How a Single Fault Led to Disaster on Flight 8501 | Mayday Air Disaster

an airb A320 on route to Singapore disappears while flying over the Java sea across my mind that what could have caused it is it an act of terrorism sabotage something extreme happening to the aircraft for days a massive search and rescue effort turns up nothing a crash at se is challenging it's difficult to lock it because you usually don't have the full flight path uh down to the surface of the ocean what they find paints are confounding picture of the final minutes of flight the plane started to bank we were very surprised by the action what are they doing the investigation uncovers a single tragic misunderstanding that claimed the lives of 162 peopley [Music] Air Asia flight 8501 cruises high above the Java Sea north of Indonesia it's a few days after Christmas and many of the 15 156 passengers aboard the airb A320 are on holiday the pilot in command is 53-year-old Captain irianto he's highly experienced with more than 20,000 hours in the air his first officer is French national Ry Emanuel plel he is 46 with about 2,000 flight hours much of it on the Airbus on this particular leg it was the first officer that was manipulating the controls the captain was in command of the flight but was performing the duties of the pilot monitoring or the non-flying pilot today's flight originated in the Indonesian city of suaya it's heading across the Java sea to Singapore total flight time is expected to be 2 hours looks like weather ahead no I don't like the looks of that 22 minutes into the flight the pilots noticed bad weather ahead on their radar anti- ice anti- ice on the crew would definitely be taking care to avoid penetrating these thunderstorms because it contains possibly extreme turbulence hail lightning everything that the air crew don't want to expose themselves and the passengers to the captain instructs the flight attendant to prepare the cabin for turbulence ladies and Gentlemen please return to your seats and fasten seat belts C unisa haaf fousi is one of four flight attendants helping to look after the passengers as they cruise at 32,000 ft as an additional precaution the captain decides to increase altitude to go above the storm clouds in their path I'm going to radio for a higher Cruise get around that weather good idea but before the captain can contact Air Traffic Control he gets a fault warning from the flight computer eam actions the plane sophisticated computers give the pilot stepbystep instructions on how to fix the issue back one off and on back two off and [Music] on warning cleared computers control most of the airb A320 systems there are basically seven computers that fly the aircraft and they add a lot of helpful features that take the workload away from the pilot Pilots are trained to follow the instructions given by the aircraft's computers a few minutes later the warning sounds again same back one off and on after addressing the fault warning the captain radio's air traffic control to request the higher flight level okay so Jakarta air traffic control Air Asia 8501 request climb to 38,000 the Jakarta air traffic controller has had an uneventful night he soon clears the pilots to climb but to a slightly lower altitude ude than the 38,000 ft requested here Asia 8501 you are cleared to 340 after permitting them to climb the controller waits for confirmation but the pilots are distracted by a third alarm Here We Go Again ecam actions Fact one off head on the controller hasn't heard back so he repeats his message here Asia 8501 you are cleared to 34 very annoying and very timec consuming to deal with this recurring problem enough of this he C [Music] actions the controller still hasn't heard confirmation from the pilots Air Asia 88501 do you read me please [Music] acknowledge but in the cockpit the fault warnings have escalated Air Asia 8501 do you read me please acknowledge in the cabin passengers have no idea their pilots are struggling to maintain control of the plane the pilots now notice that the plane is rolling sharply left level okay level something is going terribly wrong with with flight 8501 the first officer is struggling level but soon the plane is rolling again level I'm trying the pilots can't seem to regain control it's not responding Air Asia 8501 please confirm you are climbing to flight level 340 the controller still hasn't heard confirmation from the pilots when the plane starts to climb towards 34,000 ft and then continues climbing steeply even higher no Airline passenger would have ever experienced something like this under normal circumstances before it would have been a very violent shocking maneuver pull down it's not correctly the plane seems to have taken on a life of its own it climbs higher and higher as the p Pilots fight to level off then inexplicably the plane starts to drop that would certainly cause near panic in some people other people would be waiting for the pilots to quote fix it altitude I see it flight 8501 is plummeting from the sky speeding toward the ocean below the rate of descent here was very very high it seems the pilots can do nothing to save their plane it's not correcting what's going on max power [Music] slowly 43 minutes into what should have been a 2-hour flight Air Asia flight 850 one disappears from radar I'm trying news quickly spreads of the mysterious disappearance of a commercial flight to Singapore the loss of Air Asia 8501 was a classic case of a flight degenerating from mundane normal Cruise conditions to the loss of the aircraft in a span of just 20 minutes within hours relatives of the 162 passengers and crew are demanding answers How could an airplane just disappear we don't