Date: 201710
Local time of day: 0601-1200
Location: ZDV.ARTCC, CO
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZDV
ATC / advisory: Center ZDV
Second aircraft: Small Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Training / Qualification; Distraction; Workload; Time Pressure
Second reporter function: Instructor; Enroute
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 Issued New Clearance; Air Traffic Control Separated Traffic; Flight Crew Landed in Emergency Condition
Contributing factors: Airspace Structure; Company Policy; Staffing; Procedure; Environment - Non Weather Related; Human Factors
Primary problem: Procedure

Narrative: Aircraft Y was northbound 26000 feet; just inside our airspace. Aircraft X was westbound at 26000 feet. I entered the control room after being on lunch break and asked the Supervisor standing at the desk with his knee on the chair if he wanted me to follow the break list (offer the next person up for break). He indicated that he was not in charge. So I asked the CIC (Controller in Charge) if she wanted me to follow the break list; she said yes. The Quality Control manager was also standing in the control room talking to a supervisor from another area at the time. I asked the first person if they wanted a break and they said not yet. I then asked the training team; training on the radar position; if they wanted a break and the trainer said ask the trainee. I asked the trainee but he was to busy to respond so I asked him if he needed a D-side (Radar associate) he said yes. The sector was combined with two other sectors and covers a very large area.As I went to get a chair I overheard a supervisor from another area say we had a diverting aircraft coming. At this point I was just pulling up my chair trying to get around the trainer; I had not yet received a briefing. During this time the Sector was not overwhelmingly busy with aircraft; however; had a lot of unique things going on. They were training a very limited Radar controller. They had a photo mission doing North and South lines blocking 22000 to 24000 feet with a request. FSS was calling for a clearance for an aircraft; an aircraft was departing another airport was not yet airborne; 2 aircraft were in conflict heading into the airport; and getting calls from reference the diverting aircraft heading our way. The rest of the area  was getting very busy as it almost always does at this time of day and with that very loud. There were also several other IFR and VFR aircraft on the frequency at the time. THIS SECTOR FREQUENCY IS HAVING ONGOING STATIC AND FREQUENCY PROBLEMS; GOING BACK AT LEAST TWO DOCUMENTED YEARS.  As I was sitting there I was writing down the information from the a Supervisor about the divert. She was not talking to me directly; I was over hearing her behind me. The controller trainee was talking to another Sector. The coordination from the supervisor was in complete contradiction with what the controller was being told and therefore very time consuming trying to figure out what was really going on. I answered the FSS line and gave a clearance at an airport with a hold for release; waiting for the a departure to get airborne. Several other transmissions were being done and several aircraft had requests.At this point I had not received a briefing and had not singed onto the radar Assist. In the very southwest corner of our airspace the conflict alert went off between Aircraft X and Aircraft Y as Aircraft X. The Vector lines had been run out and it looked like Aircraft X was going to go behind Aircraft Y. The Radar Trainee turned Aircraft X 30 degrees left and it looked like to me that he turned right instead of left. I told the Radar controller that Aircraft X turned right instead of left; so he descended Aircraft X to 25000 feet and told him to expedite. We lost standard separation. Aircraft X made a turn to an intersection which was a right turn into Aircraft Y. I did not see the traffic or the conflict until the Conflict alert was activated.During this entire time Aircraft X was getting stepped on by other aircraft and was not responding to the control instructions in a timely manner. After the occurrence the Supervisor told me to split out one of the combined sectors when you can. The Sector was too busy for me to leave at that point and another controller split it out.After it was all said and done I overheard; twice; the Supervisor; tell upper Management that he told me to go into the Radar Assist to help the training team. That DID NOT happen and is a complete fabrication of events. I also heard him put complete blame on the Controllerin Charge. It was not her fault that the sector needed help. There was obviously a lot going on but she could not have known that from her vantage point. You literally had to be plugged in to know that the controller needed help; and that is why I OFFERED help and he took it.A new frequency on this Sector is needed. We currently have 4 frequency site pairs on the sector; with the backup receivers not being located near the original site in some cases.  These sites cause static and interference with each other to the point that most of us are literally guessing what the aircraft are saying. This causes frequency congestion in an already congested situation in the very treacherous terrain of the Colorado Mountains. If we got a whole new frequency or 2 new frequencies this could clear up all the static and interference we deal with on a daily bases.Keep Supervisors from other areas and Non-operational Upper Management people out of the control room to keep down distractions. All coordination from supervisor to supervisor should be conducted by phone or at the desk outside of the immediate operation to minimize distractions.


Second narrative: I signed back into the Sector 12 with two other sectors combined to start training with no radar Assist. Upon sitting down; we were told that an aircraft will be coming to us diverting. It was an aircraft that lost an engine and was operating on one. At that time; Aircraft X appeared to be passing behind Aircraft Y around the VOR. Within the 10 minutes from signing in and the loss of separation; the sector got very complex. An aircraft doing photo work with North and South lines at blocking 22000 to 24000 feet. He was on frequency trying to give us different coordinates of his course. The trainee also was occupied with transmitting multiple times to get a hold of another aircraft but the high altitude controller put him on the wrong frequency so he wasn't able to hear us right away. Once we got a hold of him; the trainee issued him descend now to 26000 feet then pilots discretion descent to 15000 feet. After the pilot read back the clearance; another controller asked trainee if he needed a Radar Assist. The trainee said yes. A Sector called to pass on the information for the aircraft that lost the engine. After getting offline with that sector another aircraft checked in. The trainee gave that aircraft a pilot's discretion descent to 15000 feet and told the pilot to let us know if he needed any assistance. The pilot read back the clearance and requested the weather. An air carrier also inbound to the same airport then checked in and the trainee gave him descend now to 26000 feet then pilots discretion descent to 15000 feet. After the air carrier read back the clearance the Supervisor; was asking me if the diverting aircraft needed assistance. I was informing him of the aircraft; then I went to the empty adjacent sector to quick look a sector because I wanted to see if both aircraft with clearance to 15000 feet were going to be an issue. Once I quick looked the sector I saw the conflict alert for Aircraft X and Aircraft Y. The Trainee immediately gave Aircraft X a 30 degree turn to the left; Aircraft X was about 14 miles away. Aircraft X was then given a clearance to 25000 feet; which the pilot questioned because it was stepped on. The part that hurt was when he gave the turn to Aircraft X; he was over a VOR starting a right turn. Since he was in the right turn the 30 degree left really cancelled it out.After we got out of the sector; we sat down to discuss the situation. We discussed how it would have benefited the Controller if he combined the clearance to Aircraft X. In the one transmission; turn 30 left and descend for traffic. It wouldn't have gotten stepped on and he would have started down earlier. We discussed how turning Aircraft Y also could have gotten him a little more space. We discussed if the sector was split it would have reduced complexity since the photo mission aircraft usually take up more time than those just flying through. They change altitudes; coordinates and direction. We also discussed how the vector lines can be very deceiving in this case. Aircraft X's vector line was southwest of the VOR; however; he was actually turning over the VOR.


Synopsis: ZDV Center Controllers reported the trainee failed to take appropriate action to resolve a traffic conflict.