B737-300
Flight Crew Last 90 Days 185
Training / Qualification; Situational Awareness; Confusion
Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Environment - Non Weather Related; Human Factors
We were on final descent into Tucson from approximately 15 miles northwest at 6;000 FT MSL. ATC cleared us to CALLS Intersection; and then cleared us for the visual to Runway 11L. We had discussed the high terrain in the area during the arrival briefing and were monitoring it on the aircraft display. We could also make out the terrain visually due to ambient lighting in the area. We no longer could see any terrain in front of us on the display; and we decided we were close to CALLS Intersection; which has a restriction of at or above 5;000 FT MSL. Pilot flying started a descent from 6;000 FT to 5;000 FT. Shortly after; we heard the audible warning; 'Caution Terrain'. The pilot flying executed a go-around; climbed to 7;000 FT MSL; and ATC vectored us back around for an uneventful landing. Intercept the ILS or visual approach from a fix outside of CALLS or be vectored east of final where there is no terrain.
I believe that ATC should vector all flights to join final to 11L from the north of the mountain ridge to preclude the possibility of a Terrain/Obstacle Warning in the future; especially during dark hours of operations.
A B737 descending on a night visual to TUS 11L received a TOO LOW TERRAIN warning; executed the escape maneuver and were vectored around for another approach.