What Caused the Kegworth Air Disaster? | British Midland flight 92

this video is brought to you together with curiosity stream use the link in the description below for your special deal it's the 8th of january 1989 and a brand new boeing 737-400 from british midlands airways is climbing out on its way from london heathrow in the uk to belfast international airport in northern ireland the flight is completely normal but as the crew passes 28 300 feet they suddenly feel violent vibrations shaking the aircraft and they feel a terrible smell of burnt rubber oil and hot metal the crew reacts almost instinctively and they reduce the thrust on the engine that they perceive is causing these problems this seems to sort the problem out and they start diverting but it turns out that this is only the beginning of the tragic events that will be the story of british midlands flight 92 stay tuned [Music] british midlands flight 92 was the third flight of the day for the involved crew they were operating something that would be described as a double belfast where the crew started off in london heathrow in the uk and then flew to belfast then back again to heathrow and then the same rotation again so four legs in total the weather on the day was nice with only some few clouds there was some rain forecasted in a temperature of about nine degrees and there was nothing special with the flight atop from that first two flights had been operated without a single problem the aircraft that they were flying was a brand new 737-400 that had been delivered to british midlands airways only a couple of months prior to the accident the boeing 737 400 is what we call a type variation of the boeing 737 so the flight crew had previously operated quite a lot on the boeing 737 300 but the 400 had some significant upgrades to it and there's three of them that is relevant for this story the first thing that we're going to talk about is the engines so when boeing upgraded from the 300 to 400 they went to the engine manufacturer and said we would like a slightly more powerful engine on this new variant so the engine manufacturer came back to boeing and said yep we can do that what we're going to do is we're going to change some internal components but we're also going to change the fan of the engine and whenever you do any major upgrades of an engine it needs to be re-certified again and that had been done before the 400 was fitted with these new slightly more powerful engines the second system that was slightly upgraded was the air conditioning system so the way that it works is that an aircraft tends to take what we call bleed air from the engines so this is basically siphoning off some of the high pressure high temperature air from inside of the core of the engine and then feeding the pressurization system with that in the earlier variants the way that it had worked was that air taken from the number one engine the left-hand engine would primarily go to the flight deck to the cockpit and air taken from the right-hand engine the number two engine would first of all go into the passenger cabin but in the 400 this had been changed so that actually air could be taken from both engines to both of these zones and the third system that had been upgraded was the engine instrumentation so on the older variants on the boeing 77 300 there were conventional dials which means that if you looked at the engine instrumentation you would see these clock shaped dials with a little pointer inside but on the 400 this had been changed to a kind of hybrid a more digital way of showing engine instrumentation which still utilized the dials but in this case on the primary engine indications you had also a numerical presentation inside of the dials and instead the pointers were led lights that moved on the outside of the dials all of these upgrades will have impact on what's about to happen in this story in the cockpit on this day was a 43 year old male captain he had about 13 176 hours in total of which 763 hours were flown on the boeing 737 but only 23 of those hours had actually been flown on the 400 variant the captain's previous experience had been on the back 111 and also the dc-9 together with him was a 39 year old first officer with 3290 hours of total time and 192 hours on the boeing 737 53 of which was flown on the 400 variant his previous experience was flying the short 360 for the same operator but this means that the the crew flying the aircraft on this day had very limited experience of the 737 400 which is understandable since the type had only been around for a few months before i started talking about what happened on that day i just want to make you understand what kind of training pilots needs to go through before they start flying a new variation of a current typewriting so if i for example is flying the 737 300 and i need to fly the 400 i wouldn't actually need to go in to do any simulator training instead i would do what's called difference training which is normally ground school where you read through all of the differences the system upgrades and things like that and once you are satisfied with that you normally write maybe a technical exam and then you are free to go and fly on the new type now different airlines might have different training programs involved maybe you need to fly with the line training captain for the first flight or so but there's very minimal training needed and in this case back in 1989 a british midlands wouldn't have even had any access to a simulator of the 400 since the variation was only a few months old on board british midlands flight 92 there was 118 passengers and eight crew members and for this third flight of the day the first officer was elected to be pilot flying and like i mentioned before the weather was fine it's forecast a little bit of rain uh temperature of nine degrees and some light winds outside so the preparation for the flight was normal the crew taxed it out and it took off from heathrow at the time 1952 and they climbed up initially to 6 000 feet which was the first stopping altitude on their clearance they stayed at that altitude for a few minutes before they got further clearance from our traffic control to