The cause of a plane crash that killed 4 people in June of this year at the Oakland County International Airport is still a mystery. 

Federal investigators say they've found no major mechanical problems with the single-engine Cessna 172 that crashed shortly after takeoff killing the pilot and three members of a family.    The pilot was a 19 year old Michigan man who had just earned his private license to fly a month earlier.  Troy Brothers had contacted the tower claiming he was a 'little overweight' and needed to land.  That was moments before the aircraft slammed into the ground killing all on board.