GEG TRACON controllers reported frequency problems with both 128.75 and 133.15 have been occurring for years and need to be fixed.
Synopsis
GEG TRACON controllers reported frequency problems with both 128.75 and 133.15 have been occurring for years and need to be fixed.
Narrative
Aircraft X departed off ZZZ going to PDT. We radar identified the aircraft and gave them a vector for an RNAV approach at PDT. While Aircraft X was on the north side of the PDT airport in the downwind; we realized that we lost communication with another aircraft in the airspace on 128.75. We went to standby frequency and got a hold of them. At that time; we realized we may have lost Aircraft X as well on 133.15 so we reached out to them to see if they could hear us; but they couldn't. Our standby was out for 133.15 but we tried it anyways and still couldn't hear them. After that we tried the voice bypass; on Guard multiple times; reached out to local towers to see if they could get ahold of them; also called their Dispatch to reach out to them. They were headed towards a 057 MVA level at 050 so we were doing everything we could think of to get a hold of them. We switched from standbys to mains again and got a hold of them right when they were entering the higher MVA. I told them to turn immediately and climbed them to 060. Afterwards Aircraft X said the frequency still didn't sound very good so we told all adjacent facilities to use 128.75 instead.We have had problems with these 2 frequencies for months and months and they still haven't been able to fix them yet. Honestly for years since we acquired these radar positions we have had many many problems with these 2 frequencies. I recommend they make this a very high priority to get fixed immediately. This situation could've easily ended in a fatality if Aircraft X would've flown another 10 miles or so.
Second reporter narrative
I was the Developmental controlling the aircraft. The aircraft had called on the phone for their IFR clearance and release. They took off fine and I radar contacted them; then vectored them for the approach into PDT. As they were flying at their requested altitude above the MVA; the frequencies went out. I attempted to reestablish communications with another aircraft on another frequency; then handed that aircraft off. I then attempted to reestablish communications with Aircraft X but was unable. Aircraft X continued on their assigned heading into an area with a MVA higher than their altitude. Communications were reestablished and my OJTI (On-the-Job Training Instructor) gave them a heading to lower MVA and told them to climb to an altitude above the MVA. The aircraft was then vectored to the approach with no issues.Recommend the frequencies and equipment be repaired. They have been having issues for months.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.