The Aviation Safety Reporting System (ASRS) was searched to determine errors associated with the use of the party line (PL). Pilots occasionally misinterpret and/or receive inaccurate PL information; based on this information, they make incorrect and potentially dangerous decisions. Detailed analysis revealed two types of errors: those attributed to inaccurate PL information and those resulting from incorrect flightcrew actions based on the PL. Almost half the errors involving incorrect flightcrew actions were a result of executing unauthorized clearances because of confusion caused by similar call signs. Conclusions are drawn with respect to the loss of the PL in a data link environment.