B737-300 PUSHBACK HAD STARTED BOTH ENGS AND WAS ANTICIPATING WAVE OFF. FO WAS PROGRAMMING FMC WITH ACARS INFO WHEN CAPT ADVISED READY TO TAXI. GND CTL CLRED FLT TO TAXI AND CAPT ADDED PWR. CGP ADVISED NOSE GEAR RAN OVER TOW BAR. CAPT HAD NOT RECEIVED ALL CLR SALUTE.

Narrative

PUSHBACK WAS BEING ACCOMPLISHED FROM GATE IN CLE. CAPT WAS COMMUNICATING WITH GND CREW THROUGH INTERPHONE. I WAS COORDINATING COMS WITH GND CTL ON #1 VHF RADIO. NORMAL ENG START PROC OF #2 AND #1 ENGS WAS ACCOMPLISHED DURING PUSHBACK. PRIOR TO AFTER START CHKLIST; WE RECEIVED WT & BAL INFO VIA ACARS WHICH I PROCEEDED TO LOAD INTO FMC. WE WERE ANTICIPATING A SHORT TAXI AND WANTED TO ACCOMPLISH AS MUCH AS WE COULD PRIOR TO TAXI OUT. I WAS NOT MONITORING THE PUSHBACK OVER THE INTERPHONE SO AS TO KEEP CLR COMS WITH CLE GND CTLR. CAPT CALLED FOR THE AFTER START CHKLIST WHICH WE READ AND COMPLETED. CAPT STATED WE WERE READY TO TAXI; AT WHICH TIME I REQUESTED SUCH FROM GND CTL. WE WERE CLRED TO TAXI. I VISUALLY CHKED FORWARD AND R AND RESPONDED; 'CLR R.' AS CAPT APPLIED TAXI PWR; WE RECEIVED SEVERAL QUICK BELL SIGNALS THROUGH THE INTERPHONE AND OBSERVED THE BLUE CALL BELL COCKPIT ANNUNCIATOR. I SWITCHED TO SVC INTERPHONE TO COMMUNICATE WITH THE FLT ATTENDANTS; WHO I ASSUMED WERE CALLING US. I RECEIVED NO RESPONSE. THE BELLS CONTINUED AND THEN REALIZED THE SIGNAL WAS COMING FROM THE GND PUSHBACK CREW. THE CAPT IMMEDIATELY STOPPED THE ACFT. WE WERE INFORMED THAT THE ACFT HAD TAXIED OVER THE DISCONNECTED TOW BAR. CAPT HAD NOT RECEIVED A WAVE OFF SIGNAL FROM PUSHBACK CREW. BY THE TIME I WAS BACK IN THE LOOP; I DID NOT QUESTION WHETHER OR NOT WE HAD BEEN CLRED TO TAXI FROM GND CREW AS THE CAPT HAD CALLED FOR THE AFTER START CHKLIST AND TAXI. NO WAVE OFF WAS RECEIVED BY CAPT. FO WAS PROGRAMMING FMC AND MONITORING GND CTL; PLACING HIM OUT OF THE LOOP. WE WERE USING A NEW ICAO PUSHBACK PROC THAT HAD BEEN POORLY IMPLEMENTED AND NOT STRICTLY ENFORCED BTWN FLCS AND PUSHBACK CREWS. SOME QUESTIONABLE PHRASEOLOGY WAS USED BTWN GND PUSHBACK CREW AND COCKPIT; ADDING TO FALSE ASSUMPTIONS THAT THE PUSHBACK CREW WAS NOT CLR OF ACFT.