ACFT MOVED WITHOUT FLC PERMISSION.

Narrative

WHILE PARKED AT THE GATE IN MIAMI AWAITING PUSHBACK; THE TUG DRIVER CALLED THE COCKPIT ABOUT 3 TIMES. THE CAPT RESPONDED SEVERAL TIMES; BUT THE TUG DRIVER COULD NOT HEAR THE COCKPIT RESPONSE. THEN (WITHIN ABOUT 20 SECONDS) THE TUG DRIVER JUST PUSHED THE ACFT BACK ABOUT 2 OR 3 FT WITHOUT RADIO CONTACT OR WITHOUT ANY ATTEMPT TO ESTABLISH HAND SIGNALS OR ANY FORM OF COM BY LIGHTS (IT WAS STILL DARK) OR GETTING OUR ATTN TO OUTSIDE THE ACFT IN ANY FASHION. THE CAPT AND FO IMMEDIATELY BEGAN TO BLINK ALL THE TAXI AND LNDG LIGHTS RAPIDLY. WE WERE PANICKED BECAUSE THE AIRPLANE MOVED SUDDENLY AND WITHOUT ANY WARNING. THE ACFT STOPPED AND THE CAPT IMMEDIATELY OPENED HIS SIDE WINDOW AND HUNG OUTSIDE AND YELLED TO THE TUG DRIVER NOT TO MOVE THE ACFT BEFORE HE TALKED TO US AND TOLD THE TUG DRIVER THAT WE RECEIVED HIS CALL; BUT THAT HE OBVIOUSLY COULD NOT HEAR US. HE SAID HE WAS JUST MOVING THE ACFT TO GET THE CHOCKS OUT. HE SUGGESTED USING HAND SIGNALS BUT THE CAPT DEMANDED THAT HE GET A WORKING HEADSET. AFTER CHANGING HEADSETS; 2-WAY RADIO CONTACT WAS ESTABLISHED. THE CAPT WARNED THE TUG DRIVER NEVER TO MOVE AN AIRPLANE WITHOUT 2-WAY COM BECAUSE THE BRAKES MIGHT HAVE BEEN SET. THE ACFT WAS THEN PUSHED AWAY FROM THE GATE WITHOUT FURTHER INCIDENT.