METRO SA227 NOTED TAIL HVY ON DEP MSP. FULL NOSE DOWN TRIM REQUIRED. CHKED WITH DISPATCH AND ADVISED 47 LBS HVY IN TAIL. CONTINUED TO DEST SINCE CTR OF GRAVITY MOVES FORWARD AS FUEL IS BURNED.

Narrative

SHORTLY AFTER DEP FROM MSP ACFT NOSE ROSE ABRUPTLY HIGHER THAN NORMAL +10 DEG ROTATION. I IMMEDIATELY APPLIED NOSE DOWN TRIM AND QUICKLY REACTED THE ELECTRIC NOSE DOWN TRIM LIMIT. DURING THE CLB I APPLIED FORWARD PRESSURE TO THE CTL WHEEL TO KEEP THE ACFT FROM INCREASING PITCH. AFTER LEVELING OFF AT 11000 FT WE REDUCED PWR TO A NORMAL CRUISE SETTING AND WERE ABLE TO KEEP THE ACFT LEVEL WITH ONLY A SMALL AMOUNT OF FORWARD PRESSURE ON THE CTL WHEEL. I THEN CALLED OUR OPS TO ASK IF THEY HAD ENTERED THEIR WT AND BAL DATA CORRECTLY. THEY SAID THEY HAD; BUT THE AFT CARGO BIN (CARGO #2 AND #3) HAD BEEN OVERLOADED BY APPROX 47 LBS; BUT THE UPDATED WT AND BAL DATA STILL SHOWED THAT OUR ACFT WAS WITHIN THE CTR OF GRAVITY ENVELOPE; WHICH OBVIOUSLY DID NOT COINCIDE WITH THE LACK OF NOSE DOWN TRIM REQUIRED TO REMOVE THE CTL WHEEL PRESSURE. ON PAPER OUR ACFT BALANCED; IN THE REAL WORLD IT DID NOT. WE CONTINUED TO OUR DEST CWA BECAUSE THIS ACFT'S CTR OF GRAVITY MOVES FORWARD AS FUEL IS CONSUMED. WE WERE ALSO FULL (19 PAX); SO WE WERE UNABLE TO SHIFT ANY PAX TOWARDS THE FRONT OF THE ACFT. CONTRIBUTING FACTOR IN THIS INCIDENT IS THE USE OF STANDARD PAX WTS (170 LBS) AND STANDARD BAG WTS (25 LBS) ON AN ACFT AS SMALL AS THE METROLINER. AS THE ACFT APCHS ITS MAX ALLOWABLE TKOF WT THE MARGIN OF ERROR BTWN ACTUAL AND STANDARD WTS BECOMES TOO GREAT.