- vor 22 Stunden
On 10 March 2019, Ethiopian Airlines Flight 302 crashes near the town of Bishoftu shortly after takeoff from Addis Ababa Bole International Airport, killing all 157 people on board. A faulty angle of attack sensor had accidentally activated the aircraft's MCAS system.
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00:00D1. Rotate.
00:11Just seconds after takeoff from Addis Ababa.
00:14Gear up.
00:15The pilots of Ethiopian Airlines Flight 302 are faced with an emergency.
00:20Master caution. Anti-ice.
00:24You're literally fighting to maintain control of the jet.
00:28Staff trim cut out? Yes, yes, do it!
00:31But the procedure they've been taught for the Boeing 737 MAX 8...
00:37...doesn't work.
00:39They know what to do, and they tried to do it.
00:41Investigators are astonished.
00:43If the pilots knew the proper procedure, why didn't it work?
00:47Boeing didn't say anything about the trim wheel being difficult to move.
00:54Could the pilots have been misled about how to save their plane?
00:57They've still left the Boeing MAX un-airworthy.
01:00And it caused the life of my daughter and 157 people.
01:04D-D, D-D.
01:06T, D-D, D-D...
01:14F11, C-1 a!
01:15You have to go through the plane!
01:16Already waiting, though we are up on the plane!
01:17Government'sροile data worry, right?
01:18Z-D.
01:19Boarding has commenced for 149 passengers on a short flight from Addis Ababa, Ethiopia, to Nairobi, Kenya.
01:39Perfect, thank you.
01:44This was really a UN shuttle flight.
01:46There was a UN environmental conference happening in Nairobi, so there were about a couple dozen people on the plane who were headed to that conference.
01:55All right, ground equipment is removed and engineering is clear.
01:59The captain on today's flight is 29-year-old Yared Getachew.
02:04The captain was considered one of the best pilots in the airline.
02:07He had 8,000 hours, which was unheard of for someone that young.
02:12Before start, checklist complete. Request pushback clearance.
02:16Ground, Ethiopian 302, requesting pushback clearance.
02:2025-year-old Ahmed Noor Mohamed is the first officer.
02:24Ethiopian 302, you are cleared to push.
02:28Ethiopian Airlines was considered the model airline in Africa.
02:31It had the best-run training school, and it had a well-oiled system for bringing new pilots into the airline.
02:37They're on a Boeing 737 MAX 8, a brand-new passenger jet that's already at the center of a major investigation in Indonesia.
02:53Five months earlier, a MAX 8 crashed into the Java Sea, killing all 189 people on board.
03:00That accident is still under investigation.
03:05Just before 8.30 a.m., flight 302 taxis towards the runway at Addis Ababa's Bole International Airport.
03:19Ethiopian 302, cross-run right, is 07 left at Alpha and hold short of 07 right.
03:25Cross 07 left at Alpha and hold short, Ethiopian 302.
03:31Free takeoff checklist, please.
03:34Landing lights?
03:35On.
03:43Among the passengers on today's flight is 24-year-old Canadian Danielle Moore.
03:50She's traveling to the UN summit.
03:54She really astonished us when she told us that she would be going to the United Nations Environmental Assembly in Nairobi,
04:02and she was selected out of a number of people.
04:06We thought this was so tremendous.
04:11Flight 302 reaches runway 7 right, the longest runway at the airport.
04:16Ethiopian 302, ready for departure.
04:20302, clear for takeoff.
04:21Runway 7 right, have a good flight.
04:28Ready?
04:29Ready.
04:32Takeoff thrust set.
04:43Speed increasing.
04:56Flight 302 departs on time.
05:02The 725-mile flight to Nairobi should take just over two hours.
05:11The Max 8 was designed for routes like this.
05:13It's a short hop, quick turnaround plane.
05:17Also had much more fuel efficiency compared to the previous version of the Max, about 20%.
05:22D1.
05:24Rotate.
05:41Positive rate.
05:43Gear up.
05:46Gear up.
05:47Less than 10 seconds after takeoff, the pilots get a stick shaker warning, indicating that they're in danger of losing lift and could stall.
05:56If you experience a stall right after departure, it can be extremely serious.
06:02Captain Getachew reduces his plane's pitch angle in an effort to prevent a stall.
