was a odd finding really because what pointed both ends and how can you swallow a toothpick like that so he must have been exposed to a very shocking experience [Music] but investigators can't confirm that a bomb brought down the plane they'll need to know more about the final moments of flight 394 partner 394 on route to hamburg is off radar nine separate radar stations tracked its final seconds they could provide valuable clues the most intriguing readings come from a military radar station in sweden operators there tracked the partner flight as it crossed the north sea let's start at 1436 the military radar has detected something unexpected there is another object in the same airspace as the plane it is not another airplane it appears as flight 394 started to plummet from 22 000 feet idea what it is simply didn't know what it was from the beginning we had no idea what did what it could have been it took more than half an hour something like 38 minutes and the question was what is light enough to fall that slowly and then solid enough to give radar returns like that whatever the mysterious object was it now lies at the bottom of the sea a month after the crash investigators are busy recovering sunken wreckage they've plotted the position of the wreckage on the ocean floor using side scan sonar [Music] it sends out sound waves that are reflected back when they encounter objects the sonar equipment has painted a remarkably accurate picture of the underwater wreckage it helps investigators see that the plane parts have settled over a two kilometer wide area it's an important piece of evidence it was evident that the aircraft had come apart in the air it hadn't hit the sea in one piece that was for sure the mid-air break-up suggests a bomb brought down the plane but it will take weeks to prove this [Music] in the meantime investigators hope the plane's black boxes will provide more immediate insight into the crash the plane's voice recorder and eventually its data recorder are recovered from the seabed and sent to labs for analysis both boxes were damaged in the crash investigators hope the damage to the boxes didn't affect the data well let's see what we got the voice recorder may have picked up a conversation between the pilots that can explain what happened on board the device usually records the final minutes of a flight but this cvr has done the opposite power it recorded the start of the flight but then mysteriously stopped recording just before the plane took off well it had recorded the conversation on the ground but as soon as the engines were upshifted the normal rpm for takeoff it ceased operations so that was a disappointment to us but the malfunctioning cvr did pick up an intriguing exchange between the two pilots how's the weather in hamburg oh it's clear skies good visibility hope it stays that way the cvr does tell investigators that flight 394 began with an unusual problem partner was in financial dire straits and we found out that just a few hours before the plane took off the norwegian aviation authorities sent out the telex to tell all the airports in norway to don't let a partner plane take off because they owe a lot of money in non-paid charges and fees they won't release us for takeoff until we pay the catering bill how much you got on ya seriously probably enough actually wow i'll take care of it the first officer was forced to leave the cockpit to pay the caterers for on-board meals investigators check maintenance records to find out why the cvr only recorded the crew's conversation while they were on the ground they discovered that the plane's cockpit voice recorder had been modified more than 10 years earlier modified to switch to primary ac it was altered so that when the engines were given full power for takeoff they're powerful the cvr would automatically switch from the plane's batteries to its generator and that modification was not working on this aircraft neither pilot realized that as the engines were revved up for takeoff power to the cvr was actually cut off anytime you get key investigation components such as a cockpit voice recorder and flight data recorder that don't work correctly it brings into the question the thoroughness of the maintenance and and also the continued operation safe operation of the airplanes the malfunctioning voice recorder and the unpaid catering bill lead investigators to look more closely at the history of the airplane and the company that owned it partner airlines [Music] partner operated a fleet of mostly older planes that flew to northern european destinations the convair that crashed into the north sea was one of the airline's most recent acquisitions but the plane itself was 36 years old it had a complicated history of both ownership and modification the biggest change was to the plane's engines really important modification was upgrading the engines to turbine engines on prop planes the propeller moves air backwards propelling the plane forward early prop planes used piston engines to turn the propeller but turbine engines which use a series of fans not pistons to compress air generate substantially more power [Music] heimdall learns that in 1960 the plane's original piston engines were removed and powerful new turbo props were bolted to the wings it's a modification that provides more power but could pose a risk there was a tremendous increase of horsepower installing the turbine engines i was wondering what that was doing to the structure of the aircraft heimdall has been placed in charge of analyzing the plane's engines he wants to know if the turbine engines could have torn the aging plane apart i started asking