What was found
DURING CRUISE OBSERVED SMOKE IN COCKPIT. AN EMERGENCY DECLARED. AT 15,000 FT SMOKE DISSIPATED SUBSTANTIALLY & TURBULENCE ENCOUNTERED. UNEVENTFUL LANDING. MX POWERED ACFT & RAN ENGINES NUMEROUS TIMES WITH FULL ELECTRICAL LOAD, OPERATED BOTH PAC'S IN AUTO & MANUAL MODES. UNABLE TO DUPLICATED. COALESCER SOCKS INSPECTED & DUCT TEMP SENSORS OPERATIONALLY TESTED. NO DEFECTS NOTED. INVESTIGATION REVEALED LEAKING DUCT OVER NR 1 & 2 TRANSPONDERS. DUCT REPOSITIONED & RESECURED. A DISCOLORED FLOOD LIGHT LENS ALSO REPLACED. ENGINES RAN AT HIGH POWER WITH BLEEDS ON. PACK AND ENGINE ANTI-ICE WERE RAN WITH NO EVIDENCE OF SMOKE OR SMELL. TEST FLIGHT PROVED SATISFACTORY. AIRCRAFT WAS RETURNED TO SERVICE.