2025-07 · NASA ASRS report 2269319
Flight crew reported ZLC frequency 133.25 was broken and unreadable causing frequency congestion and difficulty complying with ATC instructions when encountering conflicting VFR traffic.
We were executing the ILS Z 19 into JAC. We were told to cross Dunoir at 14000 and we were cleared for the approach. We passed Dunoir at 14000 feet and started descent for ZIBIV and were approximately at 12400 feet. The controller then advised us of traffic to our left that they were not in contact with but we could see it on our TCAS. It was slightly below and to our left. I was sitting left seat and could not see it nor could the pilot monitoring. We did not receive a TA but the controller asked us to climb immediately to 14000 ft. and to execute the missed approach as published. The frequency was very busy at the time and several aircraft said they were losing contact with Center and they were breaking up. We started climb to 14000 feet but could not fly published missed because we would have been turning towards the conflict traffic which started climbing towards us. Therefore we could not comply fully to their instructions. We also could not relay this to them due to the congested frequency. Our concern at that point was to stay away from the traffic conflict. We had the Tetons in sight but controller was concerned about terrain clearance so he asked us to climb to 16000 ft and then gave us a northerly heading. The aircraft terrain system did not audibly alert us to terrain" and we felt terrain was not a threat. After turning north; the radio became intermittent for us but we never completely lost radio contact. He vectored us back around for an uneventful approach. Radio reception in the area needs to be improved. The poor reception jammed up the frequency with pilots complaining about it. We could have alerted the controller immediately that we could not comply with their complete instructions."
During approach to Runway 19 at Jackson Hole; WY; we had a traffic conflict; which resulted in the cancellation of approach clearance; followed by being vectored by ATC for another approach. We had been cleared for and were conducting the ILS Z to Runway 19 and had crossed DNW (Dunoir) VOR and were descending on the VNAV profile towards ZIBIV. Salt Lake Center advised that we had VFR traffic at our 10:00 to 11:00 and indicated that they would keep us on frequency with them until we had cleared that traffic. We acknowledged; and as we continued we observed the target on TCAS and were trying to visually acquire it. The traffic was getting closer and converging with us and was appearing to maintain its altitude. When the traffic was within 3-4 miles; the controller observed how close the target was to us and offered to break us off the approach. We acknowledged and requested a vector away from the traffic. We were assigned to climb to 14;000 and execute the published missed approach. However; we could not comply with that clearance. Had we complied; it would have turned us directly into that traffic; which at that moment was at our altitude and also began to climb. We were also unable to communicate any of this to Salt Lake Center due to frequency congestion; which I'll also address further.We turned slightly to our right (more west and northward) to avoid the traffic; which we still had not been able to visually acquire. We fully expected to receive both a TCAS TA and an RA; however our turn prevented that. In the meantime we still were trying to communicate with the controller to inform them of our inability to comply with the clearance. In between a multitude of aircraft trying to call Salt Lake Center; the controller was able to issue us an immediate climb due to there concern for terrain avoidance. We did comply with that and climbed as directed. We also had the terrain ahead of us in sight; and it was never a threat. They vectored us northward and re-sequenced us for the ILS Z 19 approach. The subsequent approach and landing was mostly uneventful.During the arrival and approach; radio communications in the area were often broken and unreadable. Multiple aircraft in the area on the frequency were having trouble hearing or contacting Salt Lake Center on 133.25. It seemed like the problem was most pronounced around the Dunoir VOR (DNW). The two biggest challenges during this event were the problems with radio communications in the area; and a VFR aircraft maneuvering in the busy approach corridor to Jackson Hole where it shouldn't be. I have noticed an increase in events where VFR aircraft (not in contact with the local ATC facility) have caused RA's to jet aircraft operating on approaches to busy airports (ie- TEB and SDL).First; I'd like to commend the Salt Lake Center controller for trying to resolve a traffic conflict with a VFR aircraft; especially in an environment with lots of traffic (particularly jets) and with significant terrain in the area. It's a challenging job with an immense amount of responsibility.Second; I think there's a significant need for improving radio communications in the area to provide good coverage to improve efficiency and reduce hazards.Third; I'm not exactly sure how to prevent VFR traffic from interfering with arriving IFR traffic at JAC; but I do think it's a subject that deserves some focus and discussion to prevent further incidents or even accidents.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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