Dennis Muilenburg, CEO of Boeing, arrives to testify during the Senate Commerce, Science and Transportation Committee hearing in Hart Building on aviation safety and the future of the Boeing 737 MAX on Tuesday, October 29, 2019.
Tom Williams | CQ-Roll Call, Inc. | Getty Images
A Boeing engineer was concerned that the troubled 737 Max, years before it came to market, had a flight-control system that lacked sufficient safeguards, according to a document released Wednesday during a House questioning of the manufacturer’s CEO following two fatal crashes of the jetliners.
In 2015, more than a year before the planes were certified by federal regulators, a Boeing engineer asked whether a flight-control system that was involved in both deadly crashes, was safe because it relied on a single sensor.
Regulators around the world banned airlines from flying the planes after the crashes. Boeing has changed the planes’ system so that they rely on two sensors instead of one. But regulators have not yet signed off on that and other changes Boeing has made to the planes, leaving them grounded for nearly eight months, which has crimped airline profits. Boeing shares were down about 1% in late-morning trading.
The sensors, which measure the angle of attack, or angle of the plane relative to oncoming air, feed an anti-stall system on the 737 Max. Erroneous data from a sensor triggered the system, known as MCAS, during the two crashes — one in Indonesia in October 2018 followed by another in Ethiopia in March.
“Are we vulnerable to single AOA sensor sensor failures with the MCAS implementation or is there some checking that occurs?” asked the engineer in the December 2015 email. The Federal Aviation Administration approved the planes in 2017 and they are Boeing’s bestseller.
The email was obtained in an investigation of the planes by the House Committee on Transportation and Infrastructure, was released during the hearing, the second of two days of testimony by Boeing’s CEO Dennis Muilenburg on Capitol Hill this week.
“We made some mistakes,” said Muilenburg. “We own that. We’re responsible for our airplanes.”
The crashes killed all 346 people on the two flights.
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