climb initially to flight level one two zero and then they were cleared to climb to their cruising altitude of 35 000 feet and start heading towards a vor called trent during the departure the cockpit voice recorder picked up only normal professional conversation between the two pilots they seem to be a really good atmosphere going between the two and they were talking to each other on a first-name basis when the aircraft passed about 20 nautical miles south of east midlands airport and they passed a altitude about 28 300 feet this was at the time 2005 the first indications of some real problems started appearing because suddenly the crew noticed moderate to severe vibrations shaking the whole aircraft and while that was happening they also started smelling a smell of burnt rubber or oil or what was also described as hot metal and as this happened the pilots started reacting to this really really quickly the first officer said looks like we have a fire and the captain reacted to that by taking control of the aircraft and disconnecting the outer pilot and leveling the aircraft off at around 30 000 feet or so it should be noted that there was no fireball or no fire warning at this point the engine instrumentations according to the flight data recorder showed some fluctuating n1 on the number one engine that's on the left hand side uh an increase in edt on that engine as well and also an increase up to maximum indication of five when it came to vibration however this happened quite quickly and also this happened irregularly so the it looks like the engine was actually stalling and when an engine is stalling these engine indications will come and they will go so it is very possible that when the pilots look down on the end indication it could be in between these stalls in which case there would be very little indication of which engine was actually at fault the captain later stated in interviews that when he looked down on the engine instrumentation there was no obvious sign of which engine was causing the problems but he had a feeling that the smell that they were smelling and the kind of fumes and smoke that they noticed was actually coming from the back and since he had experience flying the 737 200 and 300 before he knew that if that was coming from the cabin well then the cabin was fed air conditioning from the number two engine so he thought that maybe it's the number two engine that's the problem now the first officer who had been pilot flying up until this started happening now found himself in a position of being monitoring and he looked over and the captain asked him can you identify which engine is causing the problem and he looked down at the end in instrumentation and he said it's the le it's the right one that's causing it this when you hear it it sounds that there is some ambiguity there and there definitely was but the captain who had already started thinking about this probably the right hand the number two engine he agreed to this and told the first officer to start throttling it back as the first officer is reaching over to reduce the trust on the right-hand number two engine something really curious happens because as the first officer disconnects the outer throttle and starts reducing the thrust the vibrations suddenly start reducing and the smell of burnt rubber and oil also start disappearing clearly giving the indication to the pilot that they're doing the right thing that they have identified the correct engine this whole process from when the vibrations start until they have identified the engine and started dealing with it takes only about 20 seconds which is an extremely short period in a cockpit to properly identify which engine is causing the problems but the crew is now convinced that they've done the right thing they have leveled off at 30 000 feet and the first officer calls out traffic control with a mayday call and tells them that they have indication of what looks like an engine fire a traffic control responds to this with a request for their intentions and asking them if they want to divert or so but the flight crew quite rightfully the telstra traffic control to stand by and that they will get back to them the captain asks the first officer to shut the engine down but before the first officer can start doing that he also comes in and he states actually uh um it seems to it seems to be running all right now let's see if it comes back in and it's a possibility here that captain is actually looking at the right-hand engine the number two engine seeing that the engine parameters are all within limits but the first officer tells the captain that he would like to start the engine failure shutdown checklist and he says it it seems to have stabilized now but we still have the smoke the first officer tries to start executing the non-normal checklist for the engine failure and shutdown but um but it keeps getting interrupted by air traffic control calls and also by the fact that the captain is now contacting east midlands operations for the company to see what they want them to do the company wants them to divert to its midlands which is really close by their current position so they also advise traffic control that they want to do this and of course that is then followed by several descent clearances and so on so at about two minutes and seven seconds after the initial vibration the engine start lever on the engine number two the right-hand engine is moved to cut off and the engine is shut down during this time the indications of engine number one has stabilized quite a bit from the initial surges the exhaust gas temperature the egt is at about 50 degrees higher than it was normally and the vibration indicator is still at its maximum five units but the problem with that is that it's very close to the oil quantity indicator which is kind of the dominant feature of that part of the engine instrumentation and also the pilots who have been previously flying on other aircraft like the back 111 and the dc-9 are used to vibration indicators that can't be relied upon and they're unaware that the vibration indicators on the 737 400 is actually extremely reliable at the same time in the cabin the passengers and