06:07If you're taking off and you get a stick shaker, crews are going to be hesitant, you know, to push their nose over because they're close to the ground.
06:19Master caution.
06:20Anti-ice.
06:22Okay.
06:23When Master Caution's come on, the first thing is to diagnose what's occurred and consider what implications it has on the flight.
06:37What's going on?
06:38Captain Getachew doesn't understand what's behind the multiple warnings.
06:42There's a lot going on here, and it's a very distracting, loud environment with a stick shaker going.
06:48Where do you start to deal with this complex emergency that you have?
06:58Flight 302 is only a few hundred feet off the ground as the pilots struggle to understand the problem.
07:08As far as passengers are concerned, this is a routine takeoff.
07:17Okay, contact radar.
07:19Captain Getachew decides to continue climbing.
07:21If you have a problem, the thing you want to do is get it away from the ground, where you can sort through your problems.
07:29Radar, Ethiopian 302. Good morning.
07:32Crossing 8,400 and climbing to 320.
07:37First officer Mohammed reports his altitude, 8,400 feet above sea level, which is only 750 feet above the ground.
07:46Continue climb to flight level 340.
07:50Climb to 340.
07:52Ethiopian 302.
07:55Flaps up.
07:57Flaps up.
07:58Retracting the flaps should help the aircraft climb, but it has the opposite effect.
08:081,500 feet from the ground, the jetliner with 157 people on board begins to fall.
08:15We're having flight control problems.
08:18Don't think.
08:20Don't think.
08:20You've gone from a series of cautions, a series of system malfunctions, now into a flight control problem, where you're literally fighting to maintain control of the jet.
08:34Passengers now sense that there is something wrong.
08:43One woman whose brother was on the airplane, and he called her soon after takeoff.
08:49He knew something was wrong.
08:52The plane was not climbing the way aircraft normally do.
08:55The 737's nose continues to pitch down.
08:59Trim.
09:00Come on, trim with me.
09:01Captain Getachew uses the trim switch to level his plane.
09:05The trim switch controls the position of the horizontal stabilizer, keeping the plane balanced during flight.
09:13It can be used to adjust the pitch of the airplane.
09:17Captain Getachew manages to raise the nose slightly, but not for long.
09:23The plane dips again, bringing it closer to the ground.
09:29Too low.
09:30Terrain.
09:31And the pilots are struggling.
09:34Too low.
09:35Terrain.
09:36Now you start dealing with how do we regain control and to keep the nose up while we sort through this.
09:44And that's where the time can become critical.
09:52So what?
09:53Less than three minutes after takeoff, and only 1,800 feet above the ground, the pilots of Ethiopian Airlines Flight 302 are desperately trying to get their plane to climb.
10:06Pull up.
10:08Okay.
10:09Advise me to maintain 6,500.
10:11We have a flight control problem.
10:14They're trying to reach the minimum safe altitude surrounding the airport.
10:17Ethiopia 302, would like to maintain 6,500.
10:24We have a flight control problem.
10:27Say again?
10:28We have a flight control problem.
10:29I would like to maintain 6,500.
10:32Approve.
10:33Then report intention.
10:34We'll call you.
10:35Ethiopia 302.
10:37First and foremost, they said, okay, we have a flight control problem, and that says, get other airplanes away from me.
10:44And that was a very appropriate thing to do.
10:47Set 6,500.
10:486,500.
10:506,500.
10:51Set.
10:56Speed!
10:57As they fight to climb to 6,500 feet, the plane's speed becomes dangerously high.
11:03They try to raise the plane's nose further, to decrease speed.
11:11Get up with me.
11:16Even with both pilots pulling back on their control columns, the plane refuses to climb.
11:22The forces necessary to hold that yoke are increasing, and they're increasing quite rapidly.
11:27Less than five minutes into the flight, Captain Getachew decides to turn around.
11:45Request a return, Vector.
11:46Radar, Ethiopian 302, requesting Vector back to airport.
11:50There was a lot going on in that cockpit.
11:52There were indicators going off showing a disagreement in altitude, disagreement in airspeed.
11:57The stick shaker was going off, so the best thing for them to do was to turn around.
12:01Confirmed.
12:01You want to hold or make an approach?
12:03Wish to commence approach.
12:09Turn rights, 260.
12:14260.
