American Heroes in the Cockpit! | Air Crash Investigation

this video is sponsored by nordvpn click the link in the description below and start protecting yourself on the internet today it's the afternoon on the 12th of june 1972. american airlines flight 96 which is flown by a brand new dc-10-10 aircraft is climbing out from detroit metropolitan airport as the aircraft climbs through 11 750 feet a loud bang can be heard and part of the aft cabin floor collapses into the cargo compartment below the whole aircraft fills up with dense white fog and in the cockpit the pilots are struggling to maintain control of the aircraft what has actually happened well in order to understand that we have to look at some of the design features of the dc-10 we're also going to have a look at the heroic actions about the flight crew and the cabin crew and we're going to do so with the help of the final report stay tuned [Music] american airlines flight 96 was scheduled as a multi-stop flight starting in los angeles then flying to detroit after detroit continuing to buffalo and then finally to new york and laguardia airport in the flight tech we have a really senior flight crew captain bryce mccormick 52 years old has 24 000 hours in total together with him was first officer peter whitney 34 years old 7 900 hours and flight engineer clayton burke 50 years old and 13 hundred hours there was also 56 passengers and eight cabin crew on board the aircraft being flown is a brand new dc-10-10 aircraft which was certified and delivered to its launch customer american airlines less than a year before this incident now the dc-10 10 was built for continental travel it wasn't built for extreme long haul it had three engines number one and number three situated under the wings and the number two was tail mounted the flight controls was hydraulically driven but they were activated by a series of cables and pulleys that ran mainly under the main cabin floor and when it came to the doors on the dc10 uh the passenger doors was called plug type which basically means just like on the 737 that they open inwards so that when you close them the differential pressure that you have inside of the aircraft is going to just keep the doors closed in flight however the cargo doors was of a different type these doors opened outwards and there's a good reason for that because if you have doors in the cargo hall that opens inwards they will take up a lot of valuable cargo space behind them so instead these doors will open outwards but the problem that you have with that is that you then need to create some kind of really secure locking mechanism because all of that differential pressure that you will have inside of the cargo rooms will try to push the doors open the way that this had been solved on the dc-10 was that an electrical motor will drive a rod outwards that rod will then turn a torque tube that will in turn lock into position four mechanical c-shaped locks now when that rod was driven to its full extend position a one of the links would lock into an over center position resting on a stop and when it came into that over center position it would essentially make this the locking unreversible any force that was applied to this c shape locked would be transferred through this overlocking mechanism onto the stop and it would stop there but if for whatever reason the extension of this locking rod would stop prematurely well then the link would never reach its over center position and the whole locking mechanism would be able to be reversed right all of the forces that will be put onto these c-shaped locks will then be transferred not on to the mechanical stop that it was supposed to do but onto the locking mechanism itself and its fastening bolts the designers of the door understood that there was a risk in case something would happen to the electrical motor that was driving the locks and that this over center position might not be achieved and in that case there would be a danger of the door actually opening itself so they've worked out a workaround where the actual handle of the door was connected to a torque tube that torque tube was connected to a door a vent door in the door that as long as the handle was open or not closed that vent door was open and that would stop pressurization inside of the cargo compartment and then the the handle was also further connected through linkages and some bell cranks onto a further torque tube which had some locking pins on it and the idea was that if the c-shaped locked had put themselves correctly into position well then as you close the door handle the these locking pins would lock into position and further secure the door however if for whatever reason the c shaped locks was not in position well then the locking pins would find themselves behind some metal flanges that was connected to the locks and they couldn't get in position and if that happened then it would be impossible to actually put the door handle down and this door mechanism was also connected to a indicator light in the cockpit so as soon as the handle was put down properly it closed the vent door in the door and it also closed a circuit that would show the cockpit crew that the door had been properly locked another design feature of the dc10 was that the aft cargo compartment did not have any pressure leaf vents connected to the passenger compartment above and this is going to have a major influence on the events that's to come american airlines flight 96 departed los angeles at time 1436 that's about 46 minutes after its scheduled departure time the delay was down to passenger handling and air traffic control restrictions and the initial leg where they flew from los angeles over towards detroit was uneventful the