What was found
CLT - FL 1112 - DURING TAKEOFF GROUND ROLL, CREW NOTED SMELL OF BURNING RUBBER. CREW LEFT GEAR DOWN, SMELL DID NOT DISSIPATE. CREW DECLARED AN EMERGENCY, DUMPED CABIN AIR, AND RETURNED TO CLT. FLIGHT LANDED WITH NO FURTHER INCIDENT. MAINTENANCE RAN BOTH ENGINES AND BOTH PACKS. CABIN WAS PRESSURIZED TO APPROXIMATELY FOUR PSI. SMELL COULD NOT BE DUPLICATED. AIRCRAFT RELEASED FOR SERVICE. (M)