Results from Operational Evaluations

Results from on-going operational evaluations at three airports indicate that RWSL is operating effectively and is accepted and well received by industry users. Performance assessment of the Runway Status Lights system is accomplished through both automated and manual data analysis in conjunction with relevant human factors evaluation. Data is processed and operations counts, illuminations, light anomalies, and surveillance issues are noted.

  • Technical Data
    All RWSL system input and output data are recorded during tests for post-hoc analysis and include time-stamped surveillance system inputs, fusion processing, safety logic internal data, and resulting light commands/illuminations. Correlated audio data from air traffic control radio transmission between pilots and controllers is also available for detailed analysis of specific events of interest.
  • User Feedback
    Users of the system, pilots, vehicle operators, and air traffic controllers, are solicited to provide feedback relating to many aspects of the system including correct and effective operation, operational suitability, system acceptance, comprehension of trained protocol, and workload and situational awareness issues. Elicited observer feedback also includes suggestions for system tuning and safety enhancement.

Technical Performance Assessment:
Runway Status Lights performance is assessed in many ways but key analysis elements are the numbers and rates at which anomalous light behavior occurs. Anomalies are classified into three groups:

  1. Missed Detections (MD): status lights off when they should be on
  2. False Activations (FA): status lights on when it should be off
  3. Interference (I): status lights on and interfering with safe traffic flow or clearances

Counts and rates of anomalies compared to established thresholds provide insight into the system’s technical performance by clearly presenting cases where RWSL did not perform as designed. RWSL anomaly counts continue to prove that it is operating well above standards required by the FAA. Nearly all anomalies are direct results of surveillance problems and don’t reflect logic errors within the RWSL safety logic. Continual development within the system’s fusion processing and improvements in existing and future surveillance will result in increased RWSL performance.

Human Factors Assessment:
Pilot feedback is essential for assessing the operational suitability and acceptance of the RWSL system by end users. Voluntary feedback and suggestions from pilots have resulted in changes that improved the system’s safety benefit and light configuration change for Takeoff Hold Lights (THLs) from a single to double longitudinal row that increased both the saliency and uniqueness of the lights.

Summary
Runway Status Lights is a breakthrough system that combines current technology with advanced processing and logic to create a feasible operational concept to solve a challenging yet important safety issue. RWSL meet a long-standing, well-defined safety need to prevent runway incursions and accidents. Of the few technologies specifically addressing this issue of preventing runway accidents and incursions, RWSL provides the most timely, effective, and automated way to directly increase the situational awareness of pilots and vehicle operators operating on the airport surface. In the rapid onset of a conflict, RWSL provides a last-resort safety net by providing a direct warning to pilots and vehicle operators who can respond immediately to break the developing accident chain. Runway Status Lights has been fielded successfully at three major airports in the United States and had been proven to perform exceptionally well by both technical and human factors assessment. RWSL has documented “saves” where it effectively warned pilots in several instances not to continue takeoff because another aircraft had blundered onto the runway. RWSL increases the safety of scores of airline passengers annually while operating seamlessly with current and future air traffic control procedures. RWSL also is supporting the FAA’s mission to increase airport capacity safely as the aviation industry continues to expand. Runway Status Lights system is a significant, life-saving technical accomplishment that has the potential to provide a safety benefit to millions of passengers each year.