Narrative:

First officer and I were assigned a ferry flight with no passengers. We were in VMC the entire flight. We were cleared for a visual approach and on about a 4 mile base to final leg we selected the gear down. We experienced what we perceived normal tactile sensations of the gear moving to the down position but none of the red gear unsafe lights or the green gear down and locked lights illuminated. On final; I raised the gear lever; then reselected the gear down in an attempt to obtain the three green down and locked gear lights. This made no improvement. We executed a go-around and notified the tower of our go-around and that we were experiencing gear indication problems. The tower vectored us to a right downwind initially and later took us about 10 miles out from the field where we could trouble shoot the problem. Control of the aircraft as well as responsibility for monitoring the radios was transferred to the first officer who was pilot flying while I proceeded with trouble shooting and execution of checklists. I pressed the overhead annunciator push to test button and saw all three red gear unsafe lights as well as all three green gear down lights. I attempted to extend the gear one more time and saw no improvement in conditions. We confirmed the standby nose gear pin was up indicating the nose gear was in the down position and system hydraulics showed normal pressure and quantity. The right side panel standby main gear indicator lights showed only the left main annunciator illuminated. I attempted to swap the bulbs in the standby gear annunciators to eliminate possible burned out bulbs or poor contacts causing the problem. I discovered there was only one bulb in the right main standby annunciator and it was in fact burned out. I again pushed the annunciator push to test on the overhead panel which showed that trading bulbs in the standby annunciators made no difference. We slowed the aircraft to 145 KIAS to see if the gear warning horn would sound indicating the gear was unsafe. The horn did not sound. I then went to the emergency checklist for landing gear no three green indication. The initial steps for this checklist instruct the gear horn and egpws circuit breakers to be pulled. When I opened the da-D breaker panel door to pull the gear horn circuit breaks I discovered two breakers had tripped. These were J4 (annunciator push to test) and K2 (gear indicator). It is interesting to point out that even with these two breakers tripped; all the gear indication lights illuminated with the annunciator push to test button depressed. The existing conditions/circumstances didn't seem to follow or match the direction the emergency checklist would lead us to act. We discussed the issues surrounding fom policy of not resetting tripped circuit breakers in flight and decided that this situation and set of circumstances was not consistent with the intent of the emergency checklist. Wanting to exhaust every possible avenue of confirming the gear was indeed down; we chose to reset K2. Resetting K2 caused the gear down three green indication to illuminate for a brief moment until the circuit breaker tripped again. No further reset attempts were made on any circuit breakers. I contacted the assistant chief pilot via flight phone and was conferenced in with the maintenance controller on duty. I described our situation and the indications we had. It was suggested that we do a fly-by past the tower to allow tower personnel to visually examine the condition of the gear. I suggested that we proceed with steps to lower the gear using the auxiliary hydraulic system just as another means to ensure the gear was indeed down. All agreed we had nothing to lose in trying this. I followed the checklist steps to accomplish this. Once complete we informed the approach controller we were ready for return. By the time the checklists and phone calls were completed we assessed our fuel situation and noted we had approximately 1;100 lbs of fuel remaining. I didn't feel comfortable trying to complete a fly-by the tower plus return for landing with our remaining fuel and elected to proceed to the airport for landing. We declared an emergency and requested the emergency equipment be standing by. Runway 20L was requested because it was the longest available. Additionally; we informed the tower that we would stop on the runway and needed to be towed to the FBO from our stopping point. The first officer flew a stabilized approach and made a smooth landing stopping on the centerline. We ran the after landing and engine shutdown checklists. The airport emergency equipment followed us to our stopping point. I spoke with them and informed them everything appeared to be ok-- we just needed to be towed from that point to our parking. I installed the gear pins and the tug arrived to tow the aircraft to their ramp. Upon arrival at the ramp I generated and submitted a maintenance discrepancy. The circumstances of our situation were rather unusual. I am not sure there was more we could have done to address the situation or to prevent its occurrence.

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Original NASA ASRS Text

Title: A HS125-800XP's landing gear indicator failed to indicate down and locked. While executing the gear extension checklist the gear warning circuit breakers were found out. The lights indicated safe momentarily when the breaker was reset but then popped again. An emergency was declared followed by a normal landing.

