E120 FLC ACCEPT QUESTIONABLE VISUAL SEPARATION APCH CTLR WITH AN APCH PATH XING B737.

Narrative

THE P80 CTLR ASKED US IF WE HAD THE OTHER ACFT IN SIGHT. WE SAID 'YES.' AT THIS TIME THE ACFT WAS APPROX 1000 FT ABOVE US AND 5 MI AHEAD OF US AND 3 MI TO THE E OF US. WE HAD ALREADY RPTED THE ARPT IN SIGHT. THE CTLR THEN SAID THAT THE OTHER ACFT WAS FOR RWY 28L AND WE WERE FOR RWY 28R. HE SAID 'YOU ARE CLRED FOR THE COMMUTER VISUAL RWY 28R; MAINTAIN VISUAL SEPARATION.' WE WERE NEVER GIVEN ANY SPD RESTRS OR ANY OTHER INSTRUCTIONS ON HOW HE WANTED US TO DO THIS. IN ORDER FOR US TO KEEP THE OTHER ACFT AHEAD OF US THE WHOLE TIME; WE WOULD HAVE HAD TO SLOW DOWN SIGNIFICANTLY BY CONFIGURING THE ACFT FOR LNDG FAR TOO PREMATURELY OR MADE TURNS TO THE E ON OUR OWN. THE CLRNC GIVEN WAS VAGUE. WE WATCHED THE OTHER ACFT VERY CLOSELY PULLING ALONG SIDE THEM WITH AT LEAST 2-3 MI SEPARATION AND ALLOWED THE OTHER ACFT TO PASS BEHIND US FOR RWY 28L WHILE WE CONTINUED FOR RWY 28R. IN RETROSPECT THIS WAS THE INCORRECT THING TO DO. WE SHOULD HAVE VERIFIED WHAT THE CTLR EXPECTED US TO DO EXACTLY. I BELIEVE THE ISSUE WAS THE FAULT OF US AND THE CTLR. WE SHOULD HAVE VERIFIED WITH THE CTLR ON THE INSTRUCTIONS AND CONFIGURED TO LET THE OTHER ACFT STAY IN FRONT OF US THE ENTIRE TIME AND CROSS IN FRONT OF US. THE CTLR GAVE A VERY VAGUE CLRNC -- IT WAS AS IF HE EXPECTED US AND THE OTHER ACFT TO FIGURE IT OUT FOR OURSELVES. EVEN THOUGH IT WAS A VISUAL; I BELIEVE WE SHOULD AT LEAST UNDERSTAND WHAT THE OTHER ACFT IS INTENDING TO DO. THE PRIMARY PROB THOUGH WAS OUR LACK OF ACTION TO VERIFY WITH THE CTLR AND COMFORT WITH THE SURROUNDING AREA. THERE WAS NO INCIDENT; BUT I BELIEVE THE POTENTIAL FOR ONE.