What was found
CLT - FLT 53 - EN ROUTE CLT-JAX - AFTER TAKEOFF, THICK SMOKE FILLED THE CABIN, BUT NOT THE COCKPIT. FLIGHT RETURNED TO CLT AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIR CONDITIONING PACKS AND RAN THE ENGINES AT VARIOUS POWER SETTINGS. NO SMOKE WAS NOTED. OK FOR SERVICE. (M)