What Actually happened to Air Florida flight 90?!

this video has been made possible together with skillshare which is an awesome online learning platform the 1000 first of you who uses the link in the description below will get a free trial with skillshare so go and check it out january the 13th 1982 and in washington dc in the united states a snowstorm is keeping the city in a cold icy grip on runway 36 in the local airport washington national a boeing 737-200 from air florida is getting ready to line up and take off the aircraft spools up its engines and starts to roll down the runway but only about a minute later this aircraft will come crashing into the 14th street bridge that's spanning the potomac river as it does so it will crash into seven different vehicles before it continues down into the cold icy waters below now using the final report let's have a look at all of the different things that led up to this disaster and what we can learn from it stay tuned [Applause] air florida flight 90 was flown by a boeing 737 200. it was a scheduled flight that was supposed to go from washington dc to a short stop in tampa bay in florida and then continue down to fort lauderdale also in florida on board the 737-200 there were 74 passengers three cabin crew and two pilots and the crew had arrived from miami earlier at about 1329 eastern standard time now the subsequent flight flight 90 was supposed to leave at 14 15 so that's about 45 minutes later but the problem here is that it had been snowing continuously in washington throughout the day the intensity of the snowing had been kind of varying but it was moderate to heavy snow throughout and because washington national airport only was using one runway at the time they had to at regular intervals close the airport down for snow clearing so for about an hour and 10 minutes about time 13 40 to 1450 the airport was completely closed and it was starting to build up a huge backlog of aircrafts that wanted to depart and also aircraft that wanted to come in to washington and this this will actually have a quite significant importance later on so in the cockpit of air florida flight 90 was captain larry michael wheaton he's 34 years old at the time of the accident he has about 8 300 hours of which 1800 is on the 737 and he was described by his colleague as an okay average pilot you know that would take decision just like any other pilot would now together with him in the cockpit was first officer roger alan petit who was 31 years old at the time he has about 3 350 hours and about a thousand hours on the 737 and his previous experience was in the united states air force flying the f-15 and he was described by his fellow colleagues as an absolutely excellent pilot now the flight crew was aware that washington was going to close the runway down for a while and they knew that they were going to get delayed but they didn't know exactly how much so at about 1400 that's 15 minutes prior to their schedule departure time they asked for and received their air traffic control clearance and just about 20 minutes after that five minutes after the schedule departure time they ask for the de-icing to start now what you need to understand here is that back in 1982 there wasn't as much knowledge about the different de-icing fluids hold over time as in how long these fluids would be active on the wings and be able to keep the snow from kind of adhering to the wing surface back then it was more just a matter of getting rid of the the snow and ice and then it was up to the flight crew to actually make the judgment whether or not the aircraft would be safe to take off or not so when they started the icing they started the icing on the left-hand side of the aircraft and the uh the de-icing guy he was looking at his the icing manual that was provided by american airlines at the time and it said that with a temperature of minus 4 degrees celsius that's about 24 degrees fahrenheit they needed to have a mixture of about 30 to 40 glycol and the rest hot water in order to both clear the wings and flight control surfaces of ice and to provide a bit of anti-icing so they started the ice in the left-hand side of the aircraft but as they were doing so the crew was in contact with their traffic control and air traffic control basically told them that listen it's going to be at least 20 more minutes of airport closure and on top of that you are number 12 in the queue for departure having heard that captain larry just told the icing crew that you can stop it makes no sense to continue the icing because we're gonna have to stand here and wait so said and done they continued to board the passengers to get ready for departure and which is waiting to get further clearance to start the icing and when they heard that the airport had opened again they got back into contact with the icing crew and the icing restarted again at time 1455. so this is now about 40 minutes after the scheduled departure time so they're running quite late so the guys that were the icing they switched over to a new de-icing team and curiously enough the new de-icing team they looked at the temperature and for some reason they thought that it was about four degrees warmer than it actually was so they decided that we don't need 30 to 40 glycol we only need about 20 to 30 glycol so they shifted that over and then they started to de-ice the right-hand side of the aircraft with the new mixture now since we now know quite a lot about the icing okay partly because of this accident for me it sounds very very strange that they would change the icing fluid in the middle because the way that with the ice aircraft right now it is really really important that not only you maintain the same de-icing mixture for the whole aircraft but also that every part and every surface is equally de-iced on both sides that's to make sure that you have uniform de-icing all of the aircraft for aerodynamical reasons but like i said back in 1982 this was less important right so the main point here