The US Federal Aviation Administration (FAA) ordered ground stops at airports across the north-east on Monday after a problem with radio frequencies at the Philadelphia terminal radar approach control, according to The Guardian and Reuters.

Ground stops hit Newark, Philadelphia, Teterboro, John F. Kennedy and LaGuardia — on the day 130 heads of state and government arrive in New York for the United Nations General Assembly. The FAA has not said what caused the outage; administrator Bryan Bedford told reporters a backup fiber line was accidentally cut by a construction crew in New Jersey (Reuters). FlightAware showed more than 600 delayed flights at Newark and Philadelphia, and Flightradar24 an average delay of 112 minutes at Newark. The same day, the US Government Accountability Office (GAO) published a report finding the FAA has not completed risk assessments or updated security documentation covering interference, spoofing and jamming of radio communications with aircraft, with nine recommendations accepted by the Department of Transportation.