What was found
CLT - FLT 5192 - AFTER TAKEOFF LANDING GEAR WAS SELECTED UP. THE GEAR FAILED TO RETRACT. THE GEAR WAS SELECTED DOWN WITH ALL INDICATIONS NORMAL. THE AIRCRAFT RETURNED TO CLT WHERE AN UNEVENTFUL LANDING WAS MADE. THE AIRCRAFT WAS TROUBLE SHOT AND THE LANDING GEAR BYPASS VALVE VALVE PIN WAS FOUND POPPED. THE BYPASS VALVE WAS REPLACED AND THE LANDING GEAR RETRACTION SYSTEM FUNCTION TESTED. ALL INDICATIONS WERE NORMAL. THE AIRCRAFT WAS THEN RETURNED TO SERVICE. (M)