Black boxes show “similarities” between 737 MAX crashes

March 18, 2019
Boeing Ethiopian 737 MAX
Image: CNBC

Ethiopia’s Transport Minister has revealed preliminary data from the black boxes recovered from Ethiopian Airlines Flight 302 indicate there are “similarities” to October’s Lion Air crash of a Boeing 737 MAX 8.

Minister Dagmawit Moges said French investigators had recovered all relevant data from the flight data recorder and cockpit voice recorder but did not go into detail about what the information revealed.

She said the similarities would be further investigated and more information revealed when Ethiopian investigators issue a preliminary report.

Her comments were echoed by French investigators, who told Reuters that there were similarities in the angle of attack seen on the two aircraft.

By international convention, that should come within 30 days of the crash and is generally a factual report rather than a detailed analysis.

READ: Pilot training, skill levels and automation come under intense scrutiny.

Boeing 737 MAX aircraft have been grounded worldwide amid growing public fears about the safety of the aircraft and pending modifications to flight control software and new information from the Ethiopian investigation.

Boeing chief executive Dennis Muilenburg issued a statement after the Minister’s comments saying the US aerospace giant continued to support the investigation and was working with authorities to evaluate new information as it became available.

Boeing is already working on changing pilots displays, operations manuals and crew training related to controversial software added to the 737 MAX.

The Maneuvering Characteristics Augmentation System (MCAS) is also being updated to allow access to more than one angle of attack sensor input, limit stabilizer trim commands when the software receives an erroneous angle of attack reading and provide a limit to the stabilizer command to allow pilots to retain elevator authority.

The enhancements are due to be delivered no later than next month.

“Safety is our highest priority as we design, build and support our airplanes,’’ Muilenberg said.

“As part of our standard practice following any accident, we examine our aircraft design and operation, and when appropriate, institute product updates to further improve safety.

“While investigators continue to work to establish definitive conclusions, Boeing is finalizing its development of a previously-announced software update and pilot training revision that will address the MCAS flight control law’s behavior in response to erroneous sensor inputs.

“We also continue to provide technical assistance at the request of and under the direction of the National Transportation Safety Board, the U.S. Accredited Representative working with Ethiopian investigators.”

Muilenburg said all inquiries about the ongoing accident investigation must be directed to investigating authorities.

Meanwhile, The Seattle Times reported Sunday that the US Federal Aviation Administration delegated much of the safety assessment during the 737 MAX’s certification process to Boeing and that it contained crucial flaws.

Based on interviews with current and former engineers involved in the evaluations, the newspaper said the safety analysis understated the power of the new flight control system and failed to account for how it might reset itself each time a pilot responded.

It said that when the planes entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document and the evaluation missed the potential impact of the system repeatedly pushing the aircraft’s nose down.