Narrative:

On the before landing checklist for the ILS to runway 5; we noticed we had no lights indicating any gear position on the gear indicator panel. We pushed to test all six lights and none illuminated. We continued the approach with the intent of going around to troubleshoot. We broke out at 600 ft MSL; performed a go-around; and requested the tower to visually check our gear while we went around. The tower stated that they believed the main gear were down and locked and thought the nose gear was down but could not tell if it was down all the way. There was significant weather in the entire terminal area with heavy rain showers in the vicinity. (We were IMC at all times with the exception of when we broke out on the ILS approaches.) on the go-around; we elected to leave the gear down and flaps at position 5. The captain took over the pilot flying duties on the downwind leg. As we attempted to troubleshoot the problem; we first turned to the L-12 page in the checklist and verified all the circuit breakers on that page were in. At this point; both the captain and I believed the gear was down and locked and we simply had an indicator panel failure. We attempted to independently reconfirm the gear were down with the nose and main gear view finders. I was able to confirm the nose gear down through the viewfinder; but was unable to confirm the main gear due to condensation and water on the outside of the viewfinder and the weather. About the time I made it back up to the cockpit; we were approaching base to final for another ILS approach. The captain and I determined that we had enough fuel to do one more low approach and vector around for another ILS in order to give us time to run all the applicable checklists. By the time we did this low approach; either ATC or dispatch had already declared an emergency for us and the crash vehicles were on the scene. During the low approach; one of the crash vehicles (presumably the fire chief) was in a good position to observe the gear; and relayed through the tower that they all appeared down and locked. During the subsequent radar pattern; we completed the unsafe gear indication/manual gear extension checklist and landing with unsafe gear indication checklist. The one mistake we made is when we looked at the first note on the unsafe gear indication/manual gear extension checklist about the P6 3 D 14 circuit breaker. We thought that the circuit breaker was one of the ones we had checked when we looked at all the circuit breakers listed on the L12 page and continued with the checklist. We completed all the checklist items from there on out. ATC informed us there was a heavy rain shower two miles from the approach end of the runway moving toward the airfield. The captain and I made the decision to request a short approach from ATC in order complete the ILS before the weather became a limiting factor. We completed a normal 30 flap approach to a full stop; and had the landing gear pinned on the runway before taxiing to the gate for shutdown. On taxi in; dispatch had us look at the P-6-3-D22 circuit breaker (which did not exist on this airplane); P-6-3-B22 circuit breaker (which also did not exist on this airplane) and the P6-3-D14 circuit breaker (which we pushed in and got the gear indicator lights to come on). To summarize the whole event; we generally had our hands full due to the weather conditions at the airport at the time of the event. The pilot flying was pretty much fully engaged mentally with flying the aircraft; avoiding the weather; and coordinating with ATC which left little room for putting brain cells toward backing up the checklist. We also felt somewhat time limited in that we elected to leave the landing gear down; our fuel burn rates were higher; and we wanted to stay close to the airport in case the rain showers threatened to bring the weather below landing minimums (hence one of the major reasons we elected to continue getting vectors for ILS approaches while we attempted to troubleshoot). The lesson learned for us is if a note references a circuit breaker to check; it is worth taking the time to physically find that exact circuit breaker (a second time; if necessary); putting your finger on it; and double confirming you are looking at the circuit breaker the note references. It is easy to miss one even when think you have checked them all several times.

Google
 

Original NASA ASRS Text

Title: A B737-300's landing gear indicating circuit breaker popped and so the crew received no gear indication with the gear handle down. Unable to find the circuit breaker they landed with emergency equipment standing by and at the gate found the applicable breaker popped.

Narrative: On the Before Landing Checklist for the ILS to Runway 5; we noticed we had no lights indicating any gear position on the gear indicator panel. We pushed to test all six lights and none illuminated. We continued the approach with the intent of going around to troubleshoot. We broke out at 600 FT MSL; performed a go-around; and requested the Tower to visually check our gear while we went around. The Tower stated that they believed the main gear were down and locked and thought the nose gear was down but could not tell if it was down all the way. There was significant weather in the entire terminal area with heavy rain showers in the vicinity. (We were IMC at all times with the exception of when we broke out on the ILS approaches.) On the go-around; we elected to leave the gear down and flaps at position 5. The Captain took over the pilot flying duties on the downwind leg. As we attempted to troubleshoot the problem; we first turned to the L-12 page in the checklist and verified all the circuit breakers on that page were in. At this point; both the Captain and I believed the gear was down and locked and we simply had an indicator panel failure. We attempted to independently reconfirm the gear were down with the nose and main gear view finders. I was able to confirm the nose gear down through the viewfinder; but was unable to confirm the main gear due to condensation and water on the outside of the viewfinder and the weather. About the time I made it back up to the cockpit; we were approaching base to final for another ILS approach. The Captain and I determined that we had enough fuel to do one more low approach and vector around for another ILS in order to give us time to run all the applicable checklists. By the time we did this low approach; either ATC or Dispatch had already declared an emergency for us and the crash vehicles were on the scene. During the low approach; one of the crash vehicles (presumably the Fire Chief) was in a good position to observe the gear; and relayed through the Tower that they all appeared down and locked. During the subsequent radar pattern; we completed the Unsafe Gear Indication/Manual Gear Extension Checklist and Landing with Unsafe Gear Indication Checklist. The one mistake we made is when we looked at the first note on the Unsafe Gear Indication/Manual Gear Extension Checklist about the P6 3 D 14 CB. We thought that the circuit breaker was one of the ones we had checked when we looked at all the circuit breakers listed on the L12 page and continued with the checklist. We completed all the checklist items from there on out. ATC informed us there was a heavy rain shower two miles from the approach end of the runway moving toward the airfield. The Captain and I made the decision to request a short approach from ATC in order complete the ILS before the weather became a limiting factor. We completed a normal 30 flap approach to a full stop; and had the landing gear pinned on the runway before taxiing to the gate for shutdown. On taxi in; Dispatch had us look at the P-6-3-D22 CB (which did not exist on this airplane); P-6-3-B22 CB (which also did not exist on this airplane) and the P6-3-D14 CB (which we pushed in and got the gear indicator lights to come on). To summarize the whole event; we generally had our hands full due to the weather conditions at the airport at the time of the event. The pilot flying was pretty much fully engaged mentally with flying the aircraft; avoiding the weather; and coordinating with ATC which left little room for putting brain cells toward backing up the checklist. We also felt somewhat time limited in that we elected to leave the landing gear down; our fuel burn rates were higher; and we wanted to stay close to the airport in case the rain showers threatened to bring the weather below landing minimums (hence one of the major reasons we elected to continue getting vectors for ILS approaches while we attempted to troubleshoot). The lesson learned for us is if a note references a circuit breaker to check; it is worth taking the time to physically find that exact circuit breaker (a second time; if necessary); putting your finger on it; and double confirming you are looking at the circuit breaker the note references. It is easy to miss one even when think you have checked them all several times.

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.