- 20/4/2025
Chuyến bay Airborne Express 827 là chuyến bay đánh giá chức năng (FEF) của một chiếc Douglas DC-8-63F (đăng ký N827AX) của ABX Air (thuộc Airborne Express ) đã trải qua một cuộc cải tiến lớn. Vào ngày 22 tháng 12 năm 1996, trong chuyến bay thử nghiệm, máy bay đã bị chết máy và rơi, khiến cả sáu người trên máy bay thiệt mạng. Các nhà điều tra tai nạn xác định nguyên nhân của vụ tai nạn là do đầu vào điều khiển của phi hành đoàn không đúng cách.
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TiviPhụ đề
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02:48Taxi and pre-take-off checklist complete
02:50Tower ABX 827 Heavy is ready to go
02:54The flight crew is operating a modified McDonnell Douglas DC-8
03:01The DC-8 is an incredibly reliable machine and it always has been
03:06The DC-8 is a long range, narrow body jetliner introduced in 1959
03:17As long as you use it exactly the way it was designed, they're just as tough as nails
03:21If you want, rotate
03:24At 5.40pm, flight 827 takes off
03:40Positive rate, gear up
03:42Positive rate
03:441,000 feet
03:49Roger
03:50Although it's a lesser known airline, Airborne Express, or ABX, is one of the largest cargo carriers in the United States
04:00After both Federal Express and UPS
04:04In a bid to expand its fleet, ABX purchased the aircraft that would become Flight 827 and modified it before putting it into service
04:13ABX 827 is 2,500 for 5,000
04:21MCT set
04:23Ignition off
04:25But before this plane can be added to the fleet, it has to be taken for a test flight
04:31This is known as a functional evaluation flight, or FEF
04:38A functional evaluation flight is basically to see that everything is as it's supposed to be
04:45Kick the tires, light the fires, go out and fly, and make sure she's exactly as advertised
04:51After departing Greensboro, Flight 827 is scheduled to spend about two hours flying the FEF before returning to the airport
05:01ABX 827 for our maintenance check, can we get a block of 1-0 to 1-2,000?
05:06The flight crew needs a dedicated block of airspace to perform the tests
05:11Could you take a block of 13 to 15?
05:16We can do that
05:17ABX 827, roger
05:21Climb and maintain block altitude of 1-3,000 through 1-5,000
05:24Having reached a quiet block of airspace, the crew works its way through the FEF checklist
05:32Scoops
05:35On
05:39The DC-8 scoops are part of its pressurization system
05:43Didn't get the left one, try again
05:46It's really common on test flights to have issues crop up
05:52This airplane had undergone so many changes that it needed a thorough test flight
05:57All right, scoops
05:58Off
05:59Left one ain't working
06:05With multiple redundancies built into the pressurization system, the pilots are safe to continue their flight
06:13ABX 827, turn right, heading up 360, vectors for traffic
06:21Air traffic control monitors the airspace, redirecting flight 827 when necessary
06:28ABX 827, right 360
06:30And then we're going to do our manual drop
06:35You ready for hydraulics to come off, Keith?
06:38Uh, yeah, go right ahead
06:40Okay, go ahead, Terry
06:41The manual drop tests the plane's landing gear without the use of hydraulics
06:47Okay, gear free fall 1.5 VS 0
06:52Okay, you ready?
