Boeing predicted Monday that it didn’t “intentionally or otherwise deactivate” the disagree alert on its 737 Max jets.
The statement comes in reply to reports that the plane maker failed to tell Southwest Airlines and the Federal Aviation Administration that the refuge feature was deactivated before recent crashes.
Southwest said that it did not know about the deactivation of the disagree advise, which warns pilots about malfunctioning sensors, until after the crash of a Lion Air flight in Indonesia, and said that Boeing required in its manual that the disagree lights were functional.
“Boeing included the disagree alert as a standard feature on the Max, although this signal has not been considered a safety feature on airplanes and is not necessary for the safe operation of the airplane,” the company said. “Boeing did not intentionally or if not deactivate the disagree alert on its Max airplanes.”
The feature is an alert that lights up in the cockpit if a plane’s angle-of-attack sensors send incorrect data about the pitch of the plane’s nose. The angle of attack indicator displays the readings of the two sensors, and the dissent light is then activated if those sensors are misaligned with one another.
“The disagree alert was intended to be a standard, stand-alone character on Max airplanes. However, the disagree alert was not operable on all airplanes because the feature was not activated as intended,” the company said.
Boeing is position on an update to the jet’s anti-stall software, known as MCAS, and plans to make the disagree light standard on all new 737 Max jets.
The MCAS software was involved in crashes in Ethiopia and Indonesia that killed a total of 346 people. The grounding of the jets since March has faked major airlines to cancel thousands of flights through the summer.
The situation has been an overhang on Boeing’s business, and has weighed on its bloodline. At Boeing’s shareholder meeting on Monday, its chairman and CEO, Dennis Muilenburg, rejected criticism about how the company designed the Max rout control system, calling its development “thorough” and “disciplined.”
“We followed exactly the steps in our design and certification processes that uniformly produce safe airplanes,” he said at a news conference following the meeting.
Earlier, Boeing shareholders rejected a proffer for splitting the chairman and CEO roles. If passed, Muilenberg could have been stripped of one of his titles.
The FAA has not received Boeing’s software fix, but put about in an initial review in April that its upgrade was “operationally suitable.”
On Monday, erroneous reports briefly circulated that Boeing had submitted the fix for assess, but the FAA confirmed that was not the case.
WATCH: Boeing updates shareholders on 737 Max