Narrative:

The ZDV controller gave us a descent clearance to 16000 ft with a restr to descend at a rate of at least 1500 FPM. She subsequently asked us if we were proceeding 'direct larks.' I replied that we were not, as we had been cleared direct powder intersection during the course of our initial contact with ATC. At approximately 3 mi from the powder intersection, we were instructed to contact den approach. The approach controller's first instructions on initial contact were to 'descend immediately to one five thousand.' I was the PF, and as the instructions were issued, I hit the trim switch which allowed me to both disconnect the autoplt as well as comply with the ATC instructions. I glanced at the TCASII which was still on the 20 mi range and saw a target at approximately our 8 O'clock position. The target was a solid circle, but I don't recall hearing an aural TCASII alert. Because we were in VMC, I glanced up and saw a white twin cessna with tip tanks pass overhead by what was at least 300 or 400 ft. I stated to the approach controller that it appeared a loss of separation had occurred. I informed him that I would be calling the area manager to discuss the incident.

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Original NASA ASRS Text

Title: EMB120 AND TWIN CESSNA HAD LESS THAN COMFORTABLE SEPARATION IN ZDV CLASS E AIRSPACE.

Narrative: THE ZDV CTLR GAVE US A DSCNT CLRNC TO 16000 FT WITH A RESTR TO DSND AT A RATE OF AT LEAST 1500 FPM. SHE SUBSEQUENTLY ASKED US IF WE WERE PROCEEDING 'DIRECT LARKS.' I REPLIED THAT WE WERE NOT, AS WE HAD BEEN CLRED DIRECT POWDER INTXN DURING THE COURSE OF OUR INITIAL CONTACT WITH ATC. AT APPROX 3 MI FROM THE POWDER INTXN, WE WERE INSTRUCTED TO CONTACT DEN APCH. THE APCH CTLR'S FIRST INSTRUCTIONS ON INITIAL CONTACT WERE TO 'DSND IMMEDIATELY TO ONE FIVE THOUSAND.' I WAS THE PF, AND AS THE INSTRUCTIONS WERE ISSUED, I HIT THE TRIM SWITCH WHICH ALLOWED ME TO BOTH DISCONNECT THE AUTOPLT AS WELL AS COMPLY WITH THE ATC INSTRUCTIONS. I GLANCED AT THE TCASII WHICH WAS STILL ON THE 20 MI RANGE AND SAW A TARGET AT APPROX OUR 8 O'CLOCK POS. THE TARGET WAS A SOLID CIRCLE, BUT I DON'T RECALL HEARING AN AURAL TCASII ALERT. BECAUSE WE WERE IN VMC, I GLANCED UP AND SAW A WHITE TWIN CESSNA WITH TIP TANKS PASS OVERHEAD BY WHAT WAS AT LEAST 300 OR 400 FT. I STATED TO THE APCH CTLR THAT IT APPEARED A LOSS OF SEPARATION HAD OCCURRED. I INFORMED HIM THAT I WOULD BE CALLING THE AREA MGR TO DISCUSS THE INCIDENT.

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.