ADS-B Benefits Are Limited Due to a Lack of Advanced Capabilities and Delays in User Equipage
The Automatic Dependent Surveillance-Broadcast (ADS-B) system is central to the Federal Aviation Administration’s (FAA) Next Generation Air Transportation System (NextGen) goals. ADS-B technology is expected to allow FAA to transition from ground-based radar to a satellite-based system for managing air traffic. However, in 2010, we reported that FAA faces significant risks and challenges in finalizing ADS-B’s technical requirements, managing its cost and schedules, and encouraging airspace users to equip with ADS-B avionics.
FAA recently completed ADS-B’s ground infrastructure with the deployment of 624 ground radio stations in April 2014. However, controller and pilot use of ADS-B throughout the National Airspace System (NAS) remains years away, in part because FAA has yet to resolve significant hazards identified during operational testing or conduct more rigorous testing of the entire system. Moreover, while ADS-B will provide some useful services—particularly in areas with no radar coverage—the system’s initial capabilities and benefits are limited. According to FAA, airspace users will gain the most benefits with the advanced capabilities of ADS-B In, which is expected to provide pilots enhanced merging and spacing capabilities for airport arrivals. However, requirements for ADS-B In advanced capabilities continue to evolve, creating significant challenges for certifying and equipping users with ADS-B avionics. Finally, the total cost and timeline to implement ADS-B and provide benefits for FAA and airspace users remain uncertain. FAA has increased its cost estimates for the total program by approximately $400 million and continues to adjust expected ADS-B benefits. As a result, FAA’s costs for the current ADS-B program now outweigh the potential benefits to users, and risks of further cost and schedule increases remain.
We made six recommendations to ensure ADS-B is operationally suitable, safe to deploy in the NAS, and a viable program. FAA stated that it generally concurs with all but one of the recommendations. All recommendations will remain open and unresolved until FAA provides specific information on its planned actions and completion dates, as requested in our draft report.