One Of The Worst Air Disasters In American History | Mayday | On The Move

for investigators trying to solve a plane crash the most important tool can be the black box it records every detail in the cockpit look at this where's charlie and tells investigators about vital conversations damn it's starting to rain northwest 255 runway 3 center clear for takeoff [Music] but in the crash of north west airlines flight 255 i have never been to an accident that scale it wasn't what investigators heard on the tape tci was unsaid it was what they didn't hear was checked that would lead to an astonishing conclusion [Music] bye detroit michigan august the 16th 1987. it's 8 p.m and the city is sweltering 25 kilometers from downtown detroit metropolitan airport is one of the busiest airports in the united states more than 1100 airplanes use its four runways each day [Music] today one of those is northwest airlines flight 255 bound for phoenix arizona captain john mouse is in command a las vegas native 57 year old mouse is a veteran pilot [Music] his first officer is 35 year old david dodds of galena illinois don't you tell them we're ready to go both have years of experience on this type of aircraft the md-80 is also known as the super 80 and is the second generation of the dc-9 the md-80 was was quite a bit longer it had more powerful engines us it could carry more people for that reason it was a better money maker for the airlines than the dc-9 was look at this the sky between detroit and phoenix is filled with storms several are moving quickly towards the airport there's a line here for the crew it's been a long day about 25 they've already flown from minneapolis minnesota to saginaw michigan and then detroit phoenix is their next stop on the way to santa ana california if you wait till after the storm's here you'll be delays going over water bill if they're delayed by weather they may not make their final destination let's get out of here before it starts raining [Music] the plane's 149 passengers are also eager to leave paula sheehan and her family have been visiting relatives they're heading home to arizona her daughter cecilia is only four years old looks like bags are all in why don't you tell them we're ready to go ramp 255 and delta 15. flight 255 is running half an hour late northwest 255 cleared to go okay we're cleared push let's do the checklist [Music] brakes set windshield heat it's on here's the pumps six cabin pressure controller checked auxiliary hydraulic pumps and pressure on and checked down it's starting to rain to beat the storms they need to leave immediately flight 255 begins moving from the gate to the runway northwest 255 but because of the weather northwest 255 now exit at charlie runway 3 center the ground controller gives them a last minute runway change okay out to charlie for three center northwest 255. charlie for three center right okay ladies and gentlemen we're currently number one for departure we should be rolling in a couple minutes but attendance be seated thank you by the time they get to the new runway they're 45 minutes behind schedule northwest 255 runway 3 center clear for takeoff within 17 seconds 65 000 kilograms of passengers and aircraft hurtle down runway 3c but moments before liftoff mouse discovers he can't engage the auto throttle we'll stay on tci's on set his computer isn't in takeoff mode they're on now okay clamp 100 knots at 313 kilometers per hour the pilots angle the plane's nose up for liftoff then something else goes wrong just under 50 feet from the ground the aircraft begins rolling from side to side power lifeguard copter 102. it rolls left and strikes a light pole out of control flight 255 slams into the ground skids along a highway and disintegrates when it hits an overpass [Music] i pray that everybody made it but i thought it was just a small plane because it happened so quickly i didn't know it was a bigger plane and it was just awful saw the plane come through the buy docks it's a big fireball [Music] well we got dispatch was a rainy sunday night and then he said there's an airliner down and our mood kind of just changed and the one guy looked at me dan and said well i hope it's a small one when we pulled up we saw the cockpit and the word west written on the fuselage and we looked at each other and he said it looks like a big one there's a trail of scorched bodies and debris more than a kilometer long just minutes after impact paramedic tim schroder is on the scene looking for survivors i have never been to an accident of that scale we were struck by the the the magnitude of what we were saying the large scale of it it was just it was almost overwhelming from the little that's left of flight 255 it is unlikely they'll find anyone alive i buddied up with dan and we both started entering the wreckage it was probably a minute went by and dan actually heard a noise he asked me a couple times you know do i hear anything and i said no and then finally i heard it and it was more like a faint cry when i turned my head to the right i saw an arm underneath the seat one two three lift she was covered in some blood and some soot somehow four-year-old cecilia sheehan has survived the crash but she's badly injured tim schroeder races her to hospital we have a four-year-old girl