Investigators are still putting together the pieces, but from what we know so far, it's likely that 27-year-old German co-pilot Andreas Lubitz committed mass murder-suicide when he flew a Germanwings passenger jet carrying 149 passengers and fellow crewmen into the French Alps.
Authorities say they haven't found a suicide note, but it's a safe bet that Lubitz's final act was prompted by depression (they found the meds), diminished vision, a deteriorating romantic relationship and his worry that the Lufthansa subsidiary would ground him if they found out about his problems, crashing a career he loved and blowing up his livelihood.
Though rare, pilot suicide isn't unheard of. As long as the current system remains in place, it will happen again.