Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 10; Flight Crew Total 600; Flight Crew Type 370
Situational Awareness; Communication Breakdown
Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Procedure; Human Factors
I was on a training flight to complete my Bi-annual Flight Review when a near miss collision occurred with a [single engine turboprop]. My aircraft is a [homebuilt/experimental] and we had been out performing maneuvers when we returned to my home airport of Greeley Weld (GXY). As we flew to GXY I listened to the ATIS and the winds favored runway 17. I was west of the airport and maneuvered to fly south of GXY in order to enter the runway 17 left downwind. While flying to GXY we heard an aircraft that was ahead of us entering the runway 17 pattern. We also heard the [single engine turboprop] call that he was on the VOR approach and was 2 miles NE of the GILL VOR. As we entered the runway 17 left downwind I was at 5500 feet altitude and was flying at 100 mph. The airplane ahead of us in the pattern was turning final and there was another airplane that called that they would be entering the pattern behind us. No further reports came from the [single engine turboprop]. I flew the downwind 3/4 mile east of runway 17 and maintained 5500 feet. About mid-runway the [single engine turboprop] filled the entire wind screen climbing in front of us from our lower right to our upper left. We never saw the [single engine turboprop] climbing in front of us until it appeared and I would estimate it crossed in front of us within 100 feet distance. The [single engine turboprop] was angled roughly toward the center of the airport; turning right; and climbing fast. I saw the [single engine turboprop] continue climbing behind and to my left. I completed the landing on runway 17 with no damage and taxied to my hangar without incident.  My flight review was completed and signed off. During the flight debriefing the instructor verified that I was at the correct altitude the entire downwind. The VOR approach calls for a minimum altitude of 5300 feet and the missed approach calls for a left turn. We have no idea why he climbed in front of us in a right hand turn.
The pilot of a small aircraft reported a near mid air collision with a single engine turboprop aircraft that performed a missed approach from the VOR-A Approach into Greeley Weld; CO.