Spooky: United Flight Reports "Severe Electrical Disturbance," Then TCAS Alert Over Denver

A United Airlines flight, UA779, landed at Denver International Airport (DEN) on Monday and reported a serious in-flight anomaly that combined severe cockpit radio interference with a Traffic Collision Avoidance System (TCAS) Resolution Advisory (RA) during approach. The flight crew described the electrical disturbance in their headsets as loud enough to impair intra-cockpit communication and their ability to hear ATC instructions, and shortly thereafter received an RA—the most serious TCAS alert, which directs an immediate evasive maneuver and overrides ATC guidance. The aircraft, registered N67350, is only two years old, making an airframe-based electrical fault possible but less likely than an external or ground-based interference source. The FAA is expected to open a formal investigation, consistent with its standard practice for any event involving total or near-total communication loss combined with a TCAS RA.

This incident is notable because it follows a well-documented May 2025 event at DEN in which 20 airliners experienced simultaneous radio dropouts of 90 seconds or more during approach, traced to a concurrent failure of both primary and backup radio transmitters at Denver Tower. That earlier failure prompted the FAA and airport authorities to accelerate a planned 15-year ATC infrastructure modernization down to a three-year timeline, reflecting how seriously the agency now treats DEN's aging radar and telecom systems as a safety-of-flight issue rather than a routine maintenance matter. Monday's event, whether ultimately attributed to ground infrastructure, RF interference, or an onboard fault, reinforces that the underlying reliability problems at one of the busiest hubs in the National Airspace System have not been fully resolved even as upgrades are underway.

For working pilots, the operational significance here extends well beyond DEN's colorful conspiracy-theory reputation. A simultaneous loss of clear ATC communication and a TCAS RA is a compounding-failure scenario: crews are forced to execute an immediate vertical maneuver to avoid conflicting traffic while also losing the normal channel to coordinate that maneuver with controllers. This is exactly the kind of layered failure that safety systems are designed to prevent from happening together, since TCAS is meant to function as a backstop to, not a replacement for, functioning ATC separation and communication. Crews flying into congested terminal airspace—particularly hubs undergoing known infrastructure strain—should treat this as a reminder to brief for communication-loss and RA response procedures as a combined contingency, not just as isolated checklist items, and to promptly report any interference patterns to help investigators correlate incidents across multiple flights and identify systemic causes.

More broadly, the DEN pattern illustrates a persistent challenge facing the FAA and the wider aviation industry: much of the NAS's ground-based radar and communication infrastructure is decades old, and traffic volumes at major hubs have grown well beyond what many of these systems were originally designed to support. DEN's accelerated three-year modernization timeline is itself a signal that regulators recognize the risk profile has changed, but the interval between the 2025 mass-dropout event and this week's incident shows how legacy systems can continue to produce safety-relevant anomalies even mid-upgrade. Airlines, dispatchers, and flight crews operating into high-density hubs undergoing similar modernization efforts elsewhere in the country should expect continued scrutiny of communication and surveillance reliability, and should treat any recurring interference or RA events at a given airport as data points worth reporting through ASAP or ASRS channels, since aggregated crew reports are often what drives infrastructure investment and prioritization decisions at the FAA level.