Global Express (BD700)
Air Traffic Control Fully Certified
Human-Machine Interface; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
ATC Equipment / Nav Facility / Buildings; Human Factors
I was training on a radar position. We had an IFR GLEX that was eastbound level at 040. We had a VFR C172 that we were providing traffic advisories to that was westbound level at 045. The two aircraft were on converging courses and were going to cross above and below each other.Traffic was issued to the GLEX and he had the C172 in sight. As traffic was being issued to the VFR aircraft the transmission was blocked. The C172 then started to descend rapidly into the jet. The GLEX had an RA and he had to take evasive action to avoid the C172. I would recommend making the ATC transmissions stronger so they can't be blocked by aircraft transmissions in critical situations; also better training for pilots on radio communications and traffic avoidance.
Approach Controller reported airborne conflict between an IFR GLEX and a VFR C172 that resulted in evasive action.