12:21The pilots have managed to get their plane to 6,000 feet above the ground.
12:26Pitch up with me.
12:27On the pitch.
12:28On the pitch.
12:30But now it starts to plummet.
12:33Think great.
12:44Pitch up.
12:45Caution.
12:45Terrain.
12:46Terrain.
12:47Terrain.
12:48Pull up.
12:49Mayday, mayday, mayday.
12:50Terrain.
12:51Pull up.
12:52Pull up.
12:53Flight 302 slams into the ground just 30 miles from the airport.
13:07It's the second Max 8 to have crashed in less than five months.
13:12In today's world, even a single accident is an extreme rarity.
13:17To have two within five months, it is inconsistent with the level of safety of modern airliners.
13:24We begin tonight with the mystery swirling around a deadly plane crash overseas.
13:40The new Boeing 737 crashing just minutes after takeoff in Ethiopia.
13:45157 people were on board the flight, and there were no survivors.
13:50News of the Ethiopian Airlines crash quickly makes headlines around the world.
13:55The phone rang, and my wife answered it, and I recall hearing her scream and saying,
14:03Danielle is dead.
14:09My hearing her shriek and saying those words was the death of me, too.
14:19I died.
14:20This is the last thing that any father wants to experience.
14:42A team from Ethiopia's Accident Investigation Bureau is tasked with finding out why Flight 302 crashed.
14:50Just five minutes after takeoff.
14:52To make a crater like this, the speed must have been tremendous.
14:59Much of the wreckage is buried in a crater more than 30 feet deep.
15:04You can tell that it was in a high-energy state, that just due to it creating a crater,
15:10that it had to have some kind of angle to it.
15:16The plane's two black boxes are quickly found.
15:20The Ethiopian government decides to send them to France's investigative agency
15:27to have the data downloaded.
15:35In Indonesia, the investigation into the previous Max 8 accident is still underway,
15:41as investigators get the news about the Ethiopian Airlines accident.
15:44First time I heard about the Ethiopian Flight 302 crash, I was shocked,
15:52knowing that another 737 MAX has gone down.
15:56The Indonesian accident involves Lion Air Flight 610,
16:01a MAX 8 that took off from Jakarta with 189 people on board five months earlier.
16:06I was afraid that the accident was caused by a similar issue with the Lion 610
16:14that we were investigating.
16:18The Indonesian pilots also began experiencing warnings shortly after takeoff
16:24and also reported having flight control problems.
16:27Following a series of altitude fluctuations, the pilots attempted to return to the airport.
16:36The 737 plunged into the Java Sea 11 minutes after takeoff.
16:41The investigation into that accident has zeroed in on an electronic system known as MCAS,
16:49the Maneuvering Characteristics Augmentation System.
16:52It's a piece of software in the flight control computer
16:54that directs the stabilizer to push the nose down.
17:01Investigators in Indonesia have learned that MCAS was added to the MAX 8
17:05to compensate for a design problem.
17:08In order to achieve the fuel efficiency Boeing wanted to,
17:11it needed to put bigger engines on the airplane,
17:14and in certain flight conditions, the nose had a tendency to pitch up,
17:17and that's why MCAS was introduced.
17:20If the system sensed the plane's nose was pitched too high,
17:24it would automatically adjust the plane's stabilizer to lower the nose.
17:30Indonesian investigators have determined that a faulty sensor on the Lion Air flight
17:34led MCAS to conclude the plane was climbing more steeply than it was,
17:39causing it to activate repeatedly until the plane hit the water.
17:43We found that there was some issue with the design of the system.
17:50There are 387 MAX 8s flying worldwide, with another 5,000 on order.
17:57It's rapidly becoming one of Boeing's most successful airliners.
18:01The MAX 8 was the fastest-selling aircraft in Boeing's history.
18:05Airlines were really drawn to the fuel efficiency.
18:08The pressure is on investigators to determine if a flaw with MCAS
18:12also caused the Ethiopian accident.
18:15There was worldwide attention to this investigation.
18:18The whole team was under a lot of pressure to get answers
18:21and to find out what happened.
18:22Ethiopian investigators start with the last people
18:34who spoke to the crew of Flight 302, air traffic controllers.
18:39Thanks for your time.
18:40Can you take me through the flight?
