Narrative:

Night visual approach sfo runway 10L. From locke arrival; vectors over city of san francisco at 6;000 ft; then descend to 3;000 ft; after crossing coastline outbound. Speed was 180 KTS with flaps 2 degrees extended; as I recall. Weather was clear. FMGC was loaded with the RNAV approach for runway 10L as a reference. Left turn to 140 degrees by ATC which placed the aircraft on a vector to intercept final approach course just outside of xattu on the RNAV 10L. Captain ordered 1;900 ft set in the FCU altitude window and we both had the airport; the runway and the PAPI on runway 10L in sight. Just outside of xattu; at around 2;100 ft or above (I do not recall the actual altitude indication at that moment) a GPWS terrain warning occurred. The aircraft at that time was over xattu; above the published minimum altitude of 1;900 ft; established on final; aligned with the runway 10L and the PAPI indicated correct position on the glide path as well. Although on a visual approach; we used the briefing guide for discussion of the approach; for situational awareness. The captain and I communicated clearly; quickly and precisely; verified the current parameters; instruments and visually; and both confirmed position on the approach and glide path and I also noted that the egpws did not indicate any terrain warning or caution. I verified accurate rnp and 'high accuracy' about 2 miles outside of xattu; just before the warning occurred. The approach was continued. I also put under consideration another aircraft that was on approach to runway 10R; slightly behind us and slightly higher. While not communicated; I added this to my considerations when agreeing with the captain to continue the approach. The GPWS warnings subsided shortly thereafter. Aside from the possibility of a malfunction; I assume the system sensed a momentary excessive terrain closure rate as the cause for triggering the alarm since the warning occurred upon crossing the coastline inbound; with steeply rising terrain and the fact that the airplane was descending on the approach while below the 2;450 ft radio altitude where the GPWS begins to be active.

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Original NASA ASRS Text

Title: A320 First Officer reported EGPWS activation just west of XATTU as the aircraft descended to 1;900 FT on visual approach to Runway 10L at SFO. Crew elected to continue and a normal landing ensued.

Narrative: Night visual approach SFO Runway 10L. From Locke Arrival; vectors over city of San Francisco at 6;000 FT; then descend to 3;000 FT; after crossing coastline outbound. Speed was 180 KTS with flaps 2 degrees extended; as I recall. Weather was clear. FMGC was loaded with the RNAV approach for Runway 10L as a reference. Left turn to 140 degrees by ATC which placed the aircraft on a vector to intercept final approach course just outside of XATTU on the RNAV 10L. Captain ordered 1;900 FT set in the FCU altitude window and we both had the airport; the runway and the PAPI on Runway 10L in sight. Just outside of XATTU; at around 2;100 FT or above (I do not recall the actual altitude indication at that moment) a GPWS terrain warning occurred. The aircraft at that time was over XATTU; above the published minimum altitude of 1;900 FT; established on final; aligned with the Runway 10L and the PAPI indicated correct position on the glide path as well. Although on a visual approach; we used the briefing guide for discussion of the approach; for situational awareness. The Captain and I communicated clearly; quickly and precisely; verified the current parameters; instruments and visually; and both confirmed position on the approach and glide path and I also noted that the EGPWS did not indicate any terrain warning or caution. I verified accurate RNP and 'high accuracy' about 2 miles outside of XATTU; just before the warning occurred. The approach was continued. I also put under consideration another aircraft that was on approach to Runway 10R; slightly behind us and slightly higher. While not communicated; I added this to my considerations when agreeing with the Captain to continue the approach. The GPWS warnings subsided shortly thereafter. Aside from the possibility of a malfunction; I assume the system sensed a momentary excessive terrain closure rate as the cause for triggering the alarm since the warning occurred upon crossing the coastline inbound; with steeply rising terrain and the fact that the airplane was descending on the approach while below the 2;450 FT radio altitude where the GPWS begins to be active.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.