The deadly crash in Ethiopia comes just about five months after the October 29 crash of another Boeing 737 Max plane, operated by Indonesia's Lion Air. The official spoke on condition of anonymity because Boeing's conversations with airline officials were not meant to be made public.
The families of the victims of Ethiopian Airlines Flight 302, have journeyed to the site of Sunday's fatal accident, joining each other in making the site a sacred place of grieving. "They didn't expect the Ethiopians to lose their jet while all this was going on", said Alan Diehl, a former investigator for the National Transportation Safety Board.
A voice from the cockpit of the Boeing 737 MAX asked to climb to 14,000 feet above sea level - 6,400 feet above the airport - but vanished from radar at 10,800 feet after starting a right turn home due to what the pilot described as a flight control problem, the source said on condition of anonymity because the recording is part of an ongoing investigation.
An airline spokesman has said the pilot was given permission to return.
As families wait for the results from the investigation, Ethiopian Airlines is planning to hold a service on Sunday in Addis Ababa, at the Kidist Selassie, or Holy Trinity Cathedral, where numerous country's past rulers are buried beneath its pink stone spires.
The U.S. planemaker has been working on a software upgrade for an anti-stall system and pilot displays on its fastest-selling jetliner in the wake of the deadly Lion Air crash. During that time, the pilot reported a flight control problem.
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Regulators have grounded the 737 MAX around the world, and the U.S. planemaker has halted deliveries of the several thousand planes on order for a model meant to be the future industry workhorse.
Boeing already faces lawsuits over the Lion Air crash, and lawyers say the second crash strengthens their argument that Boeing knew the plane was defective and let it fly anyway.
Norwegian Air CEO Bjorn Kjos has said his airline will seek compensation from Boeing.
For airlines that over-ordered the 737 MAX, the grounding could provide an excuse to delay or cancel purchases, analysts said, though others are scrambling to adjust business plans that bet heavily on the fuel-efficient, longer-range jets.
Southwest and American are the two largest domestic owners of 737 Max 8 and 9 jets, although they make up less than 5 percent of Southwest's fleet and less than 3 percent for American. The airline said in a securities filing Friday that the financial and operational impact of the grounding will increase if it lasts into the peak summer travel season.
The Max 8 crashes in Ethiopia and Indonesia killed 346 people. "The next steps will take some time", he said.