FLT CREW OF JS41 EXPERIENCE A FAULTY GEAR SAFE WARNING SYS ON ARR AT CVG. FAIL TO MAKE A LOGBOOK ENTRY YET FLY THE SAME ACFT THE FOLLOWING DAY AND NEED TO DECLARE AN EMER WHEN THE STANDBY WARNING SYS MALFUNCTIONED AS WELL.

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ON LNDG AT CVG; THE MAIN R GEAR INDICATOR DID NOT SHOW DOWN. WE VERIFIED ALL GEAR WERE DOWN BY USING THE STANDBY GEAR POS INDICATOR. ON DEP FROM CVG THE NEXT DAY; WHEN THE GEAR WAS SELECTED UP; THE STANDBY GEAR INDICATOR STILL SHOWED THE R MAIN LNDG GEAR AS DOWN. BECAUSE OF DISCREPANCY; WE WERE NOT SURE IF THE GEAR WAS UP OR DOWN. WE DID 'RECYCLE' THE GEAR BUT HAD THE SAME INDICATION. UPON SELECTING GEAR DOWN WHEN LNDG AT STL; THE MAIN INDICATOR STILL DID NOT WORK AND THE STANDBY SHOWED ALL 3 GEAR DOWN. BECAUSE THE R MAIN LNDG GEAR ON THE STANDBY INDICATOR HAD BEEN ON THE ENTIRE FLT; WE MADE A LOW PASS FOR THE TWR TO OBSERVE THE GEAR VISUALLY. WHEN CONFIRMED ALL GEAR WERE DOWN; WE CAME AROUND BACK TO LNDG WITHOUT ANY INCIDENTS. AS A PRECAUTIONARY MEASURE; WE CALLED FOR EMER VEHICLES TO FOLLOW US DOWN THE RWY. WE ALSO ADVISED THE FLT ATTENDANT OF A POSSIBLE EVAC AND ALSO BRIEFED THE PAX A NUMBER OF TIMES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FOLLOWING THE INITIAL FAILURE; THE RPTR DEPARTED THE AIRPLANE IMMEDIATELY UPON GATE ARR FOR PHYSIOLOGICAL REASONS. HE LEFT WITH THE UNDERSTANDING THE CAPT WOULD MAKE THE APPROPRIATE WRITE-UPS IN THE MAINT LOG. THE FOLLOWING DAY; THE RPTR ADVISED THE CREW RETURNED TO THE SAME ACFT AND THE CAPT PERFORMED THE COCKPIT SETUP WHILE THE RPTR DID THE EXTERNAL WALKAROUND. RPTR ADVISED THAT SINCE THE COCKPIT PREFLT WAS NOT HIS RESPONSIBILITY; HE ONLY DISCOVERED THE LACK OF MAINT ACTION AND THE ON GOING ANOMALY UPON RECEIVING INAPPROPRIATE INDICATIONS ON BOTH THE NORMAL AND STANDBY GEAR WARNING SYS AFTER GEAR RETRACTION ON TKOF.