NEW : Resigned and tried to improve safety record of FAA . The FAA is looking for a new chief of air traffic control . The FAA is trying to reduce ` ` unprofessional conduct '' The FAA is placing an extra overnight shift controller at several airports .
NEW : Resigned official tried to improve safety culture of FAA . The FAA is looking for a new chief of air traffic control . The agency is trying to correct `` unprofessional conduct '' The FAA is placing an extra overnight shift controller at several locations .