06:53Ready, gear down
06:55Gear, down, three green
07:01Got it
07:02We're getting a little bit of ice here
07:06The biggest hazard from icing is that it changes the shape of the wing
07:13And the airplane doesn't fly nearly as well as it did
07:16The crew comes up with a plan to avoid performance issues from ice buildup
07:22Garth, if we go up 15, I think we can get out of this stuff
07:26Uh, yeah, you can go up there, we've got that block
07:30As the flight climbs out of the weather, the crew continues the tests
07:44Next thing is our stall series
07:48For the stall series, the pilots will intentionally slow the airplane until it's just about to stall
07:55To determine when the stick shaker activates
07:58Most commercial planes use a stick shaker system
08:02It's a vibrating warning on the control column that alerts the pilots to take action before the plane actually stalls
08:11We should stall at 122, I've got to set that in my interior bug
08:15The pilots set their target speed for when the plane is expected to stall
08:19Mind set, shaker 128, you just call all your numbers, I'll record them
08:25They have to write down the airspeed at which the stick shaker triggers
08:30And then they have to write down the airspeed at which the stall begins
08:35Captain Lemming slows the plane at a rate of one knot per second to reach the stall speed
08:39Feeling some buffet here
08:44The pilots detect a change in the aircraft
08:48Yeah, that's pretty early
08:49Yeah, that's pretty early
08:50As an airplane approaches stall, it starts talking to the pilots
08:56The airplane starts vibrating or buffeting
09:00They quickly take action to avoid a stall
09:03Set max power
09:04133
09:05Then one of the plane's left engines begins to surge
09:15That's number two engine
09:24That's number two engine
09:25But that's not normal and you know it's not normal and so something like that's going to get your attention
09:31Pull it back
09:33You got it
09:39The plane now banks to the left
09:45And begins to drop
09:54The pilots attempt to level the wings and slow the plane's descent
09:58All right
10:00Okay
10:01Got it
10:03Realizing that the plane is descending below his jurisdiction
10:18The controller assigns the pilots to a new radio frequency
10:22827 changed to Indianapolis 128.4
10:25But the controller's calls to change frequencies go unanswered
10:34The flight crew is busy trying to recover the plane
10:44ABX 827, Indianapolis 128.4
10:47ABX 827, gonna stay on this frequency a minute
10:51Descending through 8000, call you right back
10:53ABX 827, you're in an emergency descent?
10:54Yes, sir
10:55Airborne express flight 827 is out of control and plummeting to the ground
11:08Rudder
11:09Yeah, got it
11:10Seeing that flight 827 is in trouble, the controller checks air traffic in the area to find the
11:23To find a safe altitude for the plane
11:25Okay, um, can you hold 7000?
11:30But there's no answer
11:32Flight 827 is less than 5000 feet from the ground and descending fast
11:40Now bring it back, left rudder
11:44Left rudder
11:45Okay, good, easy
11:49They could tell they were in an emergency, they could tell they'd lost control, they were probably frightened to death
11:55The pilots continue their efforts to recover the aircraft, but are now too low
12:00Pull up
12:02Terrain, terrain
12:04Pull up
12:05Really?
12:06Pull up
12:07Really?
12:08Airspeed low
12:10Pull up
12:11Just half an hour into a standard test flight
12:14The DC-8 crashes into the East River Mountain in Narrows, Virginia
12:26ABX 827, do you copy?
12:31ABX 827, do you copy?
12:35No one has survived
12:37The mountains lit up, and there was an explosion, black, smoke, and red and blue flames coming up off it
12:49News of the crash quickly spreads throughout the community
12:55Grief counselors arrived today at Airborne's headquarters to help family and friends cope with their loss
13:01Obviously, it's just a terrible time for everyone here, particularly at this time of year
13:08Bob McIntosh from the NTSB, the National Transportation Safety Board, leads the investigation
13:14We know this was a maintenance examination flight
13:18Obviously it was not successful, and that's about all I can tell you right now
13:23The wreckage site certainly presented some challenges
13:26We were going to have to deal with some mountainous terrain
13:30We had to get to work
13:35Benjamin Berman is one of the first team members to arrive at the crash site
13:40I got to the top of the mountain, and I looked out at the scene
13:44And it was just complete devastation
13:49I really thought, you know, what is it that could have brought that plane down?
