What was found
RIGHT BEFORE WE ROTATED HOT BLEED AIR STARTED COMING INTO COCKPIT AND A LOT OF SMOKE. WE IMMEDIATELY DECIDED TO TURN BACK TO THE AIRPORT AND LAND. THERE WERE NO ANNUNCIATORS ON THE PANEL THAT INSINUATED BLEED AIR WAS IN OVERRIDE POSITION. ALL SWITCHES WERE IN THE NORMAL POSITION DURING TAXI AND TAKE OFF AND LANDING. THE CABIN GOT EXTREMELY HOT. THE PAX SAY THE FLOOR GOT EXTREMELY HOT. WE DID HAVE A LOSS OF POWER FLYING BACK INTO THE AIRPORT.