Narrative:

On dec/wed/99, someone who rents my aircraft had no green light indication for landing gear extension prior to landing at oakland airport. The gear appeared to be properly extended, except for the absence of the green light. After recycling the gear and following other emergency procedures from the checklist, including the use of the emergency pump to lower the gear, he safely landed the airstair without a green light. The green light lit on the ground soon after landing. I was out of town at the time. When I returned and the WX cleared, I took the aircraft to red bluff, ca, where I have it maintained, to have the problem investigated. Because of the safe landing on dec/wed/99, and because there was now a green light indication on the ground, I assumed that the problem was an intermittent light, not a gear problem. I therefore retracted the gear after takeoff on the flight to red bluff. On my approach 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 emergency pump because the previous lack of success with that and because I was still assuming that I had a light problem rather than a gear problem. I landed safely and got the green light before turning off the runway. Raised on jacks in red bluff, it was determined that the problem was that the landing gear was not locking in place until the aircraft weight forced it to lock. The swing-forward landing gear locks in a position 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 weight of the aircraft after landing would push the gear into the locked position. The reason it was not locking by itself in the air was that the main gear actuator support pin (P/north 2041020-2) had broken, causing the support to come loose. The emergency pump had no effect in bypassing this failure. In retrospect, I should not have assumed an intermittent gear light just because a safe landing had been made with the problem and because it was indicating green on the ground. The gear should not have been retracted again until the plane was put on jacks.

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Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.