- vor 7 Wochen
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.