The Atlantic GLIDER, Air Transat flight 236! Explained by Mentour Pilot

hi everybody very welcome to mentor and yet another video podcast as always i hope you're doing absolutely fantastic this week it's exactly 19 years since one of the most famous aviation accidents of all time we are talking about air transat 236 the atlantic glider and in this episode i will tell you the reason why this happened i will talk about things like confirmation bias and what happened if flight crew are not properly trained about the systems and some of the malfunctions that they mount encounter and also about the incredible skill of both the flight crew and the cabin crew that led up to the final result stay tuned [Music] [Music] this video is brought to you in cooperation with nordvpn now a question for you would you ever sit down in a public toilet without closing the door well if not then you should probably ask yourself why you would ever sit down and use a public wi-fi without a proper vpn now nordvpn is your virtual toilet door it will keep prying eyes from looking into your browser history and trying to steal your password it is incredibly fast with thousands of servers over 59 different countries and also with only one subscription you can use up to six different devices those of you who uses this link here below will get a whopping 68 discount of the two-year deal with nordvpn plus one month for free so go in and use it it will cost you less than 3.71 per month so start protecting yourself on the internet today [Music] alright my friends so we are going to be talking about the atlantic glider air transat 236 this is an amazing story that contains so much things that you can learn about you know how we've gotten to where we are flight safety wise and also what happens to us as humans when we are faced with things that we just cannot make sense out of but in order to understand the air transfer 236 incident we need to start a little bit before the actual flight so the aircraft that is involved is an airbus 330 okay it has a voice royce rb211 engine fitted to it and about four days before the flight they were doing routine maintenance on this aircraft and they found in the in the oil filter um some metal chips right this is part of standard maintenance procedures and when they find metal chips in the oil filter it means that some kind of failure is about to happen like there's some kind of component that is about to fail inside of the engine but in this case they couldn't find where those metal chips were coming from so they decided rather than than trying to search further they would just change the engine and send the engine in for proper maintenance now the issue here was that air transit didn't have any spare engine in the hall of north america so they had to get a loan engine in from royce royce which was flown in from hong kong the the maintenance crew started changing the uh the engine it was scheduled to to be at work that would take a few days to do but fairly quickly they started realizing that the new engine that they had didn't fit well into the cowling they couldn't they couldn't fit all the components correctly so they started looking into why that might be and they found something called a service bulletin this is where an engine manufacturer decides to change something on an engine and in this case the royce release company had found that the rb211 engine had had some problems with the hydraulic pumps so they had put the service bulletin in about how to change the hydraulic pumps and with that they would also have to change the hydraulic lines and the fuel lines and the problem they have here is that the engines that were fitted onto the aircraft was engines that was after the service bulletin and the loan engine was an engine from before the service polyteam so there were two different hydraulic pumps this service bulletin would have shed that exactly how to do this maintenance work and what things needed to be changed but due to a computer failure in the um in the maintenance control unit they couldn't find the service bulletin so they called royce royce and they asked what to do and they got some advice basically that they needed to change all of the units in order for it to be in a after service bulletin mode the problem was that they only had the after service bulletin um hydraulic pump and had let's see fuel lines they didn't have the hydraulic line that was required so what they did was they changed the hydraulic pumps the fuel lines and then they used the old hydraulic line now when they fitted all this together and they looked at it um they noticed that the hydraulic line and the fuel line came very very close to each other but they managed to achieve some clearance in between them this was checked by the the maintenance engineers and they decided that the clearance between the two lines was enough all right but what they hadn't accounted for was the fact that when they were installing this there was no pressure in the lines but as hydraulic pressure was applied to the hydraulic line it would stiffen out and that clearance that was in between the lines would effectively disappear this was never found was never understood the engine did a proper ground run everything looked fine um so the aircraft was released the service on the 24th of august 2001 captain robert pc and first officer dirk de jager was preparing himself for a standard flight from toronto in canada over to lisbon in portugal this is a flight that takes them out over the atlantic ocean and because of that they need something called ear tops approval which means that they need to be able to fly more than one hour away single engine from any of the alternates this is not a problem the airbus 330 has airtops approval and so did the company so this was