Narrative:

Approach cleared us for a visual approach. We were at approximately 5000 ft; 250KIAS and 14 miles from the airport. Captain; as pilot flying; called for gear down. Gear indicator lights showed two green and one red annunciation. Nose gear and left main gear indicated down and locked while the right main did not. As we turned final; I transmitted to ATC our predicament and requested to discontinue the approach. ATC assigned runway heading and 3000 ft. While flying over the field at this altitude; the control tower conveyed to the approach controller that our right main gear did not appear to be extended. The captain called for the QRH; confirmed he would be the pilot flying and would assume ATC radio communications. At this point; we were left at 3000 ft and vectored to the north of the field. I then briefed the flight attendants and passengers on our situation. I performed the appropriate landing gear malfunction QRH procedures; which ultimately required that I go back into the cabin for a visual confirmation of the gear position. I called the flight attendants and explained what I would be doing; and subsequently made a PA announcement out in the cabin using the forward flight attendant PA. (The flight attendants said they were having a having a hard time hearing the PA in the cockpit with the excess noise from the gear hanging out.) one flight attendant took my place in the cockpit. Once at the proper location in the cabin; I removed one passenger seated directly above the main gear viewing window and removed a carry on bag that was underneath his seat. As I viewed through the portal; I clearly saw the red strut alignment stripes on each of the main gear were in the correct position. After checking it twice more and rereading that related section in the QRH; I returned to the forward cabin and gave another update to the passengers. I returned to the cockpit and the flight attendant returned to the cabin. After reporting to the captain; he called ATC for another approach to land. The QRH procedure explained that if the visual gear inspection was satisfactory; then just land normally; and checklist complete. But then; there is a sentence right under that; which explains: (note) if the landing gear horn sounds and cannot be silenced with flaps 25 or greater; the gear is not down and locked. The captain and I briefed each other that we would go-around again if we couldn't silence the horn; to further troubleshoot. I briefed the flight attendants on this last checklist item needing to be satisfied and to expect a normal landing. In the event of another go-around; then they would know why. Sure enough; after more flaps were selected as we approached the runway; the gear horn could not be silenced. We requested a low approach and a confirmation from ground vehicles and the control tower if everything appeared normal. Tower reported gear appears down and locked. After turning downwind again; we decided to have the flight attendants brief the passengers for an emergency landing; just to be on the safe side. We spent the next several minutes re-running the QRH checklists to see if I had missed anything. We talked about anything else we needed to do; multiple times; throughout this ordeal. We determined that everything we could have done had been done; and because our fuel was now approaching close to 3000 pounds remaining; we decided to make our final approach to land. At this point we agreed that an emergency landing with the required brace position call out was a little drastic; so we decided to define it as a precautionary landing. I called the flight attendants and confirmed that the passengers had been briefed on the emergency procedures; and that now this was going to be just a precautionary landing. I updated the passengers one last time and told them to expect a normal landing. We landed uneventfully and taxied to the gate. After shutdown; the red right main gear light returned to green; naturally. The contract mechanics told us that everything appeared to be normal with regard to the landing gear system; and that the problem was probably associated with the respective sensors.

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Original NASA ASRS Text

Title: A B737-300 right main landing gear indicated unsafe while the red gear align bars in the wheel well appeared to indicate down. After trouble shooting; checklist completion and thorough briefing an emergency was declared followed by an uneventful landing. The green light gear light illuminated after landing.

Narrative: Approach cleared us for a visual approach. We were at approximately 5000 FT; 250KIAS and 14 miles from the airport. Captain; as pilot flying; called for gear down. Gear indicator lights showed two green and one red annunciation. Nose gear and left main gear indicated down and locked while the right main did not. As we turned final; I transmitted to ATC our predicament and requested to discontinue the approach. ATC assigned runway heading and 3000 FT. While flying over the field at this altitude; the control tower conveyed to the Approach Controller that our right main gear did not appear to be extended. The Captain called for the QRH; confirmed he would be the pilot flying and would assume ATC radio communications. At this point; we were left at 3000 FT and vectored to the north of the field. I then briefed the flight attendants and passengers on our situation. I performed the appropriate landing gear malfunction QRH procedures; which ultimately required that I go back into the cabin for a visual confirmation of the gear position. I called the flight attendants and explained what I would be doing; and subsequently made a PA announcement out in the cabin using the forward flight attendant PA. (The flight attendants said they were having a having a hard time hearing the PA in the cockpit with the excess noise from the gear hanging out.) One Flight Attendant took my place in the cockpit. Once at the proper location in the cabin; I removed one passenger seated directly above the main gear viewing window and removed a carry on bag that was underneath his seat. As I viewed through the portal; I clearly saw the red strut alignment stripes on each of the main gear were in the correct position. After checking it twice more and rereading that related section in the QRH; I returned to the forward cabin and gave another update to the passengers. I returned to the cockpit and the Flight Attendant returned to the cabin. After reporting to the Captain; he called ATC for another approach to land. The QRH procedure explained that if the visual gear inspection was satisfactory; then just land normally; and checklist complete. But then; there is a sentence right under that; which explains: (Note) if the landing gear horn sounds and cannot be silenced with flaps 25 or greater; the gear is not down and locked. The Captain and I briefed each other that we would go-around again if we couldn't silence the horn; to further troubleshoot. I briefed the flight attendants on this last checklist item needing to be satisfied and to expect a normal landing. In the event of another go-around; then they would know why. Sure enough; after more flaps were selected as we approached the runway; the gear horn could not be silenced. We requested a low approach and a confirmation from ground vehicles and the control tower if everything appeared normal. Tower reported gear appears down and locked. After turning downwind again; we decided to have the flight attendants brief the passengers for an emergency landing; just to be on the safe side. We spent the next several minutes re-running the QRH checklists to see if I had missed anything. We talked about anything else we needed to do; multiple times; throughout this ordeal. We determined that everything we could have done had been done; and because our fuel was now approaching close to 3000 LBS remaining; we decided to make our final approach to land. At this point we agreed that an emergency landing with the required brace position call out was a little drastic; so we decided to define it as a precautionary landing. I called the flight attendants and confirmed that the passengers had been briefed on the emergency procedures; and that now this was going to be just a precautionary landing. I updated the passengers one last time and told them to expect a normal landing. We landed uneventfully and taxied to the gate. After shutdown; the red right main gear light returned to green; naturally. The contract mechanics told us that everything appeared to be normal with regard to the landing gear system; and that the problem was probably associated with the respective sensors.

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.