crew landed in detroit where they offloaded a couple of passengers took on some new passengers and fueled the aircraft and then added some cargo the last compartment to be secured was the aft cargo hole the ramp service agent who was in charge of closing the aft cargo door had some problems closing it he said that he let the electric engine go until it shut off itself and then when he tried to close the handle he realized that he couldn't really close it with the normal smooth way that he was used to instead he had to put all of his force onto it and even use his knee to kind of push the handle into position but when he did so the handle did click into position but he also realized that even though the handle was in the right position the the vent door on the door was still closed but in a slightly cocked position i thought that was a bit weird so he called over a mechanic who had a look at it and basically said yeah no no that looks okay and released the aircraft back to service with all the doors closed and the aircraft ready to go the crew asked to get push back clearance and further taxi clearance into whole imposition for runway city right in detroit and at time 1920 they received their takeoff clearance takeoff was uneventful they climbed out initially to 6 000 feet where they were handed over to the area control center in detroit and they told them to continue climb to flight level two one zero and join the air by victor five five four the first officer was the pal flying for the leg and they continued climb normally as the aircraft climbed through about 11 750 feet all of the flight crew members simultaneously heard a large flip when that happened basically anything that was on the floor in the cockpit became airborne so all of the dust and gravel came up and into the eyes of the pilots momentarily blinding them at the same time the left rudder pedal moved to its full deflection position the aircraft started to jaw to the right and all three engines move back towards idle now captain bryce initially thought that they had hit something that they had a mid-air collision so as soon as his eyes were clear again he took over the controls it disconnected the automatics and started trying to find out what was working and what wasn't in this aircraft he very quickly realized that he had control over number one engine and the number three engine basically the under mounted engine but that's the number two engine was not responding to any kind of trust level command he also realized that he had full aileron um control but that the aircraft was joining a lot to the right and because he was doing that he now had to input aileron towards the left in order to get the aircraft flying where he wanted to so at this point he was basically flying his aircraft in a constant side slip position now the pilot immediately understood that this was a really really serious situation so they called in a mayday call and asked to get vectors back towards detroit metropolitan airport at the same time in the passenger cabin the both the cabin crew and the passengers could hear that loud thump and as they heard that this dense white grayish fog started appearing and they could feel how the air of the cabin was rushing aft the cabin crew knew that if you would see that kind of fog appearing that was indicative of a sudden pressure drop because if you have moisture which you always have in the air and the pressure drops well then that moisture would turn into basically cloud and and that's what happened so the the cabin crew was looking out to see if the oxygen mask would be dropping but since the aircraft was below 14 000 feet which is where the automatic extension of those passenger oxygen masks would happen they never dropped but what was also happening at the same time was far more terrifying so towards the back of the passenger cabin which in american airlines there was actually no passengers seated it was a lounge area with a stand-up bar the whole floor of the passenger cabin started collapsing downwards into the cargo compartment in the back of the aircraft there were two cabins seated by their emergency exits as the floor started collapsing downward they were thrown down onto the floor and received minor injuries but this didn't stop them from carrying out their duty they moved forward and as they were moving forward they were taking passengers and moving them away from the area of the floor that was collapsing they reconvened up in the front of the cabin where they got into contact with the captain the captain obviously busy during this ordeal basically just told them that they had to prepare for an emergency landing and here is where you can see that the immense training and experience of the cabin crew started to kick in because they immediately went into work mode they started to brief the passengers not only about the emergency landing that was coming up but also about the coming evacuation they found what we call able-bodied passengers that could help in case one of the cabin crew would get hurt and basically they were doing everything right so fantastic job from the cabin crew leading up to the landing up in the cockpit the pilots know that they're dealing with some severe problems with their aircraft but they don't know how bad it is they're still not sure whether or not they've had an in-flight collision for example they're still trying to check which systems are working they've realized that their pitch control is severely affected they can control the pitch but the pitch control is very sluggish and it requires a lot of force in order to to move the elevator up and down they don't seem to have any stabilizer trim available and because of all of these things combined as they're