13:53That's our job as NTSB investigators
13:56Investigators begin their painstaking efforts to transport pieces of the demolished plane to a hangar for examination
14:07We found the four corners
14:10Looks like the plane was intact when it hit the mountain
14:12So if you can see all four corners, which are the nose, the right wing tip, the tail, and the left wing tip
14:20In close proximity probably means the airplane was intact until it hit the ground
14:25This particular wreckage scene told us that we most probably had a loss of control
14:33And that we were going to have to find the reason for that loss of control
14:38We recovered the CVR and FDR
14:42Let's get them off to Washington
14:43The cockpit voice recorder was going to tell us not only what they said, but how they said it
14:55While investigators wait for the CVR download
14:59Got the checklist for the FEF
15:01They review the checklist the flight crew was using during the functional evaluation flight
15:05To get a better understanding of what they were doing prior to the crash
15:12Looks like standard FEF stuff
15:15They're testing the flaps
15:18Rudder
15:20Landing gear
15:22Stall system
15:24There's nothing unusual on the list of tests the pilots were performing
15:27Maybe there was a problem with the plane before the FEF
15:30I'll get Berman to talk to the maintenance team that modified the plane
15:36It was an old airplane, but it had just come out of a major retrofit
15:42Can you take me through exactly what you guys did to the airplane?
15:46Well, it was a fairly major overall
15:48Investigators learned that extensive maintenance and modifications were carried out on the aircraft over the course of six months
15:55Yeah, it looks like you guys pretty well took the whole thing apart and put it back together, huh?
16:00As we looked at the maintenance records
16:03We could find that there was a great deal of work that had been done on the aircraft
16:08Perhaps something had fallen through the cracks
16:11Could technicians have overlooked something during the modification of the airplane?
16:16Causing the pilots of flight 827 to lose control
16:20Pull up
16:21Pull up
16:23Carrain, terrain
16:24Really?
16:25Pull up
16:26Really?
16:28Got the dispatch logs for the plane right here
16:31Investigators review Airborne Express flight 827's dispatch logs
16:36to see if any malfunctions were reported after the plane was released from maintenance
16:41Looks like they finished the modifications and delivered the plane on December 15th, one week before the crash
16:47Wait a second
16:51This wasn't the pilots first attempt at this flight
16:56The fact that they tried to do the fight earlier, that was really relevant
17:04Look here, the pilots conducted a partial FEF the day before the crash
17:09Scrapped at midway through low hydraulic pressure
17:15That can mean getting the landing gear down and in place or not
17:19Or being able to power the flight controls or not
17:22If the hydraulic pressure is not right, that's very serious
17:25Okay
17:26And what do you think caused the low hydraulic pressure?
17:31Did a hydraulic issue cause a loss of control?
17:35Got it
17:36Maintenance crews say that they suspected that trapped air in the lines led to low hydraulic quantity indication
17:41Did they fix it?
17:42Yeah, they replaced nose gear actuator the day of the accident
17:45But, was that the end of it?
17:48Or, could our pilots end up having issues with the hydraulics again?
17:54We needed to figure out what had been going on
17:58Could something have gone wrong in that maintenance?
18:00Investigators are able to recover the plane's rudder components from the crash site
18:08They examine them for any signs of damage to the hydraulic system
18:13No pre-impact hydraulic leaks
18:16Hydraulic system was working fine
18:19The hydraulic system wasn't a probable cause for the mishap and loss of control
18:25If it wasn't the hydraulic system, what was it?
18:27We should call the witness and listen, maybe somebody saw something
18:32You were outside your home at the time?
18:38And what did you hear?
