DHC8 OF UNIQUE CONFIGN COMPARED TO THE REST OF THE ACR FLEET IS FLOWN WITH AFT CARGO WT IN EXCESS OF LIMIT.

Narrative

WHILE TAXIING IN AT VANCOUVER; WE WERE NOTIFIED BY OUR OPS DEPT THAT OUR AFT CARGO COMPARTMENT HAD BEEN OVERLOADED IN PORTLAND. I HAD THE RAMP PERSONNEL IN VANCOUVER COUNT THE BAGS AS THEY CAME OFF THE ACFT. THEY CONFIRMED THAT THE BAG COUNT WAS CORRECT. THE HANDHELD COMPUTER WT AND BAL SYS INDICATED THAT THE AFT COMPARTMENT WAS NOT OVERLOADED BUT WAS UNDER MAX LOAD LIMIT BY 930 LBS. I WAS THEN TOLD BY DISPATCH THAT THE ACFT I WAS IN WAS THE ONE ACFT IN OUR FLEET WITH A LOWER WT LIMIT. (THIS IS DUE TO THE FACT THAT THIS ACFT HAS A DIFFERENT GALLEY/AFT CARGO COMPARTMENT SETUP FROM THE REST OF THE FLEET.) THE MAX WT LIMIT FOR THIS ACFT IS 2590 LBS. THE WT AND BAL COMPUTER INDICATED A MAX WT LIMIT OF 3660 LBS; WHICH IS THE LIMIT FOR THE REST OF THE FLEET. WITH THIS INFO; I REALIZED THAT THE AFT CARGO COMPARTMENT LOAD LIMIT HAD BEEN EXCEEDED BY APPROX 140 LBS. THE FACTORS THAT LED TO THIS INCIDENT AS I SEE IT: 1) THE COMPANY HAS 1 ACFT IN THE FLEET THAT HAS A WT LIMIT DIFFERENT THAN ALL THE REST. 2) THE WT LIMIT IS CLRLY PLACARDED IN THE COMPARTMENT BUT WAS NOT HEEDED BY THE GND AGENTS LOADING THE BAGS. 3) THE WT AND BAL COMPUTER I WAS USING SHOWED AN ERRONEOUS WT. ALL THE BOXES ON THE COMPUTER SCREEN WERE GREEN; INDICATING NO LIMITS EXCEEDED. 4) THE ACFT FLT STANDARDS MANUAL LISTS THE CARGO COMPARTMENT WT LIMITS BUT ARE NOT LISTED AS MEMORY ITEMS SINCE THE COMPUTERIZED WT AND BAL SYS IS ASSUMED TO HAVE CORRECT INFO.