the question how can an aircraft fly itself to pieces in mid-air the plane's flight data recorder should tell investigators about the operation of the engines in the moment before the crash the recorder from this flight is a primitive analog model to use the metal foil strip that rotated and some marking pins uh actually scratched on the on the metal surface on the piece of metal the antiquated data recorder proves to be another frustration for investigators it didn't record many of the parameters it was supposed to but more mysteriously the needle seems to have recorded certain signals twice the double line confounds experts who analyze the device we had no experience with anything like that we contacted several experts but none had experience with this before yeah i've never seen that before the flight data doesn't offer investigators any immediate revelations about the crash heimdall now wonders if the very fact that the recorder was malfunctioning could be a clue in itself he decides to send the flight data recorder back to the american company that made it for further analysis investigators painstakingly reconstruct the partner airplane the norwegian team recovered the the airplane with assistance from the the local authorities and the danish authorities i believe and decided to reconstruct the airplane a reconstruction is like putting together a puzzle that helps investigators focus the investigation on areas that need to be looked at and perhaps prioritize the investigation [Music] as the fuselage takes shape the reconstructed plane provides investigators with some stunning evidence [Music] the only thing that would destroy the aircraft at cruising level would be an explosion so and some of the parts looked maybe a bit serious suspicious for what's on them there were rumors that it was found explosives at in the partner plane there are traces of a powerful military explosive the amount is small but the press gets wind of it [Music] the explosive residue could be from a bomb on board the plane [Music] or from another source a nato war exercise called operation sharp spear was taking place that same day near the flight path of flight 394 one of the pilots i talked to and he said i guess it might have been the so-called cold rocket test rocket might have gone through one of the wings or diffused late in the fuselage many people now wonder if an errant warhead played a role in bringing down the planet but when the explosive residue is analyzed it's found not to have been from a bomb or a warhead there simply isn't enough of it on the plane there was a small sign of explosives but that was a very low level and looked more like a contamination than anything else battles have been fought off the danish coast the sea is littered with old munitions investigators believe the plane picked up some explosive residue while lying on the ocean floor explosives are ruled out as a cause of this crash metallurgist terry heslip has been brought in he examines the plane's reconstructed tail and makes a startling observation pieces of the plane's skin show evidence of damage from overheating which means that it was flexing and you take a coat hanger and you go like that back and forth if you hold it close to where it's going to break you'll burn your hand because you develop heat where you're doing the fatigue it's the same thing on an airplane the evidence is pointing to a problem with the plane's tail investigators are keen to look at a massive generator recovered from the rear of the aircraft the auxiliary power unit is housed inside the conveyor's rear fin it's a backup power generator that's usually only used while the plane is on the ground heimdall inspects the device and discovers that some melted plastic parts from the plane's cabin have found their way inside the apu's turbine it gives him an important new piece of information about what was happening on the plane at the moment it failed meaning that the cabin had failed when the apu was still operating the apu should not have been running while the plane was in the air the fact that it was means the apu could be behind this crash investigators try to learn more about what happened on the day of the crash they interview the mechanic who inspected the plane that morning he reports that one of the planes two main generators wasn't working and that he wasn't able to repair it regulations demand that the plane have two sources of power before it's allowed to take off [Music] the first officer comes up with a solution that will allow the flight to leave he tells the airline that he will use the auxiliary power unit throughout the flight as a substitute for the malfunctioning main generator okay i want you to write this in the log book released for flight with apu generator operative we'll use the apu to power the left side ac system apu is coming on beta lights off [Music] your power [Music] during his inspection of the apu heimdall makes an important discovery when i saw the part i saw it was not an aircraft standard part at all it was made in a very primitive way by a piece of iron and welding it together in a substantial way he notices that one of the mounts attaching the apu to the plane is broken the unit contains a rapidly spinning turbine that generates electricity if it wasn't properly held in place it could have caused this crash [Music] investigators need to know if the broken apu caused the crash they'll soon discover that it's just a piece of a much more troubling puzzle investigators have discovered that partner flight 394 was flying with a broken apu mount metallogist terry heaslip performs extensive testing on the failed part