not really an issue um they fueled the aircraft up they departed with about 46.9 tons of fuel which is five and a half tons extra that's in on top of what they needed legally so they had plenty of fuel on board the flight took off at around nine o'clock local that was about midnight utc time from toronto and the first four hours of saw the flight was completely normal everything worked like it should at time 438 approximately utc these fuel line and hydraulic lines have been kind of rubbing up against each other continuously for these four hours and at that point the fuel line ruptured and a huge hole opened up it is estimated from the final report that um they were losing about 12 to 15 tons of fuel per hour through the hole right and that should be kind of compared to the normal fuel use of an engine which is about 2.6 tons of fuel on the airbus 330. so they have now had a huge fuel leak in the number two the right-hand engine but there was no indication of this and the engine was working fine and because of the way that the fuel system is constructed on the airbus 330 the um the aircrew didn't notice anything because you have several of fuel tanks um in an airbus 330 you have two wind tanks in each wing you also have a center tank which is used first and then you have a trim tank which is sitting back in the in the aft stabilizer the trim tank normally works by transferring fuel from the back towards the front to keep the aircraft within its center of gravity limits but when the fuel starts to deplete in the wing tanks the trim tank notices this and starts transferring fuel forward and into the wing tank that is low on fuel this is something that the aircraft does absolutely automatically all right there is an indication in the cockpit but this indication since this is normal procedures and it happens all the time it's not something that the pilots would immediately pick up now what happened here was that the trim tank started its final fuel transfer all its fuel forward into the tanks way too early normally it would do that maybe half an hour or so before they arrived to the destination but in this case it was only about four hours or five hours into the flight this was not picked up by the crew instead the crew did a standard position and situation report when you fly transatlantic flights and you fly into oceanic airspace you need to at different intervals do these position reports because you are not in any kind of radar contact at that point so you need to have an hf radio especially at that time and report in your time where you are and so on to whatever control unit that you're talking to in this case it was santa maria control while the crew was doing this they did that when they passed the longitude 30 west and they took the time then to do just an overview of the systems as well so not only do the position report but check how the engine is doing how much fuel they have and so on and this is where they started noticing some strange things so when they open up the uh the secondary display and they looked at the engine instrumentation they realized that they had a much lower oil temperature on the right-hand engine they had a much higher oil pressure and lower oil quantity this this was a strange indication to have and they didn't really understand it and what they didn't know at the time was that this was actually an indication of the fuel leak but there's no way at that point that they could have made that kind of parallel because the way that oil is being cooled down is that the oil transfers past the fuel okay so fuel is being used to cool down the oil normally you have a fairly low fuel transfer rate so the oil will be kind of medium cool down but since they had this gaming hole the fuel was now rushing through the oil cooler much higher rates than they would normally i remember the the fuel is really cold they're up at 39 000 feet really cold fuel is now being transferred really really fast past the oil filter and that was cooling the oil much more and as the oil got cooler obviously its viscosity increased so that increased the oil pressure and since it's now flowing slower it was returning slower down into the oil filter and that's why they had these indications so it was an indication of the fuel leak but very hard to interpret in any case the the crew reported this back via a high frequency radio to their maintenance control center and said we have some weird indications here can you have a look into that uh maintenance control started looking into it couldn't find any reason for it anyway and while the crew was dealing with this there was an ecam message okay or an advisory e-camp stands for electronic centralized aircraft monitoring system and it's built to pop up when there is actions needed by the crew so it can be an advisory message which is something is coming on but it's still within parameters or it can be an emergency message which requires immediate attention in this case an advisory message came up but because the crew had opened the secondary display on the engine display it didn't automatically click up it was just seen as an advisory message so once the crew had finished dealing with this oil pressure issue they saw the advisory message they opened it up and they realized that they had a fuel imbalance now a fuel imbalance is basically an indication that there are more fuel in one tank than in the other right this is not good because we want the aircraft to be balanced and it wants to be stabilized for when we're controlling the aircraft but this didn't make any sense to the crew there's like there was no at that point they hadn't been trained in the simulator about uh imbalances they did deal with imbalances during simulator uh sessions every six months but that was always connected to an