Date: 201403
Local time of day: 1201-1800
Location: ZDV.ARTCC, CO
Light: Daylight
Aircraft: Light Transport; High Wing; 2 Turboprop Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb
Airspace: Class E ZDV
ATC / advisory: Center ZDV
Second aircraft: Learjet 45
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Developmental
Human factors: Training / Qualification
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Separated Traffic
Contributing factors: Weather; Procedure; Airspace Structure
Primary problem: Procedure

Narrative: We were working a sector; weather indicated IFR; but was not showing to be below minimums.  We had a couple of Eagle County arrivals lined up in sequence.  The first was an aircraft that was already talking to EGE Tower when I got a call from EGE Tower requesting a release for an air carrier.  As per the LOA; Tower has responsibility for the initial separation between departures and arrivals; so I went ahead to release the Aircraft X.  Shortly after that EGE Tower calls back stating that the first arrival aircraft had gone missed and they would hold the Aircraft X for release.  In the arrival sequence Aircraft Y was on the approach and already talking to EGE Tower.  A few minutes after the first carrier had gone missed; Tower calls back looking to release the Aircraft X because they had already received approval from TMU for the release (we were Approval Requesting DEN arrivals for TMU).  Since Tower has the responsibility to separate departures and arrivals I released the Aircraft X to 14;000 MSL because the go-around had just left that altitude.  We observed Aircraft X track depart EGE and fly the GYPSUM Departure.  Aircraft X checked on our frequency out of 10;000; then about that time Tower called indicating that Aircraft Y had gone missed.  At that time we had about 8 miles between the two aircraft plus 2;000 feet of separation.  Aircraft Y executed the missed approach and out performed the Aircraft X.  I had called Aspen Approach who owns a shelf of airspace 16;000 to FL210 over the EGE airport and I completed a point out of the Aircraft X so we could keep the Aircraft X climbing.  The missed approach took Aircraft Y on a much more direct path toward the Aircraft X and so before we were able to get vertical we lost our separation.  The two aircraft were on diverging paths when we lost separation; and had the Aircraft X been a higher performance jet then we may have been able to keep the separation needed.Possible changes to the current procedures to this would be to design a better missed procedure that could help keep the departure procedure more separated from the missed approach.  However there are very few possible changes because of the mountainous terrain.  Operational procedures could be changed but would also affect the high efficiency of the airport on high demand days.  Another possible change could be putting limitations on low performance aircraft and the separation need for Tower to release them before higher performing aircraft landing at the airport.




Synopsis: Controller reports operational error caused by high performance aircraft overtaking slower performance aircraft.