Pilots in Boeing aircraft other than the highly scrutinized 737 Max model have reported issues in recent years, with some reporting the plane rapidly descending mid-flight. According to Bloomberg, pilots of the Next Generation (NG) model have registered concerns on the Aviation Safety Reporting System—reporting instances of losing airspeed on takeoff or experiencing the plane’s nose taking a dip without their command. In October 2018, an NG plane was flying on autopilot when it went sharply to the right and the left before increasing in speed and going downward in direction. The pilots reporting the issue said this was the “fourth write-up of this issue in a few days.” A 737-800 pilot reported descending 400 feet in altitude after attempting to correct losing speed during takeoff, prompting a “don’t sink” warning to go off in the cockpit. In 2017, another 737-800 plane began descending at high speed without the pilot’s command during a landing attempt—with the pilot complaining the plane’s “pitch and path seemed erratic.”

Bloomberg also reports that Airbus had its own share of reported issues in the database. In a statement, a Boeing spokesperson said the “safety of the 737 NG is not in question,” pointing to the plane’s “20-plus years of service and 200 million flight hours.”