Addis Ababa- As we wait for the preliminary report to be released today by the Ethiopian authorities, some sources who are familiar with the investigation process said that a bird or a foreign object damaged AOA (Angle of Attack) sensor of the Ethiopian MAX 8 during takeoff.
Details are coming...
Ethiopia’s transportation minister said the plane appeared “very normal” on takeoff then suffered “repetitive uncommanded nose-down.”
“The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft.”
“Since repetitive uncommanded aircraft nose down conditions are noticed, it is recommend that the aircraft control system shall be reviewed by the manufacturer.”
Boeing said it would study the report.
The preliminary report does not conclude a probable cause. A final report would take around a year to prepare.
The similarities between the two recent crashes such as erratic airspeed and altitude fluctuations are confirmed.
As in the Lion Air accident, the left AOA sensor that triggered the Maneuvering Characteristics Augmentation System (MCAS), produced incorrect Angle of Attack data that differed from the right sensoe by about 20 degrees.
Pilots diagnosed the problem correctly and disabled the MCAS system about three minutes before the crash. They then tried to manually crunk the trim, but found it impossible.
Automatic aircraft nose down (AND) trim command was activated repeatedly (four times) by the anti-stall system (MCAS).
The speed of the aircraft was 500 knots when it hit the ground.