found alive in the wreckage she has a very weak pulse if cecilia survived perhaps others have as well rescuers spend hours looking through the wreckage for more survivors but their efforts will be in vain we actually covered anything that was a body or a body part with a yellow blanket it was just nothing but like a sea of yellow blankets basically northwest airlines at 154 passengers and crew aboard the plane died in the crash both captain mouse and first officer dodds are killed in the crash two other people died when their cars were hit by the plane this is the second deadliest airplane disaster in us history [Music] recovering in hospital with serious head wounds is flight 255's lone survivor four-year-old cecilia sheehan despite her injuries doctors say she will live maybe uh god was on her side that night within hours of the crash investigator jack drake and his team from the national transportation safety board begin looking for clues drake is a former navy pilot who's been involved in hundreds of crash investigations you know when you're at a crash site because you get this combination of burned plastic and kerosene and sometimes combined with a fire retardant foam that has has its own distinctive odor you know you've arrived when you smell it drake and his team treat the crash site like a crime scene our team consisted of 12 or 13 specialists some of whom go to the site and some of whom do their work elsewhere they set out to examine every piece of wreckage to discover what went wrong they have responsibilities for looking at different parts of the wreckage debris and do qualitative analysis of those parts we always look for the recorders first they're frequently referred to as black boxes although they're usually orange the information is usually well protected because they're encased in a in a steel box that is both heat resistant and crash resistant since the 1960s commercial jetliners have been required to carry flight data and voice recorders the cvr was first introduced in australia following the 1960 crash of a fokker f-27 the devices must be able to withstand an impact of 3400 g's and temperatures as high as 1100 degrees celsius the cockpit voice recorder is intact but the flight data recorder suffered some damage in the crash they may hold the only clues that can help solve this accident both recorders are sent to the ntsb lab in washington dc john clark is drake's flight performance engineer his first task is to make a map of the debris left behind by flight 255 when i first started seeing the wreckage your mind immediately starts turning to sorting out where it hit how it hit not where the wreckage ended up but those first few inches where the airplane was coming down clark looks for ground scars and other impact marks and interviews witnesses to piece together where the plane fell and how and that kind of gives you a sense of those last moments what the airplane was doing when it hit the ground clark begins to understand the final moments of flight 255 according to witnesses as it lifted off it couldn't climb and flew in a nose-high position [Music] that could indicate that the plane didn't have enough power to get off the ground that it didn't have enough speed or that high winds prevented it from lifting off witnesses provide investigators with a critical clue you saw fire coming from the engine several including an air traffic controller saw flames coming from the plane's engine before the crash the engines become the first focus of this investigation they look for evidence of an internal failure the plane suffered an engine failure investigators soon learned that less than a month earlier one of the plane's engines was damaged when it was hit by a foreign object it was repaired and was being monitored by mechanics to see how it performed [Music] the team studies the remains of the engine for clues that it had either caught fire or shut down on takeoff despite what the witnesses saw they find no evidence of fire or of a massive breakdown the information suggested that the engine operation had been normal the flames were the result of the fuel tank rupturing after the plane hit a light pole the fire didn't cause the crash if drake and his team are to solve this mystery they need to be certain about what happened in the last few seconds before flight 255 crashed well i think the probably the best physical evidence is what was on the flight data recorder the flight data recorder doesn't tell you about weather it tells you about aircraft parameters aircraft performance essentially second by second you know even at quarter second intervals and some parameters but ntsb technicians can't recover all the information from the recorder they send it to the manufacturer to see if they can recover the lost data while he waits for news about the flight data recorder jack drake looks more closely at the weather on the night of the crash there was some convective or thunder shower type activity that had moved through the area and its impact on the accident required a lot of analysis drake wonders how the storm affected flight 255 he listens to the cockpit voice recorder for clues he discovers the menacing weather was a concern to the crew let's get out of here before it starts raining jesus look at this drake sees