B737 Undifferentiated or Other Model
Air Traffic Control Fully Certified
Situational Awareness
ATC Issue All Types; Conflict NMAC
Air Traffic Control Issued New Clearance
Human Factors; Procedure
VFR glider traffic squawking VFR [was] not in communication with ATC circling 10 miles south of TOMSN at 17;500 FT. ZDV called to APREQ an APA landing aircraft at 19;000 FT and DEN arrival at 17;000 FT; I approved. Long before these aircraft were on my scope; I noticed the VFR traffic so I called ZDV to give them a friendly 'heads-up'. They said they saw the VFR traffic. A few minutes later Air Carrier X appears on my scope and the VFR traffic has moved closer to where Air Carrier X was also heading. Again; I called ZDV to help resolve the situation. I ask for Air Carrier X at 16;000 FT. They advise that their lowest MVA was 16;400 FT and that they would watch the VFR traffic. Air Carrier X was still 10 miles from the VFR and I would have had time to help prevent and accident. ZDV did not ship the aircraft until they were 2 miles apart. I told the aircraft to descend and maneuver at their discretion to avoid a collision. Air Carrier X responded to a TCAS RA. The aircraft passed within 0 miles and 200 feet. ZDV did nothing to prevent this near-midair even though I tried several times to prevent the problem. Also; gliders should be asked (on charts) to avoid this area. They are often observed at FL180 but action is not taken because 'their transponders may be off by up to 300 feet.'
D01 Controller described a conflict event when arrival traffic was not transferred from ZDV in a timely manner resulting in a conflict with VFR glider traffic.