Did This Captain Lie About Causing A Near Fatal Crash? | TWA Flight 841

this is the story of twa flight 841 on the 4th of april 1979 a twa boeing 727 was on the ground at jfk international airport it was headed to minneapolis saint paul international airport and minnesota the plane was delayed by about 45 minutes due to the traffic at jfk but at long last at 8 25 pm flight 841 took off with 82 passengers and seven crew members on board the jet started its climb to its cruising altitude and within half an hour it was at 35 000 feet flight 841 found 35 000 feet to be quite windy so they asked toronto control if other planes had reported any winds at either 31 000 feet or 39 000 feet atc said that those altitudes were clear until the crew opted for 39 000 feet once the 727 had reached 39 000 feet the pilots put the plane into the altitude hole mode so that it would stay there the crew then relaxed a bit as the autopilot took care of most of the flying the captain was looking for a few charts in the cockpit when he felt a slight buzzing sensation a slight vibration the sensation didn't really go away and eventually it grew into a slight buffeting sensation he looked up and saw that the autopilot was commanding a left turn but the plane was in a right turn since it was dark outside the only indication of the plane turning to the right was on their instruments he immediately turned the autopilot off and commanded an aileron roll to the left but the plane didn't respond it was still in the right role with full left aileron doing nothing the captain applied full left rudder in an attempt to right the plane but the plane stayed in the right turn the captain was concerned that the plane would roll over inverted so he pulled back power on both engines and asked the first officer to extend the speed brakes but the first officer was out of the loop at this point he wasn't really aware of what was happening as he had been calculating the plane's ground speed so the captain extended the speed brakes himself but the speed brakes did nothing in the cockpit the pilots could see tiny lights from the town below and their altimeter showed that they were descending fast they were rolling and descending towards the ground at 34 000 feet a minute in a desperate attempt to pull the plane out of its harrowing dive the captain decided to extend the landing gear the first officer extended the gear and the gears dropped at this point the plane was still rolling as it dived and the pilots were desperate for something anything to work the pilots heard a huge explosion as the cures dropped as the gear came out the captain eased up on the control column and the ailerons just a bit the landing gear trick seemed to have worked the airspeed of the jet came down and the captain was able to bring the plane to wings level but their fight was far from over just as they thought they were winning the plane started climbing the nose was up 30 to 50 degrees the captain could clearly see the moon and used the moon as a visual reference to maneuver the plane he eventually got the plane back under control and once they had leveled off at 13 000 feet the pilot saw that their a hydraulic system had failed the hydraulic system is quite important as that's what moves all of the control surfaces on the plane think of it as the lifeblood of the plane they also got a warning saying that the lower yaw damper had failed that's an actuator that controls the rudder with all these failures the captain decided to land the plane as soon as possible he decided to put the plane down at the metropolitan airport and detroit as the crew worked through the emergency checklist the plane started its approach the crew extended the flaps using an alternate method but as soon as they did that the plane lurched to the left so the captain retracted the flaps and decided to land without the flaps but that wasn't all in the cockpit two of the three landing gear indicators showed that they were in an unsafe state that meant that there was a possibility that the gear wasn't down and landing without the landing gear would be very dangerous so the captain made a pass over the airport so that people on the ground could see if the gear was down or not it was and so the crew carefully brought the plane in and the 727 landed on runway 0-3 with no issues their harrowing flight was over and everyone on board survived seven crew members did suffer slight injuries but they all recovered once on the ground they got a firsthand look at the damage that the plane had suffered and it was bad a plane has these things called slats they basically extend from the leading edge of the wing and allow a plane to fly at lower speeds and at higher angles of attack it's usually used during landings and takeoff and really helps with generating lift on flight 841 slot number seven was missing the tracks that moved it along were sheared and torn the piston that moved the slats that was broken the bolts that attached the slat to the wing were also ripped away the ailerons and the spoilers on the right-hand wing also showed some damage something violent had happened to this wing the landing gear also sustained some heavy damage the gear doors and hydraulic lines in the area were all broken some parts of the plane leaked hydraulic fluid some leaked fuel it was a mess but despite that they were able to fix it up and return the plane to service but what had caused the slat to be ripped away a slat extension at cruise speed can put a lot of stress on the airplane so that was their first avenue of investigation boeing tested the airplane to see if anything in its systems would cause an uncommanded asymmetric slat extension but they couldn't find anything wrong with the aircraft this slat should not have come out they then turned to the simulator their simulator tests did show that under the conditions that flight 841 was under the number 7 slat extension would indeed cause a roll to the right like the one encountered by the crew the tests also showed that at the right speeds the right role would overpower other control surfaces like the ailerons and the rudder that was exactly what happened to flight 841 this was because the extension of the slat would cause airflow separation on the right wing which would reduce the amount of lift generated by the right wing which meant that they wouldn't be able to control the plane which caused it to dive at 34 000 feet per minute so they now knew that the right slat did extend and once it did the aerodynamic forces ripped it away during the dive but what caused the slat extension in the first place they looked to pass accidents like this one they found a few but most of those incidents happened when the slats were being extended or retracted in this case it apparently extended of its own accord so they tested the a hydraulic system to see if a flaw there caused the slat to extend they plugged the holes in the hydraulic cables and then tested the systems to see what worked and what didn't the hydraulic lines passed they were not to blame for this they then looked at other failure modes maybe the locking mechanism failed or the actuator itself failed but nothing quite explained the damage that they were seeing on the plane more importantly when in flight at mach 0.8 the compressive loads on the slats would be about 700 pounds so even if the hydraulics or the locking mechanism failed the aerodynamic force should have kept the slat in place so after running a gamut of tests on the slats and hydraulics they came to the conclusion that there was no way that the slat would have come out on its own but our initial question still remains unanswered why did the slat extend in the first place with mechanical flaws out of the question they then looked to see if the crew might have accidentally extended the slats i mean it's happened before look at the case of china airlines flight 583 they had three theories one was that they accidentally bumped the flap lever or something two was that they accidentally engaged the alternate flap extension system or three was that they messed with the plane circuit breakers to extend only the slats to improve airplane performance usually the slats and flaps are a package deal they are both controlled by one lever but you could pull a few circuit breakers that deactivated the slats this meant that when you moved the lever only the flaps would come out with just the flaps extended the pilots could go faster or decrease fuel consumption unfortunately for the investigators the cvr did not record most of the incident it recorded a lot of conversations on the ground after the plane had landed but the crew denied ever messing with the flaps or slats in flight so here's what the investigators think happened the plane was cruising at 39 000 feet and the pilots wanted to extend only the flaps at 39 000 feet to improve aircraft performance but something went wrong and the slats began to extend instead they realized their mistake and retracted the slats most of the slats retracted except number seven the plane now banged to the right and the captain stabilized the plane and started to tend to the extended slap taking his attention away from flying the plane and causing the plane to bank to the right again but due to the plane's unique configuration and the speed the lateral controls were rendered useless this sent the plane into a dive where the plane rolled twice the aerodynamic forces exerted by the dive on the plane ripped slat number seven right off the captain didn't like these findings for obvious reasons he suggested that the actuator for the slat had failed the captain even appealed the findings in an appeals court but he lost the case what's really suspicious is the fact that the captain had a habit of erasing the cockpit voice recorder by using a bulk race feature available to the pilots he said that he did this to avoid the potential misuse of the recorded conversations he denied doing this on the accident flight but tests showed that there was no reason for the cvr to fail that day but yet 21 minutes of the 30 minute recording was blank the ntsb wasn't too happy about the captain raising the cockpit voice recorders after every flight here's a quote from the report we believe the captain's erasure of the cvr is a factor we cannot ignore and cannot sanction although we recognize that habits can cause actions not desired or intended by the actor we have difficulty accepting the fact that the captain's punitive habit of routinely erasing the cvr after each flight was not restrainable after a flight in which disaster was only narrowly averted end quote they go on to say that the recorder might not have recorded the entire event but the recording of the final stage of flight would have been incredibly useful to them in piecing together what had happened after the upset they basically said that the captain had done a very crappy thing in very polite words so what do you think who do you believe the investigators or the captain in my opinion the ntsb really did their homework on this one they do acknowledge that there are certain conditions in which the number seven slat would extend on its own for example a failure of the actuator or undue hydraulic pressure being routed to the slot but they also gave clear explanations based on flight test data simulator data and physical evidence to prove that that wasn't the case they came to the conclusion that the pilots had messed with the controls as a last resort the captain did not paint himself in a favorable light by erasing the cvr on past flights even though he said that he did not recall doing that on this particular flight let me know your thoughts in the comments below thank you for watching this episode of mini aircraft investigation if you like the videos that i make do consider liking and subscribing it will really help the channel grow i will catch you guys next time stay safe

