Six minutes after takeoff on Sunday morning, Ethiopian Airlines Flight ET302 crashed just outside Addis Ababa.
None of the 157 passengers and crew on board survived, authorities said. People from at least 35 countries are among the dead, including 18 Canadians.
The Nairobi-bound Boeing 737 MAX 8 aircraft left Bole International Airport at 8:38 a.m. and lost contact with the control tower at 8:44 a.m.
It crashed near the town of Bishoftu in what reports have described as clear conditions.
According to the Twitter account of flight-tracking website Flightradar24, the plane experienced unstable vertical speed after takeoff.
Ethiopian Airlines chief executive Tewolde GebreMariam said at a news conference that the aircraft had no recorded technical problems and the pilot had an “excellent” record.
“We received the airplane on Nov. 15, 2018. It has flown more than 1,200 hours,” he said.
WATCH: Ethiopian Airlines CEO says pilot mentioned having ‘difficulty’ and wanted to return
Prior to the crash, “the pilot mentioned that he had difficulties and that he wanted to return,” he said.
It’s not yet known what caused the plane to crash — and there may not be definitive answers for a long time.
Aviation expert Jock Williams, a retired Canadian Air Force fighter pilot and Transport Canada flight safety official, said that it could be a year before a final report is available.
“Because the agencies that do these accident reports, they don’t want to make a mistake,” he explained. “If they make a mistake, it can cost lives in the hundreds or thousands, potentially. It can also cost millions or billions of dollars so they have to get it exactly right, and that’s why it takes them so long to formulate their impression of what happened.”
WATCH: Ethiopian Airlines CEO says a pilot of crashed flight had more than 200 flight hours, plane is new
Williams said, however, that the circumstances appear to be “virtually identical” to the Lion Air disaster in October, in which the same aircraft model crashed shortly after takeoff in Indonesia, killing all on board.
“It appears that the flight crew must have said to the air traffic control authorities over the radio that they were having difficulty with either speed control or aircraft attitude control, both of which are related to an automatic trim system, which I think is unique right now to the 737-800,” he said.
The Indonesia National Transportation Safety Committee determined that Lion Air Flight 610 had experienced “erroneous input from one of its Angle of Attack (AOA) sensors,” which help to see that air flows over a plane’s wings.
In response, Boeing directed operators to “existing flight crew procedures,” where they found “erroneous input from an AOA sensor.”
However, Indonesia’s transportation safety committee also found that the Boeing 737 MAX 8 that crashed wasn’t in airworthy condition, a preliminary report found. The final report has not yet been released.
Arthur Rosenberg, an aviation expert and lawyer, said he believes the two crashes likely involve the same system on the airplane.
WATCH: Officials survey wreckage of Ethiopian Airlines plane crash
“Based on that photograph, that impact crater that I saw, this plane pretty much just came straight down,” he told The Canadian Press. “It looks like this crew didn’t really have much time to respond.”
Another aviation analyst, Scott Hamilton of Leeham News, said in a post he cautions against comparing the two crashes, especially since the black box flight data recorders have not been yet recovered.
“It should be noted that Ethiopian is considered one of the best airlines in the world and the best in Africa. It’s got a good safety record, and service is considered very good. This is in contrast to the spotty safety record of Lion Air,” Hamilton said.
The MAX 8, released in 2017, is Boeing’s latest version of the 737, one of world’s most successful planes.
“There’s more 737s flying than any other commercial jet airliner,” Williams said.
In a statement, Boeing said it would be sending a technical team to the crash site in Ethiopia to provide technical assistance under the direction of the Ethiopia Accident Investigation Bureau and the U.S. National Transportation Safety Board.
—With files from Jesse Ferreras, Global News, The Canadian Press, Reuters and the Associated Press