But before answering the million-dollar question, exactly how was such an event possible? First, all airline employees are vetted through the application process. Items such as background checks, criminal history, work experience and so forth are involved. Safety and security being the primary goals, it’s in the airline’s best interest to hire accordingly. Although physical and mental fitness is a major part of qualifications for pilots, ground-based service employees are not held to the same rigorous standards. So, moving ahead to the obvious question, unless a background check reveals treatment for mental illness, it would be unlikely that an applicant’s predisposition to temporary insanity would be uncovered.