engine failure because when we experience an engine failure then the engine that is now failed is not going to use any fuel from its main tank and the other engine will be using fuel so you will start to get an imbalance because of that and because of that as part of the engine failure checklist you will also deal with an imbalance but in most cases you would do that by heart by opening the cross feed valve which is the connection between the tanks it's a kind of a tube in between the tanks and turning off the pumps on the low side by doing that you would start to feed fuel from the tank that have the most fuel but not from the low one so that way you can start to kind of equalize out the imbalance there is a non-normal checklist for this there is a curate checklist but normally when you're flying the airbus 330 there is ecam actions to be done but in case of the imbalance there is no ecam actions it just tells you that you have an imbalance and then you are supposed to take up the qra checklist and use the checklist instead to deal with imbalance but since the crew was well versed in dealing with imbalances from their fuel from their simulator checks the captain decided to do this by heart all right so you just opened the crossfit valve turned off the the right hand fuel pumps and started transferring fuel from one side to the other obviously in this case what he was actually doing was that he was taking fuel from the left-hand side and just pushing it out this huge gaping hole on the right side if he would have taken up the checklist the first point that he would have found on the checklist would have said do not do this checklist if you think you have a fuel leak right so in case of fuel leak do not balance fuel that point had been placed into the checklist because these kind of things had happened before uh and it was known to to airbus for example that uh that these kind of things could happen and that you could potentially be losing a lot more fuel if you did this procedure and you had a fuel leak so the balance procedure was really only there like in the case of an engine failure for example or if there is a tiny imbalance because of different output pressure in the pumps in order to equalize it but in case of a fuel leak you cannot use this checklist now the crew was not even thinking about few leaks at this point like i was saying there hadn't been any real scenario training in the simulator about few leaks at all not during the type rating not during recurrent training and no real emphasis was put on it so the crew was sitting there and they were looking at the situation and what they thought they had was a computer glitch a computer fault because they saw the uh the oil pressure indications the oil quantity indications the old temperature indications and now they had this fuel indication and they were not connected so they immediately thought okay there's some kind of computer glitch here this doesn't make any sense but one thing that did worry them quite a bit was that when they did the fuel checks when they checked how much fuel they had on board remember they had five and a half ton extra when they left toronto they now saw that they had much less fuel on board right and this did not make any kind of sense to them because the engines were working normally everything had looked fine but they had this imbalance and now the fuel was disappearing and they could not make this kind of square with their mental model and their mental model was a computer glitch so the crew got their first indication that something was wrong at time zero five zero three that's when they started looking into the oil indications at time zero five thirty three they got the imbalance indication or the sword imbalance indication and only about ten minutes later they realized that we are not going to have enough fuel to go to continue on to lisbon so they started looking into what alternates they had and they found an alternate in their sword called legeth airport that's on the island of teresera they started looking into and decided to divert to this airport to get this all sorted out and while they were talking about this cabin crew came in cabin crew wanted to to tell the the pilots that they had wheelchair passengers on board and that they could relay that information to lisbon and the pilot then told the cabin crew that listen we are going to have to divert to their source because of um a technical issue but they also wanted the cabin crew to go back and have a look at the wings so the the cabin crew member went out turned off the uh the lights in the cabin because remember this is night time i went and used the flashlight and looked out of the wings couldn't see anything remember this fuel leak is happening inside of the engine on the right hand side and whatever fuel kind of vapor that will be coming out the vapor trail after the engine would be under the uh the wing and would be very hard to see especially during night time so the cabin crew member came back in told the pilot that listen i can't see anything and this just reinforced the mental model the pilots have that this is a computer glitch because now you know you have all of these indications there's no visible fuel leak something is wrong right this is what i was talking about confirmation biased okay confirmation bias is where you make up a mental model of what's going on this is what's happening and then instead of constantly questioning the mental model seeing if it's correct you just try to find the different things that reinforces the picture that you had and this is what the crew is doing at this point they are they're looking at a computer glitch and everything they hear confirms that picture even though what they actually have is a huge fuel leak right now the way to get