What was found
(CAN) AIRCRAFT DEPARTED FROM AIRPORT AND CREW SMELLED AND NOTICED SMOKE COMING FROM ONE OF THE OVERHEAD COCKPIT PANELS. AIRCRAFT RETURNED TO AIRPORT AND LANDED SAFELY. MAINTENANCE INVESTIGATED AND REMOVED LIGHTING PANEL C6NF1253-19, WHICH HAD A HOLE BURNT THROUGH THE LIGHTING PANEL WHERE ONE OF THE TWENTY LAMP ASSEMBLIES, DHCSC70025-21, IS INSTALLED. THE LIGHTING PANEL WAS REPLACED AND AIRCRAFT RETURNED TO SERVICE. NO DEFINITE CAUSE AT THIS TIME BUT SUSPECT ONE OF THE LAMP ASSEMBLIES OVERHEATED AND BURNT A HOLE IN THE PANEL.