18:42Normal taxi and takeoff.
18:43Nothing unusual until two and a half minutes later
18:46when they reported a flight control problem.
18:47Ethiopia 302, would like to maintain 6,500.
18:54Would we have a flight control problem?
18:57They asked to maintain the current headed.
18:59Requested permission to hold at 6,500 feet.
19:02And you approved the request?
19:04I did, yes, sir.
19:07All investigators know is that the pilots had a flight control problem
19:11that developed early and prevented the crew from continuing the flight.
19:14They're aware that they were dealing with a flight control issue.
19:19It would have been helpful if they could have identified
19:21which control surface they're having the problem with.
19:31The team turns to Flight 302's radar track
19:34to understand the sequence of events.
19:38Slow, shallow climb out.
19:42I look here.
19:44Instead of climbing, they lose altitude, regain it, then lose more.
19:48Instead of continuing to climb or to maintain an altitude,
19:53there is actually dips in the altitude.
19:57The radar data paints a picture of a crew struggling
20:01to keep its plane in a climb.
20:02Don't sink. Don't sink.
20:04They're trying to get to 6,500 feet, but never get higher than 6,200.
20:16They're starting to make a turn back to the airport.
20:20Now they're in a dive descending at 33,000 feet per minute.
20:23The speeds were at the maximum for this aircraft.
20:27The intensity inside the plane must have been terrifying.
20:30Let me see the Lion Air track, please.
20:44A slow climb.
20:46A series of altitude fluctuations.
20:50A turn back to the airport.
20:52And rapid descent.
20:53The fact that this plane crashed almost immediately after takeoff
21:04in very similar circumstances
21:06raised a lot of questions in everyone's minds.
21:10Investigators turn to a key piece of the wreckage
21:13for confirmation that MCAS played a role in the accident.
21:16It's in pretty good shape.
21:18You got lucky.
21:19A jack screw.
21:20The device that controls the position
21:22of the plane's horizontal stabilizer is recovered.
21:28A ball nut moves along the jack screw
21:30to help adjust the plane's pitch.
21:37Five inches.
21:42Full nose down trim.
21:43The evidence shows that the plane went into its final dive
21:48because the stabilizer had moved
21:50to an extreme nose down position.
21:54Full nose down trim is not something
21:56that you ever see in the normal flight of a 737.
22:01In the 15 years that I flew it,
22:03I don't know that we ever got even close to full nose down.
22:09The Lion Air flight is identical.
22:11A pitch trim of 1.5 degrees resulting in a rapid descent.
22:16The pilots wouldn't do that.
22:19The jack screw all but confirms
22:21that Ethiopian Airlines Flight 302
22:24and Lion Air Flight 610 had the same cause,
22:27a malfunction of the plane's electronic MCAS system.
22:31That was literally the smoking gun
22:33that definitively told them what had happened to the airplane.
22:36There's now enough evidence
22:40to convince aviation authorities around the world
22:43that the MAX 8 presents a risk to passengers.
22:46We're going to be issuing an emergency order of prohibition
22:50to ground all flights of the 737 MAX 8.
22:56The question now facing Ethiopian investigators
22:59is how could this have happened again?
23:07These documents came out four months ago.
23:10Following the accident in Indonesia,
23:12both Boeing and the FAA issued bulletins
23:15advising pilots of the steps to take
23:17if MCAS began forcing the nose down.
23:20The documents advise pilots to follow the existing procedure
23:25for a malfunctioning trim system
23:27and disengage the autopilot,
23:30set the stabilizer trim switches to cut out,
23:35and to use their manual trim wheel
23:38to counteract the automatic downward stabilizer movement.
23:42Boeing and the FAA felt that the airworthiness directive
23:44was all pilots needed to be able to recover
23:47from what they thought would be an extremely rare event.
23:49Did the pilots know about this procedure?
24:00You'd hope so.
24:03The airline has an obligation to train the pilots
24:07to ensure that there is a sufficient understanding
24:10of what the information is trying to tell them
24:13so that they act appropriately.
24:16We incorporated the Boeing bulletin into our flight manual.
24:19All our pilots were fully briefed, of course.
24:38The pilots of Flight 302 knew the procedure for disabling MCAS.
24:43The question is, did they follow it?
24:53Here it is.
24:55Let's load it up.
