The air traffic system meltdown at Newark Liberty International Airport last week “was the most dangerous situation you could have,” according to an air traffic controller on duty that day, as the fallout from the outage stretches into a second week.

The Federal Aviation Administration said Wednesday that it plans to upgrade the technology used to get radar data to air traffic controllers directing planes to the troubled Newark, New Jersey, airport, and improve staffing to alleviate problems that have caused hundreds of flights to be canceled there.