Thousands of flights were delayed or cancelled across the United States on Saturday as airlines worked to recover from a nationwide ground stop caused by problems during air traffic control system upgrade work.

Transportation Secretary Sean Duffy said a contractor was replacing old copper telecommunications lines with fibre at a remote Federal Aviation Administration (FAA) facility when the system became overloaded. Investigators are still determining whether contractor error or faulty equipment caused the problem. The resulting disruption affected communications with aircraft and radar feeds.

The FAA issued the ground stop on Friday because of communication problems at several air traffic control centres. The restriction was lifted later that evening, but officials warned that it would take time for flights and crews to return to schedule.

FAA Administrator Bryan Bedford said flight schedules were expected to recover by Sunday night, although delays could continue in the meantime.

This article was originally published by Antigua News Room. Read the original article here: US flight delays continue after FAA ground stop linked to wiring work.