A321
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Fatigue; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented
Human Factors
On our return flight we were cleared the visual approach about 20 miles south of DEN for Runway 35R. Before being handed over to Tower we were assigned 170 kts until FRONZ and intercepted the LOC and GS well south of FRONZ. South of FRONZ we were given our landing clearance and I had a gradual intercept with the GS. I am not exactly sure what happened in the interim but I remember being just inside FRONZ on the LOC and GS and we got the gear horn in which we immediately lowered the gear; got fully configured; ran the landing checklist and continued to landing. In the moment where we were it just seemed so stable just not fully configured. The Captain said the approach looked fine and we were on speed; fully configured and had the before landing checklist completed so quickly at that moment it seemed like the best decision and we landed safely. I do not feel that I was fatigued but I do remember being pretty tired on our return; we descended on the arrival without incident around some weather and the approach just seemed so uneventful. 20/20 hindsight I thought I remember thinking that the gear horn went off at 1;500 feet but I don't think that was correct and realized that it may not have qualified for the stabilized approach minimums. I feel like in the future having a bit more situational awareness of the Final Approach Fix regardless of our visual status would have helped. Communicating a bit more and using more callouts for both the Non-flying pilot and myself to hear to help with that situational awareness would have helped as well. I normally am pretty good about being in managed speed before the final approach fix as well but today I was not so I will work on making sure that speed is managed to approach speed by that point in the future regardless of ATC requests for us to hustle on our arrival.
A321 First Officer reported unstabilized approach into DEN citing fatigue as a factor.