A DC10 FLT CREW DISCOVERS AFTER THE FACT THAT THEY TAXIED OFF THE PAVED TXWY INTO THE MUD.

Narrative

WHILE TAXIING TO PARKING AFTER LNDG AT DETROIT WAYNE COUNTY METRO ARPT; R MAIN GEAR OF OUR ACFT GOT OFF THE CONCRETE TXWY WHILE MAKING A R TURN. WE WERE ENTERING COMPANY PROPERTY FROM TXWY Z AT THE 'INGRESS' POINT TO COMPANY RAMP; AND HAD TO MAKE A R TURN THEN A L TURN INTO OUR PARKING SPOT. THERE WAS A B727 PARKED NEXT TO OUR SPOT THAT WE HAD TO PASS ON OUR L DURING THIS R TURN AND THE R TURN ITSELF LOOKED AS IF IT WOULD BE APPROX 45 DEGS BEFORE WE WOULD TURN BACK L INTO OUR PARKING SPOT. BOTH THESE FACTORS CAUSED THE CAPT TO USE SUFFICIENT OVER-STEER AND RESULTED IN OUR GETTING 'INTO THE MUD.' WE DID NOT KNOW WE HAD GONE OFF THE CONCRETE UNTIL WE WERE PARKED AND THE MECH TOLD US THERE WAS MUD ON THE R MAIN GEAR TIRES. WE MADE A WRITE-UP IN THE ACFT MAINT LOG. I KNEW (THE MAIN GEAR WAS) CLOSE TO THE TXWY EDGE DURING THE R TURN BUT DID NOT THINK WE WOULD GO OFF; OR I WOULD HAVE TOLD THE CAPT TO GO FURTHER STRAIGHT AHEAD (TOWARD THE B727) BEFORE TURNING R. IN THE FUTURE I WILL PROVIDE BETTER GUIDANCE TO THE CAPT REGARDING INITIATING TURNS AND NOT BE SO COMPLACENT. COMPANY SAFETY RPT FILED REGARDING CIRCUMSTANCES OF INCIDENT WITH SUGGESTION TO USE TOW IN FOR DC10 AND LARGER ACFT ON THIS SMALL/TIGHT RAMP.