BOI LCL CTLR CLRED A BEECH SIERRA TO MAKE A SHORT APCH IN FRONT OF MOONEY ON SHORT FINAL.

Narrative

I WAS ACTING AS SAFETY PLT AS THE OTHER PLT COMPLETED A LOC BACK COURSE APCH TO RWY 28L. THE TIME OF DAY WAS JUST PRIOR TO SUNSET; AND THE SUN'S POS APPEARED TO BE ALIGNED WITH THE RWY AND JUST ABOVE THE RWY. COMBINED WITH SCRATCHES ON THE WINDSHIELD; THIS MADE IT EXTREMELY DIFFICULT TO SEE ANYTHING DIRECTLY AHEAD AND WITHIN ABOUT 30 DEGS TO EITHER SIDE OF DIRECTLY AHEAD. AS WE WERE O ABOUT A 4 MI FINAL; A BEECHCRAFT SIERRA (OR BONANZA) WAS APCHING THE FIELD FROM THE SW AND TOLD TO ENTER L DOWNWIND FOR RWY 28R. WE WERE POINTED OUT AS TFC TO HIM; AND HE WAS INITIALLY TOLD TO EXPECT TO TURN BASE LEG BEHIND US. HOWEVER; ONCE THE SIERRA WAS ON L DOWNWIND HE WAS ASKED BY THE TWR IF HE WAS COMFORTABLE ACCEPTING A SHORT APCH. HE REPLIED THAT HE WAS; SO TWR CLRED HIM FOR A SHORT APCH; POINTED US OUT AS TFC; AND REQUESTED THAT HE TURN 'NO LATER THAN THE NEW RADAR ANTENNA' WHICH IS LOCATED NEAR THE END OF RWY 28L. THE SIERRA INDICATED THAT HE WOULD COMPLY; AND HE WAS POINTED OUT AS TFC TO US. BECAUSE OF THE SUN'S POS; WE WERE UNABLE TO SEE THE OTHER ACFT; AND WE RESPONDED TO THE TWR THAT WE DID NOT HAVE THE SIERRA IN SIGHT. AS WE PROCEEDED ON ABOUT A 1 1/2 MI FINAL; THE SIERRA WAS MAKING A BASE TURN. THE CTLR TOLD US THAT THE SIERRA WOULD BE XING L TO R IN FRONT OF US; AND AGAIN ASKED US IF WE HAD HIM IN SIGHT. WE RESPONDED THAT WE DID NOT. AS WE CONTINUED; THE CTLR CONTINUED TO PROVIDE US WITH POS RPTS ON THE SIERRA; BUT WE WERE UNABLE TO SEE HIM. THE CTLR ALSO PROVIDED THE SIERRA WITH OUR POS; BUT THE SIERRA'S PLT DID NOT INDICATE WHETHER HE HAD US IN SIGHT. AS WE WERE ON SHORT FINAL AND CONTINUING TO LOOK FOR THE OTHER ACFT; IT SUDDENLY APPEARED VERY CLOSE; IN A TURN; MOVING FROM L TO R. WE NOTIFIED THE TWR THAT WE NOW HAD THE SIERRA IN SIGHT; AND THE CTLR RESPONDED THAT WE HAD COME 'CLOSER THAN HE (THE CTLR) HAD INTENDED;' AND THAT HE WAS VERY SORRY ABOUT THAT. WE DID NOT TAKE EVASIVE ACTION -- THE SIERRA WAS SO CLOSE THAT WE WERE CLR BEFORE WE HAD A CHANCE TO REACT. I BELIEVE THE PRIMARY CAUSE OF THIS CLOSE CALL WAS THE CTLR OFFERING THE SIERRA A SHORT APCH. THE CTLR WAS ATTEMPTING TO SAVE THE OTHER PLT SOME TIME BY SQUEEZING HIM IN FRONT OF US; BUT IT CREATED A DANGEROUS SIT WITH THE SIERRA XING IN FRONT OF US AS WE WERE ON SHORT FINAL. I ALSO FEEL THE PLT OF THE SIERRA DID NOT HAVE US IN SIGHT; AND I BELIEVE HE WAS FOLLOWING THE CTLR'S INSTRUCTIONS BLINDLY. (HE NEVER CALLED US IN SIGHT; AND HE PASSED CLOSE ENOUGH TO US THAT HE WOULD HAVE BEEN EXTREMELY FOOLISH FOR IT TO HAVE BEEN INTENTIONALLY THAT CLOSE.) THE LOW SUN ANGLE WAS A CONTRIBUTING FACTOR AS WELL. WE NOTIFIED THE CTLR AS WE LANDED THAT IT IS VERY DIFFICULT AT THAT TIME OF DAY ON A WESTERLY HDG TO SEE TFC APCHING FROM STRAIGHT AHEAD. THE CTLR AGAIN APOLOGIZED FOR THE CLOSE CALL. I AM NOT CERTAIN WHAT WE WOULD DO DIFFERENTLY GIVEN THE SAME SIT. WE DIDN'T HAVE THE OTHER ACFT IN SIGHT UNTIL IT WAS VERY CLOSE TO US; SO WE DIDN'T KNOW HOW TO MANEUVER TO GUARANTEE THAT WE WOULD STAY CLR OF IT. I BELIEVE THE FOLLOWING PRACTICES COULD HAVE PREVENTED THIS CLOSE CALL: 1) A CTLR SHOULD BE VERY HESITANT ABOUT OFFERING A SHORT APCH IF IT MEANS A GOOD CHANCE OF XING ONE ACFT IN FRONT OF ANOTHER ON SHORT FINAL. THE CTLR SHOULD HAVE HAD THE SIERRA'S PLT TURN BASE BEHIND US -- IT WOULD HAVE COST THE OTHER PLT A COUPLE OF MINS; BUT IT WOULD HAVE AVOIDED THE CONFLICT. 2) RATHER THAN SPECIFYING 'TURN NO LATER THAN THE NEW RADAR ANTENNA;' THE CTLR SHOULD HAVE CALLED THE SIERRA'S BASE TURN. I AM BASED AT THE FIELD WHERE THIS OCCURRED; BUT I'M NOT SURE I KNOW EXACTLY WHERE THE 'NEW' RADAR ANTENNA IS LOCATED; AND AT ANY RATE IT'S NOT A GOOD IDEA TO BE SEARCHING THE GND FOR IT WHEN THERE'S TFC TO BE AVOIDED. (I DON'T KNOW WHETHER THE SIERRA'S PLT WAS FAMILIAR WITH THE ARPT.) 3) THE PLT OF THE SIERRA SHOULD NOT HAVE BLINDLY ACCEPTED THE CTLR'S OFFER OF A SHORT APCH WITHOUT HAVING US IN SIGHT. HE GAVE NO INDICATION THAT HE EVER SAW US. TOO MANY PLTS FORGET THAT THEY; NOT THE CTLR; ARE THE PIC. IFTHE OTHER PLT DID NOT HAVE US IN SIGHT; HE COULD HAVE SIMPLY CONTINUED HIS DOWNWIND LEG AND AVOIDED THE CONFLICT.