talking to our traffic control they're requesting a long final this is a smart move because they don't know what kind of damage they have and they don't know really what the aircraft is going to do as they start to configure it for landing so asking for a long final far out at a higher altitude will enable them to kind of test the aircraft as they're going down air traffic control provides radar vectors for the aircraft to a 20 nautical miles final from where 03 left they intercept the localizer and the glide slope and as they start descending they're descending with about 800 feet per minute which is normal when you're following a glide slope but both the captain and the first officer and the flight engineer are unsure whether or not the landing gear is actually going to extend and if it extends whether or not it's going to be safe they're also discussing whether or not they're going to dump fuel but since they don't know how bad the damage to the aircraft is they don't want to risk to be dumping fuel into something that you know could potentially cause even more damage so they choose not to dump any fuel now as they're getting closer to the airport they're starting to finalize the configuration of the aircraft they select the gear down and the selector flaps down to the landing flap flap 35 and as they do so the aircraft's descent rate starts to increase from 800 feet per minute which they were before to up to 1500 feet per minute a captain knows that this is way too much and he adds thrust on its under mounted engines in order to get the engines to help the aircraft to pitch up and control the descent rate and this works the downside of that is as you're adding trust you're obviously now also adding air speed so the aircraft is flying with landing flaps at 160 to 165 knots which is a good 30 knots quicker than they normally would with this that type of configuration but they choose to continue that because they have the picture under control and in a situation like this controlling the aircraft and just getting it down to the ground and getting the aircraft to start to break is the priority they continued approach and as they're getting into the landing flare both the captain and first officer needs to input back pressure on the yoke in order to start the flare they touched down at time 1944 that's 24 minutes after they took off immediately as the aircraft touches down it starts wearing towards the right side of the runway now the captain has chosen reverse trust and as they start to wear he is putting full aileron in towards the left the first officer realizes that they're about to run off the runway so he intervenes and he cancels reverse trust on the right hand side and increases the reverse trust to maximum on the left-hand engine when he does so this means that he's now providing asymmetrical reverse trust on the left-hand side as reverses is now deployed it's starting to pull the aircraft back onto the runway again so he managed to get the aircraft under control and they slowly come to a complete stop about 2800 meters in on the runway when they come to a stop both the left main gear and the nose gear is still on the runway the right main gear is out on the grass and they immediately push for the evacuation alarm to go which initiate the evacuation and the evacuation is done really smoothly it's the six emergency exits that are available are being used uh the two aft emergency exit cannot be used because the floor has collapsed in that area but everyone gets out alive it is a true miracle and a statement through the professionalism of not only the flight crew but also the cabin crew so what has actually happened here well it became immediately apparent to the aircraft investigation team that the aft left cargo door was completely missing from the aircraft that door was found quite quickly out in a field and it was brought in for examination and when they looked at it they could see that all of the four c-shaped locks they had partially locked but the linkage was never in the over-center position and because it never went into the over-center position it meant that when force was applied to these locks that force was not transferred onto the stops as it was supposed to do instead it was transferred onto the mechanism itself and the bolts that held the mechanism in place and at a certain pressure those bolts sheared off and when that happened that released the door outward the door down was hit with the air loads which ripped it off the aircraft it was never really established why the locking mechanism hadn't extended fully and put the linkage into the over center position there had been a service bulletin sent out by mcdonnell douglas about a month before this incident talking about beefing up the electrical wiring to the motor that could potentially have been the reason for it but that was not really the point the point here to the investigation team was that there was supposed to be a fail safe in the door locking mechanism you weren't supposed to be able to close the door handle if the linkage was not in the overcooked position and the locking pins were not in so when they started looking into the door mechanism they realized that it wasn't really strong enough you could if you applied enough force onto the door handle you could force it into position by essentially bending one of the torque tubes the one that was connected to the door vent and if you did so the handle would lock into position the door went would not fully close but partially close and the other torque tube would be moved enough to close the circuit in order to show in the cockpit as the door was actually closed but the locking pins that were supposed to be there to fail safe to make sure that the