was just to get rid of the ice and keep the wings clear when the aircraft was ready to push back the aircraft the icing was completed at time 1510 and captain larry then asked the station manager who was in charge of the de-icing crew to have a look at the aircraft and make sure that it was clean the station manager got back to him and he said yeah no it looks good there's just a little bit of light dusting of snow on the on the wings which once again from my experience now would definitely start setting up alarm flags right because after the icing the aircraft should be completely clean and we do not accept any type of icing or any type of snow or deposits on the wing at any point prior to departure but a light dusting of snow didn't sound that bad and there was a wide kind of spread belief at the time that if you know there was just dust on the wings it will blow off during the takeoff anyway so this wouldn't have alarmed the flight crew much and in fact there's no sign that they went out and had a visual inspection of wings themselves anyway so the aircraft was now ready to start pushing back and at time 1524 uh captain allen requested pushback from air traffic control they received their pushback clearance and they relayed that to the ground crew but the problem here now was that because of the heavy snowfall the ramp was very slippery and the aircraft had been de-iced which meant that there was also a lot of glycol the icing fluid on the ramp so as the push back crew started to try to push the aircraft back they failed okay it was too slippery the target just couldn't get traction and they couldn't get the aircraft off from the gate now captain larry makes a request to the ground crew that indicates that his experience with wind drops was quite low because what he tells the ground crew is that guys maybe we should be maybe we should use the reversers to to help you to push back in order for you to understand why this is significant is because the boeing 737 at the time had had some problems during icing conditions specifically they've had problems when the 737 has been taxing out for takeoff during light snowfall and the pilots have been using reverses during the taxi out what has happened on at least 22 occasions that has been recorded at least is that the aircraft after having used reversers during the taxi out during the takeoff has had some quite violent pitch up movements right there the pilots have been rotated normally and the uh aircraft has reacted really really powerfully and pitched up a lot that's forced the pilots to kind of hold against it and boeing has been doing some wind tunnel testing and been checking it out and realized that the likely cause of this is the use of the reversers because the type of reverses that you have on the 737 200 is what we call a bucket type right they basically just um fold out sleeves behind the uh engine exhaust that will then redirect the flow of the engine forward and what is thought to be happening is that when they've been doing this then the snow on the ground has been melted by the exhaust gases it's been thrown forward and then reapplied onto the leading entrance of the wing where it's frozen into clear ice so boeing has put out a bulletin saying that try to avoid using reversers during the taxi out under these conditions all right because it could cause these problems and this bulletin has been implemented into the air florida manuals so captain barry should definitely be aware that you know using traverses during pushback under these kind of circumstances is not okay and in fact the pushback crew also tells him this they they are employed by american airlines and the american airlines manual for the pushback crew tells them to under no circumstances do this and this is what they're relaying to the captain but for whatever reason this is being ignored they start up the engines on stand and they use the reversers orbit only on idle power however this fails all right it doesn't make any difference the pushback is still halted so they choose to shut down the engines with the thrust reverses still extended and they get a hold of a different pushback truck the new pushback truck is stronger managed to start to push the aircraft back and at the time 15 35 the push back is completed and the aircraft starts attendance again and restores the trust traverses and now another really important piece of the puzzle that led up to this accident falls into place because as the flight crew is now finishing off their after start checklist another aircraft comes into the atc frequency and atc tells this aircraft was about to taxi into the queue that they need to maneuver around the air florida aircraft in order to get into the queue but at that point the air florida crew comes onto the frequency and says no don't worry we'll be we're just finishing off here and we'll be taxiing in and out of the way this is likely because they don't want to lose their place in the queue and because of that they are now feeling a bit of rush right so perceived time pressure involved because as the crew is now finishing off the off the start checklist and as part of the officer checklist you have the engine anti-icing if you want to put that on or off the cockpit voice recorder records that the first of the challenges and the ice and the captain respond off okay there was a lot of controversy when this tape first come out because they had to listen to multiple time because on and off sounds a bit similar but everything from the voice recorder to the flight data recorder indicates that the engine ntis was never selected on and after the crash it was also found in the off position air florida flight 90 now joins the queue for departure okay and they taxi in behind a departing dc niner and during the taxi out now and as they're standing in the queue there are multiple discussions going on in the cockpit regarding the weather right there are a lot of mentioning about potential di thing they're talking about um you know the