The Puzzling Crash Of United Airlines Flight 585 | Mayday

there's a way to make an entrance my destiny it was now a conspiracy of witches download veli [Music] today the boeing 737 is one of the most popular passenger jets in the world [Music] around the globe the plane has carried more than 12 billion passengers it's the backbone of the aviation industry [Music] but in 1991 something happened on board a 737 that sent shudders through the world of aviation [Music] oh my lord [Music] a deadly crash has investigators scrambling there was a time when i i had doubts that we'd be able to solve it it was like he was tracking a serial killer [Music] the hunt for answers will take 10 long and gruelling years the fate of the airline industry hangs in the balance and the mystery isn't solved until more than 150 people are dead so 9 40 a.m march the 3rd 1991. after a short 17-minute trip from denver united airlines flight 585 is on final approach into colorado springs it looks like a perfect day for flying but there's trouble in the air nice looking day hard to believe the skies are unfriendly [Music] there's been heavy turbulence during the flight and violent gusts of wind are forecast over colorado springs never driven to colorado springs and not gotten sick at the controls is 52 year old captain harold green a pilot with 20 years experience and a sterling reputation green's co-pilot is patricia eidsson at 42 she's one of the first female flight officers in united's history flight attendants prepare for landing at colorado springs municipal airport air traffic controller james rayfield is ready to bring flight 585 in united 585 report the airport in sight got it yep airport in sight united 585 lower landing gear united 585 is cleared for a visual approach to runway 35 weather conditions wind 320 degrees at 16 gusting at 29. as its speed decreases flight 585 becomes more vulnerable to the turbulence eidson wants to know what other planes have experienced on landing and reports lately of any loss or gain of air speed yes ma'am 500 feet a 50 knot loss at 400 feet 50 knot gain and at 150 feet a gain of 20 knots sounds adventurous thank you starting on down less than three kilometers from the airport retired policeman harold darnell is on his way to a local flea market a kilometer overhead green and ice and focus on keeping their speed constant as they descend wait a ten not change here yeah i know awful lot of power to hold that air speed as united 585 approaches the runway darnell feels something strange out of nowhere a powerful gust of wind strikes his vehicle almost blowing him off the road another 10 hour game three flaps from the control tower james rayfield can now see flight 585's final approach as the aircraft closes in on the airport the ride gets even bumpier well 4 000 feet then without warning the 737 starts to spin out of control [Music] [Applause] my gosh oh my lord crush crash [Music] rescue workers arrive within minutes but there's almost no sign of the 737 [Music] the shattered remains of the 38-ton jet lie buried in a fire black and impact crater the plane didn't it didn't skate or bounce you know like like when a plane comes in normally and lands it just nosed right in and where it hits where it stayed and i came down here and this is when i saw all of the it was horrible there are no survivors all 20 passengers and five crew members are killed instantly by the high speed impact and exploding jet fuel in ten violent seconds colorado springs has become the site of one of the most mysterious air crashes in aviation history [Music] by nightfall investigators from the national transportation safety board descend on colorado springs [Music] known to insiders as tin kickers ntsb investigators examine over 2 000 aviation accidents a year at times by picking through the metal debris of fallen aircraft [Music] while coroners mark the location of human remains in red ntsb investigators mark scraps of metal in yellow looking for clues to help them solve the mystery of flight 585 [Music] like investigating a mass murder it's a tough job walking onto a crash site among the investigators assigned to the case is malcolm brenner a specialist in human performance his job will be to find out if the crash was caused by pilot error the area was cordoned off by police and there were salvation army trucks i got a cup of coffee a cup of hot chocolate or something and i thanked them for it and they said no no thank you and they had this look in their eyes like my god you have to go into this site [Music] clues to the fate of united 585 lie mangled in a deep black hole the fuselage is crushed like an accordion in the impact crater the rest of the plane is in pieces spread over an area smaller than a football field [Music] there was a lot of fire damage there'd been a fire afterwards and was all contained in a relatively small area which uh just initial impression it can be a sign that the airplane was intact if there was a mid-air explosion or something came off the airplane you'd expect that to be a much larger site my first sense that it was going to take some time and to investigate the accident was was the damage that we saw in the parts when they're burnt and broken the process always takes longer but with their work just beginning members of the ntsb have no clue that the case of united 585 will become the longest crash investigation in aviation history [Music] a clear late winter day in 1991 turned deadly in just 10 short seconds moments from landing in colorado springs united