Date: 202010
Local time of day: 1201-1800
Location: R90.TRACON, NE
Aircraft: Widebody; Low Wing; 2 Turbojet Eng
Flight plan: IFR
Flight phase: Final Approach
ATC / advisory: TRACON R90
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Situational Awareness; Time Pressure; Troubleshooting; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance
Contributing factors: ATC Equipment / Nav Facility / Buildings
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: Our Lincoln transmitters are intermittent and randomly go unusable.  Sometimes at unacceptable and critical times. During this time I had about a dozen on my frequency; 124.0; when it just randomly became unusable.  I had 3 heavies in my IFR pattern for practice approaches.  I had an IFR jet inbound.  There were 2 VFRs inbound.  There was a VFR on a practice approach.  There was a VFR doing photo work over the lake area just west of the finals.  Plus additional satellite operations. It just suddenly wouldn't transmit.  I checked my headset.  Then I switched the plug into the second set of holes.  I tried using the foot pedal instead of my button.  I tried switching to the backup transmitters.  I tried guard frequency.  The Supervisor tried to use the PET [radio].  I switched to the override orange box and could reach 2 or 3 of them; but then only about 1 of the 5 tries would go through and the responses were broken; unreadable or very static-y.  We tried to put everyone on our backup 133.575; but it had the same issues.  We could hear pilots; but were unable to transmit anything back.  I told Tower to keep everyone on their frequency they had; and everyone was point out approved.  We frantically kept trying to reach the aircraft sitting on my frequency as they began to go through final and some began to get dangerously close to MVAs.  Finally; the combination of everything and the frequency seemed to snap back to working.In the next hour; we had probably 25% of the transmissions to aircraft not be received.  At many altitudes in areas that would typically work.  I used aircraft I could reach to relay to the ones I couldn't.  It was a nightmare. I may have had separation losses.  I think I kept altitude separation; but it was too busy and chaotic for myself or the Supervisor to work it and see. The VFR photo guy just decided on his own to head east; directly across the two finals in front of aircraft on [an] approach; without me telling him to; or without me being able to issue any traffic to anyone.  One of the heavies I had on a right base to RWY 18 at 040 took it upon himself just to turn in to the airport.  He ended up overflying at 040 before finally switching himself to tower frequency to enter their frequency.  This was the 2nd scariest thing I've ever had while working.  Not okay. The frequency transmitter issues need to be identified and fixed.  Just because they start working again; is not good enough.  We also need a real backup that we can use that transmits from a different source.  When our backup seems to go out at the exact same time; it is useless.  Our Omaha and Offutt frequency options are not in range for low Lincoln sector aircraft.For the last 2-3 weeks; something is wrong with the transmitting capabilities of our Lincoln sector frequencies.  Our primary 124.0 frequency will all of a sudden just not go out to the pilots.  We try switching to main/stand-by and it makes no difference.  We switch and do all the coordination with other facilities to use our backup frequency; 133.575; but then it has the same issue.  Sometimes we can use the Orange Voice Backup Override boxes; but it is also intermittent and when it goes out is maybe 2 by 5 at best with a lot of static and crackling.  If we try to work them in by leaving them on Omaha and/or Offutt frequencies; 120.1 or 124.95; the range isn't good enough to reach low aircraft on the south/west side of Lincoln and we lose contact that way completely. This is an urgent; serious issue.  When we called it into MOCC (Mid-States Operations Control Center) a week or two ago; the tech responded to us that 'it was probably due to the storm passing through' even though there was only light (level 1 and 2 precipitation).  When it came back online they just called it back in service without fixing anything or identifying the problem.  Yesterday it occurred while I had around a dozen aircraft on frequency.  The sudden loss of communications nearly caused major incidents and could have been catastrophic.  Luckily I had most of them altitude separated as an additional precaution at the time; but we still had a near MVA (Minimum Vectoring Altitude) bust as a result and may have lost separation in the chaos.  The Supervisor tried to use the PET; but our range doesn't reach Lincoln on them; and when it did intermittently go through; only stepped on my transmissions I was making through the override box and made it worse.




Synopsis: R90 Approach Controller reported frequency outages; at this location; during a peak period.