Fractional Captain reported receiving a terrain warning while descending for a visual approach. The Captain arrested the descent; performed a go-around; and safely landed without further incident.

Narrative

Go-around was performed by SIC (Second in Command) in right seat after EGPWS (Enhanced Ground Proximity Warning System) Terrain Pull Up" warning alert was triggered during the visual approach into ASE for Runway 15. Weather during the visual approach was clear skies; visibility greater than 10 SM; winds south-southwest at 6 - 10 kt.; OAT -3°C. Cold weather correction for -5°C was applied to waypoint altitudes. The approach was flown with autopilot - ON; autothrottles - ON; and NAV and VNAV engaged. Speed set to Vref+10 and fully configured in accordance with company procedures. Except; the altitude at JARGU was entered as 13400 AT or BELOW due to Aspen Approach vectoring us at 13;000 ft. MSL. After passing waypoint DOYPE the flight path angle; FPA; went from -3.96 to -4.98. The airplane pitched downward to track the new FPA and the rate of descent increased from 1000 FPM to over 2000 FPM. EGPWS triggered a terrain caution alert; then an immediate terrain warning alert. Descent was arrested and a go-around was executed. Airplane was vectored around for another visual approach. Approach setup was entered exactly as first approach except the approach was hand-flown prior to DOYPE waypoint to the west to avoid terrain and rejoined final to CEYAG waypoint. Landing was normal without further incident. The EGPWS alerts that have been reported in bulletin are not airplane specific nor FMS specific. I feel the GARMIN 5000 FMS in Aircraft X operates very accurately. It flies the profile but seems to overshoot or undershoot the flight path angle between waypoints. Causing increased rates of descents close to terrain. Maybe the altitude at CEYAG could be raised to decrease the FPA between DOYPE to CEYAG. Or; omit DOYPE and move the waypoint to the west side of the hill; then follow the valley around to line up on the computed FPA to CEYAG and the PAPI. Or; move all waypoints slightly to the west and rename them to take advantage of the low terrain/valley until past DOYPE and hill Triangle Peak."