want to speculate any right now of course plane has been missing for 12 hours and there's a deep sense of all the authorities know is that the plane vanished from radar Somewhere over the Java sea speculation runs wild about what could have brought the airliner down it crossed my mind uh what could have caused it is it an act of terrorism sabotage something extreme happening to the aircraft but it was very difficult to come up with a clear picture on the first news reports as to what had taken place it's been only a few months since Malaysia Airlines flight 370 disappeared in eerily similar circumstances Vanishing from radar without sending any Mayday call search and rescue vessels are dispatched but combing the vast and choppy sea between Sumatra and Borneo is a mammoth task an international team of air safety investigators flies in to join the local experts in Jakarta Ray nuro is an air crash investigator with the indones Ian National Transportation Safety Committee the air traffic control radar data is our main source to detect the location of the aircraft they begin by interviewing the air traffic controller so uh can you tell me what happened they were the ones who could tell us a little bit more about what had happened they had seen uh the plane trajectory the plane flight path they learned that the plane was flying towards an area of bad weather when you start out in an investigation you look at everything in this case there were weather considerations and then then they started losing altitude [Music] fast and then it disappeared from radar at 24,000 ft thank you very much how could this plane being in cruising altitude um suddenly climb and fall with a very high rate of descent could the aircraft have lost engine power in a violent storm the weather might be involved to the accident so we tried to get more information on the weather [Music] data can I get the weather overlay for this map please investigators examined detailed weather charts from the day of the accident there were thunderstorms here and here it's quite large uh red color so I assume there's been a bad condition on the area it was monsoon season and so there's a lot of thunderstorms they can do damage to the airplane uh that it's something that you learn early as a pilot and it's something that you adhere to very strongly you do not fly through thunderstorms then they start mapping the flight track to see if the plane could have entered the storms they were cruising out itude then here they asked for deviation they made it here and then they started to drop they almost F into the first storm but then just missed it bad weather the first possible explanation for The Disappearance of flight 8501 proves to be a dead end this is a spot they were last seen on radar based on flight 8501 's last radar coordinance investigators have at least narrowed down the search area dozens of rescue vessels and aircraft from multiple countries scour the target area a crash at is challenging it's difficult to lock it because you usually don't have the full flight path uh down to the surface of the ocean the Indonesian president decides to address a nation in morning two days into the search the first pieces of wreckage are recovered from the karamata straight in the Java sea main rage was found not far from the point that we predict based on the ATC radar soon Searchers are finding bodies among the first is that of flight attendant kirona Haida fi in a moving tribute hundreds attend her funeral funerals for many more follow of the 162 passengers and crew there are no survivors as the wreckage is brought in for examination investigators can see that the task ahead of them is daunting why would a highly sophisticated airliner flying at cruising altitude suddenly fall from the sky we have a lot of little pieces everywhere my first reaction was it's not going to be easy is it all like this a cra SE challenging because usually the main interesting parts are underwater and that's a little bit difficult to get them with much of the plane still missing at the bottom of the sea investigators studied debris found floating on the surface to see if the plane exploded they look for distinctive smaller pieces with burnt [Music] edges [Music] the debris that was recovered did not exhibit any telltale signs of having been subject to a bomb explosion This Plane didn't blow up the pieces of Air Asia 8501 are large and clean we could eliminate uh a possible uh in Flight breaker it's a step forward but unless they can find the Black boxes the mystery of Air Asia flight 8501 may never be solved the flight recorders offer the only hope of figuring out what was happening in the cockpit the search for them goes into high gear the flag box search team assisted by Singapore France UK and China we utilize SES scan sonar and underwater andman camera all black boxes are equipped with an electronic Beacon that transmits a signal underwater ship-based sonar systems can detect the signal and help guide Searchers towards the black boxes when we get this signal we're in a range of about 2,000 M from them so this help us narrow it down to where they are and then the divers then have to to try to find them but weather complicates the search the depth we the B about 40 m and the sea was rough and we couldn't go every day where we wanted to go so we had to adapt our strategy to the weather after a two week search they finally succeed the Black Box were found first on 12th of January the flight data recorder and the following day we found the cockpit voice recorder around the same area we were relieved to get the boxes uh because this was a real major step towards the explanation of what had happened investigators