Air traffic controllers at San Francisco International Airport (SFO) are already hailing the airport movement area safety system (Amass) as an aviation success story after it alerted them to a potentially hazardous situation involving a business jet and a regional airliner on one of SFO’s runways.

Controllers had instructed the business jet to taxi into position for an intersection departure about 6,000 ft down the runway. As the regional airliner approached the airport, bright green indicators called “hold bars” illuminated the ground radar display, indicating the regional was headed inbound to the runway occupied by the business jet.

Simultaneously, a text message appeared and a voice alert sounded, confirming the regional aircraft’s flight path. Controllers subsequently instructed it to execute a missed approach well before the runway. It later returned and landed safely.

“It worked as advertised,” said National Air Traffic Controllers Association (Natca) representative Dan Ellenberger. “This alert demonstrates the benefits of an important safety tool.”

Amass was first commissioned in June and is now in use at SFO, Detroit and Los Angeles. Commissioning a system involves installation, a testing phase of at least 30 days and, finally, controller use for at least 30 days to ensure a complete evaluation.

Controllers at five other facilities are using Amass and are awaiting full commissioning. The FAA’s ongoing efforts to improve runway safety call for continued installation and operation of Amass at another 25 of the nation’s busiest airports by the end of this month.

The incident at SFO was eerily reminiscent of an accident at LAX in February 1991, when a USAir Boeing 737 landed on Runway 24L, where a Skywest Airlines Fairchild Metro was waiting for an intersection takeoff. Thirty-four people died, including everyone aboard the Metro III.