intensity of the snowfall being moderate and basically it seems to be an awareness in the cockpit that the current weather conditions is a threat for the departure however not long after they joined the queue the captain is starting to make some quite strange remarks uh remarks like well i don't know about my wing but my windshield is sure going to be the iced and the first officer responding with like well yeah you know we only really need the inside of the wings anyway the outside of the wing is going to blow free once we pass 18 knots and things like that and it is very likely that what the captain is referring to here is that ahead of them they have a dc9 which have the back mounted engines and they actually are discussing whether or not they can use the hot exhaust from the dc-9 in front of them to de-ice their own aircraft and even though that might sound like a good idea it's like a you know like a hair dryer blowing hot air on you it should be a good idea to use that to the eyes once again there are clear descriptions in their wind drops manual about not doing this in fact when you're taxing out after another aircraft in these kind of conditions you want to extend the distance to the aircraft in front of you and that is because it is not a uniform way of de-icing an aircraft and this hot air that's coming out of the engines of the preceding aircraft the only thing it potentially will do is to melt the contamination that you have on the wings and then it's going to re-freeze again into contamination that is going to be way worse aerodynamically for the wing and it's going to stick to the wing in a completely different way than just snow on the wings at time 15 48 this is now almost a full hour after the the icing was commenced the um the first officer is starting to make some comments about their engine instrumentation and it is likely here that what the first officer is starting to pick up on is that there is ice forming inside of the engines now at this point we need to discuss a few things first of all the holdover time of the icing fluid like i mentioned before back in 1982 this wasn't fully understood right the whole of the time is basically the time that the the icing fluid will be effective that will keep the wings clear all right and the way that we calculate the hold over time right now is that we start the calculation of the holdover time from the start of the application of the second fluid or if it's just a one step the icing like they were using on flight 90 then you start the whole of the time from the start of the dei thing okay so that would have been almost an hour before and with this kind of intensity of snowfall and with the low kind of glycol content that they had in the icing fluid it's very likely that at this point that the icing fluid is not effective anymore and a lot of snow is starting to accumulate on the aircraft wings but icing inside of the engines has a different danger to it remember how we said before that the crew elected to have the engine ntis off in the afterstar checklist yeah so what is likely happening at this point is that ice is starting to form on the spinner of the aircraft right because it's loads of snow being ingested into the engine and normally the the isis system uses hot bleed air to de-ice both the engine lip and the spinner to make sure that they are free of eyes and the reason that is so important is because when you set the trust on the 727 200 you use a indication called epr which stands for engine pressure ratio and that epr essentially is the difference in pressure between the front of the engine and the back of the ambient so there is a probe that even the spinner that's taking up the pressure measured at that point and then there is another probe in the back of the engine and the epr is basically the pressure from the probe in the back which is the p7 divided with the pressure in the front which is the p2 but if you start to have icing building up on the spinner well then the entrance to this p2 sensor is blocked so it will start taking pressure from inside of the spindle instead where there is a little drainage hole but the pressure inside of the spinner is lower than the pressure outside with the kind of air is being sucked in past the probe and if you divide the p7 output which is still okay with a much lower p2 output which is now blocked you're going to get a higher epr indication right so in the cockpit you see a higher epr but the other instrumentations like for example n1 and egt the exhaust gas temperature it's going to show strange values all right so it's going to show lower values than normal because you're not actually getting the the pressure that you think you're getting from the instrumentation and this is a very insidious fault it is explained in the manual but it is likely that the crew that has very very low experience of winter operations uh wouldn't pick up on this all right it's it's very hard to pick up however the first officer is now seeing that you know there are fluctuations on the engine instrumentations and they think that that might be because of the preceding aircraft and the hot air from their engines actually being ingested into their engines and that's what's causing these fluctuations but it isn't really early indication of problems to come the captain is now still in the queue and he continuously makes remarks about the preceding aircraft like no no don't go that way i need you to de-ice my other wing as well indicating that he is still focused on trying to use the exhaust from the preceding dc niner to de-ice his aircraft that and i mean even though you you know think that that might be working it's still an indication that you know that you have eyes building up on your aircraft and today that will just not be accepted right if you have any kind of doubt whatsoever about icing on your aircraft there's only one thing to do and that is to turn back to the terminal and get de-iced again the first officer at this point though is pointing