What was found
(CAN) DURING A POST C-CHECK TEST FLIGHT THE CREW WAS FLYING THE ACFT AT 16,000FT, WHEN THEY PERFORMED AN ALTERNATE FLAP EXTENSION TEST. THE ACFT DID EXTEND THE FLAPS AND SLATS PROPERLY. THE CREW RETRACTED THE FLAPS IN A NORMAL CONFIGURATION. THEN THEY DEPLOYED THE FLAPS AGAIN AND AT THAT TIME, THEY GOT AN OVERHEAD PANEL CAUTION LIGHT IN THE FORM OF A SLAT EXTEND LIGHT REMAINING ILLUMINATED. THE CREW CONFIRMED THE FAILURE IN FLIGHT AND RETURNED TO BASE. THE CREW REPORTED THAT THE HANDLING OF THE ACFT WAS UNAFFECTED AT THE TIME OF THE FAILURE AND DURING ALL REMAINING PHASES OF FLIGHT INCLUDING THE LANDING.