my initial reaction was that that the welding was bad was probably inappropriate he slipped wants to know when the strut broke if it happened during the plane's last flight it could explain the accident i could see the impact markings and the progression markings on it that showed that it did not fail in a single overload during this last accident flight the way the broken mount is worn down also tells he slipped that the mount holding the apu in place didn't break on the day of the accident it was broken long before flight 394 took off investigators now need to know what effect the broken mount had on the flight 40 000 rpms did a lot of damage yeah but it goes damp the apu is a large gyroscope having a tremendous amount of energy in it when it's rotating and if that energy is transmitted to the surroundings the fuselage the structure it could impact the whole vibration pattern in the thing investigators want to know if anyone had felt vibrations on this particular plane interviews with people who flew on it provide some answers listen we appreciate you coming in thanks a lot [Music] now you said you felt some rumbling on the plane is that right one person stated that the plane that crashed vibrated far more than the two other conveyors owned by the company did anything seem unusual on the plane but others failed to mention the vibrations and a good flight it's a puzzling situation investigators know the apu mount was broken before the flight but they still don't know if it even played a role in the crash or whether it would have affected the plane's tail then the reconstruction begins to clear things up heimdall discovers that two doors from the plane's tail have not been found when we reassumed the parts from the tail we saw that the rudder had been torn apart in two major pieces and some parts are missing in particular the doors between the fin and rather than missing the shroud doors are two small doors located on the vertical fin of the plane they provide mechanics with access to weights inside the fin that control the rudder's movement heimdall makes a dramatic find about the doors themselves they were constructed with an aluminium honeycomb liner from his days in the air force heimdall knows they have a unique property this is thin aluminum foil as you know and it has the good reflective properties for radar and it's very light the military use it to disturb radar signals call it chaff investigators now realize that the unidentified object picked up by swedish radar was probably a piece of one of the shroud doors but when we connected the missing doors and honeycomb with the radar data we knew that it had happened up at cruising altitude because the slow falling object had come from very high level cruising attitude practically investigators conclude that the tail began to break apart at 22 000 feet before it plummeted from the sky but why had the doors fallen off in mid-flight [Music] whatever caused the shroud doors to tear off likely caused the crash investigators know that the rudder's counterweights are located just inside the shroud doors [Music] if a rudder moves too violently from side to side the weights do as well we found enough pieces to show that that was just pounding these these doors and the first real components that came off were the honeycomb in those doors investigators conclude that around the time of the accident something caused the rudder to swing violently back and forth but they still don't know what the apu with the broken front shock mount on its own running in flight would not cause the aircraft to come apart and the tail to come apart there had to be extra factors there for that to occur investigators continue searching for those extra factors then partner airlines proposes one they point to the f-16 that passed over the plane just minutes before the plane veered off course whoa look at that 11 o'clock f-16 partner claims the military jet was flying faster than it should have been [Music] they also believe that it came much closer to the flight than officially reported partners they contacted the swedish investigator and he came out with the answer that the f-16 could probably have gone through this sound barrier as it passed just over the partner plane when the fighter jet or any other plane breaks the sound barrier you have this pressure wave and their theory was that this pressure wave just got a plane to disintegrate in the air but the norwegian f-16 pilot testifies that he was more than a thousand feet above the convoy when he passed it investigators calculate just how close the f-16 would have had to be in order to seriously disturb flight 394. they determined that for the f-16s pressure wave to have affected the convair it would have had to fly within a few meters of the plane there's no evidence the two planes were ever that close okay good work [Music] ninety percent of the plane's wreckage has been recovered from the sea but investigators still don't know what caused the conveyor's tail to come off in mid-air [Music] during the course of the investigation finn heimdall is given a promotion but he has no idea how to solve the puzzle that haunts his nation they asked me to be in charge of the rest of the hardware investigation i was standing in a heap of wrecked parts and thinking i'll never get to an end of this investigators get a break when the faulty flight data recorder is analyzed in the united states the manufacturer has asked its top expert to come out of retirement and examine the device manufacturer fairchild referred us to a previous employee and we found him in california the expert tells investigators that the needle that was