A B737 crew experienced a gear unsafe light upon gear retraction. Returned to departure airport.

Attributes
ACN	505052
Time
Date	200103
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 5000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	505052
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : gear unsafe light other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist flight crew : landed as precaution
Supplementary
Problem Areas	Aircraft Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

Departed runway 9L ord. Moved gear lever to 'up' to raise the gear. Left red gear unsafe light stay on. Leveled off at 5000 ft and reduced the power to stay at 220 KTS to troubleshoot. I was aware of the log history and that this had occurred before. This was my leg and I was flying. I asked the first officer to move the gear leer to 'off.' shortly after that, the left green gear down and locked light came on and the red unsafe light stayed illuminated. I xferred flight control and radios to the first officer. I then called the purser and gave a quick explanation. After that I called dispatch and got a patch maintenance kept cutting in and out, but after a while we agreed to move the gear leer down and we got 3 green. We landed without event. We did not do a cabin advisory or declare an emergency. I felt comfortable with the log history and the 3 green indications that we had a safe gear to land on and anticipated a routine landing. Our landing weight was low (about 90000 pounds) and I took the controls back for a flaps 40 degree landing on runway 9R with a right crosswind. Everything else was uneventful.

Original NASA ASRS Text

Title: A B737 CREW EXPERIENCED A GEAR UNSAFE LIGHT UPON GEAR RETRACTION. RETURNED TO DEP ARPT.

Narrative: DEPARTED RWY 9L ORD. MOVED GEAR LEVER TO 'UP' TO RAISE THE GEAR. LEFT RED GEAR UNSAFE LIGHT STAY ON. LEVELED OFF AT 5000 FT AND REDUCED THE PWR TO STAY AT 220 KTS TO TROUBLESHOOT. I WAS AWARE OF THE LOG HISTORY AND THAT THIS HAD OCCURRED BEFORE. THIS WAS MY LEG AND I WAS FLYING. I ASKED THE FO TO MOVE THE GEAR LEER TO 'OFF.' SHORTLY AFTER THAT, THE L GREEN GEAR DOWN AND LOCKED LIGHT CAME ON AND THE RED UNSAFE LIGHT STAYED ILLUMINATED. I XFERRED FLT CTL AND RADIOS TO THE FO. I THEN CALLED THE PURSER AND GAVE A QUICK EXPLANATION. AFTER THAT I CALLED DISPATCH AND GOT A PATCH MAINT KEPT CUTTING IN AND OUT, BUT AFTER A WHILE WE AGREED TO MOVE THE GEAR LEER DOWN AND WE GOT 3 GREEN. WE LANDED WITHOUT EVENT. WE DID NOT DO A CABIN ADVISORY OR DECLARE AN EMER. I FELT COMFORTABLE WITH THE LOG HISTORY AND THE 3 GREEN INDICATIONS THAT WE HAD A SAFE GEAR TO LAND ON AND ANTICIPATED A ROUTINE LNDG. OUR LNDG WT WAS LOW (ABOUT 90000 LBS) AND I TOOK THE CTLS BACK FOR A FLAPS 40 DEG LNDG ON RWY 9R WITH A R XWIND. EVERYTHING ELSE WAS UNEVENTFUL.

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.