Over the past two weeks, several equipment outages at the Philadelphia-based air traffic control center that guides planes to and from Newark Liberty International Airport, have raised questions on just how safe it is to fly at one of the nation’s busiest airports.

Technology and staffing problems have plagued the airport, one of the nation’s busiest hubs. Officials say they are trying to resolve the issues, but concerns remain.

Another equipment outage struck air traffic controllers for Newark Liberty International Airport on Sunday morning, briefly disrupting some inbound flights and further highlighting the ongoing technology issues plaguing the airport.