the cabin crew have noticed basically the same thing as the pilots have they noticed the severe vibrations in the front they got what some passengers described as smoke even though in later interviews they couldn't really describe the color or the thickness of the smoke but they smelt the rubbery oily um hot metal smell coming in and passengers that were sitting on the left-hand side of the aircraft also described signs of engine fire on the left-hand side things like torching or sparks coming out of the engine just after the crew has shut down the right-hand engine the captain called for the purser the chief flight attendant to come up and he asked him did you have any smoke in the cabin to which the person responds yes we did and the captain then tells him to start preparing the aircraft for landing and the fact that they've had a problem with the right-hand engine the the takes about 30 seconds and then the person comes back again to the captain and he tells him that listen the the passengers are quite panicky in the back and this prompts the captain to make a pa and in the pa the captain explains that they've had an issue with the right-hand engine that has produced a bit of smoke but it's now okay they've shut down that engine and that we are diverting to east midlands airport and that will be landing in about 10 minutes now this confused quite a few of the passengers which had clearly seen sparks and smoke coming out of the left-hand engine but none of them really thought about bringing it to the attention of the cabin crew and the cabin crew who had also seen some of this spark coming off weren't really listening into the pa because they were now preparing for the unexpected imminent landing in the cockpit the workload is now really really high because when they decided to divert to east midlands they actually were quite close already to the airport which meant that they started getting radar headings and descent clearances quite rapidly they were changed over from london control to manchester control and then to east midlands control and on the frequency there were several other aircraft as well which meant that the frequency quite busy the first officer who's been busy dealing with the engine failure shutdown checklist for the engine number two is now starting to go through the end one engine operative descent and approach checklist as well and while he's doing that he's also trying to load the new approach into the ils number two seven east midlands into the fmc but he's struggling with doing that because he's not used to these on route diversions he hasn't done many of them and he's unaware of the fact that you need to go into the root page and change the destination to the new destination of these midlands before you can start loading the new approaching this takes about two to three minutes for him to complete and on top of this the captain is flying the aircraft completely manually okay he has not re-engaged the autopilot which it could have done but all of this together creates a very high workload environment and since the trust has now been reduced because they're descending in towards east midlands it means that there's now no indications really except for maybe slightly higher egt of any problems with the number one engine during the descent about seven minutes after the initial failure occurred the captain actually does try to re-evaluate the situation he starts saying on the cockpit voice recorder now what indications did we actually get here it was high vibrations on the aircraft and smoke and then he was interrupted by a change of frequency of air traffic control and a further descent clearance and a new radar heading and after that interruption this review was never taken up again unfortunately at time 2017 all of the checklists are completed and the crew starts receiving final vectors for the ils approach number two seven in east midlands initially they get a radar heading of two two zero degrees which brings them through the localizer to the other side uh in order for them to get a little bit extra track miles and they get a descent clearance to three thousand feet when they reach 3000 feet they get a right-hand turn to establish on the ils and as they reach 3000 feet they're actually leveling off for a little while and as they're leveling off they now need to get some trust again so they're increasing the trust on the number one engine uh which initially is actually responding to that trust request but as it does so the vibration indication also jumps up to five units again which is the maximum indication the pilots are now preparing for the landing they have selected flaps one they select flaps two flaps five they establish themselves on the glide slope still using the number one engine still without any real indications of having some problems with it except for the vibration indication at about 4.3 nautical miles they select the landing gear down flaps 15 and they start completing the one engine operative deferred items landing checklists one minute later at 2.4 nautical miles final and at 900 feet things now happen really really quickly suddenly the engine number one stops producing any trust it's just like it stops working okay immediately when this happened the captain realized the mistake they've made and he calls for the first officer to please start to try to restart ending number two as he's doing this he's also pitching the aircraft up trying to extend the glide of the aircraft to hopefully reach the airport 17 seconds later the crew receives an engine fire warning on engine number one the captain quickly tells the first officer to not do the engine fire drill because he's hoping that he's still getting a little bit of trust out of the engine if they would have done the fire drill at this point that would have shot the engine completely down but this doesn't help them at time 2024 the captain grabs the pa mic and calls to the cabin prepare for a crash landing prepare for a crash landing two seconds after that the stick shaker starts activating and the stick shaker then remains activated until the aircraft impacts the ground the impact happens on the eastern side of the m11 motorway that