April 4 (UPI) -- Ethiopian authorities said Thursday Boeing must review its aircraft flight control system on the 737 Max 8 before allowing the airliner to fly again.
All Max 8s worldwide were grounded after an Ethiopian Airlines plane crashed last month and another in Indonesia last fall. The pilot of Ethiopian Airlines Flight 302 performed according to Boeing's operations manual but was not able to control the aircraft, Ethiopian Minister of Transport Dagmawit Moges said Thursday.
The plane crashed after take-off March 10 in Addis Ababa, killing all 157 aboard. The accident prompted all governments, including the United States, to ground the new model pending the crash investigations. The flight recorders from the Ethiopian crash are being examined in France.
Investigators said in a preliminary report Thursday they're focused on the airliner's Maneuvering Characteristics Augmentation System, which forces the aircraft into a dive to avoid stalling. The system is triggered by the angle-of-attack sensor, which officials say could've given pilots false readings.
"Since repetitive uncommanded aircraft nose-down conditions were noticed in this preliminary investigation, it is recommended the aircraft flight control system related to flight control ability be reviewed by the manufacturer," Moges said.
She also called on authorities to determine whether the system was reviewed properly before the planes went into service.
Similar problems were found in the Indonesia crash last October under similar circumstances. Nearly 200 people died in that crash.
Ethiopian Airlines said Wednesday its pilots follow the procedures outlined in the manual by Boeing and guidelines from the Federal Aviation Administration to handle emergency situations in flight.
"Despite their hard work and full compliance with the emergency procedures, it was very unfortunate that they could not recover the airplane from the persistence of nose-diving," the carrier said.
Boeing last week submitted a software update for the Max airliners, which is under review by the FAA, NASA and international regulators.