The chief executive of Boeing said the company made a “mistake” in handling a problematic cockpit warning system in its 737 Max jets before two crashes killed 346 people and he promised transparency as the aircraft maker works to get the grounded planes back in flight.

Boeing CEO Dennis Muilenburg told reporters ahead of the Paris Air Show that Boeing’s communication with regulators, customers and the public “was not consistent. And that’s unacceptable.”

The U.S. Federal Aviation Administration has faulted Boeing for not telling regulators for more than year that a safety indicator in the cockpit of the top-selling plane didn’t work as intended.

Pilots also have expressed anger that Boeing did not inform them about the new software that’s been implicated in the crashes in Indonesia and Ethiopia.

“We clearly had a mistake in the implementation of the alert,” Muilenburg said.

He expressed confidence that the Boeing 737 Max would be cleared to fly again later this year. The model has been grounded worldwide for three months, and regulators need to approve Boeing’s long-awaited fix to the software.

Muilenburg called the crashes of the Lion Air and Ethiopian Airlines jets a “defining moment” for Boeing, but said he thinks the result will be a “better and stronger company.”

Sensors malfunctioned

Speaking aheas of the industry-wide show, Muilenburg said Boeing is facing the event with “humility” and focused on rebuilding trust.

In the United States, Boeing has faced scrutiny from members of Congress and the FAA over how it reported the problem involving a cockpit warning light.

Rescuers work at the scene of an Ethiopian Airlines flight crash near Bishoftu, Ethiopia, on March 11. (Mulugeta Ayene/Associated Press)

The company discovered in 2017 that a warning light designed to alert pilots when sensors measuring the angle of a plane’s nose might be wrong only worked if airlines had purchased a separate feature.

The angle-measuring sensors have been implicated in the Lion Air crash in Indonesia and the Ethiopian Airlines crash in March. The sensors malfunctioned, alerting software to push the noses of the planes down. The pilots were unable to take back control of the planes.

Boeing told the FAA of what it learned in 2017 after the Indonesia crash in October. Boeing and the FAA have said the warning light wasn’t critical for flight safety.

Muilenburg forecast a limited number of orders at the Paris show, the first major air show since the crashes, but said it was important to attend to talk to customers and others in the industry.

He also announced that Boeing is raising its long-term forecast for global plane demand, notably amid sustained growth in Asia.