Background

Following the 2013 Asiana Airlines Flight 214 crash at San Francisco International Airport, where the aircraft struck a seawall during landing due to an incorrect glide slope approach, aviation authorities sought advanced technological solutions to prevent similar incidents.

Implementation

In 2019, San Francisco International Airport (SFO) became one of the first major international airports to implement a comprehensive Real-Time Kinematics (RTK) monitoring system to enhance the safety of aircraft approach paths. The system featured strategically positioned ground-based RTK reference stations around the airport perimeter and was fully integrated with the existing Instrument Landing Systems (ILS). It provided real-time data feeds directly to Air Traffic Control (ATC) displays and included automated alert mechanisms to notify controllers of any glide path deviations that exceeded defined safety parameters.

Results

The implementation of the RTK monitoring system at SFO led to significant improvements in approach path safety. There was a 94% reduction in deviations exceeding 0.5 degrees from the optimal glide slope, demonstrating a major enhancement in precision. The system enabled early detection of 23 potentially dangerous approach configurations, allowing corrective actions before situations became critical. In seven high-risk cases, where aircraft were significantly below the correct approach path, timely interventions prevented possible incidents. The system also improved situational awareness for both Air Traffic Control (ATC) personnel and flight crews, while reducing controller workload through automated monitoring and real-time alerts.

Lessons Learned

The SFO implementation demonstrated that RTK technology, when properly integrated with existing systems, provides a crucial safety layer without adding complexity to pilot operations. The success has led to similar implementations at airports in Europe and Asia, establishing RTK as a new standard in approach safety.