SFO Radar just went out :/

A radar outage at San Francisco International Airport (SFO) has prompted air traffic control to place arriving and departing aircraft in holding patterns, creating significant flow disruptions across one of the busiest air traffic hubs on the West Coast. While specific technical details surrounding the failure remain limited, radar outages of this nature at major terminal facilities typically involve either a primary ARTS (Automated Radar Terminal System) or STARS (Standard Terminal Automation Replacement System) failure, a loss of the associated radar feed, or a communication infrastructure breakdown that renders the displayed picture unreliable or unavailable to controllers. In any of these scenarios, standard protocol requires ATC to revert to non-radar separation standards, dramatically reducing the number of aircraft that can be safely sequenced into and out of the terminal environment at any given time.

For pilots operating into or out of the Bay Area airspace — including those on Part 121 airline operations, Part 135 charter flights, and Part 91 business jet operators — a radar outage at SFO has cascading effects well beyond the immediate holding stack. Non-radar separation requires controllers to apply significantly larger longitudinal and lateral spacing between aircraft, often 20 nautical miles or more depending on altitude and phase of flight, compared to the 3-5 nautical mile radar separation normally applied. This reduction in throughput rapidly saturates the terminal airspace and generates system-wide Ground Delay Programs (GDPs) that propagate delay to departure airports across the country. Operators with fuel-sensitive aircraft or tight crew duty time windows should plan for extended airborne holds and should coordinate with dispatch for updated fuel release planning and alternate airport options.

SFO presents unique challenges during any radar degradation event due to its geographic and meteorological environment. The airport's proximity to the Bay, combined with the frequency of low ceilings and reduced visibility driven by marine layer intrusion, means that many operations at SFO already operate near IMC minimums with heavy reliance on precision approach infrastructure and tightly coordinated radar sequencing. A simultaneous radar outage and instrument meteorological conditions would compound complexity considerably for TRACON controllers at NorCal Approach, who manage some of the most congested and complex airspace in the National Airspace System. Even under VMC, the loss of radar surveillance removes the safety net that allows controllers to detect and resolve traffic conflicts in real time.

Radar outages at major terminal facilities highlight a persistent vulnerability in NAS infrastructure that aviation stakeholders have tracked for years. The FAA's ongoing STARS deployment and NextGen modernization programs are intended to provide more redundant and resilient surveillance capabilities, but aging terminal radar infrastructure at legacy facilities continues to generate episodic outages. Business aviation operators and flight departments should maintain contingency planning for SFO that includes pre-identified alternates such as Oakland (KOAK), San Jose (KSJC), and Sacramento (KSMF), along with familiarity with the Bay Area's LAHSO procedures and converging runway operations that may be suspended during degraded ATC capability. Monitoring NOTAMs, TFR tools, and FAA Command Center advisories in real time remains essential for any operator routing through the NorCal airspace during system anomalies of this type.