airlines flight 585 fell out of the sky at 370 kilometers per hour all 20 passengers and five crew members died [Music] the national transportation safety board begins a painstaking investigation into the crash engine turbines hydraulic pressure gauges the cockpit voice recorder and in-flight data recorder are all carefully extracted from the site photographed and sent to the lab for analysis an important first step in the investigation is the analysis of the cockpit voice recorder with pilot error a factor in seventy percent of air disasters malcolm brenner's job is to see what role pilots green and eidson played in the crash this crew was and i felt this at the time was one of the more impressive crews i'd ever dealt with there was a little bit of tension release a little bit of humor the captain said never driven to colorado springs and not gotten sick the first officer suggested that they add extra speed as a safety margin the captain agreed with it it was good interaction got it yep airport in sight united 585 lower landing gear this is a sense of an excellent crew caught randomly if anything so again that was my first impression is that this would be consistent more with a hardware situation as more about flight 585 becomes known mechanical failure becomes a serious suspect [Music] just seconds before it crashed the plane rolled onto its back and spun wildly out of control investigators wonder if the sudden motion was caused by the plane losing an engine or a wing from the state of the aircraft on site it's clear that it was intact at the time of the crash what investigators don't know is if the engines were still working at impact [Music] technicians examined the engine turbines they discovered dirt has been drawn deeply into every crevice these blades were clearly spinning and sucking in air at the time of impact the engines may have been running but technicians aren't sure how well the plane's hydraulic pressure dials are destroyed their glass covers broken the indicator needles have been snapped off by the force of the impact but even these ravaged dials tell a tale on close inspection investigators find a critical mark at the moment of impact a dent was made on the faceplate by the jarred indicator needle it proves that when united 585 crashed its engines were running normally [Music] with engine failure ruled out there seems to be only one other mechanical explanation for why 585 suddenly rolled over and then fell out of the sky [Music] it appears increasingly likely that the plane had suffered a catastrophic problem with its flight controls investigators quickly become suspicious of the rudder at the back of the tail we focused in after eliminating other flight control surfaces that we thought could contribute to the role we started looking at the rudder bring that up so i can take a look at it investigators begin their examination of the rudder on site but the violence of the crash makes the job extremely difficult almost nothing left [Music] most of the planes parts are too crushed or burned for testing but a vital component is still reasonably intact the power control unit or pcu used constantly during flight especially during landings the pcu performs like a car's power steering when the pilot pushes on a rudder pedal the pcu uses hydraulic fluid to convert gentle movements of a pilot's foot into the pressure needed to move the 737's enormous rudder the heart of the pcu is something called the dual servo valve [Music] shaped like a soda can it has two slides which glide past one another directing the flow of pressurized hydraulic fluid that moves the rudder [Music] this servo valve is is very unique that it is in effect two valves in one and that that creates a whole range of interactions that don't occur in a in a more conventional hydraulic valve [Music] when a technician opens the power control unit chips of metal are found floating in the hydraulic fluid it's a disturbing find these particles could cause the servo valve to jam making it impossible to work the plane's rudder it's a chilling prospect could a microscopic fault bring down a 38-ton jet it's difficult for phillips to tell while more intact than much of the wreck the pcu and dual servo valve are both damaged the airplane crashed and burnt in a pretty confined area and there was a lot of damage to the flight control components and the things we were testing and needed to test and look look at the more damage the components are the harder it is to to take measurements and do functional testing to test what he does have phillips travels to california to the labs of parker hanafin where the rudder control unit is made [Music] the curious metal chips floating in the pcu's chambers are dismissed phillips is told that filters keep them out of the delicate servo valve that directs fluid and moves the rudder nothing else is found that could explain any sudden movement of the rudder on flight 585 we didn't have any absolute indication or information that we could point to that said the rudder power control unit the servo valve or any any part of that flight control system caused that accident phillips still suspects a mechanical problem but with no conclusive evidence that the pcu or servo valve caused the crash he's forced to sign off on the tests it's a pass with philips at a dead end only bad mountain weather remains as a primary suspect an expert on weather-related aviation accidents greg salatollo is trying to determine if heavy winds on the day of the crash were a factor there is a is a history of