supposed to be recording the plane's altitude was shaking so much that it was leaving another mark on the foil but then he goes one step further the fdr has a capacity to record for hundreds of hours by unspooling the metal foil completely he sees that the fdr has been vibrating severely for months we saw that this had happened something like 360 operations hour before the accident i had never seen an abnormality like that before and it took us a while to figure out what was going on here it now seems the apu wasn't the only thing vibrating on this plane investigators decide to chart the history of the vibrations chronologically they notice an unusual change in the pattern of vibrations two months before the crash the vibrations suddenly stopped for a number of weeks virtually no vibrations for at least 16 flights both increasing intensity and frequency up to the summer of 89 and then the pattern changed after getting better the pattern of vibrations got worse again right up until the crash what happened here investigators now need to find out what changed on the plane during the two-week period when the vibrations stopped why was it out of service where was the work done the airline tells investigators that during that time the plane was receiving a major overhaul in western canada thank you we'll be in touch the work was done by the plane's previous owner a canadian company that specializes in servicing conveyors during the various test flights there the fdr recorded almost no excessive vibrations this healthy pattern continued on several passenger flights once the overhaul was done and the plane returned to norway investigators review the maintenance records heimdall finds that during the overhaul mechanics found signs of wear on one of the four bolts that connect the vertical fin to the plane's tail these four bolts are the only things holding the tail to the fuselage [Music] during the overhaul of the convair in july of 1989 a mechanic replaced one of the four bolts the information from the flight data recorder reveals that the vibrations in the tail stopped right after that one bolt was replaced you see that and as i go across incredibly investigators are able to recover all four of the bolts which were holding the tail in place [Music] terry heaslip thoroughly analyzes the bolts he makes a final stunning discovery the three bolts that weren't replaced were not approved parts we did metallurgical uh testing and we did mechanical testing and by doing all of these analyses we worked out that the three of the assemblies were not up to scratch they were they were bogus assemblies his analysis shows that the faulty bolts were incorrectly heat treated when they were made as a result they are only 60 as strong as they should have been investigators finally know why the tail was vibrating for months three of the bolts holding it in place were too weak they just weren't hard enough unbelievable three bolts holding the tail to the rest of the plane were not authentic parts they were well disguised fakes the weak bolts mean investigators now must answer a critical question why didn't the tail come off in the previous 16 flights where it vibrated excessively why this last flight investigators already know that on the day of the accident flight a power generator wasn't working and that the pilots improvised a solution okay i want you to write this in the log book released for flight with apu generator operative we'll use the apu to power the left side apu is coming on the pilots didn't realize that the apu mount was broken and the motor was vibrating considerably their decision to run it throughout the flight made a bad situation worse the reason why things got bad on this particular flight is that the apu was literally floating on two mounts instead of three this along with the faulty bolts created even more vibrations in the tail of the plane and when you get the two of them shaking if they ever get into sync what we call resonance with each other disaster the investigators conclude that the vibrations in the tail and the vibrations from the apu could have combined into a lethal force now this is what we got from the guys at mit technically the vibrations could have torn the plane apart if the two loose items are start to vibrate in the same frequency now you're going to get or are a multiple of that frequency you get what's called coupled harmonics and the uh one vibration is feeding the other one they're feeding each other and making each other worse and worse [Music] the most famous example of coupled harmonics occurred on the tacoma narrows bridge in washington state in 1940 the newly built steel and concrete bridge began swaying lengthwise and then a crosswind started dipping it left to right the two vibrations moving in different directions combined to create a violent twisting motion that tore the bridge apart investigators calculate that the same effect tore apart flight 394 and we said my gosh that's exactly the phenomena we have here this lethal combination of vibrations caused the tail to sway back and forth so violently that the rudder jammed to the left this forced the plane into a left turn so abrupt that it increased airflow over the right wing creating greater lift and causing the aircraft to roll the plane recovered briefly but the rudder jams to the left again and the shroud doors explode it rolls a second time the tail begins to disintegrate after that the crew didn't have a home investigators conclude that it was the three bogus bolts that initiated the partner crash then i looked at that and said man oh man how could that be in a crucial component of crucial fitting