Narrative: First Officer and I were assigned a ferry flight with no passengers. We were in VMC the entire flight. We were cleared for a visual approach and on about a 4 mile base to final leg we selected the gear down. We experienced what we perceived normal tactile sensations of the gear moving to the down position but none of the red gear unsafe lights or the green gear down and locked lights illuminated. On final; I raised the gear lever; then reselected the gear down in an attempt to obtain the three green down and locked gear lights. This made no improvement. We executed a go-around and notified the tower of our go-around and that we were experiencing gear indication problems. The tower vectored us to a right downwind initially and later took us about 10 miles out from the field where we could trouble shoot the problem. Control of the aircraft as well as responsibility for monitoring the radios was transferred to the First Officer who was pilot flying while I proceeded with trouble shooting and execution of checklists. I pressed the overhead annunciator push to test button and saw all three red gear unsafe lights as well as all three green gear down lights. I attempted to extend the gear one more time and saw no improvement in conditions. We confirmed the standby nose gear pin was up indicating the nose gear was in the down position and system hydraulics showed normal pressure and quantity. The right side panel standby main gear indicator lights showed only the left main annunciator illuminated. I attempted to swap the bulbs in the standby gear annunciators to eliminate possible burned out bulbs or poor contacts causing the problem. I discovered there was only one bulb in the right main standby annunciator and it was in fact burned out. I again pushed the annunciator push to test on the overhead panel which showed that trading bulbs in the standby annunciators made no difference. We slowed the aircraft to 145 KIAS to see if the gear warning horn would sound indicating the gear was unsafe. The horn did not sound. I then went to the emergency checklist for Landing Gear No Three Green Indication. The initial steps for this checklist instruct the gear horn and EGPWS circuit breakers to be pulled. When I opened the DA-D breaker panel door to pull the gear horn circuit breaks I discovered two breakers had tripped. These were J4 (Annunciator Push to Test) and K2 (Gear Indicator). It is interesting to point out that even with these two breakers tripped; all the gear indication lights illuminated with the annunciator push to test button depressed. The existing conditions/circumstances didn't seem to follow or match the direction the emergency checklist would lead us to act. We discussed the issues surrounding FOM policy of not resetting tripped circuit breakers in flight and decided that this situation and set of circumstances was not consistent with the intent of the emergency checklist. Wanting to exhaust every possible avenue of confirming the gear was indeed down; we chose to reset K2. Resetting K2 caused the gear down three green indication to illuminate for a brief moment until the circuit breaker tripped again. No further reset attempts were made on any circuit breakers. I contacted the Assistant Chief Pilot via flight phone and was conferenced in with the Maintenance Controller on duty. I described our situation and the indications we had. It was suggested that we do a fly-by past the tower to allow tower personnel to visually examine the condition of the gear. I suggested that we proceed with steps to lower the gear using the auxiliary hydraulic system just as another means to ensure the gear was indeed down. All agreed we had nothing to lose in trying this. I followed the checklist steps to accomplish this. Once complete we informed the approach controller we were ready for return. By the time the checklists and phone calls were completed we assessed our fuel situation and noted we had approximately 1;100 lbs of fuel remaining. I didn't feel comfortable trying to complete a fly-by the tower plus return for landing with our remaining fuel and elected to proceed to the airport for landing. We declared an emergency and requested the emergency equipment be standing by. Runway 20L was requested because it was the longest available. Additionally; we informed the tower that we would stop on the runway and needed to be towed to the FBO from our stopping point. The First Officer flew a stabilized approach and made a smooth landing stopping on the centerline. We ran the after landing and engine shutdown checklists. The airport emergency equipment followed us to our stopping point. I spoke with them and informed them everything appeared to be ok-- we just needed to be towed from that point to our parking. I installed the gear pins and the tug arrived to tow the aircraft to their ramp. Upon arrival at the ramp I generated and submitted a maintenance discrepancy. The circumstances of our situation were rather unusual. I am not sure there was more we could have done to address the situation or to prevent its occurrence.

Data retrieved from NASA's ASRS site as of April 2012 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.