start by listening to the cockpit voice recording it should reveal pilot conversations and other sounds from inside the cockpit of flight 8501 okay let's start when they ask permission to climb play recording Jakarta Air Traffic Control Asia 8501 request climb to 38,000 to clear storm clouds up to that point the flight was normal was uneventful continue recording almost immediately investigators make a discovery cam actions back one off and on Fact Two off and on warning cleared they were dealing with some kind of warning play recording e cam actions same okay the warning came back they were getting continual fault uh warnings uh through the what's called an ecam system electronic Central aircraft monitoring system play recording Here We Go Again ecam actions Fact one off and on Fact Two off and oh it's cleared at this point uh the crew's Behavior was standard was normal they were quiet they were communicating on what checklist to apply Air Asia 8501 you are clear to 34 okay stop we know from the controller that he never heard back from them again play there it is again ecam actions then the the recording reveals something surprising no I've got a better idea the captain appears to have done something different and then there's a new warning called recording now the autopilot has disengaged an unexpected disengagement of the auto throttle and auto thrust system results in a pretty loud uh warning this is a very serious concern to the investigators what was that okay let's see what we have Master caution why checking level level investigators now hear yet another cockpit warning stall warning the airplane would have warnings to tell the pilot that they were getting close to an aerodynamic stall Paul slowly what's going on Paul an arrow dnamic stall occurs when the angle between the wings and the oncoming air gets too steep the amount of air flowing over the wings is reduced the aircraft loses lift and can no longer stay a loft it's a highly uncommon event to have an Airbus stall particularly in Crews because is protected from stalling normally the computer won't allow the aircraft to stall it won't allow the Wings To Go at too high an angle to the air flow and stall the aircraft what caused this technically Advanced plane to stall the autopilot disconnects the aircraft stalls they struggle to recover it makes no sense only the FDR data can reveal what was happening with the aircraft the moment the crisis hit until that data is ready for analysis the deadly midair stall remains a mystery what were you guys struggling with one of the questions that the investigators would have faced is why and how did an aircraft that is supposed to be stall proof end up stalling pull down [Music] slowly the flight data recorder should provide answers but it needs to be flushed of salt water before it can be red in the meantime investigators pulled the plane's maintenance records to look for Clues they soon make a discovery the aircraft seems to have an issue with its rtlu rtlu is the rudder travel limit unit the plane had had a history of rtlu fa failures the rudder travel limit unit is a computerized component that prevents the rudder on the tail from deflecting too far in either Direction when the plane is traveling at high speed if the flight computer detects any problems with its Rudder limiter it sends a warning to the cockpit records show the aircraft's rudder travel limit unit had been malfunctioning for almost a year 23 reports of the exact same failure the rtlu failures on this particular airframe had become increasingly frequent there were 11 in the last couple of months and 23 in the preceding period which is highly unusual that seems like a lot of failures with the rtlu could these be connected to the mystery warnings the pilots were experiencing it could be a major breakthrough 3 days before the crash there were two exact same failures why was this happening after each failure maintenance workers reset the rtlu nah as long as the reset resulted in the computer de prompt pass maintenance Personnel doesn't have to investigate further Stu this they just kept resetting it and then putting it back in service but they never found a permanent fix they were returning the airplane to service after reset and from a legal standpoint it did clear the problem but obviously whatever the fault was they hadn't found it because the problem continued to reoccur the aircraft seemed to operate perfectly despite the warnings even the day before the crash the plane had successfully flown from suaya to quala lumur have we got the unit the plane's rtlu is among the wreckage that's been recovered from the Java [Music] sea let's send it back to the manufacturer and see if they can find something the unit is sent to France for [Music] analysis finally investigators get to examine a key piece of evidence the flight data recorder if they can download all the flight data it should provide a detailed picture of exactly what was happening with the electrical and mechanical control systems on the aircraft after the Black Box recovered they transferred to our laboratory we worked to the um Indonesian investigation Authority in extracting the data which requires a lot of precautions since the flight recorders had been immersed move it down to a little bit on examination they discover the data board has been damaged by the impact of the crash it's uncertain whether the information they desperately need will be [Music] retrievable the download begins even though the condition of the blackb was damaged we managed to recover all of the data success okay so let's start with those chime warnings okay so here's the first warning it clearly was the rtlu okay they do the fix simply