Narrative:

In cruise, shortly before descent, the left gear green light came on by itself. As there was no noise, yawing, or speed reduction associated with the green light and because the left gear red light did not come on, the green light was assumed to be false and probably due to a sensor malfunction. Raising the gear handle to the up position put the light out. We descended for approach shortly thereafter and about 10 mi out with the gear handle off and the throttles at idle (all red gear lights on) the left gear red light went out and the green light came on. Once again the light was assumed to be false with no other indications of actual gear extension. I decided to consult with sam prior to landing and requested delay vectors for that purpose. In consultation with sam, we lowered the gear and all lights and sensations were normal. However, since the lights were now suspect, sam and I agreed that further verification was necessary. Thinking that a fly-by the tower for a visual inspection would create less anxiety for the passenger, I requested same. During the fly-by, one pilot and the local controller thought the gear normal. However, 2 or 3 others in the tower cabin attendant thought the left gear might by only partially extended. Therefore, I decided on an inspection of the downlock via the viewpoint by the first officer. He reported that he could not see the downlock at all and that it looked like the gear was not at the proper angle. At this point I informed sam and commercial radio that we were contemplating a partial gear up landing, that I needed to get in conference with sam, dispatch and an appropriate flight manager. During the next hour or so the ffa, and crew, including one cja, prepared the cabin for evacuate/evacuation. We, in consultation with the assembled company advisors, tried various maneuvers in attempting to get the gear down. The first officer returned to the cabin 2 more times to verify proper downlock indications and was unsuccessful each time. Accordingly, with all appropriate checklists completed and/or reviewed, we timed our arrival over the outer marker with approximately 3200 pounds of fuel remaining. The approach and landing was made with flaps at 40 degree, touchdown was about 500' down runway 30R on the right gear, left engine was shut down, right reverser deployed and used with moderate right braking until the aircraft settled on the left gear which held. The aircraft was stopped approximately 5000' down the runway. I inspected the landing gear and could find nothing wrong. However, when I looked through the downlock viewport, I could not identify either the left or right downlock stripes. One mirror was either dirty or scratched and the other was apparently aimed improperly as the view was of the inboard wheel rather than the downlock strut and stripes.

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Original NASA ASRS Text

Title: GEAR LIGHT POPPED ON DURING CRUISE. CONSULTATION WITH MAINTENANCE, ALL CHECKS PERFORMED, MADE 'PARTIAL GEAR' LNDG.

Narrative: IN CRUISE, SHORTLY BEFORE DSCNT, THE LEFT GEAR GREEN LIGHT CAME ON BY ITSELF. AS THERE WAS NO NOISE, YAWING, OR SPEED REDUCTION ASSOCIATED WITH THE GREEN LIGHT AND BECAUSE THE LEFT GEAR RED LIGHT DID NOT COME ON, THE GREEN LIGHT WAS ASSUMED TO BE FALSE AND PROBABLY DUE TO A SENSOR MALFUNCTION. RAISING THE GEAR HANDLE TO THE UP POSITION PUT THE LIGHT OUT. WE DESCENDED FOR APCH SHORTLY THEREAFTER AND ABOUT 10 MI OUT WITH THE GEAR HANDLE OFF AND THE THROTTLES AT IDLE (ALL RED GEAR LIGHTS ON) THE LEFT GEAR RED LIGHT WENT OUT AND THE GREEN LIGHT CAME ON. ONCE AGAIN THE LIGHT WAS ASSUMED TO BE FALSE WITH NO OTHER INDICATIONS OF ACTUAL GEAR EXTENSION. I DECIDED TO CONSULT WITH SAM PRIOR TO LNDG AND REQUESTED DELAY VECTORS FOR THAT PURPOSE. IN CONSULTATION WITH SAM, WE LOWERED THE GEAR AND ALL LIGHTS AND SENSATIONS WERE NORMAL. HOWEVER, SINCE THE LIGHTS WERE NOW SUSPECT, SAM AND I AGREED THAT FURTHER VERIFICATION WAS NECESSARY. THINKING THAT A FLY-BY THE TWR FOR A VISUAL INSPECTION WOULD CREATE LESS ANXIETY FOR THE PAX, I REQUESTED SAME. DURING THE FLY-BY, ONE PLT AND THE LCL CTLR THOUGHT THE GEAR NORMAL. HOWEVER, 2 OR 3 OTHERS IN THE TWR CAB THOUGHT THE LEFT GEAR MIGHT BY ONLY PARTIALLY EXTENDED. THEREFORE, I DECIDED ON AN INSPECTION OF THE DOWNLOCK VIA THE VIEWPOINT BY THE F/O. HE REPORTED THAT HE COULD NOT SEE THE DOWNLOCK AT ALL AND THAT IT LOOKED LIKE THE GEAR WAS NOT AT THE PROPER ANGLE. AT THIS POINT I INFORMED SAM AND COMMERCIAL RADIO THAT WE WERE CONTEMPLATING A PARTIAL GEAR UP LNDG, THAT I NEEDED TO GET IN CONFERENCE WITH SAM, DISPATCH AND AN APPROPRIATE FLT MGR. DURING THE NEXT HOUR OR SO THE FFA, AND CREW, INCLUDING ONE CJA, PREPARED THE CABIN FOR EVAC. WE, IN CONSULTATION WITH THE ASSEMBLED COMPANY ADVISORS, TRIED VARIOUS MANEUVERS IN ATTEMPTING TO GET THE GEAR DOWN. THE F/O RETURNED TO THE CABIN 2 MORE TIMES TO VERIFY PROPER DOWNLOCK INDICATIONS AND WAS UNSUCCESSFUL EACH TIME. ACCORDINGLY, WITH ALL APPROPRIATE CHECKLISTS COMPLETED AND/OR REVIEWED, WE TIMED OUR ARR OVER THE OUTER MARKER WITH APPROX 3200 LBS OF FUEL REMAINING. THE APCH AND LNDG WAS MADE WITH FLAPS AT 40 DEG, TOUCHDOWN WAS ABOUT 500' DOWN RWY 30R ON THE RIGHT GEAR, LEFT ENGINE WAS SHUT DOWN, RIGHT REVERSER DEPLOYED AND USED WITH MODERATE RIGHT BRAKING UNTIL THE ACFT SETTLED ON THE LEFT GEAR WHICH HELD. THE ACFT WAS STOPPED APPROX 5000' DOWN THE RWY. I INSPECTED THE LNDG GEAR AND COULD FIND NOTHING WRONG. HOWEVER, WHEN I LOOKED THROUGH THE DOWNLOCK VIEWPORT, I COULD NOT IDENTIFY EITHER THE LEFT OR RIGHT DOWNLOCK STRIPES. ONE MIRROR WAS EITHER DIRTY OR SCRATCHED AND THE OTHER WAS APPARENTLY AIMED IMPROPERLY AS THE VIEW WAS OF THE INBOARD WHEEL RATHER THAN THE DOWNLOCK STRUT AND STRIPES.

Data retrieved from NASA's ASRS site as of August 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.