- Lion Air flight JT 610, a Boeing 737 Max, crashed into the sea in October 2018. All 189 people on board died.
- The official crash report, released by Indonesia last week, gives a definitive timeline of what happened on the doomed flight.
- It shows that the pilots tried more than 20 times to stop the plane’s computer forcing its nose down. But they could not bring it under control, and the plane crashed into the sea at 450mph.
- This is the full timeline of the fatal flight, according to investigators.
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Lion Air flight JT 610 took off from Jakarta’s Soekarno-Hatta International Airport at 6.20 a.m. on October 29, 2018. Less than 13 minutes later it smashed into the sea, killing everyone on board.
It was the first of two fatal crashes for Boeing’s 737 Max. A second crashed over Ethiopia in March 2019, leading to the grounding of the plane, and plunging Boeing into an ongoing crisis.
The final report, released by investigators last week, pointed to flaws in Boeing’s design of the plane, as well as mistakes by the airline and its staff.
The timeline it outlines shows the crew wrestling to control the plane as automatic anti-stall software, known as MCAS, overrode their instructions and pushed the nose down more than 20 times. It crashed into the Java Sea at around 450mph.
Here is what happened on board:
6.18 a.m.: JT 610 was given clearance to take off from Soekarno-Hatta International Airport. On board are 189 people: 181 passengers, 2 pilots, and 6 flight attendants.
It was bound for Pangkal Pinang on Indonesia’s Bangka Island.
Before the plane took off, the crew noted that the weather conditions on the route were good.
6.20 a.m., 16 seconds: Unusual readings were recorded while still on the ground, less than 30 seconds before takeoff. Two displays in the cockpit recorded different wind speeds, while the plane’s two angle of attack sensors, which measure its orientation in the air, disagreed by a substantial 21 degrees.
6.20 a.m., 32 seconds: The plane experienced a “control column stick shaker” warning, which physically shakes the plane’s controls to alert the pilots of a potential stall. It continued for most of the flight.
This video shows the controls column stick shaker on flight simulator for the Boeing 737-800, a predecessor to the 737 Max.
6.20 a.m., 37 seconds: The plane sounded a “takeoff configuration warning” — a generic alert which flags potential problems. The report says the captain queried the alert, but gives no further detail.
6.20 a.m, 40 seconds: Takeoff. The captain is flying. Problems begin to come thick and fast.
6.20 a.m., 44 seconds: Sensors started recording two different airspeeds. The first officer asked the captain what the problem is, and if they should turn back. He did not respond.
The plane’s black box, recovered after the crash, said one indicator recorded a speed of 164 knots while the other recorded 173 knots.
6.21 a.m., 12 seconds: The first officer told the captain that on-board sensors were giving two different altitude readings, more than 200ft apart. The captain spoke with an air traffic controller in the terminal, who said to climb higher.
The altimeter on the captain’s primary flight display indicated 340 feet, while the first officer’s indicated 570 feet.
6.21 a.m., 28 seconds: The first officer asked the controller to confirm the altitude of the plane. The controller said it was 900ft. On the plane, one display said 790ft, the other said 1,040ft.
6.21 a.m., 37 seconds: The captain asked the first officer to run through a memorized checklist for what to do when the plane is giving unreliable airspeed readings. The first officer did not respond. The first officer suggested flying downwind, which the captain rejected.
6.21 a.m., 52 seconds: The first officer asked permission to move into a holding pattern, citing a “flight control problem.” The controller did not respond to the holding pattern request, and later did not remember it being made.
6.22 a.m., 4 seconds: After a suggestion from the first officer, the captain adjusted the plane’s flaps from the “Flaps 5” setting, to the more flat “Flaps 1” setting. He then asked the first officer to take over the controls.
6.22 a.m., 15 seconds: The controller noted that the plane’s altitude was decreasing, from 1,700ft to 1,600ft. The plane’s controls still showed two different speeds.
6.22 a.m., 24 seconds: The captain and controller agreed that the plane should climb to 5,000 feet. The plane still showed two different speeds.
6.22 a.m., 32 seconds: An alarm warned that the plane was flying at a steep angle. The black box showed the plane briefly banked to 35 degrees, as if to turn.
6.22 a.m., 44 seconds: The plane, which appears not to have made it to the planned 5,000ft, instead rapidly descends 600ft. It has been in the air just two minutes.
6.22 a.m., 48 seconds: Sensors on the plane radically disagree about its angle of attack. One says the plane is flying with its nose pointing 18 degrees up, the other says it is flying with the nose 3 degrees down.
Angle of attack sensors compare the angle of the wings to the direction of the plane, to establish the orientation of the plane in the sky. Angle of attack data is what triggers the MCAS system on a 737 Max — the faulty system which led to the crash.
This video explains the measurement:
Boeing has been criticised for how the Max design relied on information from only one angle of attack sensor, meaning that a single faulty reading could trigger MCAS.
6.23 a.m, 0 seconds: The plane warns of low speed. There are still contradictory readings of how fast it is actually going.
The controller said the ground speed of the aircraft, shown on the radar display, was 322 knots.
But the black box showed the captain’s flight display indicated the speed was 306 knots, and the first officer’s indicated 318 knots.
6.23 a.m., 4 seconds: The control column stick shaker again warned of a possible stall. The plane warns of both too much speed and not enough speed.
6.23 a.m., 9 seconds: The captain asked the first officer for a memorized checklist of what to do, but gets no reply.
6.23 a.m., 15 seconds: An automatic system on board the plane begins to force its nose down, activating for 11 of the next 17 seconds.
According to the timeline, this is not yet in response to the MCAS system which will ultimately force the plane to crash.
6.23 a.m., 39 seconds: The cockpit voice recorder picks up a sound of pages turning, suggesting the pilots looked at a manual. The captain turned the aircraft nose up.
6.23 a.m., 48 seconds: The first officer gave the warning “flight control low pressure” — which appears to refer to pressure in the hydraulic systems that control the plane. Separately, an altitude warning sounds.
6.24 a.m., 5 seconds: The captain again asked for a checklist of what to do when the plane’s airspeed recorders can’t be relied on, but the first officer said he could not find it. The cockpit voice recorder again picked up the sound of pages turning.
6.24 a.m., 52 seconds: The plane’s flaps changed position, though the cockpit voice recorder did not any note any discussion about changing them. The controller gave instructions to change the plane’s direction and altitude. The captain turned the plane’s nose up.
6.25 a.m., 11 seconds: The plane’s flaps changed position, again without discussion between the pilots.
6.25 a.m., 27 seconds: The plane’s MCAS system begins to activate. In six and a half minutes time it will have crashed the plane. First. it pushes the nose down for two seconds. The captain interrupted it, pushing the nose up for six seconds.
MCAS and its failings are now well-known in the aviation world. But many 737 Max pilots say they had no idea it even existed until after the crashes. It probably took the two Lion Air pilots totally by surprise.
MCAS was meant to stop the 737 Max from stalling, counteracting a tendency for the nose to drift upwards by forcing it back down.
Boeing did not mention the MCAS system – what it is or how to manage any malfunctions – in the flight manual for pilots.
6.25 a.m., 40 seconds: MCAS activated six times in the next two minutes, pushing the plane’s nose down until the captain interrupted it.
6.27 a.m., 3 seconds: The controller told the plane to change direction to avoid traffic in the air. The first officer, still reading the checklist for how to deal with bad airspeed readings, did not respond until the third time.
The cockpit voice recorder showed that the pilots frantically read through the manual for a solution as the plane went out of control.