resetting the entire system the procedure to reset the system was much like your PC rebooting the PC they only had to turn the system off and turn it back on again Fact Two off and on two more times the rtlu warning goes off and each time they did the right thing then it went off on a fourth time then suddenly there was a glitch what is they do different after the fourth time the warnings change there is now a fault with the aircraft's two main computers known as the flight augmentation computers put the new data up on that screen something caused both computers to fail at the same time but nothing in the data shows what the crew did different ly after the last warning what does come to light is that when the autopilot disengaged the rudder moved slightly now let's see the plane started to bank to the left the electrical Interruption on the flat control computers created a rer movement of about 2° to the left 2° does not sound like a lot but at the speed they were flying it's exactly what caused them to roll left 54° that's almost twice the normal bank that you would feel in an airliner now look at this it took them 9 seconds to do anything about the bank despite the Steep Bank angle it seems the crew was slow to react and level the plane during the first 9 seconds there was no crew inputs on the controls following this role that reached uh 54° then the first officer suddenly reacts pulling hard to the right then left again and just as suddenly he starts to pull up all they had to do was steady the plane what were they doing the FDR data shows that the plane climbed steeper and steeper until they reach a remarkable 45° pitch up then it's stalled investigators know that the captain did something different something that led to a computer glitch causing the autopilot to disconnect and the plane to bank sharply but they don't know what he did the single event of autopilot Auto throttle disengagement sends the investigators in two different directions one what caused it two how did the crew handle it as investigators struggle to answer puzzling questions about flight 851 and its crew hello NC they get an important new lead wait wait slow down what [Music] happened a mysterious action by the captain to solve a routine error appears to have set off a deadly sequence of events investigators are still trying to understand what happened when they receive some new information start from the beginning where was he 3 days before the accident on a 2th December this same Captain was about to fly from Indonesia to qu lumur when he had an rlu malfunction he asked for an engineer to come to the cockpit and try to fix that rtlu problem again yeah it just keeps coming back the maintenance engineer rebooted the [Music] system uh but the problem came back I've got an idea he then pulled the circuit breakers for the main computer maintenance on the ground has a very specific list of circuit breakers that says you can utilize pulling these circuit breakers to reset computers within the airplane as the captain watched the problem was fixed problem solved and can I do the same thing if it happens again yeah just do what the EAP tells you to do don't tell me he tried to do that in the air investigators think that they now know what the captain did that led to the crisis in the cockpit begin simulation to see if they're right they decide to simulate the cockpit warnings heard in Flight okay so let's start with the rtlu warnings okay Fact one off Fact Two off enough of this after the fourth rtlu warning he takes a new approach he C actions no I've got a better idea investigators believe the captain pulled two critical circuit breakers Captain pulls circuit breaker [Music] one the result is immediate and there goes the autopilot disconnect warning investigators can now be certain of one thing this had to be what he did he was perhaps copying what he'd seen the ground engineer do but of course the consequences in flight to disabling critical systems are quite different the captain wrongly assumed that if it worked on the ground it'll work in Flight circuit Breer the circuit breaker which is part of the flight augmentation computer is something that should never be pulled out in the air pulling the circuit breakers has devastating consequences the captain didn't anticipate unfortunately he was not pulling circuit breakers that affected only the rudder limiter system but ones that also disable the flight augmentation computer which tripped the autopilot the auto throttle and all the normal mode protections that the aircraft had the plane begins to roll over the next 9 seconds it rolls 54° yet no one does anything to stop it what took them so long to react the first officer would have been looking here and here when the autopilot warning was disconnected and a captain was still standing behind the first officer's seat what was that it's likely that neither pilot was looking at the attitude indicator that showed the plane was banking that's why it took them 9 seconds to notice what this gaug here was telling them as the plane started to roll the first officer was focused on the fault warnings he didn't notice that the plane was banking until the captain sat back down [Music] again oh my god oh despite losing control of these systems the high-tech plane did have the capacity to get back on course after the initial roll why didn't the first officer just steady the plane and re-engage the autopilot investigators have to try to understand what was going on inside the Pilot's heads the co-pilot's movement of the stick to its extreme rightmost position resulted in a very violent role to the right two to three times what would be programmed as the maximum for an Airbus