San Francisco International Airport (SFO) has announced that it has received approval from the Federal Aviation Administration (FAA) to use a new ground-based augmentation system (GBAS) to assist landing aircraft.
The GBAS uses a broadcast station located on the airport grounds to produce an enhanced GPS signal that is more accurate than the signal provided by satellites alone. Equipped aircraft will be able to use this system to land at SFO with a greater degree of precision.
With this approval, the GBAS can be used to replicate existing landing procedures at SFO. Its implementation will also allow the airport to propose innovative future procedures specific to the GBAS. The airport operator hopes that the technology will eventually help reduce noise in nearby communities.
The FAA has yet to formally adopt this landing technology on a federal level, but SFO intends to demonstrate its effectiveness for use at airports across the nation.
“This is a major milestone in a journey that began over five years ago. There are many potential benefits to GBAS, but our primary hope for this technology is to help reduce aircraft noise in our communities. We have much more work to do, but this is a critical first step. My sincere thanks go out to our project team, all the airlines who supported its development, United Airlines, who conducted real-world flight testing, and the FAA for certifying this system for use.”
The GBAS uses receivers and broadcast antennae to correct inherent errors in satellite-based GPS due to atmospheric conditions, minor clock errors and satellite positions. Using its highly accurate fixed position, it compares locational information from nearby satellites and produces a corrected GPS message that is broadcast to aircraft landing at SFO. Uncorrected, GPS is accurate to about 40 meters, but with GBAS the accuracy improves to within 2–3 centimetres.
This precision provides benefits such as improved safety and performance during bad weather. In addition, the technology also offers the potential for new landing procedures, which could reduce community noise by allowing aircraft to approach the airport from higher altitudes or from further offshore. SFO has initiated these innovative procedures for community review and comment and hopes to submit a series of procedures to the FAA for evaluation. If approved, SFO plans to implement new GBAS procedures within the next few years.
SFO has been pursuing GBAS for over five years, working with airline flight crews and FAA technical staff to install and test the required hardware. These efforts included testing of GBAS procedures in flight simulators and real-world testing by United Airlines on non-passenger flights. The final phase involved FAA flight testing of the system to support operational use at SFO.
