ZDV controller described a loss of separation event; when during step down altitude assignments to e...

Narrative:

The aircraft; a TBM8; was landing ege. He was direct to voaxa which I had changed to due a faster aircraft behind him. I cleared him to rlg and told him that he could expect the approach from that fix. I also had a G-4 landing ege. I had him turn to voaxa since he was faster. I was stepping him down reference the TBM8. I had informed both pilots of the moderate turbulence reports that I received for the approach in to ege. When the TBM8 was descending out of 170; I gave the G-4 a descent clearance to 170. All of a sudden the TBM8 said that he's in severe turbulence and climbing. He did not say to what altitude. I then called traffic to both aircraft and told the TBM8 when he could; to stop climb. I eventually got the aircraft away from each other; but not before separation had been lost. Both aircraft reported severe turbulence to ege tower and we filed PIREPS for them. Recommendation; more traffic calls phraseology.

Original NASA ASRS Text

Title: ZDV Controller described a loss of separation event; when during step down altitude assignments to EGE; one aircraft encountered turbulence and initiated an unexpected climb toward another aircraft.

Narrative: The aircraft; a TBM8; was landing EGE. He was direct to VOAXA which I had changed to due a faster aircraft behind him. I cleared him to RLG and told him that he could expect the approach from that fix. I also had a G-4 landing EGE. I had him turn to VOAXA since he was faster. I was stepping him down reference the TBM8. I had informed both pilots of the moderate turbulence reports that I received for the approach in to EGE. When the TBM8 was descending out of 170; I gave the G-4 a descent clearance to 170. All of a sudden the TBM8 said that he's in severe turbulence and climbing. He did not say to what altitude. I then called traffic to both aircraft and told the TBM8 when he could; to stop climb. I eventually got the aircraft away from each other; but not before separation had been lost. Both aircraft reported severe turbulence to EGE Tower and we filed PIREPS for them. Recommendation; more traffic calls phraseology.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1002955
Time
Date	201204
Local Time Of Day	1801-2400
Place
Locale Reference	ZDV.ARTCC
State Reference	CO
Aircraft 1
Make Model Name	Gulfstream IV / G350 / G450
Operating Under FAR Part	Part 91
Flight Phase	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	TBM 700/TBM 850
Operating Under FAR Part	Part 91
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Inflight Event / Encounter Weather / Turbulence

ZDV controller described a loss of separation event; when during step down altitude assignments to ege; one aircraft encountered turbulence and initiated an unexpected climb toward another aircraft.