I was landing at SFO today on 19L and saw all the fire rescue equipment out and about. As we exited the runway a NW A330 landed on the 28's, which was odd since they hadn't been available for us -- in fact, a couple minutes later they resumed using 10R for departures. Meanwhile after he landed all the equipment followed him, and last I saw the A330 was out near either the end of 28R or maybe on taxiway Z or towards the UAL maint base, couldn't really see well from where I was.

NWA's website shows that flight 27 SFO-NRT diverted back to SFO due to mechanical problems and isn't scheduled to head out until 8:00am Sunday.

Does anyone know what happened?