From FAA safety.gov
Line Safety Audits completed by the airlines revealed 23% of errors and 38% of the threats occur before ever leaving the ground. A crucial part of the flight process is pre-flight planning. Accident analysis reveals that preflight planning is often inadequate or entirely ignored. An important part of this flight process is the obtainment of information for your departure, arrival, AND alternate airports. This should include utilizing a current Airport Facility Directory, obtaining current NOTAMs, AND having a current Airport Diagram.