18:40The team begins to interview witnesses to see if anyone heard or saw something that could point to the cause of the crash
18:47The local newspaper people were there asking people what they had heard and seen that
18:57At night
18:58All you could see was just parts
19:01Just a plane had cleared out a big path
19:04That area was full of information
19:07Witnesses describe seeing the plane descend out of the clouds at a steep angle and hit the mountain at high speed
19:15Thank you so much for your time
19:21I think we've got something
19:23Three witnesses confirm they could hear the plane making a banging sound followed by a slapping sound
19:29Kind of odd noise
19:33It sounded
19:35Kindly low and it started coming up real loud
19:38The witnesses told us if there was slapping and banging that they heard
19:43If air flow entering the engine is disrupted, it can cause the engines to backfire
19:56If air flow over a wing is disrupted, it can make a slapping sound
20:02Both can be signs of a stall
20:04If the witness reports were true, it suggested that possibly there was an engine issue that may have been part of the sequence of events
20:15However, it would require further examination of the flight data recorder
20:19NTSB investigators turned to the plane's flight data recorder to confirm whether flight 827 was in a stall before it crashed
20:30Isolate the airspeed
20:32There's a gradual reduction in airspeed here
20:38One knot per second, looks like they were setting up for the stall series
20:42And then here, the airspeed falls off a cliff
20:45That's a stall
20:49Let's see the engine parameters
20:51They search for further confirmation that flight 827 stalled
20:56That looks like a compressor surge from the number 2 engine
21:03That tracks with what the witnesses said they were hearing
21:06Lack of airspeed and a compressor surge are clear signs that the plane stalled
21:10Give me the roll angle
21:13They were banking left, right, left, right, left
21:20They were in a roll reversal
21:23A roll reversal is a phenomenon that occurs when a plane banks steeply to the left and right
21:30The airplane started to roll
21:33Radically from side to side
21:35If you look at the flight recorder traces you can see an 80 degree bank one way
21:40115 degree bank the other way, which is more than
21:43More than knife edge flight
21:45And now the airplane does exactly the opposite of what you were asking it to do
21:49Yeah, that's four roll reversals before the crash
22:00How did the crew of flight 827 allow their plane to get so out of control?
22:05With the arrival of flight 827's cockpit voice recorder, or CVR, investigators zero in on the test the pilots were conducting immediately before the plane stalled
22:19Are you ready?
22:22Ready
22:23Ready
22:25Next thing is our stall series
22:27We should stall at 122
22:29I'm gonna set that in my interior bug
22:32Mind set
22:35Shaker 128
22:36If you just call all your numbers, I'll record them
22:39Investigators listen to the pilots working their way through the stall series
22:49Feeling some buffet here
22:52Yeah, it's pretty early
22:58So the plane entered the stall sooner than they expected
23:01Yeah
23:04When I was looking through the transcript before there was something that Captain Lemming said earlier in the flight
23:10Uh...
23:12Captain Lemming, we're getting a little bit of ice here
23:14Garth, if we go up 15, I think we can get out of this stuff
23:20Uh... yeah, you can go up there, we've got that block
23:25So ice builds up, disrupts air flow over the wing
23:28Decreases lift, increases drag
23:30And the plane would have stalled at a higher air speed than the calculated
23:32Did ice accumulation on flight 827 cause a premature stall?
23:45It's happened before
23:47December the 12th, 1985
23:49Evidence suggested that shortly after taking off from Gander International Airport in wintry conditions
23:57A buildup of ice on Arrow Air Flight 1285 caused the plane to stall at a higher air speed
24:04Leading to a crash that killed all 256 people on board
24:08Investigators study meteorological reports to determine if flight 827 was flying through icing conditions
24:18There's a scattered area of light rain here along 827's flight path
24:24Cloud tops out at around 14,000 feet
24:28What was our altitude block again?
24:30Uh... 13 to 15,000
24:33The type of weather they were in the night of the accident was really conducive to icing
24:39They were in prime territory to pick up ice whenever they were in the clouds
24:43What speed did the pilots say they expected the stall?
24:47Stall 122, shaker 128
24:51Well, according to the FDR, the plane stalled at 126 knots
24:58It's only 4 knots earlier
25:04So even if there was ice, it was likely to have had little impact
25:08I mean, certainly not enough to make the plane unrecoverable
25:13Whether there was a great deal of contribution from ice, we could never determine
25:19But, uh, the consensus was that it was not a major element in the cause of the accident
25:25You said stall 122 knots, shaker 128?
25:31Well, when we were listening to the CVR, I don't remember hearing the stick shaker
25:36The purpose of the stick shaker is to get your undivided attention
25:42Not only by noise, but by shaking you
25:44Because there's only one thing that that's telling you, and that is, if you slow anymore, I'm gonna stall
25:55Let's have a listen
25:57Did the pilots receive proper warning that their plane was entering a stall?