like that in the tail i couldn't believe it the report on partner flight 394 sends shockwaves throughout the aviation industry it's the first time that a fatal plane crash has been linked to unapproved spare parts it raises a frightening question how many of the parts being put into planes around the world are bogus the partner crash that was the seminal event that started people actually having to recognize the unapproved parts problem and the fact that the worldwide inventories of aircraft parts in fact were contaminated [Music] there are six million moving parts on a 747 alone the spare parts business is a 45 billion dollar industry and at the time of the crash that industry was largely unregulated mary schiavo is the former inspector general of the department of transportation the agency that oversees the faa no one knew how large the problem was they knew it was a problem because of a crash but how big was the problem united states so we set out to measure it we started by auditing the faa's own parts bins and the faa's own parts bins contained 39 bogus parts what we found is that the parts had come from parts broker which was a huge percentage of the parts supply industry 95 of them were not authentic [Music] the faa would soon find bogus parts on an airplane widely considered to be the most secure plane on earth [Music] there are 5 000 parts brokers in the united states many of them in the miami area parts brokers had no regulation whatsoever you had a telephone and a fax you were parts broker overnight you could be in the parts brokerage business and you could get them anywhere you chose you get them from junkyards you could get them from scrap facilities you could get it from old planes you could get them from crashes you could get them from people who are willing to manufacture and don't care about the law spare parts for airplanes are expensive a single bolt like the one holding on the partner flight's vertical fin can cost up to 250 a bogus one can cost as little as 30 which makes it a bargain and when you have situations like you have today and airlines are bottom line driven and you've got eight or ten major airlines in the united states for example that are on the verge of bankruptcy they're looking to cut costs the faa launches a major investigation into illegal parts and uses sting operations to uncover unscrupulous dealers investigators uncover a black market industry that makes thousands of worn and inferior parts look brand new these are really good counterfeits it's very difficult to tell at the time of the partner accident there were checks and balances in the system that was supposed to keep bogus parts from getting on major airlines for instance each spare part needs someone's signature to verify its authenticity it has to have some documentation that states that it's airworthy it has to have a maintenance release by some certificated entity but investigators discover that in addition to a huge market in spare parts there's also a burgeoning market for counterfeit faa tags [Music] execute search warrants and find the people that printed stacks of fake yellow tags in many cases they'd sign with the name of an actual inspector but they just forged the signature [Music] the tag in this business is worth more than the part at first investigators believe the problem is mostly with smaller airlines smaller operators and repair stations are usually the people who are most vulnerable to this aftermarket broker parts problem they're shocked when they discover that bogus parts have been found on what is supposed to be the most tightly controlled plane in the world air force one it reached all the way to what many people consider literally the highest levels of aviation the aviation that flies around the present united states supposedly in an airtight supply chain we had bogus parts cases that touch those aircraft the faa responds quickly more than a hundred dealers are arrested with every conviction we were able to raise the level of awareness not only of the problem but of the severe consequences if you want to risk somebody's life and i actually think that the most important thing that we did was get criminal convictions as a result of their investigation the faa institutes a much more rigorous system for documenting airplane parts they threaten airlines with criminal charges if they knowingly accept bogus parts things are different today because we have a whole body of regulations much more than we had in the 80s and 90s even to address the problem you have to get the mechanic who's actually got the wrench in his hand to a point of sophistication where he's knowledgeable enough to to smell a bad part to smell a bad piece of paper and it is possible to do the new regulations achieve their goal in the two decades following the crash of partner 394 there wasn't a single fatal accident attributed to bogus parts years after the partner crash finn heimdall became the head of the norwegian accident investigation board my friend was a major puzzle that an aircraft for no obvious reason could more or less disintegrate in mid-air his report into the accident resulted in major changes that likely saved lives that's the positive thing but the negative of course is the tragedy the personal tragedy to many people one of the smallest parts on a norwegian charter plane failed in 1989 because investigators found the cause of that accident passengers around the world are safer less likely to be on a plane that's fitted with bogus parts [Music] [Music] you

Channel: Wonder

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Length: 50min 33sec (3033 seconds)

Published: Sat Jan 22 2022