B737 flight crew reported no green light on the left main gear on initial extension. Aircraft divert...

Attributes
ACN	1413985
Time
Date	201701
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	Main Gear
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 239
Person 2
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 234 Flight Crew Type 12000
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

We were on the approach when we lowered the gear handle. The left main gear showed a red light and the other two (right main and nose) were green. This indicated to us that the left main gear was not down and locked. The captain called for a go-around and we did. We climbed up to a safe altitude and attempted to bring down the gear two more times but continued to only get two green lights. We started to run the checklist needed in the QRH but realized we had to make a decision on where to land because the weather [at our destination] was above and below mins constantly. We made the choice to divert to our alternate because the weather there was above one mile visibility and the longest runway was 12;000 ft. As we got closer to [the alternate]; we continued to run the required QRH checklist and ended up using the manual gear extension lever to lower the left main gear. After doing this; we had our three green lights needed for us to land safely. Upon landing; the gear held the weight of the aircraft and we taxied to the gate safely.

Original NASA ASRS Text

Title: B737 flight crew reported no green light on the Left Main Gear on initial extension. Aircraft diverted due to weather and runway length and landed uneventfully after manual gear extension.

Narrative: We were on the approach when we lowered the gear handle. The left main gear showed a red light and the other two (right main and nose) were green. This indicated to us that the left main gear was not down and locked. The Captain called for a go-around and we did. We climbed up to a safe altitude and attempted to bring down the gear two more times but continued to only get two green lights. We started to run the checklist needed in the QRH but realized we had to make a decision on where to land because the weather [at our destination] was above and below mins constantly. We made the choice to divert to our alternate because the weather there was above one mile visibility and the longest runway was 12;000 ft. As we got closer to [the alternate]; we continued to run the required QRH checklist and ended up using the Manual Gear Extension Lever to lower the left main gear. After doing this; we had our three green lights needed for us to land safely. Upon landing; the gear held the weight of the aircraft and we taxied to the gate safely.

Data retrieved from NASA's ASRS site 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.

B737 flight crew reported no green light on the left main gear on initial extension. Aircraft diverted due to weather and runway length and landed uneventfully after manual gear extension.