Narrative:

My aircraft (an light transport X) and another company aircraft (light transport Y) were scheduled to depart durango, co, for dallas at about the same time. The light transport Y was delayed so I departed first with the light transport Y about 5 mins behind. Initial climb under ZDV control was normal, with the light transport Y having to step climb behind us due to our different performance capability. I was handed off to ZAB passing through approximately FL240 and advised we were climbing to FL290. About 5 mins later I heard the light transport Y check in with abq and reported climbing to FL280. Abq told them to stop their climb at FL270. At about the same time I looked just forward and below my aircraft and saw the light transport Y just forward and about 200' below. I started a turn to the right and observed the light transport Y pitch over and begin to descend. I asked ZAB what altitude the light transport Y had been cleared to and was told they had been cleared to FL280, but were told to stop at FL270. It appears that ZDV had cleared the light transport Y to an altitude we had not vacated.

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Original NASA ASRS Text

Title: CPR-LTT X INVOLVED IN NMAC WITH COMPANY LTT Y. LTT Y CLEARED TO FL280 OVERTOOK LTT X CLIMB TO FL290. LESS THAN STANDARD SEPARATION OCCURRED AT FREQ CHANGE AND TRANSFER OF CONTROL FROM ZDV TO ZAB.

Narrative: MY ACFT (AN LTT X) AND ANOTHER COMPANY ACFT (LTT Y) WERE SCHEDULED TO DEPART DURANGO, CO, FOR DALLAS AT ABOUT THE SAME TIME. THE LTT Y WAS DELAYED SO I DEPARTED FIRST WITH THE LTT Y ABOUT 5 MINS BEHIND. INITIAL CLB UNDER ZDV CTL WAS NORMAL, WITH THE LTT Y HAVING TO STEP CLB BEHIND US DUE TO OUR DIFFERENT PERFORMANCE CAPABILITY. I WAS HANDED OFF TO ZAB PASSING THROUGH APPROX FL240 AND ADVISED WE WERE CLBING TO FL290. ABOUT 5 MINS LATER I HEARD THE LTT Y CHK IN WITH ABQ AND RPTED CLBING TO FL280. ABQ TOLD THEM TO STOP THEIR CLB AT FL270. AT ABOUT THE SAME TIME I LOOKED JUST FORWARD AND BELOW MY ACFT AND SAW THE LTT Y JUST FORWARD AND ABOUT 200' BELOW. I STARTED A TURN TO THE RIGHT AND OBSERVED THE LTT Y PITCH OVER AND BEGIN TO DSND. I ASKED ZAB WHAT ALT THE LTT Y HAD BEEN CLRED TO AND WAS TOLD THEY HAD BEEN CLRED TO FL280, BUT WERE TOLD TO STOP AT FL270. IT APPEARS THAT ZDV HAD CLRED THE LTT Y TO AN ALT WE HAD NOT VACATED.

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.