Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 148.28; Flight Crew Total 22000; Flight Crew Type 13200
Communication Breakdown; Distraction; Training / Qualification; Workload; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented
Human Factors
On final; Runway XXL; ZZZ; Night; 1000 foot ceiling; Me (Captain) flying; gusty winds; very light load; FO low currency- only 150 hrs in type since hired 1 year ago; and has not been flying much. I was hand flying at 2;000 feet on normal ILS. Called for gear down; flaps 15 at approximately 2;000 feet and flaps 30 landing; check at about 1500 feet. FO ran check list; while I hand flew the approach. The winds were gusty; our target was +15 ref and it was night.  I saw flap refs change on airspeed tape; and glanced at gear lights when FO ran checklist; but I did not have full attention to FO duties since it was dark and gusty. We broke out at 1;000 feet; I called clear to land and set missed approach altitude. At 500 feet we simultaneously got the 500 auto call out and Too Low Flaps. I simultaneously; started a Go-Around (finger to toga button) and looked at flap gauge - which was at 25. But I hesitated on the go-around when I saw why we got the GPWS. I commanded flaps set to 30; which the FO immediately did. We were then about 350-400 feet and stable; and I continued to a normal landing. After landing I realized; even though there was adequate time to set the flaps to 30; I should have gone around. We debriefed after parking. The FO said he just missed the flaps in setting and checking on the checklist; most likely due to being low time in aircraft and rusty from time off. I missed his wrong setting; due to the dark and the gusty winds requiring my attention. I said I should have gone around; and that he as well should have told me to. I am confident if I had not immediately recognized why we got the too low flaps and immediately corrected it; I would not have continued.
Air Carrier Captain reported a TOO LOW FLAPS warning and an Unstabilized Approach.