When it comes to safety culture at Boeing, there is a “disconnect” between senior management and workers, and employees responsible for checking the company’s planes question whether they can raise issues without fear of retaliation, according to a panel of outside experts.

The aviation-industry and government experts also said safety training and procedures at Boeing are constantly changing, leading to confusion among employees.

The comments were contained in a report Monday to the Federal Aviation Administration. Congress ordered the study in 2020, when it passed legislation to reform how the FAA certifies new planes after two deadly crashes involving Boeing 737 Max jetliners.

Safety at Boeing is being re-examined after last month’s blowout of an emergency door panel on an Alaska Airlines Max jet. Accident investigators said in a preliminary report that bolts used to help hold the panel in place were missing after the plane underwent repairs at Boeing’s factory in Renton, Washington.