ADDIS ABABA • The captain of a doomed Ethiopian Airlines jetliner faced an emergency almost immediately after take-off from Addis Ababa, requesting permission in a panicky voice to return after three minutes as the aircraft accelerated to abnormal speed, a person who reviewed air traffic communications said on Thursday.
"Break break, request back to home," the captain told air traffic controllers as they scrambled to divert two other flights approaching the airport. "Request vector for landing."
Controllers also observed that the aircraft, a new Boeing 737 Max 8, was oscillating up and down by hundreds of feet - a sign that something was extraordinarily wrong.
All contact between air controllers and the aircraft, Ethiopian Airlines Flight 302 to Nairobi, was lost five minutes after it took off Sunday, the person said.
The person who shared the information, speaking on the condition of anonymity because the communications have not been publicly released, said the controllers had concluded even before the captain's message that he had an emergency.
The account of the cockpit communications shed chilling new detail about the final minutes before the plane crashed, killing all 157 people aboard. The crash, which has led to a worldwide grounding of Max 8s, was the second for the best-selling Boeing aircraft in less than five months.
Break break, request back to home.
MR YARED GETACHEW, captain of Ethiopian Airlines Flight 302, as heard on the black box recording three minutes into the flight.
The regulatory authorities in the United States and Canada say similar patterns in the trajectories of both planes may point to a common cause for the two crashes. But they cautioned that no explanation had been ruled out yet, and said the planes might have crashed for different reasons.
The new disclosures about the last moments of Flight 302 came as pilots were discussing what they described as the dangerously high speed of the aircraft after it took off from Addis Ababa's Bole International Airport.
Pilots were abuzz over publicly available radar data that showed that the aircraft had accelerated far beyond what is considered standard practice for reasons that remain unclear.
"The thing that is most abnormal is the speed," said Mr John Cox, an aviation safety consultant and former 737 pilot.
"The speed is very high," said Mr Cox, a former executive air safety chairman of the Air Line Pilots Association in the United States. "The question is why. The plane accelerated far faster than it should."
Ethiopian Airlines officials have said the crew of Flight 302 reported "flight control" problems to air traffic controllers a few minutes before contact was lost.