A quality control lapse at Boeing discovered in December has proved less significant than it at first appeared. Airlines worldwide have inspected the rudders on the more than 1,400 Boeing 737 MAX aircraft in service globally for loose bolts and found no faults. After an international airline discovered a rudder bolt with a missing nut while performing routine maintenance in December, Boeing inspected the MAXs it had under assembly and found one other instance of a loose rudder bolt on an undelivered jet. Though the fault was not considered an immediate safety concern, on Dec. 27 Boeing then re…