A NASA official says some of the U.S. space shuttles flew for 25 years with flaws in the rudders of the tail section, the New York Times reported Tuesday.

Shuttle Program Manager William Parsons said some gears in the two-part rudder, which also acts as a speed brake, were apparently installed improperly in at least one shuttle when they were built in the late 1970s and early 1980s.

The shuttle Discovery flew 28 missions with a flawed speed brake actuator, but experienced no failure, he said.

“Loss of the rudder speed brake would mean loss of the vehicle, loss of the crew,” he said.

The rudder speed brake is used to guide and slow the shuttle during its high-speed re-entry and landing.

Parsons said the speed brake actuators on the other remaining shuttles, the Atlantis and the Endeavour, would be removed, inspected and replaced because of suspected problems, including unexpected corrosion found on some of the parts.