24:57The cockpit voice recording from Ethiopian Airlines Flight 302
25:01has been successfully downloaded by technicians in France.
25:04Okay.
25:05Let's hear it.
25:09V-1.
25:11Rotate.
25:12Positive rate.
25:14Gear up.
25:16Take off roll as normal.
25:18Investigators listen for clues
25:20that can explain how MCAS brought down the plane.
25:23Climb to 340, Ethiopian 302.
25:27Flaps up.
25:28The MCAS system is designed to activate
25:33only when it senses that three conditions are met.
25:37Nose up.
25:38Flaps fully retracted.
25:40And autopilot off.
25:45That's the autopilot disconnecting.
25:47Oh, okay.
25:49So now they've met the three conditions
25:51for MCAS activation.
25:54Investigators continue listening
25:56for evidence that MCAS activated,
25:58pitching the plane downwards.
26:01We're having flight control problems.
26:03Right on, Q.
26:08He's losing altitude.
26:14MCAS is pushing the nose down.
26:15Trim.
26:19Come on, trim with me.
26:21Trim up.
26:22Trim up.
26:22Trim up.
26:23Come on, trim up.
26:26Investigators hear the pilot struggling
26:28to trim their plane nose up.
26:30So you begin to get this tug of war
26:32between the pilot trimming nose up
26:35and MCAS trimming nose down.
26:37But MCAS is relentless.
26:39It doesn't stop.
26:40Trim.
26:41Trim up.
26:45The team then hears an exchange
26:47that transforms the investigation.
26:53Stab trim cut out?
26:54Stab trim cut out?
26:55Yes, yes, do it.
26:58Stab trim cut out.
26:59Can you pause for a second?
27:02They did it.
27:03They set the trim switches to cut out,
27:08exactly as Boeing advised them to do.
27:11I think that's the surprise
27:13the crew attempted to do that procedure,
27:17and it wasn't successful.
27:19The autopilot disengaged.
27:21We heard the alarm.
27:21They set their stabilizer trim switches
27:25to cut out.
27:28Now they need to manually trim
27:30to get their nose back up.
27:32Let's hear it.
27:34Catch up.
27:35Catch up.
27:35Catch up.
27:36Do it with me.
27:39Is the trim engaged?
27:42No.
27:43Shall I try it manually?
27:44Try it.
27:44The 737 has a manual backup
27:50about how to move trim using cables,
27:52and the wheel has actually got a handle in it
27:56where you can manually trim it.
28:00It's not working.
28:03No, I'm not pitch.
28:05No, I'm not pitch.
28:06But the pilots are not able
28:08to adjust the pitch manually.
28:09They don't physically have enough strength
28:12to move the horizontal stabilizer
28:15via the manual trim wheel.
28:18They're trying to do this.
28:20But it doesn't sound like it's working.
28:24And then they come up with a solution
28:27that seals their fate.
28:29Put them up.
28:31No.
28:32Oh, no.
28:33No.
28:34Unable to pitch the plane up manually,
28:37the pilots make one final desperate move.
28:41They re-engage the automatic trim
28:43to help move the stabilizer.
28:49Unfortunately, that wakes the beast.
28:51And then it's going to sit there
28:52and it's going to trim it down
28:53one more time again
28:54so it works against them.
28:57Action.
28:58Pitch up!
29:00Pitch up!
29:01Pitch up!
29:02There was no way to control the airplane.
29:03The pitch was going to continue to go nose down.
29:07Pitch up!
29:08Pitch up!
29:09Pitch up!
29:10Pitch up!
29:11Pitch up!
29:12Pitch up!
29:13Pitch up!
29:14Pitch up!
29:15Pitch up!
29:20They knew what to do.
29:22They tried to do it.
29:24But for whatever reason,
29:26it didn't work.
29:29The Ethiopians have made a stunning discovery,
29:34one they quickly share with the world.
29:36The crew performed all the procedures repeatedly provided by the manufacturer,
29:44but was not able to control the aircraft.
29:48The aircraft.
29:53Stab trim cut out?
29:55Stab trim cut out?
29:56Stab trim cut out?
29:57Yes, yes, do it!
29:58Investigators are left with a burning question.
30:00Stab trim cut out.
30:02If the pilots did what Boeing advised,
30:05why weren't they able to pull out of the dive that MCAS put them into?
