WASHINGTON (Reuters) - The U.S. National Transportation Safety Board on Monday said more than 40 foreign operators of Boeing 737 airplanes may be using planes with rudder components that may pose safety risks.

The NTSB last week issued urgent safety recommendations about the potential for a jammed rudder control system on some Boeing 737 airplanes after a February incident involving a United Airlines flight.

The NTSB also disclosed Monday that it has learned two foreign operators suffered similar incidents in 2019 involving rollout guidance actuators. "We are concerned of the possibility that other airlines are unaware of the presence of these actuators on their 737 airplanes," NTSB Chair Jennifer Homendy said Monday in a letter to FAA Administrator Mike Whitaker.