B737 flight crew encounters failure of landing gear warning lights on landing.

Attributes
ACN	786118
Time
Date	200805
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 25l
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 240
ASRS Report	786118
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

On ILS approach to runway 25L at ZZZ; when gear handle lowered; no gear down and locked indications. Had red nose gear light only. Checked circuit breakers; as did the first officer; and all were in. Check lights test and all lights tested except left main -- neither light worked. Replaced bulbs in same and still lights did not test. First officer completed manual gear extension checklist and went to cabin to check view ports of mains and the nose view port in the cockpit. Did the lights test in bright and dim position. Prior to this; we missed and flew down runway for tower to give us a visual. Tower said gear appeared to be down. Declared an emergency; briefed dispatch; maintenance; operations; and flight attendants and passenger on situation. Told passenger that I believed the gear was down; but that we were going to have flight attendants brief emergency landing procedures and have the emergency equipment standing by as a precaution. Normal landing and rollout. Taxied clear of runway and had line pin gear before we taxied to gate for normal deplaning. After landing; the gear sensing/light circuit breaker popped; creating normal indications that aircraft was still airborne. Biggest distraction and workload was when first officer left cockpit to check view ports. Autoplt was used to manage workload. It was a mechanical issue. First officer and flight attendants did super job.

Original NASA ASRS Text

Title: B737 FLT CREW ENCOUNTERS FAILURE OF LNDG GEAR WARNING LIGHTS ON LNDG.

Narrative: ON ILS APCH TO RWY 25L AT ZZZ; WHEN GEAR HANDLE LOWERED; NO GEAR DOWN AND LOCKED INDICATIONS. HAD RED NOSE GEAR LIGHT ONLY. CHKED CIRCUIT BREAKERS; AS DID THE FO; AND ALL WERE IN. CHK LIGHTS TEST AND ALL LIGHTS TESTED EXCEPT L MAIN -- NEITHER LIGHT WORKED. REPLACED BULBS IN SAME AND STILL LIGHTS DID NOT TEST. FO COMPLETED MANUAL GEAR EXTENSION CHKLIST AND WENT TO CABIN TO CHK VIEW PORTS OF MAINS AND THE NOSE VIEW PORT IN THE COCKPIT. DID THE LIGHTS TEST IN BRIGHT AND DIM POS. PRIOR TO THIS; WE MISSED AND FLEW DOWN RWY FOR TWR TO GIVE US A VISUAL. TWR SAID GEAR APPEARED TO BE DOWN. DECLARED AN EMER; BRIEFED DISPATCH; MAINT; OPS; AND FLT ATTENDANTS AND PAX ON SIT. TOLD PAX THAT I BELIEVED THE GEAR WAS DOWN; BUT THAT WE WERE GOING TO HAVE FLT ATTENDANTS BRIEF EMER LNDG PROCS AND HAVE THE EMER EQUIP STANDING BY AS A PRECAUTION. NORMAL LNDG AND ROLLOUT. TAXIED CLR OF RWY AND HAD LINE PIN GEAR BEFORE WE TAXIED TO GATE FOR NORMAL DEPLANING. AFTER LNDG; THE GEAR SENSING/LIGHT CIRCUIT BREAKER POPPED; CREATING NORMAL INDICATIONS THAT ACFT WAS STILL AIRBORNE. BIGGEST DISTR AND WORKLOAD WAS WHEN FO LEFT COCKPIT TO CHK VIEW PORTS. AUTOPLT WAS USED TO MANAGE WORKLOAD. IT WAS A MECHANICAL ISSUE. FO AND FLT ATTENDANTS DID SUPER JOB.

Data retrieved from NASA's ASRS site as of May 2009 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.