pass past east midlands airport that's about one kilometer short of runway two seven it impacts with the tail first and then with the two main landing gear as the impact the two main landing gear gets sheared off the aircraft then bounces off gets slightly airborne for another fraction of a second before a second much major impact happens on the western side of the embankment for the m11 highway when this second impact happens the aircraft breaks into three pieces of which the tail gets folded over the central piece of the aircraft out of 118 passengers and eight crew members 47 passengers perish in this horrible accident but what actually caused this accident after the quite lengthy rescue effort was finished at the site the uk air crash investigation team came to the site and started trying to figure this out they started gathering up eyewitness accounts from people who had seen the aircraft coming in and also talking to passengers and the crew members and the recommendations that came out of this accident has actually far reaching implications to how we work in a cockpit today and i'll tell you all about it after this message from my sponsor i want to take this opportunity right now to just thank the sponsor of this episode which is curiosity stream and i love to have them on the sponsors because i know that you guys are watching this episode because you just like me love nerding out into a great documentary or a non-fictional story and that's exactly what curiositystream is all about they are a subscription streaming service with thousands of high quality non-fictional stories or documentaries from some of the best filmmakers in the world now i am watching right now something called hurricane the anatomy it's a mini-series and i had no idea that i knew so little about hurricanes if this sounds interesting to you then go to curiositystream.commentorpilot use the coupon code mentor pilot and that will give you a whopping 25 of the yearly fee and that comes down to wait for it 14.99 per year which is just insanely cheap for what you get so if that sounds interesting go down click the link support me by supporting my sponsors and enjoy as the investigation started into british midlands flight 92 the first thing that the air crash investigators wanted to know is why did the vibrations and that smell of smoke appear in the first place and they started looking into what was left of the engines at the scene during the approach several eyewitness accounts had said that they had seen flames coming out of the the number one engine on the left-hand side of the aircraft that also seen part of that engine falling down so the aircraft investigation team went out they managed to find most of the fragments that was left under the approach path of flight 92 and they started puzzling together a piece they very quickly realized that the number two ending on the right hand side had only damages that were kind of you know consistent with the impact of the aircraft but when they started looking into the left-hand engine they noticed that while it had very similar impact um damage like the other engine there was two significant differences one there was sharing as in there was signs of engine fire on that side and two when they looked into how the fan blades had been damaged they found one fan blade fanday number 17 that seemed to have been damaged in a completely different way than the other ones it seemed to have broken off rather than having been bent inwards or broken because of the impact forces so this led the investigation team to start looking at the engine as such and looking into the fact that this was a relatively new variation of this engine when the manufacturer that manufactured the cfm56 started rebuilding it for the purpose of getting more trust out of it they had to rebuild the fan of the engine and after that new fan was installed it had to be tested during testing of this new fan they used a test bed that was sitting on ground level and was set to try to replicate all of the conditions that the engine might find itself within its operating envelope but it turns out that this test bed didn't do a perfect job and there was a small vibration that was left undetected and this little vibration was found to be able to create fatigue cracking in the fan blades so what happened on the accident flight was that at about 28 300 feet the fan blade number 17 broke loose and when it did so it created severe vibrations within the engine now those vibrations actually caused the other fan blades to start to rub up against the abradable kind of circumfering material of the engine that's what caused the smell of burnt rubber and smoke in the cabin and the fan blade in itself most likely got embedded into the engine cowling where it sat for almost the remainder of the flight when the pilots disconnected the outer throttle the outer throttle had actually been set to reduce the thrust slightly on engine number one and because that was happening at the same time as the pilot disconnected the outer throttle and started reducing trust on the engine number two that reduction in trust on engine number one actually managed to stabilize that engine reducing the vibration and also removing the smell so the fact that the pilots were reducing engine number two actually had nothing to do with the reduction in vibration it was just a very un fortunate coincidence then as the aircraft continued to descend in towards east midlands and they reached 3 000 feet the captain put the trust on on engine number one again this increased the vibrations again started shaking the engine and during the later stage of approach at about 900 feet it's likely that what remained of the family number 17 that had got embedded into the cowling got loose again and further damaged the fan which led to the immediate loss of trust on engine number one and also to the engine fire that followed when it comes to the operating crew there were also several findings made by the air crash investigation team they started by looking into the training of the pilots and they found that the pilots were properly trained and that in their training syllabus they had indeed been taught to not make