Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Total 1313; Flight Crew Type 1179
Confusion; Human-Machine Interface; Situational Awareness; Training / Qualification; Workload; Distraction
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Became Reoriented
Procedure; Airspace Structure; Environment - Non Weather Related; Human Factors
SFO flight was final leg of two day trip. We agreed upon letting [First Officer] fly the next two legs with VFR conditions and light winds; etc. Neither of us thought of the restriction in SFO requiring 100 hours for a new First Officer. The SFO approach should have been flown by myself. The First Officer was very experienced flying into SFO being based there as a [Company] Captain for many years before [us]. With the operational challenges and comfort with SFO; we both missed it.	The flight to SFO was expected to be challenging enroute due to moderate turbulence much of the way across the U.S. As it turned out; starting off at 30;000 feet and then climbing to 38;000 feet resulted in a very comfortable and uneventful flight. We briefed the DYAMD 4 and FMS 28R BRIDGE Visual early and in great detail with a robust conversation on techniques for the BRIDGE Visual. I recommended not attempting to try things such as switching to APP at end game; just use LNAV and VNAV (and the PAPI) for the entire approach which we agreed upon doing. We were given a 'Descend VIA' clearance on the DYAMD 4 with course only after ARCHI which is pretty standard. Visibility was outstanding and we could see the runways well outside of ARCHI. After ARCHI we were given two descents and two or three speed restrictions. At the same time; we were notified of approaching traffic for Runway 28L and to maintain visual separation with the traffic. This traffic was back at our 8 to 7 o'clock position and required some effort to monitor. As it turns out; the traffic was actually trying to go to OAK. During the resultant turn off and away from Runway 28L and across our 6 o'clock; I got a good dose of landing lights and diverted my attention back out of the flight deck to watch the traffic. When I returned inside I was tasked with gear; flaps; checklist; etc. What I failed to notice immediately is that LVL CHG was still selected to aid in controlling speed and without asking for the altitude window to be reset to the next lowest altitude. The aircraft did not have the Speed Intervene button and the First Officer chose this method vs. returning to VNAV and using manual throttles after the second level off as I was expecting.Consequently; the aircraft started to descend below the normal path crossing SAMUL as final flaps were selected; and I was busy inside with the checklist; tower call; etc. The First Officer clicked off the autopilot and started to correct for the steeper than normal descent. As I looked out to crosscheck; I saw the PAPI lights going towards all red. Tower called us at this time to notify that we were low on path. The First Officer was shallowing the descent with perhaps a bit too much emphasis on being smooth. Tower called a second time to tell us that we were triggering a low altitude alert. I assured them that we were already correcting. We intercepted the normal glidepath at 800 feet and landed uneventfully. Once at the gate; we debriefed the sequence of events; errors made; and how VNAV would have been the proper mode to be in with TDZ set and the requirement to reset the altitude window with use of LVL CHG and the restriction that it cannot be used below 1;000 feet. Even though I felt it was a perfect night with easy conditions and a straightforward arrival/approach; I failed to realize how challenging the approach could be as a crew with just a simple distraction or two at an untimely moment and our differing experience levels in the mix. Ultimately; the SOPs work to include SFO's Special Qualification status.
B737 Captain reported the First Officer who did not meet the special SFO requirement of 100 hours flew an approach into SFO and descended below the glidepath.