that there were several storms along the flight path and they were getting closer to detroit there's a line here and a line between these two another one here about 25 miles wide thunderstorms can create a very dangerous threat to pilots since there was severe weather in the area we always worry about microbursts microbursts occur when columns of air shoot down to earth as a plane passes through winds batteries from all directions making it difficult to control in a microburst condition you can get very shifting winds and also vertical winds that try to push the airplane into the ground so you can get loss of air speed a very rapid rise in air speed and then also actually push the airplane toward the ground and it requires very aggressive flying on the part of the flight crew this unusual weather condition had killed before in 1985 a microburst brought down a delta airlines flight in dallas killing 137 people [Music] at the time of the detroit accident there was no device at airports to accurately detect microbursts instead pilots relied on reports from other crews [Music] jack drake discovers that 27 minutes before liftoff captain mouse and first officer dodds received such a brown this is warning you just had a microburst out here the dust just exploded down there investigators suspect that a microburst may have slammed flight 255 to the ground as it tried to lift off it was right after departure when the accident occurred if they had struck a very strong microburst that would be a candidate for one of the possible causes satellite images taken at the time of the crash and weather data from the airport sensors show that there were storms near the airport at the time of the accident but there's no evidence of a microburst wind and rain but nothing that could be a microburst around the time of the crash the airport sensors did record a dangerous gust of wind on the runway powerful enough to set off alarms in the tower upon further investigation drake discovers that flight 255 was still at the gate at the time of that alarm so the winds couldn't have brought the plane down but they did have a huge effect on captain mouse's flight plan the crew's pre-flight dispatch package stated that they would take off from runway 21 left but with the sudden change of wind direction ground control sends flight 255 to runway 3c the shortest of three available runways northwest 255 now exhibit charlie runway threesome okay out to charlie for three center northwest 255 charlie for three center road okay controllers try to have planes take off into the wind the additional wind flowing over a plane's wings gives it more lift and helps it get off the ground taking off into the wind is safer but taking off on the shorter runway now means first officer dodds must recalculate the plane's takeoff weight there's a runway change you have to determine if the weight of the aircraft will permit it to accelerate and climb out safely and this varies depending on the length of the runway temperature altitude of the airport perhaps first officer dodds made a mistake in his calculation 44 4 how can we do that like for a full airplane if he did it could explain why the md-80 wasn't able to make it off the ground runway 3c simply wasn't long enough using calculations based on average weight of luggage and passengers on board drake's team confirmed dodd's estimate the plane weighed 144 047 pounds well below the allowable limit for runway 3c it should have been able to get off the ground drake's investigation has hit another dead end he and his team are running out of possibilities until technicians can decode the damaged flight data recorder the team must rely on the physical evidence that's been found at the crash site but when investigators study the cockpit center console they're forced to consider an almost unimaginable cause is this the way it was found to get the plane off the ground the flaps on the wings should have been extended to the 11 degree position but the way the flap handle is damaged suggests the plane's flaps were retracted when it crashed the pin had left a mark this happens because the aircraft comes to a very sudden stop and the handle jangles around and and it's a metal to metal contact that's exaggerated by the impact don't stay on that indicator was that the flaps were zero or fully retracted and the slats were retracted as well flaps and slats are extensions that slide out of the back and front of the wing they make the wing bigger which increases the amount of lift they can provide they must be extended for takeoff if the slats are retracted in for the most part with today's modern jets the airplane is not capable of flight if the crew tried to take off with the flaps retracted it would be an astonishing blunder b1 but a pilot who was lined up directly behind flight 255 on the runway is certain the plane's flaps were extended you're sure the flaps were extended pilots and other aircraft that were close to the point where the takeoff had begun were telling us that they thought the flaps and slats were deployed to a normal position investigators can't be sure whether the flaps were extended or not the clues they need lie somewhere in the sea of debris recovered from the crash site [Music] eventually investigators find the evidence they