out of something like that is to constantly apply the pi oc model remember i did a video about that where you check what the problem is you get constant information you look at options you uh look at selecting whatever options you want to do execute that and evaluate crucially evaluate right but you always evaluate your situation based on new information and try to do so from kind of an objective view angle obviously at this point the crew is situated in you know a lot of stress there's a lot of strange indications the fuel is constantly tripping down and during this the the the the captain is who's pilot flying is in contact with uh maintenance control center he does different configurations of the the fuel system depending on what you know he thinks might be right but ending up in the end in the same situation where fuel is just flowing from both tanks out through the hole at time 559 that's about 25 minutes after they saw the initial initial indication of the fuel imbalance the fuel is indicating three tons in the left wing one ton in the right way and about 14 minutes later the right engine flames out okay so when that engine flames out the crew goes through the engine failure checklist they start the descent down to their single engine service ceiling which is what you have to do if you have an engine failure in cruise i've done a video about that if you want to check it out as well um and they're still not understanding why this is happening they're still thinking that this might be a computer fault of some sort they now have about 600 kilos in the whole aircraft right both tanks all tanks 600 kilos left at this point the the first officer calls out a mayday call they call out may they may they may their ultron set two three six and that they have fuel problems and an engine failure he also does a pa to the cabin crew and the passengers telling them that they're going to land shortly and that it might be an off-field landing so they're preparing the cabin for a potential ditching all right at time 0 6 26 so that's 13 minutes after the initial ending failure they're now at about 65 nautical miles away from legeth airport and they're at flight zero level four thousand feet more or less the remaining left-hand engine starves of fuel and flames out now it becomes very quiet guys with both engine flames out the aircraft becomes quiet the only thing that you can hear is the air rushing over the wings and air outside the all the cabin lighting would have disappeared and been replaced by the emergency lighting which is only showing the emergency exits so this would have been terrifying back in the in the cabin for the passengers but the cabin crew is doing a great job at this point there are briefing in both french and in english and they also found a cabin crew member who can speak portuguese to make the uh the instructions for how to put the emergency life vests on and how to prepare for a potential evacuation later on at about 17 000 feet as the aircraft is now gliding down toward legeth what's going on in the cabin is that the oxygen masks are falling out that's because the engines which are normally pressurizing the aircraft are both failed so the the aircraft is leaking pressurization out which means that the cabin altitude is slowly going up to meet the aircraft's actual altitude and when the cabin altitude goes about 14 000 feet the oxymasks automatically falls down and that would probably have scared the passengers even more the flight crew is now concentrating on getting the aircraft down safely onto legeth the captain which is an expert pilot has been flying 14 000 hours in total and has actually got quite a lot of glider experience as well is handling the aircraft beautifully down towards the airport he ends up at about an eight miles final from way three three at thirteen thousand feet so very very high you would normally be about three thousand feet at ten miles if you have both engines running so he asks to do a 360 turn to lose altitude when you do a 360 turn when you're gliding in an airline and you will lose between four or five thousand feet that means that he will end up on final again at about eight thousand feet so still high very high um but at this point he also um extended the slats as part of the both engine failure checklist on the airbus 330 they're also extending the landing gear and he is executing these s turns on final in order to to lose altitude and energy as much as possible now if you've seen the the video that i did about when i was in the simulator and i lost both engines and i had to return back to dublin where it was taken off from you'd have seen that i did the same thing that i kind of flew through the localizer and then snaked my way back that's just in order to to lose as much energy as possible when you realize that you are much higher than you want if you are not sure it's better just to aim straight for the airport but captain pique ended up over the threshold at about 200 knots which of course is much higher speeds than you normally have he touched down about a thousand feet down the runway that's about 300 meters down the runway which is pretty much where we normally touch down but because he didn't have flight spoilers and ground spoilers working because of the loss of of both engines the aircraft had so much energy that bounced up again and it touched down a further 350 meters further down the runway now he doesn't have that much runway left so he just slams on the brakes and since once again he only has brake accumulator pressure and there's no anti-skid system working as he puts full max manual braking on the wheels lock up lock up they start to just shear down the the tires until the tires blow up the aircraft falls down onto its landing gear and continues to kind of skid