30:09Pitch up!
30:10Pitch up!
30:18Investigators turned to the flight data recorder from Ethiopian Airlines Flight 302
30:23to better understand why MCAS was activated, causing the plane to crash.
30:28Right here.
30:3010 seconds after takeoff.
30:32Readings for angle of attack, airspeed, and altitude begin to diverge.
30:38MCAS is only supposed to activate when the MAX 8 reaches an extreme angle of attack,
30:44or high-pitch angle.
30:47A sensor on each side of the airplane calculates the angle of attack
30:51by measuring the plane's angle into the oncoming air.
30:58Sure looks like a sensor issue.
31:00The captain's side can't be right.
31:02Absolutely.
31:04The data shows a steep spike in the captain's angle of attack reading.
31:12That explains the stick shaker.
31:13Yup, false alarm.
31:17The plane was never in danger of stalling.
31:20The warning was triggered by faulty pitch data
31:23from a malfunction in an angle of attack sensor.
31:26The captain's side shows a pitch up of as much as 74 degrees.
31:30The first officer's side is correct.
31:32A steady 15-degree pitch.
31:35Investigators discover the malfunction was only on the captain's side.
31:40So, up until this point, the flight is actually fine.
31:44On the Ethiopian airplane, something happened to that sensor just shortly after takeoff.
31:50So, one faulty sensor brings down the plane.
31:55A single failure should not be catastrophic.
31:58There should be backup, there should be redundancy,
32:00so if there is something that occurs within the system,
32:04that the crew should be able to counter it.
32:08The FDR data can show us when the MCAS activated.
32:15The team studies how MCAS behaved for Flight 302.
32:20Here, here, and here.
32:26The plane pitches down even though the pilots are pulling up on their control columns.
32:32The faulty sensor led to four separate activations of the MCAS system,
32:37driving the plane's nose down as the pilots were trying to pitch up.
32:41The fourth MCAS activation pitched the nose down when the plane was only 6,000 feet above the ground.
32:49It put the plane into a steep and rapid descent.
32:53Pitch up! Pitch up!
32:54From which the pilots could not recover.
32:57Pull up!
33:03So, why couldn't the pilots disable the MCAS,
33:06even though they followed the recommended procedure?
33:10Investigators examine Flight 302's speed leading up to the crew's attempt to override the MCAS.
33:17They lift off at 140 knots.
33:19Absolutely perfect.
33:21But as they climb, their speed increases.
33:24It reaches 340 knots by the time they try to use manual trim.
33:30The overspeed warning sounds here and stays on for the rest of the flight.
33:36Normally, you would be in the 220-250 knot range.
33:42This was 100 knots plus faster than that.
33:45No wonder they couldn't move their trim wheel.
33:50The speed increased the air load on the stabilizer,
33:53making it impossible for the pilots to move it manually with their trim wheel.
34:01It's not working.
34:02Once you get to high speed, you're no longer strong enough as a human to move it.
34:13Why such high speed?
34:14Have a look at their autothrottle setting.
34:17They lift off with the autothrottle in takeoff mode.
34:20Right about here, the autothrottle should be pulling back from takeoff thrust to climb thrust.
34:27But that never happens.
34:29It stays at max takeoff thrust.
34:32Same sensor, I guess.
34:34Uh-huh.
34:35The autothrottle is also connected to the left side angle of attack sensor.
34:40Once the sensor failed, that disabled the autothrottle system, so the power stayed where it was.
34:49We're having flight control problems.
34:50As they dealt with the escalating crisis, the pilots didn't notice that their thrust levers remained at maximum takeoff power.
34:59737s are very powerful jets, and they will continue to accelerate very rapidly if you don't reduce the power.
35:07Boeing didn't say anything about the trim wheel being difficult to move.
35:14Or about air speed.
35:18The Ethiopian investigators now turn their attention to the advice Boeing gave pilots after the Lion Air accident.
35:26The Lion Air flight had necessitated this airworthiness directive, so the question becomes, was that enough?
35:32No mention of them tests.
35:35No mention of how much force may be needed to trim manually.
35:39No mention of air speed.
35:42That's a lot to leave out.
35:44The investigation has uncovered shortcomings in the guidance Boeing provided following the Lion Air accident.
