ACR MLG ACFT SKIDDED OFF END OF RWY DURING THE TURN OFF OF THE RWY AFTER LNDG.

Narrative

ON APCH TO RWY 23; SDF; LIGHT RAIN WAS RPTED BY TWR ON FIELD HAVING STARTED A FEW MINS EARLIER. A FULL (40) FLAP LNDG WAS MADE WITH AUTO-SPOILERS AND REVERSERS. THROUGHOUT APCH AND LNDG PHASE; RWY APPEARED CLR AND DRY AND LNDG PROCEEDED NORMALLY ON ROLLOUT. SINCE THIS WAS A SHORTER RWY AND WE WERE RELATIVELY HVY; TOUCHDOWN WAS MADE SLIGHTLY EARLIER THAN NORMAL AND BRAKING APPLIED AS NECESSARY. REVERSERS WERE STOWED AT 60 KTS AND BRAKING TO TAXI SPD WAS DONE AS THE END OF THE RWY WAS APCHED. A TURN TO EXIT TO THE TAXIWAY WAS INITIATED NORMALLY. AFTER 10-20 DEGS OF TURN; THE ACFT WAS NOTICED TO STOP TURNING AND MAIN GEAR WERE NOTICED TO BE SLIPPING. HVY BRAKING WAS APPLIED BUT THE ACFT CONTINUED OFF THE RWY AT APPROX 5 KTS. THE SLIPPING OCCURRED AS THE ACFT REACHED THE FRESHLY PAINTED RWY MARKINGS AT THE END OF THE RWY. THE LIGHT; MISTING-TYPE RAIN COMBINED WITH THE FRESH PAINT; MADE ENOUGH OF A SLICK SURFACE THAN NORMAL. TAXI SPDS FOR TURNING WERE TOO FAST; IN MY VIEW. LOOKING BACK ON IT; I WISH I HAD SLOWED TO A MUCH MORE CONSERVATIVE SPD PRIOR TO THE PAINT AND INITIATING THE TURN.