rash decisions when faced with a complex situation especially not shutting down an engine without properly checking it but they also found that there were some lags in the checklist so there was no checklist for a combination of engine vibrations and smoke for example they also looked into the new type of engine instrumentation that they were faced with on the 400 and they found that maybe the vibration and the indication of the high vibration wasn't optimal when it came to how the crew had actually reacted when faced with this problem they found out that the previous knowledge that especially the captain had of previous aircraft types where the air conditioning system had a different layout than what it had in the 400 could have played the part because he was biased based on technical knowledge that was not correct for the 400 but it was also clear from the investigation that the first officer was not really sure when he was diagnosing problem and that he in interviews later on really couldn't state why he chose to say that it was engine number two rather than engine number one that was faulty this has led to some real improvements in the way that we handle engine failures and any kind of engine problems today really first of all the division of rules making sure that one pilot always flies the aircraft and the other pilot deals with the problem when the autopilot is engaged and when there is extra capacity the one who's flying the aircraft is also taking care of the radio so that leaves the full attention of the pilot monitoring to deal with the non-normal and the checklist secondary always verifying all of the engine parameters and talking in between each other before we take any decision that shuts down an engine the other thing that has also come out of porchly this investigation is the adaptation of decision making tools like for example piosi which i've done a video about where we when we're faced with a very complex situation we take a step back and we look at what's the problem what information do we have what options do we have we select an option we execute that option and then we evaluate it okay and with a special emphasis here on the evaluate because if they would have made this initial mistake but then they've gone through their actions and they have gone back they would have realized at a very early point that it was actually the incorrect engine that had been shut down and that would have given them much more time to do an in-flight engine restart and hopefully this accident would never have happened the other thing that also became clear and this is a message for all of you out there is that there was no real information going from the cabin crew and from the passengers forward to the pilots even though the pilots were making pa talking about how they had shut down the right engines the passengers knew that it was the left endian that had the problems this was not communicated forward to the pilots obviously passengers and also to some extent the cabin crew would probably always think that the pilots have all of the information that they need but it's always good to share any knowledge so if you see something that's strange out there if you see smoke fire or just something that doesn't look right it's always a good idea to kind of ding the call bell tell the cabin crews that they can forward that information to the the pilots and me as a pilot today when i talk to the cabin crew i always ask them what they've seen i don't give them what they've seen i don't ask them did you see any smoke i asked them did you see anything just to get an unbiased picture of what they have seen before i start to evaluate it on top of this the decision that the captain took to call prepare for a crash landing prepare for a crash landing just prior to impact meant that several of the passengers actually adopted the brace position while other passengers did not because the brace position wasn't really implemented well back in 1989 and this meant that there was a wealth of information available to the investigation team later on to see how the passengers injuries were impacted by the use or non-use of the brace position and this has further led to a research group that is trying to implement the best possible brace position for crashes like this one thing that i want to take before i leave you is that i always get questions on videos like this why didn't they have closed circuit tv monitors why weren't there any cameras you know pointing out the engines that they could check in the cockpit to see what was going on and that was actually raised in this accident report as well so one of the 31 recommendations that came out of this crash was to implement these kind of cameras and i have reached out to iasa um to see since this was a recommendation in this crash why that hasn't been implemented yet and they have promised to get back to me but at the filming of this episode i still haven't received an answer back from them but i'm expecting to get that very shortly i hope that you found this video very interesting guys and if you did then i hope that you have subscribed to the channel and that you've highlighted little notification bell if you want to help support me and the channel then i hope that you would consider becoming a patreon as well my patreons are really helping out my channel and we're having weekly zoom hangouts where i get to talk to them and they can ask questions and it's really really great the crew to be part of have an absolutely fantastic day wherever you are and i'll see you next time bye you

Channel: Mentour Pilot

Views: 407,775

Rating: 4.9540281 out of 5

Keywords: british midlands flight 92, british midlands crash, vuelo 092 british midlands, kegworth air disaster, kegworth air disaster documentary, kegworth plane crash, kegworth disaster, air crash investigation, air crash investigation 2021, air crash documentary, air crash compilation mayday, mentour pilot crash, mentour pilot, Boeing 737, Boeing 737 400, east midlands airport, east midlands airport crash, fear of flying, fear of flying help, air crashes explained, pilot life

Id: xbCTTKw3o5o

Length: 33min 34sec (2014 seconds)

Published: Fri Aug 06 2021