Channel: Mini Air Crash Investigation

Views: 257,140

Keywords: air crash investigation, air crash confidential, why planes crash, aviation safety, twa, twa airline crash, TWA airline crash, 727 crash, nat geo, mayday, when flying turns deadly, TWA 727 near crash, theflightchannel, mentour pilot, minesotta air crash, jfk air crash, mini aci, educational, simulator, aviation safety crash, why planes are safe, trans world airlines crash, aviation, airplanes, documentary, planes, passenger jet crash

Id: hX3xtCwZg2k

Length: 13min 20sec (800 seconds)

Published: Thu Dec 30 2021

Reddit Comments

[u/more_mars_than_venus]

The NTSB reached a conclusion not supported by evidence.

If the Captain lied, why would the F/O and Engineer cover for him? If I was in that position and the Captain was experimenting with the plane to the point of risking passengers lives, I wouldn't lie to cover for him. I find it far more likely that when Boeing was asked to evaluate their own plane and determine if they were responsible, they did exactly what one might expect: protect their bottom line.

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Edited to add: Good blog about this accident: https://danieltenace.com/2021/04/05/aircraft-accidents-and-lessons-unlearned-xlviii-twa-flight-841/

[u/Spin737]

Good material, but the narrator always sounds like this is his first time hearing any of the words.