CESSNA 177RG LANDS AT RBL; CA; WITH UNSAFE GEAR INDICATION AT END AT FERRY FLT THAT FOLLOWED A LNDG WITH THE SAME INDICATION ON THE PREVIOUS FLT. GEAR ACTUATOR SUPPORT PIN WAS FOUND BROKEN.

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ON DEC/WED/99; SOMEONE WHO RENTS MY ACFT HAD NO GREEN LIGHT INDICATION FOR LNDG GEAR EXTENSION PRIOR TO LNDG AT OAKLAND ARPT. THE GEAR APPEARED TO BE PROPERLY EXTENDED; EXCEPT FOR THE ABSENCE OF THE GREEN LIGHT. AFTER RECYCLING THE GEAR AND FOLLOWING OTHER EMER PROCS FROM THE CHKLIST; INCLUDING THE USE OF THE EMER PUMP TO LOWER THE GEAR; HE SAFELY LANDED THE AIRSTAIR WITHOUT A GREEN LIGHT. THE GREEN LIGHT LIT ON THE GND SOON AFTER LNDG. I WAS OUT OF TOWN AT THE TIME. WHEN I RETURNED AND THE WX CLRED; I TOOK THE ACFT TO RED BLUFF; CA; WHERE I HAVE IT MAINTAINED; TO HAVE THE PROB INVESTIGATED. BECAUSE OF THE SAFE LNDG ON DEC/WED/99; AND BECAUSE THERE WAS NOW A GREEN LIGHT INDICATION ON THE GND; I ASSUMED THAT THE PROB WAS AN INTERMITTENT LIGHT; NOT A GEAR PROB. I THEREFORE RETRACTED THE GEAR AFTER TKOF ON THE FLT TO RED BLUFF. ON MY APCH TO RED BLUFF I LOWERED THE GEAR AND GOT NO GREEN LIGHT; ALTHOUGH THE GEAR APPEARED TO BE FULLY EXTENDED. I RECYCLED THE GEAR 3 TIMES; GETTING THE SAME RESULT. I DIDN'T TRY THE EMER PUMP BECAUSE THE PREVIOUS LACK OF SUCCESS WITH THAT AND BECAUSE I WAS STILL ASSUMING THAT I HAD A LIGHT PROB RATHER THAN A GEAR PROB. I LANDED SAFELY AND GOT THE GREEN LIGHT BEFORE TURNING OFF THE RWY. RAISED ON JACKS IN RED BLUFF; IT WAS DETERMINED THAT THE PROB WAS THAT THE LNDG GEAR WAS NOT LOCKING IN PLACE UNTIL THE ACFT WT FORCED IT TO LOCK. THE SWING-FORWARD LNDG GEAR LOCKS IN A POS WHICH IS HIGHER THAN THE LOWEST POINT OF THE ARC WHICH IT TRAVELS THROUGH DURING EXTENSION. IT ACTUALLY GOES UP FROM ITS LOWEST POINT TO LOCK IN PLACE. THE WT OF THE ACFT AFTER LNDG WOULD PUSH THE GEAR INTO THE LOCKED POS. THE REASON IT WAS NOT LOCKING BY ITSELF IN THE AIR WAS THAT THE MAIN GEAR ACTUATOR SUPPORT PIN (P/N 2041020-2) HAD BROKEN; CAUSING THE SUPPORT TO COME LOOSE. THE EMER PUMP HAD NO EFFECT IN BYPASSING THIS FAILURE. IN RETROSPECT; I SHOULD NOT HAVE ASSUMED AN INTERMITTENT GEAR LIGHT JUST BECAUSE A SAFE LNDG HAD BEEN MADE WITH THE PROB AND BECAUSE IT WAS INDICATING GREEN ON THE GND. THE GEAR SHOULD NOT HAVE BEEN RETRACTED AGAIN UNTIL THE PLANE WAS PUT ON JACKS.