Medium Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 14600
ATC Issue All Types; Conflict NMAC
General None Reported / Taken
Human Factors; Procedure
We were being vectored to land on Runway 11L TUS and on an extended left base with a visual on the runway. We were at 6;000 FT MSL and abeam the FAF when we were given a clearance for the visual approach to Rwy 11L. We were turning to final in a left turn; descending; and configuring to land; when I spotted traffic low a 10 o'clock. The traffic appeared to be climbing from below; opposite direction and turning away slightly. I initially thought it was a corporate jet; but a second or so later I realized that it was a C-172 about 300-400 FT horizontal and opposite direction to us as we descended through it's altitude of about 4;000 FT MSL. We had an MEL for our TCAS so it was inoperative. Earlier; I had heard approach query GA traffic if they had the [airliner] at 5;000 FT; but we were given no traffic advisories or warned of any in the area. That was disconcerting; and I keyed the mike and said 'Cessna traffic opposite direction.' But; it was then past us. We were handed over to Tower and cleared to land. I asked Tower if the Cessna was under someone's control and they said; 'Yes; TRACON.' Taxiing back in; Tower said that TRACON had told them that the Cessna had us insight. But; Tower also said that they got an 'alert' for the event. Expect the unexpected; especially without TCAS.
For this incident; I was the non-flying pilot; I never saw the conflicting aircraft (so my statements are based on what the Captain told me); and our TCAS was non-operational (deferred under MEL guidance). The weather at Tucson was VFR. We were turning base to final to Runway 11L and cleared the visual. ATC never gave us a heads up that there was traffic in our area. The Captain suddenly piped up and ask if I saw that (referring to the passing of a high winged Cessna estimated to be between 300 and 400 feet off our left wingtip and co-altitude). ATC then instructed us to contact Tower and they cleared us to land. We ask Tower if they knew of the other aircraft and they replied that approach control was in contact with them and that the Cessna stated that we were in sight. We landed uneventfully. While taxing in Tower said that their 'bells and whistles' had sounded.This incident might have been avoided; if ATC had informed us of possible conflicting traffic; if we were not offered the visual but flew the full ILS approach with other traffic in the area; if ATC had kept us under IFR longer or directed the Cessna to turn away from us; if the Cessna pilot maneuvered on his own to provide more clearance from us; or if our TCAS had been operational.
Air Carrier flight crew experiences a NMAC with a C172 during a visual approach to Runway 11L at TUS.  The traffic was not reported to the flight crew by ATC and the TCAS was MEL'ed; so no evasive action was taken by the crew.