A320
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 168; Flight Crew Type 239
Situational Awareness; Communication Breakdown; Human-Machine Interface
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Overcame Equipment Problem
Aircraft; Procedure; Company Policy
ILS 28R approach SFO; 500' ceiling winds 280@22 10 miles vis. Captain briefed flaps 3 approach and landing. ATC assigned 160 knots until AXMUL. Aircraft was flaps 2 gear up prior to AXMUL. At AXMUL Captain called for gear down; managed speed; landing checklist which I executed. I made the 500' call out and Captain replied 'stable'. I verified on speed and glide slope. I commented that airspeed bug was well above briefed Vapp; 'must be mini ground speed' due to the large head winds. Inside the 500' foot call out we received an audible 'too low; flaps' call. Both of us looked and verified flaps still at 2. Captain then immediately called for flaps 3. I positioned flaps to 3 and Captain made a normal uneventful landing. We heavily debriefed what happened after the flight. Captain admitted he had forgotten to call for flaps 3. Captain said he should have gone around but at the time felt flap change and landing was safe option vs flaps 1 go around back into the weather. I thought I had properly run the landing checklist. It was very dark on the flight deck so I brought up the map light to read the checklist. I believe when I did that it affected my night vision enough that I did not notice flaps read 2 and not 3. I do remember seeing the flaps 3 config ECAM message which may have contributed to me think we were correctly configured.
A320 First Officer reported flaps not at proper setting; un-stabilized approach; and failing to go around according to policy.