events where there have been airplane accidents attributed to mountain waves of rotors in 1966 a boac 707 near mount fuji uh disintegrated in a mountain waving rotor high winds crashing over mountain peaks leave so-called wind rotors in the lee side invisible highly turbulent downdrafts that come plunging down with devastating power and are extremely dangerous to aircraft we found a great deal of evidence looking at the surface upper air data and talking to witnesses in the area that voters were a possibility an explosion it was right over there salatollo hears several eyewitness reports of bizarre mountain weather on the day of the crash one of the most intriguing is from harold darnell whose truck was struck by a powerful gust of wind just moments before 585 crashed but as greg salatollah combs through his evidence the theory that a wind rotor knocked the plane from the sky is getting less and less likely nice looking day hard to believe the skies are unfriendly wind rotors are areas of extremely low barometric pressure so if flight 585 did pass through one its altimeter reading would have spiked as the plane was blown suddenly upwards there was no evidence that we saw that on the flight data recorder of 585. what the flight recorder did show was a fast and deadly drop in altitude as the plane fell to earth it's been 21 months since the investigation into the crash of united flight 585 began almost two years in which the ntsb has studied the crew the weather the rudder and thousands of other pieces of evidence they've come up empty-handed for only the fourth time in its history the ntsb releases a report which doesn't reach a conclusion the cause of the crash of flight 585 is undetermined we had put a lot of time and effort in into the investigation and we just weren't sure what had happened it was like he was tracking a serial killer he was frustrated that they had not solved 585 he did not want that to happen again but almost two years after the report on 585 is released the killer strikes again at 7 p.m on a clear windless day us air flight 427 is nearing pittsburgh captain peter germano and first officer chuck emmett are getting ready for their final approach [Music] folks from the flat deck we should be on the ground about ten more minutes sunny skies a little hazy slight attendance please prepare for landing i'll ask you to check the security of your seat belt thank you usair 309 descend and maintain 6000. as they close in on the airport the pilots are on the lookout for another flight about 10 kilometers ahead of them looking for the traffic [Music] turning one zero zero usair 427 [Music] i see the jet stream as they pass through the turbulence left behind by the other flight their jet suddenly and alarmingly rolls left hold on nothing the pilots do seems to have any effect [Music] 427 emergency oh shoot oh come on oh god [Music] rescue crews arrive quickly but the fate of flight 427 is tragically clear there's no hope for the 132 passengers and crew the human carnage is so bad authorities declare the crash site a biohazard usair 427 accident was the first u.s accident where biohazard suits were used and it made it more difficult they were uncomfortable they were hot and to this day when i put on a pair of rubber gloves for any reason i'm instantly transformed back to the site in pittsburgh captain john cox a 737 pilot and a flight system specialist with the airline pilots association is asked to join the team investigating the crash of flight 427 as coroners attempt to collect human remains ntsb lead investigator tom howter already knows his hunt for clues will be long and painstaking when we first arrived at the crash site well first of all there was no aircraft there there were only bits and pieces of the airplane it wasn't really recognizable as an airplane with the help of eyewitnesses information from the flight data recorder and the cockpit voice recorder investigators begin to quickly see some striking similarities between 427 and the unsolved case of united 585 in fact they seem to be mirror images of each other on final approach united 585 rolls right while us air 427 rolls to the left both crews are caught by surprise and after just a few terrifying seconds both aircraft plummets straight into the ground certainly the whole team was aware of the previous accident with united 585 in colorado springs we try to keep that in the back of our minds and take a look at this one as to what it presents to us as the investigation continues the list of similarities grows 427s engines were also attached and functioning at the time of impact but for all the similarities there's one important difference unlike united 585 as us air 427 approached pittsburgh weather conditions were dead calm folks from the flat deck we should be on the ground about 10 more minutes sunny skies a little hazy taking a look at the flight data recorder information the aircraft's approaching pittsburgh it's an extremely smooth night there's just no turbulence at all the pilots are relaxed they're talking about the landing flight attendance please prepare for landon ask you to check the security of your seat belts thank you as he did in the case of united 585 greg phillips will once again lead the investigation into the mechanical aspects of the crash almost immediately he makes a promising discovery miraculously much of us air 427's tail and rudder appear intact [Music] the hydraulic devices inside the tail have also sustained very little damage phillips and howter prepare to send the parts