ADDIS ABABA, Ethiopia — The captain of a doomed Ethiopian Airlines jetliner faced an emergency almost immediately after takeoff 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 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 on Sunday, the person said.