A British Airways captain was forced to grab the controls of a stalling passenger jet 4,000 feet over London, narrowly averting disaster. The co-pilot tried to solve the issue but failed, forcing the captain to physically step in, a scenario that’s been reported as virtually unheard of in the aviation sector. Sources said the incident was the U.K.’s “most serious near miss” in years. Experts have even warned it could have resulted in a “hull loss”—a jet wrecked beyond saving. The captain has reportedly been placed on “stress leave” over the incident, which is now subject to investigation by U.K. aviation authorities.