need inside a section of the plane's left wing each component of the slat system has its own drive system and one one of those was interrupted by the light pole that passed through the wing 18 feet of the left wing was severed the cable controlling the slats was sliced in two when the wing hit the light pole based on where the cable was cut investigators can tell whether the slats and flaps were extended or retracted it severed two cables and if you lined up those two severed ends it corresponded with the slats being in the full retracted position it looks increasingly likely that the crew never extended their flaps only the damaged flight data recorder can verify this fortunately technicians have finally been able to rescue all its data a digital history of flight 255's performance until the moment of impact i knew that if we had a good recorder we were going to get data back the flight data recorders in combination give you that time history that goes together with the physical evidence or physical damage as expected the fdr confirms what the evidence has been showing investigators [Music] flight data recorders told us that the flaps and slats had not been extended it's a major breakthrough drake now knows what brought down flight 255 but the flight data recorder doesn't answer a more troubling question so why weren't the flaps deployed for some reason a seasoned crew forgot one of the most basic steps involved in getting an airplane off the ground two months after the crash northwest airlines flight 255 sole survivor cecilia sheehan is released from hospital we can't be sure why the little girl survived she's a very little girl buckled into a big seat and she was more protected than adults that might have been sitting around her she was very lucky jack drake needs to know what contributed to the death of her family and all the other victims he finds an important clue on the cockpit voice recorder it shows that the last minute runway change caused confusion in the cockpit once the aircraft began to taxi blacker than hell out there no exit at charlie runway three centers other activities were introduced that had the potential to cause distractions did he say three center three center yeah that's why i was thinking we had to go that way i was thinking 2-1 well he made a wrong turn which might have been confusing uh because they had to go a different route where's charlie right at the end of this round charlie was no it is charlie sure i think so the crew got lost on the way to runway 3c round northwest 255. i i guess we went by charlie we're going to three center right uh northwest 255 affirmative make a left turn at fox drive they finally got to the runway 45 minutes late ladies and gentlemen we're currently number one for departure should be rolling in a couple of minutes flight attendants be seated thank you but jack drake finds something missing on the cvr it seems the crew overlooked a very important step we're okay for the center runway aren't we before they got lost the crew of flight 255 performed a number of checklists but possibly due to the confusion of the runway change they seem to have completely neglected the taxi checklist they apparently didn't consider the checklist and and key in the checklist is the configuration of the aircraft for for departure and the flight data recorder showed that was never done there are hundreds of small steps for a crew to take to get a passenger jet off the ground most of them are covered by checklists the checklist is a means by which you ensure that important items are positioned or done properly instead of doing it by memory and having the possibility of a lapse of memory flight crews use a very rigorous and regimented procedure of following the checklist verify that each switch each dial each lever is in the proper position before taking the runway for departure [Music] the first item on the taxi checklist is flaps one of the things that would have been included in their checklist was to configure the slats and flaps for low-speed flight but because they didn't run the checklist the crew never set their flaps to the take-off position i think charlie was no it is charlie sure i think so they hadn't done this checklist at the time they normally would and as the activities piled up that were potential distractions they were further and further away from the point at which they would normally perform that function their mindset was probably that they had completed the pilots got an indication that their plane wasn't properly configured during takeoff they couldn't activate the auto throttle because their computer wasn't in takeoff mode another step covered by the taxi checklist won't stay on tci is on set this should have alerted them that they didn't perform the checklist if it occurred to them at that point that we might have missed something else on the checklist that could have led to a rejected takeoff they are on now 100 knots okay apparently that didn't happen and so the takeoff was continued with disastrous results an alarm should have sounded when the pilots tried to take off with their flaps retracted but for some reason investigators can't hear it on the cockpit voice recorder when it activates it alerts the crew that the aircraft is not in a configuration that's safe