out to the captain that he's skeptical about this procedure he says that i think that this is just giving us a false sense of security i don't think that this is working but the captain just continues anyway at time 1557 the crew is now finishing the before takeoff checklist they verify the takeoff speeds 138 for v1 vr 140 and v2 at 144 and the takeoff epr setting we're going to use of 2.04 the first officer asks the captain whether or not he wants to add something to the take-off briefing because of the slushy weather but the captain just said nah you know unless you have any questions or anything that you want to add i'm quite happy with it and this indicates that the first officer is expecting the captain to kind of point out some of the threats with this you know it's a slushy runway it might be slippery or if they're going to do any differences in rotation technique in fact the first officer is talking about maybe holding the nose wheel off the ground a little bit like in a soft airfield takeoff you know the 727 200 could actually land on non um asphalt runways as well but the captain is just disregarding this it doesn't seem like this is going to bother him much at this point two minutes later at time 15 59 air florida flight 90 is getting their lineup clearance and they're told to taxi in position and get ready for an immediate takeoff because they are landing traffic only about two and a half nautical miles out and this is also really important to remember okay remember how i talked about the fact that there was a big kind of backlog of aircraft both coming in and departing so air traffic control is now tightening up the arrival schedule right there's loads of aircraft coming in on approach and they want the departing aircraft to get out of the way as quickly as possible in order to continue to feed aircraft in it's very likely that you know the crew that hears this knows that okay we are going to have to go really quickly here so once again there is a perceived time pressure built in and there is a risk with that type of perceived time pressure because you don't want the pilot that are departing especially in these kind of heavy wind drop situations to not have sufficient time to evaluate their engine instrumentation before they go right that's a bad thing in fact nowadays we do what's called an engine run up before we start rolling precisely in order to be able to evaluate how the engine is performing and also potentially shed ice that might form on the fan blades but there is no time to do this on this departure once the aircraft is lined up they receive their take-off clearance with the additive do not delay and the the last ever transmission that comes back from florida flight 90 is just a simple okay the captain now hands over the controls to the first officer who's going to be the pilot flying for this leg and as the first officer is increasing trust on the engine the captain explains good look at that that's really cold possibly now referencing to the engine instrumentation the fact that the epr is rising really really quickly and the engine instrumentation is fluctuating okay um the the really cold bit might just be in reference to the fact that if it's cold outside the uh the epr might rise a bit quicker at least in in his mind what it's more likely indicative of here is the blocked p2 probe in the in the front of the engine the first officer responds with god look at that that doesn't look right does it and the aircraft is now rolling down the runway and the first officer makes another call saying it that that's not right but the captain respond yeah yes it is and they continue to accelerate past 80 knots the first officer continues to say no i don't i don't think i don't think that's right and the captain doesn't respond to this nine seconds later they can first of all say well yeah maybe it is captain calls out 120 and the first of respond what the ah i don't know all of this indicates that the first officer is very skeptical about what it's seeing and that is probably because the epr that they have set for takeoff is 2.04 however the egt the n1 all of them are showing much lower figures it has been shown afterwards that the epr that they actually had set was probably closer to what 1.7 rather than 2.04 which is a lot less than what they need during these kind of conditions and another thing that has been shown is that their takeoff role took a lot longer so while it would on a normal takeoff would have taken about 30 seconds or so in this case it took 45 seconds which is significantly longer so all of this the trust level position the indications of the other engine instrumentation everything is looking weird and the first officer is well aware of this but the captain who is the pilot monitoring in this case and the one that should be looking at the engine instrumentation doesn't seem to mind this all right there is a possibility here that the captain is more worried about the landing traffic behind him and what will happen in case he rejects the takeoff to the landing traffic right so there is this time pressure there is this feeling that they want to get away because they are you know an hour and a half late already and all of this is now playing in together to pushing this aircraft off the ground the captain calls out b1 rotate v2 the first officer rotates and on the cvr you can hear like a whoa and the captain is saying push forward forward so once again it is now likely that what we talked about before the fact that if you have a lot of contamination on the leading edges of the 727 200 it has a tendency to pitch up quickly this is likely what happened but they're also getting just after a few seconds the first stick shaker right so the stick shaker is now coming in at a much higher speed than this crew is expecting it to come in right their indication of the speed is correct but they're still getting stick shaker and that is most likely because the wings are contaminated with a lot of snow and ice and when you