ACFT ROLLS BACKWARD AFTER FLC RECEIVES CHOCKS INSERTED SIGNAL. GND PERSONNEL INJURED.

Narrative

ON FLT FROM CMH TO MSP. WE ARRIVED AT GATE AND FOLLOWED OUR COMPANY RAMP AGENT'S SIGNALS INTO THE GATE PER OUR COMPANY POLICY. I STOPPED THE ACFT AND SET THE BRAKES AND WAITED FOR THE RAMP AGENT TO GIVE ME THE CHOCKS IN SIGNAL AS WELL AS THE EXTERNAL PWR CONNECTED SIGNAL SO WE COULD SHUT DOWN THE R ENG. THE RAMP AGENT GAVE ME THE CHOCKS IN SIGNAL AND THEN THE EXTERNAL PWR CONNECTED SIGNAL; AT WHICH TIME I SHUT THE R ENG DOWN AND CALLED FOR THE PARKING CHK. OUR COMPANY POLICY HAS THE FO READ THE PARKING CHK AND THE CAPT RESPONDS ACCORDINGLY. WHEN MY FO CALLED BRAKES; I RESPONDED WITH CHOCKS IN BRAKES OFF. AFTER RELEASING THE BRAKES; I NOTICED THE ACFT ROLLED BACKWARDS AND PROMPTLY RESET THE BRAKES. I DON'T KNOW FOR SURE; BUT IT SEEMED THE ACFT ROLLED 6 INCHES TO MAYBE A FT BACKWARDS. I LEFT THE ACFT WITH THE BRAKES SET. NO ONE APCHED ME AFTERWARDS TO INDICATE THERE HAD BEEN ANY KIND OF PROB OR THAT AN INCIDENT HAD OCCURRED. LATER THAT SAME DAY; I LEARNED THAT A RAMP AGENT HAD INJURED HIS HAND WHILE PLACING THE CHOCKS UNDER THE MAIN WHEELS. I CAN ONLY SPECULATE AT THIS TIME IF THE RAMP AGENT DID NOT HAVE THE CHOCKS PROPERLY SET UNDER THE TIRES AND THAT THE ACFT ROLLED BACK ONCE THE BRAKES WERE RELEASED. I DO KNOW THAT WE DID RECEIVE THE CHOCKS IN SIGNAL; WHICH IS OUR SIGNAL THAT IT IS OKAY TO RELEASE THE BRAKES. I ALSO GAVE THE AGENT A THUMBS UP SIGNAL TO VERIFY THE FACT. MY FO ALSO SAW THE RAMP AGENT GIVE ME THE CHOCKS IN SIGNAL.