Date: 201210
Local time of day: 1201-1800
Location: SAN.Airport, CA
Flight conditions: VMC
Light: Daylight
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight phase: Initial Approach
Airspace: Class B SAN
ATC / advisory: Tower SAN
Aircraft component: Indicating and Warning - Landing Gear
Component problem: Design
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: During a day VMC approach to Runway 27 in SAN; we briefed and were slowing for configuration for landing. I was at idle power for most of the approach from about 15 miles out due to a 10-15 KT tailwind. The gear was lowered; followed by the flaps at the proper airspeed's to the landing position of 40 degrees. I called for the Before Landing Checklist at about 1;500 FT still at idle so as to be in the slot at 1;000 FT which was accomplished. The three red lights were probably there also at this time; but my mind dismissed them as wrong because; in this model of aircraft; they are red any time the gear is not down and the thrust levers are at idle. At approximately 500 FT I did my normal 'five green at 500 FT' check as I always do to double check the landing configuration. At that time; I saw the five green lights I normally do; but this time I also saw three red lights in the gear indicators. My mind raced to figure out why the red lights were there but about that time we got a single 'too low gear' audio warning. Instantly the First Officer pushed on the gear handle and the red lights went out and the audio warning never came on again. We landed without further incident in SAN.Several issues (not excuses; but reasons) were at play here about why neither myself; the First Officer; nor a Captain Jumpseater didn't recognize the red lights on the panel during or after the Before Landing Checklist. First of all; in this model of aircraft (which this was the third consecutive flight of the day in this one); those red lights are on during all descents when the thrust levers are in idle and I recall I was in idle from about 15 miles out to just prior to 1;000 FT. Therefore; my mind became numb to them as being a warning. Second the sun was a minor factor in that; while landing to the west at SAN and with sunglasses on; the instrument panel in this aircraft is very dim (at best). Third; the First Officer has thrown the gear handle down hundreds; if not thousands; of times and he has never seen the gear handle not seat itself after extending the gear. He estimated the gear handle only had to be pushed in a fraction of an inch to make the red lights go out. We had no other indications of 'no gear'. After all; with the flaps set to any position more than 10 degrees without the gear being down; it will set off the configuration warning tone. Also; I had heard the 'chunk' of the gear going down; felt the correct feeling of drag caused by the extended gear; and saw the three green lights. How I missed the three red ones at the same time and in the same place; I still cannot explain. I take full responsibility for not seeing the three red lights in conjunction with the three green lights during the Before Landing Check. I was in the process of trying to figure out why I was seeing the red lights at about 500 FT (with the throttle not in the idle position as during the majority of the approach) when the aural warning alerted us. The First Officer acted quickly and properly to re seat the gear handle and for that I'm thankful. I was in the process of executing a go-around but the problem was solved before I could initiate go-around actions. The cure to this would be to make this model aircraft like the newer models in gear indications and pay attention to what is actually being displayed and not what you think you should see.




Synopsis: B737-300 Captain experiences a 'too low gear' GPWS warning at 500 FT AGL during approach; and three red gear disagree lights are noted above the gear handle. The First Officer nudges the gear handle into its' detent and the lights immediately go out; followed by a normal landing.