have that the aerodynamic efficiency of the wing just is not there okay so now the crew is sitting in a really bad situation they have lower trust than they need they have contamination on the wings they have now a stick shaker the aircraft is unable to climb and it has been showed in simulations of this that if they had only one or the other so if they had the correct trust set with icing they would have been able to climb out of it or if they had the incorrect trust set and not that much ice on the wings they will also have been able to climb out and if they would have reacted quickly by getting the nose forward and getting out of this stall they might also have been able to fix this but this is all happening now in a matter of seconds and the aircraft initiates a climb but as soon as it gets out of what we call the ground effect the aircraft just stalls only a few seconds later the last sad message on the cvr has been picked up and it is the first officer says we're going down larry and captain responding i know at time 1601 only about a minute after the aircraft initiates its take-off role the 737-200 hits the northbound span of the 14th street bridge that is spanning the potomac river as it impacts the bridge it has a really high nose attitude this has been told by eyewitnesses so the back part of the aircraft strikes the bridge and it also strikes seven different vehicles before it goes off on the other side of the bridge the impact pitches the nose downwards and the aircraft crashes into the icy potomac river below where it penetrates the ice and it splits into several pieces 74 people inside of the aircraft dies as the aircraft impacts the potemac river including both pilots and two cabin crew four other people die on the bridge as the aircraft impacts the vehicles that are standing there and four are seriously injured and the only reason that a few people survived this accident was the heroic actions of both some of the passengers inside of the aircraft and and also the the hard work of the rescuers both the people working in the helicopters and bystanders around the national transportation safety board initiates its air crash investigation and comes with a final report and in the final report they state that the probable cause of this accident was the flight crew's failure to use engine ntis during ground operation and takeoff their decision to take off with snow ice on the airfoil surfaces and on the aircraft and the captain's failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings contributing to the accident were the prolonged ground delay between the icing and the receipt of atc takeoff clearance during which the airplane was exposed to continual precipitation the known inherent pitch up characteristics of the boeing 737 aircraft when the leading edge is contaminated with even small amounts of snow and ice and the limited experience of the flight crew in jet transport winter operations and then there are a lot of different recommendations concerning the training of flight crew for winter ops operations the uh awareness of the dangers of wintrop's operation and the effect of anti-icing on the airframe so this is one of the most important accidents that's happened during the last few decades when it comes to just raising the awareness of the threat of winter operations right from this we have gotten our now much more stringent procedures regarding holdover timetables anytime that ideates an aircraft today i have to you know really carefully calculate how long my hold over time is and throughout my operation out i have to continuously review whether or not the outside conditions has changed and that might have changed my hold over time and if we see any kind of indication of any ice accumulating well then we are required to either go out and verify that this is so this is not the case and in most cases just turn back to the the icing platform again and get the aircraft the ice a second time basically when in doubt there's no doubt always the ice this has come from this accident so no matter how tragic this accident was and the horrible loss of life included we have gotten a much more safe aviation industry as a result of it this video has been made possible together with skillshare who is sponsoring this video now skillshare is an absolutely fantastic online learning platform with thousands of high quality video courses and pretty much anything that you can imagine anything from like professional photography to how to improve on your youtube channel which i have personally been using or another thing that i've been using together with my son lucas is a course called learn how to fly an airplane with howard forder where we've been you know looking at the lesson and then he has been using his uh flight sim 2020 simulator to actually do the lessons afterwards which is really really cool now skillshare is also really affordable it's less than ten dollars a month to use so if you're a curious person who wants to improve in whatever area that you want well then the 1000 first of you who uses this link here below will get a free trial of skillshare so you can go out you can see if there's any course in there that will you know apply to your curiosity and then um continue to use it i bet you will like it [Applause] let it go [Applause] yes [Music] [Applause] foreign [Applause] we're going down [Music] [Music] you

Channel: Mentour Pilot

Views: 355,182

Rating: 4.9135594 out of 5

Keywords: air florida flight 90, air florida flight 90 crash, air florida flight 90 cockpit voice recorder, air florida flight 90 crash video, air florida crash potomac 1982, air florida flight 90 crash animation, air florida flight 90 cvr, air florida crash, air florida 737 crashes in the potomac, Mentour Pilot, mentour pilot passenger land plane, Boeing 737, Boeing 737MAX, Fear of flying, air crash investigation, air crash investigation 2020, air crash investigation 2021

Id: iUmnFOiIijY

Length: 34min 59sec (2099 seconds)

Published: Fri Feb 26 2021