to the manufacturer parker hanafin for testing as soon as possible they need answers pressure on the ntsb to solve the accident is growing quickly not only are the crashes of flights 585 and 427 disturbingly similar both of them involve the same kind of airplane a boeing 737 but with serious questions being raised about the plane's safety billions of dollars and perhaps the airline industry itself are at risk we couldn't live with the fact as investigators of having two unsolved 737 accidents the airplane is in too much use too wide of use around the world it carries too many people every day unsolved was not an acceptable answer if 427 was an undetermined accident we could not find to cause this accident there was a great chance that what there was a if there was a third accident with the 737 fleet under similar circumstances that the 737 fleet would have been grounded careful with it the investigation into the crash of flight 427 may be the most important in the history of the ntsb but it won't be easy answers are still years away in just three years two boeing 737s have crashed in the united states with no survivors and in both cases the planes were under full power but the pilots were unable to control their jets in the crash of united flight 585 ntsb investigators were unable to find a cause now they're searching for clues into the second crash us air flight 427 as the investigator in charge i never allowed myself to think this investigation could go undetermined just we kept on pushing and kept on researching as long as we had things to research we kept on going to find their killer the ntsb can't afford to rule anything out from the possibility that a collision with birds brought four to seven down to strange even bizarre theories they looked at electromagnetic interference they got calls from people saying it might be russian death rays they considered everything there were a couple of witnesses who gave reports of the aircraft suddenly descended and hovering before it blew up we discounted those but the investigation's primary suspect is the dual servo valve part of the power control unit that moves the 737s rudder and a suspect in the crash of united 585 parker hanafin made the valve at its lab in california investigators look inside the main cavity of the us air power control unit just like in the earlier crash they find tiny chips of metal floating in the hydraulic fluid but once again parker and boeing repeat their claim filters designed to stop any debris from interfering with the delicate metal slides have done their job investigator greg phillips wants to be absolutely sure if the chips were blocking the slides they would have left tiny scratch marks behind where they rubbed against the metal [Music] but phillips can't find any another pass okay phillips has technicians put the servo valve from flight 427 through as many tests as he can think of trying to find a weakness if he can find one it could explain why two planes were ripped from the sky but he comes up empty that unit passed all its operational tests there wasn't any indication that it had failed and it operated within the parameters we expected it to once again the investigators are forced to shift their focus back to the pilots by studying the plane's flight data recorder investigators know that the jets rudder was deployed fully to one side what's called rudder hard over we were definitely focused on a rudder on on hard over rudder a full rudder input for about 20 seconds it can be caused either by hardware something unknown in the hardware or it can be caused by pilot input first officer chuck emmett who was flying 427 did indeed step down hard on his rudder and then held it there while the plane plummeted towards the earth it raised a grisly question was he trying to fly the plane into the ground in looking at this and being a pilot myself is like this doesn't seem like rational behavior what the hell is this human performance specialist malcolm brenner listens closely for evidence on the cockpit voice recorder in this case they had microphones right by their mouths and you can hear as well as in real life or better you can hear uh breathing sounds i see the jet stream the cockpit recordings indicate that flight 427's troubles began at the moment it flew through the jet wake of a delta airlines 727 that had just passed in front of them both pilots are startled by the wake i see the jet stream the first officer breaks off at the end of a sentence i i see the jet stream and there's no more discussion of the jet stream or anything else they both focus something happened here captain says she it was such a smooth flight that it was momentary jolt that they just hadn't anticipated and with that the the pilots got on the controls and immediately you know put in a rudder input the cockpit recorder even records the thumping sound of the jet stream turbulence as 427 flies through it as flight 427 encounters the turbulence brenner hears something unusual first officer emmett begins to grunt the grunting is unusual uh the controls are designed so that pilots don't need to grunt they're specially designed around human capabilities so to have someone grunting is typically a sign of an emergency by matching data from the flight recorder with the crew's voices brenner is able to confirm that emmett's grunts begin a split second after he pushed down on the rudder pedal and three to four seconds after the wake turbulence affected flight 47 [Music] [Applause] on their own the cockpit voice recordings prove