Narrative:

Established on final approach, tower asked us to increase speed to 200 KTS for a short period. I was flying and checking my instruments, captain was looking at airport then his instruments. We both looked up at same time and saw a commuter light transport filling up the left side of our cockpit windows. We were both very startled. The light transport had overshot his turn on to final for runway 8L. The controller had never told us about this aircraft. A slight deviation by us to the left could have resulted in a midair collision. It seems the speed increase the controller asked for is what had us parallel to the light transport. We contacted the controller and he said the light transport had us in sight. This seems unusual as we had to speed up to catch him from behind. The problem never would have occurred if the controller would have simply informed us of the light transport. It should be mandatory that controllers advise both aircraft when shooting parallel visibility approachs. (Advise of the position of the other aircraft.) 150' does not leave much room for error.

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Original NASA ASRS Text

Title: CLOSE PROX ACR-LGT COMMUTER-LTT BOTH MAKING PARALLEL VISUAL APCHS TO DEN RWYS 8.

Narrative: ESTABLISHED ON FINAL APCH, TWR ASKED US TO INCREASE SPD TO 200 KTS FOR A SHORT PERIOD. I WAS FLYING AND CHKING MY INSTRUMENTS, CAPT WAS LOOKING AT ARPT THEN HIS INSTRUMENTS. WE BOTH LOOKED UP AT SAME TIME AND SAW A COMMUTER LTT FILLING UP THE LEFT SIDE OF OUR COCKPIT WINDOWS. WE WERE BOTH VERY STARTLED. THE LTT HAD OVERSHOT HIS TURN ON TO FINAL FOR RWY 8L. THE CTLR HAD NEVER TOLD US ABOUT THIS ACFT. A SLIGHT DEVIATION BY US TO THE LEFT COULD HAVE RESULTED IN A MIDAIR COLLISION. IT SEEMS THE SPD INCREASE THE CTLR ASKED FOR IS WHAT HAD US PARALLEL TO THE LTT. WE CONTACTED THE CTLR AND HE SAID THE LTT HAD US IN SIGHT. THIS SEEMS UNUSUAL AS WE HAD TO SPD UP TO CATCH HIM FROM BEHIND. THE PROB NEVER WOULD HAVE OCCURRED IF THE CTLR WOULD HAVE SIMPLY INFORMED US OF THE LTT. IT SHOULD BE MANDATORY THAT CTLRS ADVISE BOTH ACFT WHEN SHOOTING PARALLEL VIS APCHS. (ADVISE OF THE POS OF THE OTHER ACFT.) 150' DOES NOT LEAVE MUCH ROOM FOR ERROR.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.