CLOSE PROX COMMUTER-SMT GA-SMA SOUTH OF TVL IN ATA TO RWY 36.

Narrative

WE WERE IN VMC CONDITIONS MAKING LEFT TFC FOR RWY 36 AT TVL IN AN SMT AT OUR MAX LNDG WT (14000#). JUST PRIOR TO OUR CALLING THE TWR; SMA X RPTED S OF THE ARPT AND WAS TOLD TO MAKE A STRAIGHT IN FOR RWY 36. APPROX THE SAME TIME OF OUR CALL TO THE TWR; AN SMA Y RPTED NE OF THE ARPT AND WAS TOLD TO MAKE RIGHT TFC FOR RWY 36. WE HAD CALLED FROM THE NW AND WERE TOLD TO MAKE LEFT TFC AND RPT ABEAM THE TWR. WHEN WE MADE OUR DOWNWIND RPT ABEAM; THE SMA Y IN RIGHT TFC WAS ABEAM US ON THE OPP SIDE OF THE RWY. WE WERE ADVISED TO FOLLOW THE SMA X ON A 4 MI FINAL AND ADVISED THAT WE WERE NOT IN SIGHT. WE HAD TO SLOW CONSIDERABLY TO FOLLOW THE SMA X; MAKING US A LITTLE UNCOMFORTABLE CONSIDERING THE SURROUNDING TERRAIN; OUR WT AND THE MANEUVERING THAT WOULD BE REQUIRED OF US IN OUR APCH TO RWY 36. FOLLOWING THE SMA X REQUIRED THAT WE EXTEND OUR DOWNWIND IN AN ENVIRONMENT WHERE SUCH AN EXTENSION WAS NOT VERY FEASIBLE AND WHERE OUR BEST COURSE OF ACTIONS IN THE EVENT OF ABORTING OUR APCH WAS TO CIRCLE TO THE E SIDE OF THE ARPT--AN AREA THAT WAS BLOCKED. WE DID MANAGE TO PROVIDE THE NECESSARY SPACING BTWN OURSELVES AND THE SMA X; AND WERE THEN CLRED TO LAND. WE ALSO WERE ADVISED BY THE TWR THAT WE WERE IN SIGHT. AT THAT TIME THE SMA Y WAS TOLD TO FOLLOW US. HOWEVER; BY NOW IT WAS APPARENT THE SMA Y WAS GOING TO HAVE PROBS MAINTAINING PROPER TERRAIN SEP AND SEP FROM US. THE TWR ADVISED THE SMA Y TO MAKE A 360 DEG TURN. THE SMA Y MISSED THE CALL AND PROCEEDED TO CONVERGE ON US. THE TWR THEN TOLD THE SMA Y TO PASS BEHIND US ON FINAL. AT NO TIME DID THE TWR ADVISE US OF THE SMA Y'S POS; NOR DID THE TWR RECEIVE ANY INDICATION THAT THE SMA Y HAD US IN SIGHT. THE SMA Y PROCEEDED TO MAKE A TURN DIRECTLY TOWARD US; WHICH REQUIRED THAT I MANEUVER THE ACFT AROUND HIM. WE SPOTTED THE SMA Y APPROX 5 SECS PRIOR TO WHAT WOULD HAVE BEEN A DEFINITE COLLISION. WE MANAGED TO SALVAGE THE APCH AND LAND SAFELY. DUE TO OUR ACTIONS; THE SMA Y CAME ONLY WITHIN A COUPLE HUNDRED FEET OF OUR ACFT; BUT THE ENTIRE SITUATION WAS ONE THAT SHOULD HAVE NEVER TRANSPIRED. WE QUERIED THE TWR WHETHER THE SMA Y WAS CLRED TO CROSS OUR FINAL APCH COURSE AND WERE QUITE SURPRISED TO RECEIVE AN AFFIRMATIVE RESPONSE. NO FURTHER EXPLANATION WAS GIVEN AND HAVING FOUND THE TWR PERSONNEL AT TVL TO BE LAISSEZ-FAIRE IN THE PAST; WE DECIDED TO TAKE THIS MATTER UP WITH A MORE RESPONSIBLE AGENCY. WE ATTRIBUTED THE CAUSE OF THE INCIDENT TO BOTH THE PLT OF THE SMA Y AND TO THE TWR CTLR AT TVL. HOWEVER; IF WE WERE TO WEIGH THE CAUSES; THE CTLR WOULD BE THE MAJOR RECIPIENT. THE ENTIRE SITUATION SEEMED AS IF THE CTLR WAS NOT IN CTL AND WAS JUST WAITING TO SEE WHAT WOULD HAPPEN. WE FEEL IT WAS USING POOR JUDGEMENT TO DIRECT TFC INTO SUCH A CONFINED AREA WHEN 1) THE TWR HAS LITTLE OR NO POSSIBILITY OF SIGHTING TFC ON LEFT DOWNWIND TO RWY 36 BECAUSE OF OBSTRUCTIONS TO VISION; AND 2); POSSIBLE ESCAPE ROUTES ARE LIMITED BY TFC CONVERGING FROM VARIOUS DIRECTIONS--IN PARTICULAR TO HAVE TFC ON BOTH LEFT AND RIGHT DOWNWIND IN WHAT IS A BOX TYPE SITUATION; AND 3); WHEN ACFT OF DIFFERENT CATEGORIES ARE INVOLVED (THE SMT IS A CATEGORY C) IN A CIRCLING SITUATION. I WOULD HIGHLY RECOMMEND THE TWR PERSONNEL REVIEW THEIR SITUATION; TAKING INTO CONSIDERATION THE SURROUNDING TERRAIN AND THE TYPE OF TFC THEY SVC; AND MAKE SOME PROCEDURAL REVISIONS.