26:03Feeling some buffet
26:05Yeah, it's pretty early
26:07That's a stall right there
26:08That ain't no shaker
26:15So, they're slowing the plane down, waiting for the shaker to activate
26:18Then all of a sudden, they're in a stall
26:20No warning
26:21So the shaker failed
26:24With no stall warning there, the pilots had, in a sense, a right to believe they weren't stalled
26:29Well, what's going on here? Well, it's not a stall because the stick shaker's not vibrating
26:34Well, the question is, when did it fail? During the flight, or before?
26:38Or before?
26:49To determine if the stick shaker malfunctioned, investigators searched the wreckage for stall components that might have survived the fiery crash
27:03Nothing, huh?
27:04Yeah, that's what we thought
27:07The stall system was completely destroyed
27:10We never were able to exactly identify what that failure point was in the system
27:18Our team wanted to find out how much maintenance and inspection had taken place on the system
27:25With no clues in the wreckage
27:31NTSB investigators speak to the maintenance technician about Flight 827's stall warning system
27:38Hey, entry time
27:40Did you test the stick shaker?
27:43Yeah, we did
27:45On...
27:48On December 5th
27:49Two weeks before the accident
27:52How extensive the test?
27:53Quite extensive
27:55And look
27:59The shaker, the heating components
28:01The stick shaker system passed all those pre-flight maintenance checks
28:06What about the transducer?
28:09Let me check
28:10Let me check
28:12The transducer is a small flap nestled in the recessed part of the wing
28:18It moves backwards when airflow is detected
28:21When there is insufficient air over the wings, it moves forward and triggers the stick shaker to activate
28:27No, no, it doesn't look like we tested the transducer
28:37That part is not covered by the pre-flight test
28:44It suggests that the failure of the stick shaker to work was a bad transducer
28:48But to me, why it failed wasn't as important as what the effect of it failing was on the crew
29:01Getting some buffet here
29:04Yeah, it's pretty early
29:06That's a stall right there, that ain't no shaker
29:08Even without the stick shaker activating, the flight crew knew they were in a stall
29:12That's number two engine
29:16Bring it back
29:17Okay, good
29:19But if they knew
29:21Left rudder
29:22Why couldn't they recover?
29:23Easy
29:24Bring it back
29:25Pull up
29:26Rudder
29:27Really?
29:37Investigators returned to Flight 827's CVR
29:39To get a better sense of the actions the pilots took when their aircraft went into a stall
29:45That's a stall right there, that ain't no shaker
29:49Set max power
29:51133
29:54So as soon as they recognize they're in a stall, they push power to the engines
29:58That's the right move
30:02That's number two engine
30:03There's the engine, Serge
30:05Pull it back
30:10So what'd they do next?
30:14All right
30:16Okay
30:18Start bringing the nose back up
30:26They pulled the nose up
30:28That would make the stall worse
30:29Pulling back on the control column in response to a stall is inconsistent with a normal stall recovery
30:36And would not reduce angle of attack and break the stall
30:42Well that's what would have triggered the role reversal
30:46How'd they deal with that?
30:50Rudder?
30:51Got it
30:52Rudder
30:53Got it
30:54Left rudder
30:55Left rudder
30:56Left rudder's buried
30:58Investigators discover that in addition to moving the control wheel right and left
31:03The pilots also use the rudder to stop the plane from rolling
31:07You have to be ahead of it and that's a very difficult thing to do
31:11So they spend almost a minute trying to fight the role reversal with the rudder
31:18No mention of a stall
31:22Investigators suspect that the pilots were so preoccupied dealing with the role reversal
31:28That they failed to realize that the plane was in a stall
31:30Still doesn't explain why captain lemming would have pulled back on the yoke to try to recover from the stall
31:43To recover from the stall you can't pull back
31:46You need to point the nose of the airplane down even more
31:50In order to gain speed or you will not recover
31:53You will fly into the mountaintop in Virginia
31:55Parane, parane, pull up
32:00Parane, parane
32:04And we wanted to know why
32:07Why did he do that?