locks would not move out of position they were never activated and remember how we talked earlier about the fact that there was no pressure relief kind of connection between the lower cargo hold and the passenger cabin but what that meant was that when the door blew off the cargo compartment immediately depressurized but because there was no connection because there was no wear from the air in the passenger cabin to escape in and depressurize itself that differential pressure that you now had between the passenger cabin and the cargo hold started to push up against the floor itself and the floor was never built to take those kind of forces so it started collapsing in towards the cargo hold area to basically let the air go somewhere and what did we have inside of the passenger floor the control cables and pulleys to both the flight controls in the vertical stabilizer and the horizontal stabilizer and the number two engine so as the passenger floor started collapsing inwards this severely damaged and moved the control cables causing the deflection of the rudder pedal in the cockpit and causing the rudder to turn the aircraft towards the right also severely restricting the elevator control cables it also shut down engine number two and all of this together explained the flight control problems that the crew had after the initial depressurization after the investigation the investigation team came to the following conclusion probable cause the national transportation safety board determines that the probable cause of this accident was the improper engagement of the latching mechanism for the aft bulk cargo compartment door during the preparation of the airplane for flight the design characteristics of the door latching mechanism permitted the door to be apparently closed when in fact the latches were not fully engaged and the lack lock pins were not in place they gave two very specific recommendations one require a modification to the dc10 cargo door locking system to make it physically impossible to position the external locking handle and vent door to the normal door locked position unless the locking pins are fully engaged two require the installation of relief vent between the cabin and aft cargo compartment to minimize the pressure loading on the cabin flooring in the event of a sudden depressurization of the cargo compartments now the wording in that conclusion and those recommendations clearly indicate that what the ntsb was looking for here is something called an ad an air worthiness directive this is when basically a aircraft manufacturer together with the licensing authority goes out and states that this has to be done right it's in within a reasonable time frame this modification has to be done in order for the aircraft to remain airworthy but for whatever reason that never happened instead a service bulletin which is a much weaker kind of directive was issued basically instructing airlines to insert kind of a support bracket around the torque tube at the top of the door that would stop the torque tube from bending and basically complying with the first recommendation from the ntsb when it came to the second recommendation mcdonnell douglas was looking into the feasibility of actually installing these type of vents but it wasn't something that was mandated to happen i also want to send a huge thank you to the sponsor of this episode which is nordvpn now i use nordvpn myself especially when i'm out traveling to you know through airports or restaurants where i might be using local wi-fi it's very good to know that my data will not be able to trace when i do so but to be perfectly honest what i use it the most for is to get past these pesky regional restrictions when it comes to netflix for example you know by the click of a button i can just change my location to be in the united states and there's loads more and better tv shows to watch there if you are interested in this then use the link here below that link will give you a whopping seventy percent discount on the two-year deal with no vpn and you can use that deal to up to six different devices on the same deal so go down click the link and consider supporting me by supporting them guys i hope that you are finding this series about famous incidents and accidents in the aviation history fascinating and if you are i hope that i have earned a subscription from you now if you want to subscribe then click the subscribe button and also highlight the um notification bell so you make sure that you get a notification any time that i send out a new video and i would also love to hear from you what do you think you know what is the next incident you would like me to cover put it into the comments below or contact me in the mentor aviation app or the free discord server all right i'm gonna link to it up here you can just click on it get either the app or discord server and contact me i love hearing from you guys until next time have an absolutely fantastic day oh and i forgot to tell you guys because that airwareness directive was never issued next week we'll be talking about a very similar but far more terrifying accidents [Music] you

Channel: Mentour Pilot

Views: 548,141

Keywords: american airlines flight 96, aa flight 96, Aviation accident, Aviation incident, The Windsor incident, Windsor, Ontario, Seconds from disaster, Air crash, air crash investigation, air crash investigation 2020, air crash investigation 2021, air crash investigation full episodes, mcdonnell douglas dc-10 documentary, mcdonnell douglas dc-10 landing, mcdonnell douglas dc-10 crash, mcdonnell douglas dc-10, mentour pilot crash, mentour pilot engine failure, Nervous passenger

Id: Gv5EQlzM1B8

Length: 25min 2sec (1502 seconds)

Published: Fri Mar 19 2021