very little but it seems clear that the crew weren't trying to crash their plane something happened which took them by surprise they reacted as quickly as they could but nothing they did seem to help it's been almost two years since the crash of flight 427 and the investigation has stalled now two 737s have gone down in startlingly similar ways and investigators still don't know why we were all frustrated as months wore into years what were we missing it definitely took a toll in their personal lives they worked incredibly long hours they never stopped thinking about it we were going up against an aircraft that had an incredible safety history it was really everything you could see for 30 years this has been a great airplane um we were trying to prove that there was something wrong with the straight a student it clearly was on his mind he at one point had a nightmare about it where he dreamed that he was in front of a congressional committee that was grilling him on now there had been a third 737 crash and in tom's dream all the cameras were pointing to him and a congressman asked why didn't you ground the fleet unsure of where to look next and with the trail of evidence getting colder investigators need a break in the case and fast east wing 517 you're clear for landing on june the 9th 1996 they finally get the break they've been looking for captain brian bishop is on final approach to richmond virginia when without warning his east wind jet rolls sharply to the right we didn't know to what extent but we knew we had a problem with the rudder i turned the yolk the opposite direction and stood on the opposite rudder pedal the pedal didn't move for me for over 30 seconds the 737 flies in a precarious right bank as bishop fights to keep it from rolling over then suddenly the unknown forces holding the jet let go snapping the wings back to horizontal in a matter of seconds [Music] it released itself went back to normal we had started the checklist almost before i could finish the sentence all of a sudden there was a just a lamb for a second time the 737 is pushed onto its side for 30 harrowing seconds the 737 takes on a life of its own then once again as quickly as it began the rollover stops after the second time i looked at the first officer and i said declare an emergency tell the controller we have flight control problems [Music] as they slow down to land the risks increase if a third rollover occurs they won't have enough airspeed to recover i did at some point tell my first officer to look out the window and find a dark spot it was nighttime when we were looking to avoid a neighborhood or a populated area and he very calmly responded that hey here's a spot over here but there is no third rollover bishop brings flight 517 in high and fast and lands safely taxing in is when i realized my legs were shaking we got the aircraft to the gate and i did pick up the pa to make an announcement to try to explain what had just happened to these people picking up their microphone i realized there was nothing i could say to make this any better and probably for the first time in a long time i was at a loss of words so i simply put the microphone down and let it go with that but bishop won't remain speechless for long by the next day the investigation team has arrived in richmond [Music] flight data recorded was undamaged an airplane undamaged and launched to the scene the the airplane literally didn't move i stayed in its location the airport till we got down there there were a lot of faa a lot of ntsb and they all wanted to talk to us very badly it gave the ntsb a tremendous break because suddenly they had a 737 that had had a rudder incident that was intact and they had a pilot who was alive and who could talk about it i think they were much happier to have the airplane than me i think the airplane probably gave them more to research than i ever could ntsb investigators quickly determined that what happened on board east wind flight 517 is alarmingly similar to events on flights 427 and 585 if they can discover why bishop 737 rolled over they may be able to crack two mysterious and fatal accidents and when we said well what happened they said there was something wrong with the rudder pedal the pedal wouldn't go down i was standing on the rudder pedal and i couldn't get it to go down my god with bishop's first person testimony investigators immediately zero in on eastwind's rudder controls the power control unit is removed inspected and then tested again and again to the frustration of everyone the unit performs perfectly we tested that aircraft as is it was intact we went through it completely we did flight tests with it and it passed all tests after a five-year hunt for clues a third mysterious rudder event on a 737 and a live pilot as a witness tom howter still lacks the evidence he needs to crack his case he decides to push his chief suspect flight 427's rudder controls a little harder one fellow mentioned a test they had done in the military of a thermal shock where if you had the actuator being very cold and put in very hot hydraulic fluid it would cause it to react in strange ways so we put together a thermal shock test and this test was extreme to say the least [Music] on august 26 1996 in valencia california ntsb investigators gathered to watch the torture test of usf427's pcu after soaking it in dry ice the pcu is blasted with nitrogen gas to simulate the minus 40 degree temperatures at 10 000 meters then it's quickly injected with superheated hydraulic fluid and given the