normally in an attempt to understand the first officer's actions investigators study how the human brain behaves in Flight a sense of balance is maintained by liquid levels in the ear canals when that shifts violently the brain can get mixed signals that affect balance the FDR data shows how dramatic the plane's movements were so the plane rolled 54° left and he pulled back almost level in Just 2 seconds that would scramble anybody's Gyros maybe that was the confusion as soon as the first officer had leveled the aircraft the fluid in his ear canals keeps spinning to the right the aircraft is level but there's a very strong illusion from the ears that you're turning to the right he pushes the plane all the way to the left but why level I am I am the natural response would be to to roll the aircraft back to where it came from into the 54° of bank which was what they thought the level was and then he pulls it as hard as he can and the plane starts climbing this is a massive input the airplane would pitch up very quickly what's going on he was completely baffled his vertigo may have led him to believe that the aircraft was pitching down so he's actually recovering from an imaginary pitch down he was disoriented with all the alarms that were going off with the rapid left right left rolls and with the the generally deteriorating situation I think the crew had started to lose their spatial awareness completely investigators finally understand what must have been going on with the first officer's confused state of mind but if the first officer wasn't operating the controls correctly why didn't the captain take the one step that could have saved the lives of everyone on board investigators study the captain's behavior during the role hold down they know from the recordings that he was trying to help write the plane pull down I'm trying it's not responding he wants his first officer to stop climbing up and push the nose down pull down but his command is confusing it's either you pull up or you push down one thinks that the co-pilot is holding a side stick pull means pull it back which means go up and down means push it forward so pull down is a contradictory command in that case the captain should have said nose down nose down the first officer continues pulling back on his side stick until the very end the input of the first officer pull down was the exact wrong thing to do what's going on he clearly didn't understand the command so why didn't the captain take full control of the airplane he tried to take over here and over here stop correting there is a button on top of the side stick that can let you take full control to lock the other pilot out so that you know what's going on the data shows that the captain did push the take control button but only briefly he didn't push it long enough to take over the plane it's not responding but at the end he never took control it meant that both Pilots were trying to fly at the same time both pilot started to controlling the aircraft when that happened the control of the aircraft become ineffective if he'd spoken three simple words the plane could have been saved the training is you say I have control and the other pilot stops making inputs in this case that that wasn't happening investigators now know that pilot error led to a spatially disoriented first officer the captain who could have helped by communicating more clearly or taking over the plane did neither investigators can never be certain why the case is building to a close when they get another piece of information the results of the rtlu analysis are in it was a series of warnings from that unit that triggered the events that led to the crash ecam actions the failure of the crew at experience with the Ruder limiter system was actually a negligible filer was a nuisance and uh the procedures to reset it back one off and on were simple fact two off and on warning St all the captain had to do was keep on following the ecams instructions the plane had had a history of aru failures throughout the year and this failure had never been fixed microscopic examination of the unit's Electronic Module finally reveals the cause of those repetitive failures we found out that there was a crack in the soldering joint on the Electronic Module which caused the rtlu to work from time to time only and had the correct maintenance test been applied problem solved the ru Electronic Module would have been removed the airplane should have been sent for troubleshooting um and you could have broken the the chain of events for investigators discovering that such a minute fault sparked events that led to to the death of all 162 people on board makes this all the more tragic as they prepare their final report it's clear that the crash of Flight 8501 has exposed a series of serious problems the final report calls for improved maintenance protocols to help eliminate minor recurring problems like the rtlu fault before they lead to a major catastrophe when you start having four five 6 8 10 recurring problems it's seeing that the traditional methods are not working and that you need to do much more heavy duty Diagnostics until they find the problem Paul hold down and the other lesson we take from the accident was the communication between pallots to make sure the communication was well to avoid the different interpretation of the command this is a case that the industry learned some very hard lessons but the thing most importantly is that the industry implements those lessons so that we don't have another [Music] one

Channel: Mayday: Air Disaster

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Id: -PtKqPF30Qs

Length: 42min 36sec (2556 seconds)

Published: Fri Apr 12 2024