Narrative:

Cavu in den, being vectored for visual approach to runway 25 at den. A B737 being vectored for runway 26R and another unknown aircraft for runway 26L. Arriving on den VOR 046 degree radial. Approximately 20 NM from airport given heading 190 degrees to intercept final approach course, told to descend from 11000 ft to 9000 ft. Advised of B737 traffic passing above and to our right. I was PNF, first officer flying aircraft. Approximately 10 NM from airport advised ATC airport in sight and subsequently cleared for visual to runway 25. The B737 high above us sbound going to runway 26R and having difficulty spotting other traffic and confusion with approach control as to their clearance for a visual approach to runway 26R. B737 advises receiving TCASII warnings. We turn wbound for runway 25 the same time the B737 finally clarifies clearance for visual runway 26R. As we turn right B737 turns right and descends for runway 26R. We were to follow but my new hire first officer is slow to reduce to approach speed and said he was confused as to B737 intentions. Very quickly we caught B737 and were directly underneath B737, now with speeds matched. I estimate 800 ft of separation. The B737 advised of TCASII warnings. Approach control advised B737 that we (me) had them in sight. I instructed my first officer to turn to a northwest heading and slow down. I advised approach control again that we had the B737 in sight and that we were turning, slowing, and descending. As we did, the B737 moved left to align with runway 26R and we maneuvered back to runway 25 and landed with no further problems. It seems to be very common when den is using runway 26L, runway 26R, and runway 25 for visual approachs that turboprops are turned for a longer and lower altitude final approach and jets, especially arrs from the west, are kept higher and turned on to shorter finals. While this may save fuel, it always causes conflict because the turboprops always fly a faster final approach. Controllers don't seem to realize how fast a turboprop can slow down. As a result turboprop crews are always 'running up' on the jets in the last 6 mi. Turboprops can also more easily make a steep and yet fast descent without problems. To make the den procedures safer it would seem best to put the turboprops on the high short final and the jets on the long final, allowing them more time to slow and descend.

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Original NASA ASRS Text

Title: HANDLING OF COMMUTER AND ACR ACFT FOR PARALLEL RWY VISUAL APCHS.

Narrative: CAVU IN DEN, BEING VECTORED FOR VISUAL APCH TO RWY 25 AT DEN. A B737 BEING VECTORED FOR RWY 26R AND ANOTHER UNKNOWN ACFT FOR RWY 26L. ARRIVING ON DEN VOR 046 DEG RADIAL. APPROX 20 NM FROM ARPT GIVEN HDG 190 DEGS TO INTERCEPT FINAL APCH COURSE, TOLD TO DSND FROM 11000 FT TO 9000 FT. ADVISED OF B737 TFC PASSING ABOVE AND TO OUR R. I WAS PNF, FO FLYING ACFT. APPROX 10 NM FROM ARPT ADVISED ATC ARPT IN SIGHT AND SUBSEQUENTLY CLRED FOR VISUAL TO RWY 25. THE B737 HIGH ABOVE US SBOUND GOING TO RWY 26R AND HAVING DIFFICULTY SPOTTING OTHER TFC AND CONFUSION WITH APCH CTL AS TO THEIR CLRNC FOR A VISUAL APCH TO RWY 26R. B737 ADVISES RECEIVING TCASII WARNINGS. WE TURN WBOUND FOR RWY 25 THE SAME TIME THE B737 FINALLY CLARIFIES CLRNC FOR VISUAL RWY 26R. AS WE TURN R B737 TURNS R AND DSNDS FOR RWY 26R. WE WERE TO FOLLOW BUT MY NEW HIRE FO IS SLOW TO REDUCE TO APCH SPD AND SAID HE WAS CONFUSED AS TO B737 INTENTIONS. VERY QUICKLY WE CAUGHT B737 AND WERE DIRECTLY UNDERNEATH B737, NOW WITH SPDS MATCHED. I ESTIMATE 800 FT OF SEPARATION. THE B737 ADVISED OF TCASII WARNINGS. APCH CTL ADVISED B737 THAT WE (ME) HAD THEM IN SIGHT. I INSTRUCTED MY FO TO TURN TO A NW HDG AND SLOW DOWN. I ADVISED APCH CTL AGAIN THAT WE HAD THE B737 IN SIGHT AND THAT WE WERE TURNING, SLOWING, AND DSNDING. AS WE DID, THE B737 MOVED L TO ALIGN WITH RWY 26R AND WE MANEUVERED BACK TO RWY 25 AND LANDED WITH NO FURTHER PROBS. IT SEEMS TO BE VERY COMMON WHEN DEN IS USING RWY 26L, RWY 26R, AND RWY 25 FOR VISUAL APCHS THAT TURBOPROPS ARE TURNED FOR A LONGER AND LOWER ALT FINAL APCH AND JETS, ESPECIALLY ARRS FROM THE W, ARE KEPT HIGHER AND TURNED ON TO SHORTER FINALS. WHILE THIS MAY SAVE FUEL, IT ALWAYS CAUSES CONFLICT BECAUSE THE TURBOPROPS ALWAYS FLY A FASTER FINAL APCH. CTLRS DON'T SEEM TO REALIZE HOW FAST A TURBOPROP CAN SLOW DOWN. AS A RESULT TURBOPROP CREWS ARE ALWAYS 'RUNNING UP' ON THE JETS IN THE LAST 6 MI. TURBOPROPS CAN ALSO MORE EASILY MAKE A STEEP AND YET FAST DSCNT WITHOUT PROBS. TO MAKE THE DEN PROCS SAFER IT WOULD SEEM BEST TO PUT THE TURBOPROPS ON THE HIGH SHORT FINAL AND THE JETS ON THE LONG FINAL, ALLOWING THEM MORE TIME TO SLOW AND DSND.

Data retrieved from NASA's ASRS site as of July 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.