for takeoff maybe it went off but we just can't hear it the investigation team is determined to find out why the take-off warning didn't sound technicians analyze the cockpit voice recorder for more clues and they find something unusual [Music] they picked up some enunciations on the cvr that were not correct this warning is alerting the crew that the plane is about to stall but it should be coming from two speakers in the cockpit technicians notice it's only coming from one as the airplane lifted off there was a stall warning and it has a typical characteristic of a sound like stall all because there are two enunciations and the purpose of that is to provide redundancy but that redundancy wasn't there we had a single stall i went to an mba sitting on the ramp at detroit and a captain took us through the process of checking out to demonstrate those different sounds let's start with the config warning the takeoff configuration warning is what would have alerted them about the flaps and slats can we get the stall warning sound he activated the stall warning system by a test switch and it said stall all the voice on the left channel is slightly different from the voice on the right as it should be but that's not what clark heard on flight 255's voice recorder can you make it sound like this [Applause] to get a singular stall he had to pull power to one side or the other and one way he demonstrated that is he pulled the p-40 circuit breaker a circuit breaker is the electrical switch that protects the circuit from damage caused by overload the p40 circuit breaker is an important one in this investigation it handled both the failed takeoff warning and the stall warning systems what struck me was he said i hear people doing it i of course don't do it myself but let me show you how and he reached around behind him around behind the seat and down low and pull the p40 circuit breaker without looking and then when he ran the stall warning system we got the singular stall stall it's a major clue clark could only reproduce the strange sounding stall warning by pulling the same circuit breaker that's connected to the take-off warning this tells investigators that the breaker was tripped when flight 255 tried to take off then john clark notices something else about the p40 circuit breaker you could see smudge marks around the decals on each side of the circuit breaker it looked like finger marks where oil had built up and dirt and grime over the years so it told me that that circuit breaker was being used routinely by a lot of pilots can you tell me why that is so worn it turned out that the takeoff configuration warning could be a nuisance to pilots if you're doing a single engine taxi you have to push the throttle up further to get a power to taxi and you set off the takeoff warning system and so they would pull the circuit breaker to silence it it's irritating it's a warning it's it's meant to alert you and if it's going off routinely all the time it gets on their nerves and so apparently pilots were routinely silencing those takeoff lines investigators suspect that the crew of flight 255 tripped the breaker to avoid the irritating takeoff warning and then with the added delay from the runway change and the impending storm they proceeded to take off without doing the taxi checklist that might explain why the alarm didn't sound when they tried to take off with their flaps retracted we don't know if the pilot did pull that circuit breaker on that particular flight there was certainly one error and the potential for two i think the extensive use of the circuit breaker because of the smudge marks around the circuit breaker and the pilot statements i think it's highly likely that he did it appears the downing of flight 255 was caused by pilot error now investigators can accurately piece together what happened that night in detroit but it would take another shocking accident for the airline industry to learn its lesson [Music] jack drake's team has discovered what caused the crash of flight 255 but cannot prevent it from happening again one year later in dallas delta flight 1141 tried to take off without their flaps extended the investigators who had been working on the north west crash are stunned i was very frustrated to learn that that another airline had done the same thing in a different aircraft type about a year later the delta crash would uncover potentially deadly flaws in the checklists commercial pilots are trained to follow the delta and northwest crashes killed 170 people and had eerily similar causes in both disasters the workload in the cockpit increased jesus look at this northwest 255 i've now exited charlie runway if you get out of here pretty quickly and in both the pilots failed to perform vital elements of their checklists it is very unusual for a crew to not perform a checklist it's they have done it hundreds upon hundreds of times brakes windshield heat is on cabin pressure controller was checked the normal procedures uh were a little bit out of the norm and as a result it got overlooked to prevent this from happening again aviation officials turn to a government agency that knows the importance of clear procedures four three two one nasa [Music] they're in there ready to go all right jack drake and his team wanted the