Narrative:

The captain was the pilot flying; I (the first officer) was the pilot not flying. We were cleared for the visual approach to runway 11L in tucson; arizona. The captain made a right downwind; then a right base; then intercepted the localizer for the visual approach (backed up by the ILS) to runway 11L. After calling the field in sight and subsequently cleared for the visual approach; the captain entered direct 'wason' in the FMS and set 5;500 ft in the altitude window on the MCP; which I confirmed per the approach plate. As we were descending just outside of 'wason' toward 5;500 ft and simultaneously intercepting the localizer; we received a GPWS 'terrain' 'pull-up'. The captain immediately went toga and climbed over 1;000 ft. At this point; since we were still 8 or 9 miles from the runway and still in a normal position to continue the approach to a normal VFR landing (still with ILS backup); the captain elected to continue the visual (ILS backup) approach to a normal landing and taxi-in. I believe the captain flew all the correct altitudes; consistent with the ILS runway 11L step-down altitudes listed on the approach plate. Further; what I believed triggered the GPWS was the 4565 ft obstacle located just outside of 'wason' which we would've flown almost directly over during our controlled descent to 5;500 and 'dogleg' localizer intercept. Since the enhanced GPWS is predictive in nature; I believe the software was projecting a 'continued' descent (i.e. Below 5;500 ft) toward this database obstacle; even though we were subsequently going to 'level out' momentarily per the step-down altitude guidance on the approach plate. Therefore; GPWS issued the warning as a direct result of this 'descending projection'. Again; I believe the captain complied with company SOP's and executed properly. The terrain outside of wason (on the approach to runway 11L) has been known to trigger GPWS; since the altitude clearances are so tight and the aircraft is normally descending for the approach. Enhanced GPWS is predictive and thus sometimes 'projects' continued descents on 'step-down' approaches. Nonetheless; all GPWS warnings must be obeyed and proper SOP's followed; and were followed in this event. I believe it would be helpful to include data on the tus airport advisory page with draws attention to the rising terrain around 'wason' on the approach to runway 11L; and the subsequent egpws potential (particularly on VFR arrivals).

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Original NASA ASRS Text

Title: A321 flight crew reports an EGPWS terrain warning approaching WASON on a visual ILS to TUS and takes evasive action. The FCU altitude had been correctly set to 5;500 FT but the EGPWS software was not aware of the planned level off and triggered the warning.

Narrative: The Captain was the pilot flying; I (the First Officer) was the pilot not flying. We were cleared for the visual approach to Runway 11L in Tucson; Arizona. The Captain made a right downwind; then a right base; then intercepted the localizer for the visual approach (backed up by the ILS) to Runway 11L. After calling the field in sight and subsequently cleared for the visual approach; the Captain entered direct 'WASON' in the FMS and set 5;500 FT in the Altitude Window on the MCP; which I confirmed per the Approach Plate. As we were descending just outside of 'WASON' toward 5;500 FT and simultaneously intercepting the Localizer; we received a GPWS 'Terrain' 'Pull-Up'. The Captain immediately went TOGA and climbed over 1;000 FT. At this point; since we were still 8 or 9 miles from the runway and still in a normal position to continue the approach to a normal VFR landing (still with ILS backup); the Captain elected to continue the visual (ILS backup) approach to a normal landing and taxi-in. I believe the Captain flew all the correct altitudes; consistent with the ILS Runway 11L step-down altitudes listed on the Approach Plate. Further; what I believed triggered the GPWS was the 4565 FT obstacle located just outside of 'WASON' which we would've flown almost directly over during our controlled descent to 5;500 and 'dogleg' localizer intercept. Since the Enhanced GPWS is predictive in nature; I believe the software was projecting a 'continued' descent (i.e. below 5;500 FT) toward this database obstacle; even though we were subsequently going to 'level out' momentarily per the step-down altitude guidance on the Approach Plate. Therefore; GPWS issued the warning as a direct result of this 'descending projection'. Again; I believe the Captain complied with company SOP's and executed properly. The terrain outside of WASON (on the approach to Runway 11L) has been known to trigger GPWS; since the altitude clearances are so tight and the aircraft is normally descending for the approach. Enhanced GPWS is predictive and thus sometimes 'projects' continued descents on 'step-down' Approaches. Nonetheless; all GPWS Warnings must be obeyed and proper SOP's followed; and were followed in this event. I believe it would be helpful to include data on the TUS Airport Advisory Page with draws attention to the rising terrain around 'WASON' on the approach to Runway 11L; and the subsequent EGPWS potential (particularly on VFR Arrivals).

Data retrieved from NASA's ASRS site 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.