Addis Ababa - The new insights from the investigation of the Ethiopian 737 MAX 8 crash could cause considerable problems for Boeing.
According to the Wall Street Journal, the pilots of the crashed Ethiopian 737 MAX 8 acted exactly according to the emergency procedures written on the checklists and then deviated from them.
After another fatal crash in Jakarta, Indonesia in October, Boeing had published guidelines for the 737 MAX jets on how to disable the automated anti-stall system known as MCAS (Maneuvering Characteristics Augmentation System).
The second crash of the same type in Ethiopia killing all 157 people on board led to a global flight ban for the Boeing's 737 MAX series jets and raised questions about the certification process of the aircraft.
According to a source who spoke to the Wall Street Journal, the pilots had initially turned off a switch powering the trimmer that is used to tune the horizontal stabilizer as it was pushing the nose of the airplane down.
The pilots then used a manual crank to stabilize the aircraft, but decided to turn on the electric trim in short because the manual attempt did not generate the desired results.
Last week, a Boeing 737 pilot told Reuters that it wasn't easy to make large trim changes to correct the position of the aircraft with a manual wheel.
The manual trim wheel is generally used to make small adjustments in the horizontal stabilizer.
Boeing declined to comment on the issue when asked by Reuters news agency.
“We are not commenting on an active accident investigation per international protocols,” a Boeing spokesman said.
The manufacturer was expected to submit the software updates to the FAA last week for review, but the agency said the manufacturer delayed the submission as it requires additional work.
According to the report, the pilots of the Ethiopian Flight 302 had to turn on the switch again, which powers the trimmer, but this action also reactivated the automated anti-stall system and caused the plane to continue to receive strong downward commands from the MCAS.
A preliminary report is due within 30 days from the date the accident occurred according to international rules.