FAA grounds all flights at US airports, citing 'extraordinary circumstances'

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The Federal Aviation Administration has grounded all flights at airports across the United States, citing "extraordinary circumstances and for reasons of safety".

The order, issued on Friday evening UK time, halts every departing aircraft in the country until further notice. The agency has not said what prompted the stop, and the cause of the disruption is not yet known.

The grounding followed an earlier FAA statement that it was experiencing air traffic control communication issues. Shortly before the nationwide order, the agency halted traffic in Chicago because of the same problem.

In an alert to operators, the FAA said:

"DUE TO EXTRAORDINARY CIRCUMSTANCES AND FOR REASONS OF SAFETY. ATTENTION ALL AIRCRAFT OPERATORS, BY ORDER OF THE FEDERAL AVIATION COMMAND CENTER ALL AIRPORTS ARE GROUND STOPPED. ALL DEPARTING TRAFFIC SHOULD REMAIN GROUND STOPPED UNTIL FURTHER NOTICE. INBOUND INTERNATIONAL FLIGHTS WILL BE MANAGED ON A CASE BY CASE BASIS."

A ground stop prevents aircraft from taking off and is normally applied to a single airport or region. A nationwide order affecting every US airport is a rare step.

Inbound international flights, which would include services from the UK, are being handled individually rather than turned back as a matter of course, according to the FAA alert. The agency has not set out how long the restrictions are expected to last.

CBS News reported that Midway International Airport in Chicago had also been issued a ground stop before the national order came into force.

The FAA has given no further detail on the nature of the communication fault, which parts of the air traffic control system are affected or whether any aircraft already in the air have been disrupted. Airlines have yet to say how many passengers are affected.