NTSB’s warning follows the investigation of a February incident involving a United Airlines flight, where a jammed rudder control system nearly resulted in a catastrophic situation

The National Transportation Safety Board issued urgent safety recommendations to Boeing over a steering defect related to its 737 planes, adding its growing list of woes.

The National Transportation Safety Board is issuing “urgent safety recommendations” for some Boeing 737s—including the embattled 737 MAX line— warning that critical flight controls could jam.