LGT ACFT DURING PUSHBACK; FLC STARTED ENGS; GND CREW REQUESTED CAPT RELEASE BRAKES SO THEY COULD DISCONNECT THE TOW BAR. THE TUG DRIVER APPARENTLY WAS OFF THE TUG TO HELP. AFTER THE BAR WAS REMOVED THE ACFT STARTED ROLLING FORWARD BEFORE GND CREW ASKED FOR BRAKES SET AND THE TOW BAR DAMAGED THE NOSE TIRE.

Narrative

THE PUSHBACK CONTINUED UNDER NORMAL OPERATING PROCS UP TO SETTING THE PARKING BRAKE. THE GND CREW THEN ADVISED THE CAPT THAT THEY COULD NOT RELEASE THE TOW BAR. GND CREW ASKED CAPT TO RELEASE BRAKES SO THE TUG COULD BE MOVED TO ASSIST IN THE TOW BAR DISCONNECT. IT WAS OBVIOUS TO THE COCKPIT CREW THAT THE NOSE GEAR WAS BEING ROTATED AS THE TILLER WAS MOVING. THEN THE ACFT BEGAN ROLLING FORWARD -- BOTH ENGS WERE RUNNING. THE CAPT ASKED THE GND CREW IF ALL WAS OK. NO RESPONSE. THE FO COULD SEE THE TUG OUT HIS WINDOW. HE SAID THE DRIVER WAS GETTING BACK INTO THE TUG AND RECONNECTING HIS HEADSET. AT THAT POINT THE CAPT APPLIED BRAKES AND STOPPED THE ACFT. COMS WERE ESTABLISHED. FLC WAS TOLD THAT THE NOSE TIRE WAS DAMAGED WHEN THE AIRPLANE ROLLED FORWARD ONTO THE TOW BAR. BOTH NOSE TIRES WERE REPLACED BEFORE FLT. THE ISSUE IS A BREAKDOWN IN PROC BY THE GND CREW. THERE MAY HAVE BEEN A PROB WITH THE INTERCOM HEADSET OR WIRING BUT THE DRIVER SHOULD NEVER HAVE LEFT THE TUG; KNOWING THE ACFT BRAKES WERE NOT SET. A CONTRIBUTING FACTOR WAS THAT 1 OF THE 2 GND CREW WAS NEW TO THE JOB. WHILE THE ONLY DAMAGE WAS A TIRE; POTENTIAL FOR PERSONAL INJURY EXISTED. SUPPLEMENTAL INFO FROM ACN 400335: COMS WERE RE-ESTABLISHED AND THE GND CREW ONLY SAID THAT THEY HAD 'HAD HEADSET PROBS' AND THAT THEY HAD 'NOTICED TIRE DAMAGE DURING PUSHBACK' AND THAT THEY WANTED US TO TAXI BACK TO THE GATE TO HAVE MAINT LOOK AT OUR NOSE TIRE. THEY DID NOT NOTIFY THE CREW THAT CONTACT WITH THE TOW BAR HAD CAUSED THE TIRE DAMAGE. THE FLC WERE NOT INFORMED OF WHAT HAD ACTUALLY CAUSED THE TIRE DAMAGE UNTIL WE REACHED OUR LAYOVER HOTEL AND WERE CONTACTED BY FLT MGMNT PERSONNEL. MGMNT PERSONNEL HAD BEEN NOTIFIED AFTER THE GND CREW HAD FILED A RPT STATING 'ACFT PWRED FORWARD AND CONTACTED TOW BAR.' MGR ALSO INDICATED THAT ONE OF THE GND CREW WAS NEW. BASIC FACTS: CAPT HAD NOT CLRED GND CREW TO DISCONNECT. FO HAD NOT REQUESTED TAXI CLRNC. THROTTLES WERE NOT ADVANCED. UNDER NORMAL OPS; THE GND CREW DIRECTS THE CAPT TO 'SET BRAKES.' AFTER THEY INFORM THE CAPT THAT THE TOW BAR IS DISCONNECTED; THE CAPT CLRS THEM TO DISCONNECT THEIR HEADSET. IN THIS CASE; THEY HAD DIFFICULTY DISCONNECTING THE TOW BAR. THE REQUEST TO 'RELEASE BRAKES' SO THEY COULD REPOS THE TOW BAR WAS A NON-NORMAL PROC. SINCE THE FO HAD SEEN THE TUG DRIVER JUMP BACK IN THE TUG AND RECONNECT HIS HEADSET; IT APPEARED THAT HE HAD GOTTEN OUT OF THE TUG TO HELP THE OTHER GUY. IN WHICH CASE; NO ONE WAS OPERATING THE TUG TO HOLD THE ACFT IN PLACE AND NO ONE WAS ON THE HEADSET TO COMMUNICATE WITH THE CAPT. RATHER THAN 'REPOS THE TOW BAR' AS THEY HAD STATED; THE GND CREW APPARENTLY DISCONNECTED THE TOW BAR WHICH SUBSEQUENTLY ALLOWED THE ACFT TO ROLL FORWARD. NO ONE WAS ON HEADSET TO DIRECT THE CAPT TO 'RESET THE BRAKES.'