35:50In Indonesia, investigators have discovered that a maintenance error led to the failure of the crucial angle of attack, or AOA, sensor in the Lion Air accident.
36:04What caused its failure on the Ethiopian flight?
36:10Investigators examine maintenance records for any evidence of trouble.
36:14So the Ethiopian investigation did look into the maintenance to the sensor. There was none. It's the original install to the airplane.
36:23They do uncover several other maintenance issues on the four-month-old plane.
36:28That's a lot of electrical faults for a brand new airplane.
36:38The Ethiopian team suspects the AOA sensor on Flight 302 failed due to an underlying electrical fault.
36:44The sensor failure is also being scrutinized by the NTSB.
36:48We also looked at how the AOA could fail, and what that failure would look like.
36:55That analysis is coming to a very different conclusion about the origins of the failure.
37:0744 seconds after they start to roll, this happens.
37:11The captain's angle of attack, air speed, and altitude values deviate.
37:14The NTSB travels to Collins Aerospace, the manufacturer of the angle of attack sensor, and asks their engineers to look at the fault data for Flight 302.
37:26Six seconds later, the heater on the sensor goes offline.
37:33Master caution. Anti-ice.
37:36Okay.
37:38These simultaneous failures all point to one thing.
37:41The sensor broke off. It's the only explanation.
37:45To determine what could have caused the sensor to break off.
37:50Have a look at this.
37:52They compare the FDR data to data from a bird strike.
37:58They're almost identical.
37:59The U.S. investigation side felt that the data supported more of an in-flight impact with the angle of attack sensor.
38:15The hazard posed by eagles and other large birds is well known at Addis Ababa's airport.
38:20The airport in Addis Ababa had had problems with bird strikes. The airport had several mitigation strategies in place because of that.
38:31D1. Rotate.
38:32D1. Rotate.
38:33D1.
38:34D1.
38:35D1.
38:36D1.
38:37D1.
38:38D1.
38:39D1.
38:40D1.
38:41D1.
38:42D1.
38:43D1.
38:44D1.
38:45D1.
38:46D1.
38:47D1.
38:48D1.
38:49D1.
38:50We were having flight control problems.
38:52Whether the sensor failed due to electrical failure or a bird strike,
38:56investigators now know why Ethiopian Airlines Flight 302 crashed shortly after takeoff.
39:03Here's a chain of events.
39:06The failed sensor triggers a series of warnings and alarms.
39:14Gear up.
39:20The erroneous angle of attack data causes MCAS to activate, pitching the nose down.
39:28Don't think. Don't think. Don't think.
39:37They do what Boeing recommends and move the trim switches to cut out.
39:40Stab trim cut out? Stab trim cut out?
39:43Yes, yes, do it!
39:46Stab trim cut out.
39:47But they're unable to manually trim.
39:51The wheel is almost impossible to move.
39:54They never recover.
40:02On the pitch! On the pitch!
40:04It was very obvious to them that they no longer had control of the airplane
40:09and that they couldn't stop this.
40:12Recovery was impossible.
40:14Pitch up!
40:15Pull up! Pull up! Pull up!
40:18Lady, lady, lady!
40:19For the NTSB, the MAX 8 accidents provided a valuable lesson about assumptions made by aircraft manufacturers
40:45regarding how pilots respond to emergencies.
40:48I think these two accidents are going to be the watershed events on how we look at the human factors for design and certification.
40:57As a result of the two accidents, Boeing overhauls the MAX 8's MCAS system.
41:03The MCAS system now relies on information from two sensors.
41:08It will only activate once, and it will not override pilots' ability to control the airplane with the control column.
41:16Boeing also offers pilots enhanced training on the MCAS system.
41:19Many feel the changes Boeing made to the MAX 8 came too late.
41:31Ethiopian 302 should have been prevented.
41:34Boeing should have got to the root causes of the problems on the Lion Air flight.
41:39Boeing didn't.
41:40For the devastated family of Danielle Moore, Boeing's greater failure was not advising pilots about the danger of MCAS.
41:48The bulletin from Boeing was not good enough to prevent an accident.
41:54The plane was still unsafe.
41:55And it caused the life of my daughter and 157 people.
42:08In November 2020, after a 20-month grounding, the MAX 8 is cleared to fly.