Flights at Chicago's two main airports were already halted over communications problems before the FAA issued its nationwide ground stop, according to the agency's status feed and reports from several outlets. The FAA has not said whether these problems are linked to the national order.
Clash Report says Advisory 107 stopped flights bound for O'Hare from 3:10pm to 4:30pm ET, citing 'equipment / outage' and 'comms issues'. Midway received a matching stop three minutes later under Advisory 109.
The travel blog Paddle Your Own Kanoo reports that problems were first reported at about 3:30pm ET, when Kansas City Air Route Traffic Control Center entered a ground stop for intermittent equipment outages. This has not been independently checked.
NewsOn6 says radio problems at the Kansas City centre have been reported by aviation monitoring accounts and news outlets, but notes that the FAA advisory does not confirm that link. News9 said the connection between the earlier Chicago stops and the national order was unclear.
The FAA status page later showed departure delays at O'Hare, Newark, Teterboro, Phoenix, Las Vegas, Houston and Orlando, Clash Report says.