command to start working as we were standing there listening to the the actuator move left and right left and right it stopped and it was not commanded to stop it just jammed stopped working completely take a look [Music] systems investigator greg phillips now asks that the valve be taken apart and scanned for scratches [Music] they find none look at that doesn't leave a trace it's a crucial breakthrough to solving an almost perfect crime not only have they proven that the valve which controls the rudders can jam no evidence is left behind tom howter and his team have now found that a small hydraulic valve that controls the rudder of the world's most popular commercial jetliner can jam in the right circumstances it's an ominous discovery but incredibly there's another shocking surprise in store for the investigators [Music] october the 15th 1996 for the last five years the national transportation safety board has been struggling to crack its toughest case [Music] two completely separate but seemingly linked accidents the crash of united 585 killed 25 passengers and crew three years later the u.s air flight 427 disaster took another 132 lives [Music] now after examining hundreds of clues investigators have made a surprising discovery [Music] a new test has revealed that under the right circumstances the hydraulic valve that moves the 737's rudder can jam it is jammed but the surprises aren't over the most important breakthrough came when a boeing engineer examining the data from that test discovered some numbers that indicated the valve at that point had actually reversed [Music] whoa it's a stunning revelation not only can the servo valve jam but it can then function in reverse it means that anytime a pilot tries to correct a rollover by pushing on the rudder the rudder might turn in the opposite direction causing a fatal accident and the reversal is like driving your car you turn to right it goes left you're not going to figure out this failure mode until you go off the road and in these cases that's the pilots were faced with something so unusual that they didn't understand what was happening what the hell is this they had evidence now that the valve was unique that the valve not only could jam but would reverse 427 emergency that would explain why the first officer chuck emmett would keep his foot on the rudder pedal because he's thinking why isn't the plane going right and he's feeling the plane go to the left to the very end chuck emmett pushes hard hoping his rudder will help him pull out of his deadly spiral tragically he has no way of knowing that he's steering the aircraft straight into the ground [Music] never driven to colorado springs and not gotten sick flight attendants prepare for landing satisfied that they've determined the cause of the crash of usf427 the ntsb turns its attention to the unsolved case of united 585 another thing going back to colorado springs you could follow a progression of what the captain was doing he's close to the ground and suddenly rudder reversal he puts in a little bit of pedal the pedal violently pushes his leg back rudder reversal certainly fits what i know about this crew and how it fits we were able to show the failure mode it matched the flight data recorder from each aircraft it felt like a glove so we now had a lot more information we could apply to united 585 and based on that we redid the accident report from rudder reversal to impact took less than 10 seconds 585's flight crew had no chance to save their plane or passengers in the aftermath of the investigation sweeping changes were made to improve the safety of the 737 and the entire aviation industry [Music] new training protocols were designed to help pilots react to unusual in-flight events in the 737 fleet pilots are now trained on how to react to both rudder hard overs and reversals the scenario usc 427 accident if the crew had the information that we have today i believe they would have landed safely in pittsburgh that evening the faa also directed boeing to redesign the rudder's dual servo valve to eliminate the potential for reversal boeing spent hundreds of millions of dollars to replace the valves on thousands of 737s around the world one thing we don't like of the safety board is to have an undetermined accident because then we can't make a change to improve safety so out of us air 427 united 585 we have a much safer 737 fleet [Music] it took ntsb tin kickers 10 years to solve the mysterious crashes of flights 585 and 427. the longest investigation in aviation history [Music] there's still some people in aviation who don't think the ntsb got it right but i became convinced after talking to many many many people pilots engineers people at boeing and spending a lot of time with the investigators that they did get it right since the replacement of the 737 servo valves there hasn't been a similar crash of the most popular most profitable plane in the world [Music] you

Channel: On The Move

Views: 139,726

Keywords: Colorado Springs, aerodynamic principles, aircraft malfunction, airline disaster, airline safety regulations, aviation forensic analysis, aviation investigations, aviation protocols, catastrophic events research, cockpit voice recorder, emergency response procedures, flight data analysis, flight dynamics analysis, flight emergency, flight navigation systems, flight path reconstruction, flight training protocols, flight trajectory analysis, pilot error, tragic plane crash

Id: cxuJDD9hX-A

Length: 50min 13sec (3013 seconds)

Published: Wed Apr 06 2022