B757 FLC CROSSED RWY HOLD SHORT LINES AT STL DURING TAXI IN DUE TO RESPONDING TO ANOTHER ACFT'S SIMILAR SOUNDING CALL SIGN.

Narrative

A B757 CROSSED THE HOLD SHORT LINES ON RWY 12R WITH AN ACFT Z ON SHORT FINAL; RESULTING IN A GAR. ACFT X MISTAKENLY TOOK A CLRNC FOR ACFT Y TO TAXI TO THE GATE. THIS IS PART OF AN OVERLYING PROB THAT HAS ARISEN AT STL. THERE HAVE BEEN NUMEROUS OCCASIONS LIKE THE AFOREMENTIONED. FORTUNATELY; THEY HAVE NOT RESULTED IN RWY INCURSIONS. ACR HAS IMPLEMENTED NEW 4 DIGIT; SIMILAR SOUNDING CALL SIGNS AND OTHER PROCS THAT HAVE EITHER CREATED DISTRS OR HAVE PLTS CONFUSED BECAUSE THE RESULT HAS BEEN TO CREATE SITS LIKE THE RWY INCURSION. THERE HAVE BEEN AN INCREASED NUMBER OF READBACK ERRORS AND JUST AN OVERALL CONFUSION ON THE ARPT. IN MY OPINION; THIS ARPT HAS BECOME VERY UNSAFE AND IS AN ACCIDENT WAITING TO HAPPEN IF SOMEBODY DOES NOT GET CTL OF ACR CALL SIGNS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THERE HAVE BEEN NUMEROUS FLC READBACK AND REPLY TO WRONG ACFT CALL SIGN INCIDENTS OVER A 10 MONTH PERIOD. THERE WERE 8 INCIDENTS IN ONLY 1 HR DURING A RECENT VISIT BY AN FAA HEADQUARTERS OBSERVER. THIS AND OTHER INCIDENTS HAVE BEEN RECORDED AS PLT DEV FOR INVESTIGATION BY THEIR FACILITY AND FAA FLT STANDARDS. THESE INCIDENTS HAVE BEEN BROUGHT TO THE ATTN OF THE AIRLINE; BUT NO RESOLUTION HAS BEEN ESTABLISHED TO DATE.