Ethiopian crash report highlights sensors, software, leaves questions

Minnie Murray
April 6, 2019

Boeing plans to cut its monthly 737 aircraft production by almost 20 per cent as it works to manage the grounding of its MAX aircraft in the wake of two deadly crashes, CEO Dennis Muilenburg has said.

The preliminary findings released on Thursday by transportation authorities in Addis Ababa put the American aircraft giant under even greater pressure to restore public trust, with almost 350 people dead in crashes involving its formerly top-selling 737 Max aircraft in less than five months amid mounting signs the company's onboard anti-stall systems were fault. It also noted that the accident is still being investigated. Boeing's procedures instruct pilots to leave the MCAS disconnected and continue flying manually for the rest of the flight.

Boeing is working to develop a software fix that will get the 371 grounded 737 Max jets back in the air.

"These guys are executing the check list", Dennis Tajer, a spokesman for the American Airlines pilot union, said of the Ethiopian pilots after reviewing the report.

Investigations indicated the Ethiopian pilot had called on the first officer to pull up the plane's nose which together they tried to raise up but failed.

A preliminary report on the Ethiopian Airlines crash released on Thursday did not directly blame the MCAS, but did speak of the plane's constant and uncontrollable nose-diving, which could have been caused by the software if it were fed false data from a damaged sensor. Aviation authorities should verify that the issues have been adequately addressed "before the release of the aircraft to operations", she said.

The airline said on Thursday that the investigation team found that the pilots who were commanding Flight ET 302 had followed Boeing recommendations and the United States Federal Aviation Administration's approved procedures to handle the most hard emergency situation created on the airplane.


The crash in Ethiopia resulted in the worldwide grounding of the 737 Max, the revamped version of a plane model that accounts for a third of Boeing's operating profit. Pilots of each plane struggled in vain to regain control over the automated system. High speed also made it impossible to recover in the final seconds when the plane's nose pointed downward into their final, high-speed dive.

The 737's air data computer also uses angle-of-attack (AOA) information to adjust airspeed readings.

The accident came only five months after another 737 Max crashed.

This update, along with the associated training and additional educational materials that pilots want in the wake of these accidents, will eliminate the possibility of unintended MCAS activation and prevent an MCAS-related accident from ever happening again.

What did the pilot's father say?

Data from the FDR along with recordings from the cockpit seemingly confirm that the Ethiopian pilots followed Boeing's procedures on how to defeat an erroneously triggered MCAS.

The 29-year-old captain had more than 8000 flight hours overall, including more than 1400 on older 737s, the report said.

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