u.s space agency to help create checklists that decrease the odds of items being skipped asaf de ghani was a research scientist working with nasa after the accident he took on the project of improving a flight crew's pre-takeoff procedure we looked for any research that was done on checklist or procedures in general and in fact we couldn't find anything so digani had to start from scratch but there are dozens of different checklists to examine most of the ones on flight 255 were printed on a single card they listed the tasks the crew had to carry out but didn't give them a way to keep track of what was and what wasn't done at the time of the northwest crash there were several types of mechanical checklists in use the us air force used a scrolling checklist once a checklist item is completed the pilot scrolls to the next one american airlines used a system that allowed pilots to cover up completed items with a plastic slide so only the non-completed items would be displayed as after ghani set out to see firsthand how pilots were using checklists he wanted to make it less likely for them to make mistakes [Music] he sat in cockpits and observed 42 different crews in action dergahni concluded that many checklists were badly designed there's a certain flow by which you go about checking things and the idea is to prevent the case where you're doing one thing here one thing there checklist should have a certain flow which is a logical flow and not one which is kind of random and they're ready and they're going through there dergahni also found a much more serious problem with checklists if pilots are interrupted they sometimes forget where they left off responder checked and on there's many cases where people will do a b c d an air traffic call would come they'd have to respond to it and that's an interrupt northwest 255 now exited charlie runway 3 center yeah they will go back to the checklist and skip a certain item and continue on the list assuming that the whole list was done people were very concerned about that to ensure no steps are missed airlines train their pilots to return to the top of a checklist following the interruption and start over again as after ghani sees a problem and we found that if checkers are very very long and meticulous that's overburdening the crew and they sometimes would not want to start again from the beginning to address the problem digani suggests changes across the airline industry one of our recommendations from the study is to try to take long checklist and chunk into small pieces so that if an interruption happens then doing another four or five items you know it's not a big effort as opposed to doing 20. even made recommendations about the typeface that airlines use so they can be more easily read by pilots perhaps the biggest advance to checklists is the move from paper to computers since at the time computer technology was coming into the cockpit it made a lot of sense to think about the electronic checklist today digani and his team are studying smart checklists that keep track of checked items they provide pilots with a visual indication of where they are on the list and in some cases verify that the task has been correctly carried out electronic checklist shows you which item was completed and which item was not [Music] computerized checklists are now slowly making their way into the cockpits of commercial airplanes they make it far less likely that an accident like northwest 255 could happen again the faa also ordered a modification to the alarm system of all commercial jetliners to prevent nuisance alarms the takeoff warning was redesigned so it could not sound unless the plane was actually taking off [Music] jack drake went on to investigate hundreds of accidents over a 26-year career with the ntsb the crash of flight 255 taught him a valuable lesson this one is a worldwide example of the importance of following checklists and configuration being completed correctly on every takeoff and so it became something that was a part of the training curriculum in virtually every airline around the world the case of northwest 255 is no different there's a series of events runway change task saturation an overlooked checklist a failed takeoff warning system put all of those together those links in a chain and you end up with the accident if you were to break any one of those links the accident wouldn't have happened flight 255 will also be remembered for its lone survivor cecilia sheehan she's never spoken publicly about the death of her family but she stayed in touch with the people who rescued her that day she's full of life and the conversations we have it's more about you know her sports and her husband and her vacations she just said maybe one day she'll come out and tell the world what cecilia is doing [Music] you

Channel: On The Move

Views: 309,893

Keywords: on the move, cars, planes, trains, documentary, documentaries, full length documentaries, plane documentary, mayday series, mayday, plane disasters, airport, runway, plane pilot, pilot, hd documentary, 2021 documentary, united airlines, plane crash, air accident, air crash, air disaster, plane accident, air emergency, plane disaster, plane emergency

Id: dQIV2b7sJdU

Length: 47min 3sec (2823 seconds)

Published: Tue Aug 31 2021