B737 Undifferentiated or Other Model
Fatigue; Workload; Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
General None Reported / Taken
Human Factors; Procedure; Environment - Non Weather Related; Company Policy
We where scheduled to fly pairing a pairing that contained 2 red eyes both of which fly during the window of circadian low (WOCL) for our local base time. After the first red eye to the midwest I got about 3 hours sleep in at the hotel. That afternoon we did 2 legs and arrived at the hotel around well after midnight. I stayed up until over an hour trying to prep for the next night. I slept until mid morning getting about 6 hours sleep. I tried that afternoon to take a nap but was unsuccessful. Now I was in a position where I felt OK heading to the airport but knew I would be tired arriving after an all night cross country. The only choice I felt I had was to either preemptively call in fatigued or fly and hope for the best. I choose to fly but hit a wall half way across the country. Both the First Officer and myself where having an extremely hard time just staying awake. On final luckily it was VFR. The First Officer kept us fast and we failed to meet the configuration/speed gates on final. We where both so tired we where slow to recognize the problem.  We should have gone around but failed to do so. We landed uneventfully but this could have gone very wrong if we had met any real challenges.
A Captain flew a trip which included two red eyes both of which in the window of circadian low (WOCL). The second night both pilots were extremely fatigued and during an unstabilized approach did not go around because the situation was not recognized.