US flights resuming after FAA alert system outage causes disruption

Domestic flights across the US were temporarily grounded on Wednesday morning, after an IT failure in a critical aviation safety system.

The Federal Aviation Administration (FAA) said that the system that alerts pilots and airlines about any hazards was not functioning. The breakdown led to more than 7,800 flights being delayed and 1,200 being canceled , the flight tracking website FlightAware showed.

The White House said there was no evidence of a cyber-attack but the causes of the IT failure would be investigated in full by the Department of Transportation.

International US-bound flights were continuing to take off from Europe and elsewhere.

Crowley said he had noticed that US air travel had become precarious.

More than 20,000 flights were scheduled to depart airports in the US on Wednesday, according to aviation analytics firm Cirium, with almost 2.9m seats.

The delays affected carriers around the US. American Airlines, the biggest carrier by volume, said it was working with the FAA to minimise disruption. United Airlines said it had paused all domestic flights.

A Notam is a notice containing information essential to personnel concerned with flight operations, but not known far enough in advance to be publicised by other means.

Information can go up to 200 pages for long-haul international flights and may include items such as runway closures, general bird hazard warnings or low-altitude construction obstacles.