By Matina Stevis-Gridneff and Yonathan Menkir Kassa
March 29, 2019 12:18 p.m. ET
ADDIS ABABA, Ethiopia—It took less than six minutes to deepen one of the gravest crises in the history of Boeing Co.
At 8:37 a.m. on March 10, Captain Yared Getachew and First Officer Ahmed Nur Mohammed were accelerating an Ethiopian Airlines Boeing 737 MAX along runway 07R of Addis Ababa’s highland airport.
The flight conditions were perfect—warm and cloudless—at 8:38 as the jet lifted above the hills to commence the one hour and 40 minute shuttle to Nairobi.
Something almost immediately went wrong. At 8:39, as the jet reached an altitude of 8,100 feet above sea level, just 450 feet above ground, its nose began to pitch down.
Mr. Mohammed radioed the control tower, his crackling voice reporting a “flight-control problem.” The tower operators asked for details as Mr. Getachew, a veteran with 8,000 flight hours, fought to climb and correct the glide path. By 8:40, the oscillation became a wild bounce, then a dive.
“Pitch up, pitch up!” one pilot said to the other, as the Boeing jet accelerated toward the ground. The radio went dead.
At 8:44, the airliner crashed into a field just 30 miles from the runway. All 157 people on board were killed instantly.
This reconstruction of the final moments of Ethiopian Airlines Flight ET302, described in new detail by people close to the crash investigation, airline executives and pilots, paints a picture of a catastrophic failure that quickly overwhelmed the flight crew.
It appears to support a preliminary conclusion reached by Ethiopian officials. According to people familiar with the matter, investigators believe an automated flight-control feature activated before the plane nose-dived into the ground.
This emerging consensus, the first findings based on data retrieved from the flight’s black boxes, is the strongest indication yet that Boeing’s misfiring system was at the heart of both the Ethiopian Airlines crash earlier this month and a Lion Air flight in Indonesia, which crashed less than five months earlier. Both doomed jets were Boeing 737 MAXs. The two crashes claimed 346 lives. A report from Ethiopian authorities is expected within days.
The Justice Department and other U.S. federal agencies are investigating whether Boeing provided incomplete or misleading information to regulators and airline customers about the 737 MAX aircraft to get the jetliner certified as safe to fly. The focus on disclosures is part of a broader investigation into how the plane was developed and certified.
Pilots flying the 737 MAX around the world were only alerted to the stall-prevention system after the Lion Air crash, and saw almost no mention of it in manuals, according to the pilots and industry officials. Most didn’t have visible cockpit warnings that would have alerted pilots to a malfunctioning sensor, and they had no access to simulators that could replicate the kinds of problems that doomed Lion Air flight 610.
In that crash, the stall-prevention system, based on erroneous sensor information, repeatedly pushed the plane’s nose down and, according to a preliminary report, the pilot battled the flight controls while facing a cacophony of alarms before losing control and plunging into the Java Sea, killing all 189 people on board.
Boeing said it is updating the MCAS software and making safety alerts that had been optional a standard feature. The fix has been undergoing flight trials since Feb. 7, Boeing said, before the Ethiopian airliner crashed.
Ethiopian Airlines—Africa’s largest carrier—is fighting to defend its record. Across this vast nation of 105 million people, the state-owned airline has in recent years become emblematic of, and indispensable to, Ethiopia’s ascent from one of the world’s poorest countries to a regional powerhouse. The closely-linked fates of carrier and country are now under the spotlight, raising the stakes for the airline to effectively manage the fallout of the accident.
Minutes after the plane crashed, Ethiopian Airlines chief executive officer felt a buzz in his pocket. Tewolde Gebremariam was attending Sunday service with his family at the Medhane-Alem Cathedral close to the airport when his phone rang.
It was the number for the airport’s “collaborative decision-making system,” a task force of airline, air-traffic control and airport officials who work together to ensure flight traffic is managed efficiently.
“We’ve lost ET302 from the radar,” the voice on the other end of the line said in Amharic, Ethiopia’s national language.
By the time Mr. Gebremariam reached the airport, it was becoming clear the plane had crashed.
“Right there, immediately,” Mr. Tewolde thought of the Lion Air crash, he said in an interview. “The similarities were very striking. The impact, both were brand-new airplanes, both were MAX, and [they both crashed] in a short time, quickly after takeoff.”
As two air force helicopters prepared to lift off to search for ET302, pilots on the airport runway were getting restless.
Lazarus Kuol was in line for departure, preparing to take off on his single-engine turboprop aircraft on a medevac flight to the southwestern city of Jinka. He was due to collect two Chinese patients and bring them back to Addis Ababa for treatment.
The waiting pilots, listening to the control tower’s shared frequency, heard the operators discuss an emergency and order all aircraft to remain grounded, while two incoming planes were told to delay landing. The tower had lost contact with ET302. Maybe it was a communication problem, Mr. Kuol thought, or maybe they made an emergency landing on the flat farmlands southeast of the capital.
The minutes passed with no word from the missing aircraft or the search-and-rescue mission, and Mr. Kuol began to fear the worst.
He was given clearance to take off at 09.50, the second aircraft to depart Bole International Airport after ET302 went missing, and began to listen to the exchange between two radio frequencies, “Addis Center,” the main control-tower, and “Harar Meda,” the air force base.
“We can’t see it in the lowland,” said one of the two air force helicopter pilots dispatched to search for ET302. “We’ll climb on the highlands to look.”
In fact, the helicopters were circling over the crash site without realizing. The dive had been so fast and so steep that the aircraft had bored a crater into the ground and fractured into thousands of pieces. It was hardly visible from air.
“When I went to the site, the plane was completely below ground,” said Mr. Gebremariam, the CEO. He took off in another helicopter as soon as the crash site had been identified. “At that time, we knew there were no survivors.”
He notified the country’s Prime Minister, Abiy Ahmed, who first tweeted about the crash in Amharic at 10.48am local, just over two hours after the doomed flight had taken off.
At 10.50am, the news broke abruptly into the quiet Sunday mornings of the families of the 157 on board, and the rest of the world.
“The Office of the PM, on behalf of the Government and people of Ethiopia, would like to express [its] deepest condolences to the families of those that have lost their loved ones on Ethiopian Airlines Boeing 737 on regular scheduled flight to Nairobi, Kenya this morning,” a tweet from his official account said.
—Robert Wall, Andy Pasztor and Andrew Tangel contributed to this article.
Write to Matina Stevis at matina.stevis@wsj.com