towards a complete stop on the runway this is a fantastic feat by both of these pilots now as they come to a complete stop there are some small fires that breaks out around the the blown-up tires which the uh firefighters immediately put out but because of this and the fact that they have a fuel leak captain piche decides to evacuate the aircraft and during the evacuation 14 passengers and two cabin crew members get some mild injuries and why am i highlighting this well that's because when i did my video about qantas flight 32 i got a lot of questions from people saying that why didn't the the captain just decide to evacuate just to be on the safe side and what i was trying to explain in that video and i am explaining now is that evacuation itself can cause quite a lot of injuries the absolute best thing to do is to do a rapid disembarkation using normal stairs if it is possible in this case quite rightfully they decided to evacuate but it goes to show that the only injuries during this whole ordeal with all of these technical problems and the dual engine failure and the landing and everything the only injuries they actually came when they evacuated the aircraft and that was also partially due to that was found in the investigation later that people were reluctant to jump out to the slides they would have to be kind of pushed out by the cabin crew and also they were trying to get their hand luggage with them at least a few of them did so once again if you are in an evacuation situation follow the cabin crew come on get out as rapidly as possible jump out and get away from the aircraft the aircraft um received some minor damages it had some structural problems because of the wings and a little bit of the body because of the very high force when they touched down both the first and the second time and obviously they had the the landing gear um issue because of the burned out tires so but it was fixable the aircraft went back to flying and in the final report after this was all over and by the way as always i'm linking down to the final report in the description of the video there was a couple of findings so the way that the spare engine had been fitted to the aircraft without proper regard to this to the service bulletin was shown to be the cause of the fuel leak in the first place okay that was that was number one number two the crew not being properly trained to deal with imbalances caused by few leaks and not having dealt with few leaks during their training in any kind of reasonable way let them down the rabbit hole of starting to balance fuel by heart which made them miss the crucial step of asking themselves whether or not they had a few leak and also they weren't really um even if they would have seen that it's possible that they wouldn't have considered it a fuel leak because of their limited training because of this next finding was that airbus needed to provide more indications of the possibility of a fuel leak but basically more training for the flight crew and there was also some general indications around what happens in the cockpit crm wise once you have a mental model made up and then you go into this confirmation bias stage that how hard it is for the pilots to get out of that and in order to kind of rectify a previous uh mental model mistake so we have learned loads of this right this is one of those incidents that have led to more emphasis in training not only on airbus but on boeing as well about how to deal with a few leaks and how to read non-normal checklists things like this so once again this incident has led to a lot of improvement safety-wise in the airline industry and this is how we deal with this this is why i'm doing these videos by the way so that you guys can listen to this and you can see where they you know went wrong where the mistakes were made and then we as an industry can become better both maintenance-wise both from an airline point of view from pilot point of view we always try to learn from incidents like this guys i hope that you've enjoyed this i hope that i have earned a subscription for you if you like videos like this then make sure that you subscribe and you highlight the little notification bell so that you know when i come up with new videos and check out the other videos in this series i've started to make a few of them there will be more coming next week i promise i'm not going to do a video about an incident or accident i'm going to do something about the system instead so stay tuned for next friday when that video will come out but for now come in join me in discussions down here in the comments of the video or get the absolutely free mentor aviation app where you can discuss with me or other professional pilots about things like this and yeah see you next time i guess have an absolutely fantastic day and i'll see you next time bye-bye right guys i really hope that you like that if you want more content like that more aviation content but then check this out i hope that you have subscribed to the channel and that you've highlighted the little notification belt see you inside of the mentor aviation app and have an absolutely fantastic day [Music] [Applause] bye you

Channel: Mentour Pilot

Views: 382,936

Rating: 4.9510016 out of 5

Keywords: Air Transat 236, The Atlantic Glider, Dual engine failure, How to become a pilot, Airbus A330, Airbus A320, Airbus A350, Airbus A380, Mentour Pilot, Mentour Pilot Boeing 737, Boeing 737MAX, Mentour Pilot Boeing 737MAX, Azores, Aircrash investigation, Pilot life, Boeing, Boeing 747, Boeing 787, Fuel leak, Jet engine fuel leak, Landing, Takeoff, Feat of flying, fear of flying help, Nervous flyer, Nervous flyer help, cockpit video, RAT, Ram Air Turbine, Air crash

Id: 9becqrhsedE

Length: 32min 15sec (1935 seconds)

Published: Sat Aug 29 2020