Safety investigators on Thursday issued “urgent” recommendations to Boeing and the Federal Aviation Administration over a potential problem on some of the aircraft manufacturer’s 737 Max jets. The National Transportation Safety Board found that pedals that pilots use to steer the aircraft on runways can get stuck when moisture leaks into a rudder system and freezes. The recommendations followed an investigation launched after a United Airlines pilot reported in February that the rudder pedals on their 737 Max 8 were jammed in a neutral position as the plane traveled down the runway following landing at Newark Liberty International Airport in New Jersey. The captain was forced to use the tiller—a cockpit handle that turns the wheel below the aircraft’s nose—and the plane veered on to a high-speed turnoff. No injuries were reported during that incident, in which 155 passengers and six crew were on board. According to the FAA, United is the only airline that is affected by the new recommendations, and the parts at risk of the jamming problem are no longer in use.