32:09Especially at those most critical moments
32:16Morning Bob
32:18Looking to see if there's anything in ABX's operations manual on the DC-8
32:22Here's a copy
32:23Investigators search through ABX's procedures to understand why Captain Lemming pulled back on the control column to recover from flight 827 stall
32:35Wait
32:37Bob, did you see this?
32:39It says that priority in a stall recovery is to maintain altitude by increasing the pitch
32:46Pulling back on the control column increases the pitch of an aircraft
32:53Well it might be okay for an approach to a stall but not for an actual stall
32:57So the things that you do to recover from an approach to stall
33:04Are totally different from what you do to recover from an actual stall
33:09If you're right over the trees you got to try the approach to stall recovery because you're going to hit the trees
33:14If you're at 36,000 feet and you stall if you don't put the nose down 5 or 10 degrees you're not going to recover
33:24That can't be the current procedure can it?
33:26Uh, I've got a joint memo with the FAA
33:39Investigators discover an update to Airborne Express's flight test procedures
33:43Now what's it say?
33:46The updated procedure called for a reduction of pitch to recover from a stall
33:51The revised procedure called for pilots to lower the nose when entering a stall
33:57The opposite of what Captain Lemming did
33:59The change was made after a loss of control incident in May 1991
34:05What flight was that?
34:10It was a DC-8 during a post modification FEF
34:14The same plane and flight as A-27
34:17On May the 16th 1991 another Airborne Express DC-8 lost control during an FEF
34:25The pilots managed to recover from the stall
34:29And the policy has been to reduce pitch during a stall ever since
34:33So why didn't the crew of flight 827 use the updated procedure?
34:41Okay
34:43We learned that the director of flight technical programs was responsible for the procedures
34:48The checklists and the selection and training of pilots
34:51As a result we wanted to talk to him to learn more
34:55The NTSB meets with the airline's director of flight technical programs
35:00To determine why the crew of flight 827 didn't follow the updated procedure
35:05Just have a few questions to ask and then I'll let you get back to work
35:08Of course
35:10How do ABX pilots train to recover from a stall?
35:13I tell them whatever you do don't lose altitude
35:16So if you're in a stall you set max power and you increase the pitch of the aircraft
35:19Well that's different from the updated policy which calls for a nose down pitch recovery
35:26Correct
35:28He just didn't agree that that was necessary
35:30If you increase the pitch it will make the stall even worse
35:33If the engines are properly spooled as you're approaching a stall
35:37You can power your way out of it
35:39The director believed that if the engines were running properly
35:42Pilots could increase thrust and fly out of a stall
35:45He had his own opinions about what should be done and they were not in agreement with the proper procedure
35:54See what I don't get is
36:06Old procedure, new procedure, there is no procedure that says to pull back for the duration of the stall
36:12I keep going back to the way they were dealing with this role reversal
36:14Rudder
36:18Rudder
36:19Rudder
36:20Got it
36:21And left rudder
36:23The crew were unable to recover the airplane in the approximately 90 seconds that it took
36:30From when this lack of the stick shaker was identified to when it impacted terrain
36:34And our question was why?
36:37Investigators assess ABX's DC-8 flight simulator to see exactly how the flight crew experienced a stall during their training
36:46Now I'm going to slow this thing down into a stall
36:49There's the stall
36:55There's the shaker
37:00There's the stall
37:01Now I'm going to pull back on the yoke like our pilots did
37:05So I continued to raise the nose up higher and higher
37:09And I was just astounded at what the simulator did
37:15Or mainly what it didn't do
37:26Well we're in a stall
37:28And there's no roll, no pitch down
37:31Nothing like you would see in a real life stall
37:34The simulator just kind of reached the end of its program
37:37It just sat there
37:40If this is how they were trained they would have no idea how a stall truly feels
37:48Their training was not only zero training, it was negative training
37:53It gave them a false impression of what they would experience
37:56They would have been startled
37:59Left rudder
38:01At what the wings did with the roll
38:03Okay easy, don't, don't
38:04Don't
38:06And they would not have recognized it necessarily as a symptom of a stall
38:11Because in their simulator it didn't have that symptom
38:15Maybe they didn't realize they were still in the stall
38:17But surely there were other indicators that they were falling out of the sky
38:21Why didn't the pilots of flight 827 realize they were diving towards a mountain?
