AN AIRBUS 320 AFTER PUSHBACK WITH TUG AND TOWBAR DISCONNECTED THE ACFT ROLLED FORWARD APPROX 4 FT.

Narrative

DURING PUSHBACK FROM GATE XY WHILE DRIVING THE TUG; I WAS CALLED BY HAND-HELD RADIO; AND NOTIFIED BY THE ZONE CTLR THAT THE RAMP PEOPLE WOULD BE REMOVING A PIECE OF LUGGAGE BECAUSE THE PAX HAD NOT BOARDED THE ACFT. ALONG WITH THE USUAL LANGUAGE BTWN THE FLT DECK AND MYSELF I TOLD THE CAPT WE WOULD BE HELD ON THE RAMP UNTIL THE LUGGAGE WAS LOCATED AND REMOVED. ALL OF THIS COM TOOK PLACE WHILE THE ACFT WAS MOVING BACKWARD TOWARD THE STOP POINT. AFTER STOPPING THE ACFT THE RAMP DID REMOVE THE BAG. BY THAT TIME I HAD CLRED THE CREW TO START #1 ENG. WHEN THE RAMP PERSONNEL WAS CLR I OKAYED THE CREW ON #2 ENG; AND TOLD THE CAPT THE TOWBAR AND STEERING LOCKOUT PIN WAS REMOVED. HE THEN TOLD ME TO REMOVE THE HEADSET CORD AND HE WOULD WATCH FOR MY TAXI GUIDANCE AND RELEASE TO TAXI. WHEN I HAD DONE THAT I MOVED THE TUG BACK TO SIGNAL THE CREW AND THE ACFT ROLLED FORWARD APPROX 4 FT. WHEN THE CREW REALIZED THE MOVEMENT THEY APPLIED THE BRAKES. I AM SURE I DID NOT COMMAND THE CREW TO SET THE PARK BRAKE AFTER PUSHING BACK AND STOPPING THE ACFT. BECAUSE OF THE DISTR FROM OUTSIDE COM SOURCES; CREATING AN IRREGULARITY IN THE NORMAL ROUTINE; HAVING SECURITY BAGS REMOVED WHILE AT THE GATE WOULD BE HELPFUL. AND THE ACFT WAS NOT DAMAGED.