B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP)
Flight Crew Type 2976
Distraction; Fatigue; Situational Awareness
Deviation - Altitude Undershoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Environment - Non Weather Related; Human Factors; Procedure
Arrival DYAMD3 briefed and ILS 28R briefed. Verified all altitudes and speed constraints prior to brief. Speed assignment of 250 kts given for traffic. Speed entered into FMC and a discussion of the speed constraints on arrival because the initial two are 280. We opted to leave FMC with input values of 280 instead of changing. Cruise altitude FL360 and given a descent clearance to FL320 and executed by DES NOW prompt in VNAV PATH. A descend via clearance was given and 8000 set in window. Another discussion on setting of airspeed ensued as the FMC would not accept 250 kts over the hard coded 280 kts at LAANE. However; 250 kts was entered at FLOWZ and therefore allowed the FO to enter 250 kts at LAANE. I visually saw the input from the FO on the FMC. During descent on DYAMD3 encountered wake from a heavy which turned the autopilot off. FO re-engaged autopilot shortly afterwards. We were also given the Quiet Bridge routing to RWY 28R. I visually noted the change on the DEP/ARR page that the FO had input; only the approach was changed with transition of ARCHI. I did not check the legs page as I normally do; fatigue; and reverify the route/speed/altitude. NORCAL approach 128.32 queried when we were going to descend from FL250. I visually checked FMC and saw 250/FL250 over FLOWZ and referenced the chart which is FL190 to 14000. Then radar vectors in a box pattern to get to correct altitude. No further problems. We debriefed and could not identify the exact cause of the error to prevent future errors.
B737 Captain reported they failed to make a crossing restriction on arrival into SFO. Fatigue and distraction from a wake turbulence encounter were cited as contributing factors.