38:33Okay, put yourself in the pilots shoes
38:37You realize you're in a stall
38:40Feeling some buffet here
38:41Yeah, it's pretty early
38:43That's a stall right there
38:44That ain't no shaker
38:46You push power to the engines
38:48Pull back on the yoke
38:50Start bringing the nose back up
38:52Your number 2 engine surges
38:56That's number 2 engine
39:07Pull it back
39:09Now you're dealing with a roll
39:19Planes banking left and right
39:21You're applying rudder
39:22Rudder
39:23Rudder
39:24Got it
39:25Rudder
39:26Rudder
39:27Got it
39:29You've got ATC in your ear telling you to switch frequencies
39:31827 change
39:3210, Indianapolis, 1, 2, 8.4
39:35You look outside, what do you see?
39:38Nothing
39:44Right
39:45Because it's pitch black out and you're in the clouds
39:48There's no visible horizon, you're just flying on instruments
39:51They had no visual cues
39:53Exactly
39:55You're now removing the visual aspect of a horizon out there that can help anchor you
40:01You're just stacking the deck against yourself
40:04Now, the question is
40:06What were they doing flying a stall series test at night in the first place?
40:12Investigators review the flight's dispatch logs to retrace the pilot's steps on the day of the accident
40:18The FEF was scheduled for 1.20pm, but the maintenance delays pushed it past sundown
40:25Had they just pushed it to the next day, none of this would have happened
40:28So why didn't they?
40:30Why go through with the FEF at night?
40:35Right
40:36One of the key decisions was to conduct the check flight later at night than they'd planned in the darkness hours
40:45And so, you know, did anyone pressure him to doing that?
40:48What is the ABX policy on when to fly an FEF?
40:51Investigators returned to ABX's Director of Flight Technical Programs to find out why the pilots proceeded with an FEF at night
41:01No policy necessarily, just a preference to fly them during the day
41:06Do ABX pilots understand the risks of flying an FEF at night?
41:10Sure
41:11And I'd rather they conduct them during the day, but there's no prohibition against doing them at night
41:17What are the recommended weather conditions for flying an FEF?
41:20Preferences to fly in clear skies and not on instrument, but we have no specific restrictions on that
41:26We discovered that there was no written policy prohibiting this flight from being conducted at night
41:36The NTSB's investigation has uncovered numerous factors that led to the crash of Flight 827
41:43Stick shaker malfunction, incorrect stall procedure, negative simulator training, FEF at night
41:51If just one of these factors not been present, the crew would likely have survived
42:01I think this accident was caused by a failure to recognize that a functional evaluation flight requires rigorous preparation
42:10And criteria and controls be placed on it to protect the pilots who are flying it
42:17Start bringing the nose back up
42:19This was not God reaching down and slapping an airplane out of the sky
42:25There were reasons for this happening and this could have been avoided
42:29In the wake of the crash of Flight 827
42:33The NTSB makes a series of recommendations to make functional evaluation flights safer
42:39And to better prepare pilots for stall conditions
42:43This accident brought a lot of significant changes to the industry
42:47We issued recommendations to try to improve airline oversight and FA oversight of functional evaluation programs
42:58And those efforts were successful
43:02Flight simulators used for airline training were made much more realistic
43:06Every airline pilot receives training in recovering the airplane from the high-altitude stall
43:15Where they have to use this Airborne Express revised stall recovery procedure to get the job done
43:22The report also recommends a revision to the DC-8 maintenance manual
43:26Calling for regular calibration and testing of the complete stall warning system
43:33There might have been other airplanes out there, you know, flying around in service
43:37Where the stall warning system really wasn't working
43:40It's a sobering thought and a significant one
43:43The strength of aviation safety is a direct result of learning the most we can learn from every single accident
43:54This wasn't an accident in vain
43:56Yes, it could have been prevented, but now we know how
43:57But now we know how
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