Narrative:

Landing gear was extended at normal location outside OM on ILS runway 9 at sav. There was no green light indicating the nosewheel was down and locked. Gear was recycled -- still no green light. Landing was aborted and the field was overflown at about 1500 ft MSL. Tower advised the nosewheel was down. We entered a right downwind and eventually went back to approach control while we worked through the problem. The QRH didn't really address our problem (wheel down with no light). We tested the light (would not test) and switched lights with left main gear (still would not test). I checked the gear down and locked visual indicator and could not confirm the gear was locked. The window was dirty (covered with thin black film). Plus I was looking into a dimly lit area that was backlit by the bright outside conditions. In addition, our procedure states to 'verify that the mechanical indicator(south) are aligned.' in the case of the nosewheel, the indicators are always aligned whether the wheel is locked or not. It is impossible to tell from this system. An emergency was declared, the cabin was prepared and an emergency landing (precautionary) was made. The landing was normal. The nose gear was locked. No injuries reported. Jiggling the light at the gate caused the light to work again. Maintenance checked plugs, connections, switches, and found no abnormalities. Callback conversation with reporter revealed the following information: reporter states that the maintenance in sav was on a contract basis and that the aircraft gear was pinned and jacked while inspection of the gear and indication system was checked. Nothing was found out of order. The bulbs in the indication system were checked and bases cleaned and in the process of doublechking the cannon plugs, all lighting and gear indications began to test normally. Reporter suspects possibility of multiple poor electrical contacts. The flight crew flew the aircraft to an air carrier maintenance facility where a plane change occurred. This flight was without further incident as all lights worked properly. The reporter remains concerned that he did not feel comfortable in looking through the viewports and not completely confident that the indicators were indicating that the gear was definitely down and locked or if the indicators needed to be rerigged and realigned. The air carrier SOP for preflight is only to check that the light that shines on the alignment marks is working. To actually check the marks would take a ladder and flashlight.

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Original NASA ASRS Text

Title: B737-400 LANDS SAV WITHOUT POSITIVE NOSEWHEEL DOWN AND LOCKED INDICATIONS, EMER LNDG.

Narrative: LNDG GEAR WAS EXTENDED AT NORMAL LOCATION OUTSIDE OM ON ILS RWY 9 AT SAV. THERE WAS NO GREEN LIGHT INDICATING THE NOSEWHEEL WAS DOWN AND LOCKED. GEAR WAS RECYCLED -- STILL NO GREEN LIGHT. LNDG WAS ABORTED AND THE FIELD WAS OVERFLOWN AT ABOUT 1500 FT MSL. TWR ADVISED THE NOSEWHEEL WAS DOWN. WE ENTERED A R DOWNWIND AND EVENTUALLY WENT BACK TO APCH CTL WHILE WE WORKED THROUGH THE PROB. THE QRH DIDN'T REALLY ADDRESS OUR PROB (WHEEL DOWN WITH NO LIGHT). WE TESTED THE LIGHT (WOULD NOT TEST) AND SWITCHED LIGHTS WITH L MAIN GEAR (STILL WOULD NOT TEST). I CHKED THE GEAR DOWN AND LOCKED VISUAL INDICATOR AND COULD NOT CONFIRM THE GEAR WAS LOCKED. THE WINDOW WAS DIRTY (COVERED WITH THIN BLACK FILM). PLUS I WAS LOOKING INTO A DIMLY LIT AREA THAT WAS BACKLIT BY THE BRIGHT OUTSIDE CONDITIONS. IN ADDITION, OUR PROC STATES TO 'VERIFY THAT THE MECHANICAL INDICATOR(S) ARE ALIGNED.' IN THE CASE OF THE NOSEWHEEL, THE INDICATORS ARE ALWAYS ALIGNED WHETHER THE WHEEL IS LOCKED OR NOT. IT IS IMPOSSIBLE TO TELL FROM THIS SYS. AN EMER WAS DECLARED, THE CABIN WAS PREPARED AND AN EMER LNDG (PRECAUTIONARY) WAS MADE. THE LNDG WAS NORMAL. THE NOSE GEAR WAS LOCKED. NO INJURIES RPTED. JIGGLING THE LIGHT AT THE GATE CAUSED THE LIGHT TO WORK AGAIN. MAINT CHKED PLUGS, CONNECTIONS, SWITCHES, AND FOUND NO ABNORMALITIES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THE MAINT IN SAV WAS ON A CONTRACT BASIS AND THAT THE ACFT GEAR WAS PINNED AND JACKED WHILE INSPECTION OF THE GEAR AND INDICATION SYS WAS CHKED. NOTHING WAS FOUND OUT OF ORDER. THE BULBS IN THE INDICATION SYS WERE CHKED AND BASES CLEANED AND IN THE PROCESS OF DOUBLECHKING THE CANNON PLUGS, ALL LIGHTING AND GEAR INDICATIONS BEGAN TO TEST NORMALLY. RPTR SUSPECTS POSSIBILITY OF MULTIPLE POOR ELECTRICAL CONTACTS. THE FLC FLEW THE ACFT TO AN ACR MAINT FACILITY WHERE A PLANE CHANGE OCCURRED. THIS FLT WAS WITHOUT FURTHER INCIDENT AS ALL LIGHTS WORKED PROPERLY. THE RPTR REMAINS CONCERNED THAT HE DID NOT FEEL COMFORTABLE IN LOOKING THROUGH THE VIEWPORTS AND NOT COMPLETELY CONFIDENT THAT THE INDICATORS WERE INDICATING THAT THE GEAR WAS DEFINITELY DOWN AND LOCKED OR IF THE INDICATORS NEEDED TO BE RERIGGED AND REALIGNED. THE ACR SOP FOR PREFLT IS ONLY TO CHK THAT THE LIGHT THAT SHINES ON THE ALIGNMENT MARKS IS WORKING. TO ACTUALLY CHK THE MARKS WOULD TAKE A LADDER AND FLASHLIGHT.

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.