On March 10, 2019, at 08:38, Ethiopian Airlines’ Flight 302 took off from Addis Ababa’s Bole International Airport bound for Jomo Kenyatta International Airport, Nairobi.
On board were 157 people including the two pilots, Captain Yared Getachew, 29, and First Officer Ahmednur Mohammed Omar, 29.
The Boeing 737-8 Max, also had five cabin crew and one In-Flight Security Officer.
At 08:36:12 the airplane lined up on the runway and a minute later, Mr Omar reported to tower that they were ready for take off and the Air Traffic Control issued take off clearance. The pilots were then advised to contact radar.
Shortly after lift off, the left Angle of Attack (AoA), a sensor that helps to avoid an aerodynamic stall, became erroneous.
The plane’s airspeed and altitude values from the left air data system began deviating from the corresponding right side values.
Faulty sensor At 08:39:30, the radar controller identified ET-302 and instructed it to climb 34,000 feet. At 8:39:51, the first faulty sensor activated, putting the plane on nose-down for nine seconds.
The pilot pulled to pitch up the airplane. At 8:40:22, the second automatic nose-down trim activated, pushing the plane, again, on a nosediving position.
This saw the plane’s ground proximity warning system sound “Don’t Sink!” For three seconds and “Pull Up!” Also displayed on its flight display for another three seconds.
At 08:40:43, the third nosedown sensor activated pushing the nose downwards.
Seven seconds later, Captain Getachew told the first officer “advise, we would like to maintain one four thousand. We have flight control problem.”
Mr Omar complied and the request was approved by air traffic control. Following the approval, the new target altitude of 14, 000 feet was set but the captain was unable to maintain the flight path and requested to return back to Bole airport.
At 08:43:21, the nose-down trim activated for about 5 seconds. This now saw the plane pitch at a 400 angle.
At this point the plane’s descent rate increased from 100 feet per minute to more than 5,000 feet per minute Warning At 08:43:36 the enhanced ground proximity warning system (sounded “Terrain … Terrain … Pull Up … Pull up …!” At 08:44, the aircraft hit the ground.
These details are part of a 130-page interim report released by the Ethiopian Aircraft Accident Investigation Bureau. They were released yesterday on the one-year anniversary of the crash, giving for the first time an inside look of what could have happened to Flight 302.
The report shows the aircraft plummeted to the ground at speeds of 500 feet per second, with its nose down at 400.
“At the end of the flight, computed airspeed values reached 926km/hr. Pitch values were greater than 400 nose down and descent rate values were greater than 33,000 feet per minute,” the report said.
“The aircraft impacted the terrain creating a crater approximately 10m deep, with a hole of about 28m width and 40m length. The damages to the aircraft are consistent with high energy impact,” added the report.
In their findings, the Ethiopian investigators have singled out faulty systems on Boeing 737 MAX as the leading cause of the crash, concentrating on the technical elements of the flight.
By Allan Olingo