Medium Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Last 90 Days 200; Flight Crew Type 1615
Situational Awareness; Confusion
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented
Procedure; Human Factors
We were set up for 8L; visual conditions. Just before turning base leg we were told to expect 8R. We set up the radios and FMS; ATC vectored us to about 2 miles outside MATON (FAF) we descended to 2;000 feet; which is the crossing altitude at MATON. We were cleared for the visual approach to 8R; it was in sight. Everything was normal; the approach mode was armed. Because we were intercepting both the LOC and GS at the same time very close to MATON; we didn't expect to see the GS signal immediately. At MATON the airplane pitched up rather dramatically to around 15 degrees and the autothrottles pushed up the power and pulled it back; it was very confused. I clicked off the autopilot immediately and pushed the nose over; and then remembered hearing ATC tell someone else much earlier; when we were still planning for 8L; that the GS was out of service on 8R. We recovered the situation but in the process gained almost 500 feet at MATON. Whether it was the right thing to do or not we recovered it and landed. We were certainly configured per the stabilized approach criteria; but our speed was a bit fast; maybe 15 kts fast most of the way down. The landing was in the touchdown zone. So we may not have met stabilized approach criteria; and we definitely gained close to 500 feet coming over the FAF. It is; of course; my job to know that the GS was Out of Service (OTS); but the runway change happened fast. Either way; I've never seen an autopilot behave that way to a lack of GS signal. I did not write it up as I really wasn't sure WHAT to write up; it was just responding to erroneous signals. I rather felt this was my fault as I never should have engaged the GS; but this is our standard procedure for any approach with an ILS; visual or not. It isn't necessarily the responsibility of ATC to remind every single pilot that the GS is OTS either.
Air carrier Captain reported a late runway change resulted in an unstabilized approach to a landing.