A B747-400 2 MAN CREW FOLLOWING AN ATLANTIC XING FAILED TO SET THE PARKING BRAKE WITH AN ENG RUNNING. THE FO STOPPED ACFT WITH NO DAMAGE.

Narrative

WE ARRIVED AT IAD AFTER FLYING FROM LONDON. THE CAPT TAXIED IN; WHILE I WAS CALLING OUT GS AND VERIFYING BRAKE PRESSURE. WE WERE HAND MARSHALED TO A STOP; AND THE CAPT TURNED THE SEATBELT OFF TO LET THE PEOPLE UP. THE #1 ENG WAS RUNNING STILL; DUE TO A REQUEST FROM STATION OPS TO NOT START THE APU. I WAS WATCHING THE OVERHEAD PANEL TO ALERT THE CAPT OF WHEN THE EXTERNAL PWR WAS AVAILABLE. FROM THE CORNER OF MY EYE; I SAW THE ACFT MOVING AND YELLED 'PARKING BRAKE;' WHILE IMMEDIATELY GETTING ON THE BRAKES AND STOPPING THE ACFT. FORTUNATELY; THERE WAS NO PHYSICAL DAMAGE OR INJURIES. AFTERWARDS; THE CAPT COORD WITH THE GND CREW TO HAVE THE PLANE PUSHED BACK TO THE PROPER POS. THINKING BACK ON THE INCIDENT; I SEE SEVERAL FACTORS THAT INFLUENCED WHAT HAPPENED: 1) WE WERE FATIGUED AFTER AN ATLANTIC XING WITH A 2-MAN CREW. OUR DAY STARTED ABOUT XA00 BODY TIME FOR US. 2) I AM STILL UNSURE WHETHER THE CAPT REALLY SET THE PARKING BRAKE OR FORGOT. AT THE TIME; I THOUGHT THAT HE DID. 3) I WAS DISTR BY TRYING TO MONITOR THE RUNNING ENG AND WATCHING FOR EXTERNAL PWR TO BE CONNECTED TO ADVISE THE CAPT AND SHUT DOWN THE REMAINING ENG. 4) I REALIZE NOW THAT I SHOULD HAVE PRIORITIZED MONITORING THE SETTING OF THE PARKING BRAKE BEFORE I TURNED MY ATTN TO THE OTHER TASKS.