The series is a result of a two month review of federal air safety documents in the Aviation Safety Reporting System or ASRS. The documents are part of a system that is little known outside of aviation circles. It allows anyone involved in flying to anonymously and confidentially report incidents, accidents or problems they witness or are involved in. We reviewed 2000 such reports on Pittsburgh International Airport, dating back to 1988. The review revealed many incidents and even accidents that the public never heard about. The investigation also uncovered a pattern of problems with runway and taxiway signs at the airport that have led to near miss incidents on the ground. The investigation also revealed an alarming number of accidents between planes and ground vehicles in the terminal parking area.