Many flights have been delayed at the busy hub because of radar outages, shortages of air traffic controllers and construction on a runway.

Controllers switched frequencies and planes were “safely separated,” officials said. The 90-second outage on Monday followed communications problems at Newark’s airport.

Dozens of family members filed a joint complaint against 15 aviation officials, accusing them of negligence and violating South Korean law.

Technology and staffing problems have plagued the airport, one of the nation’s busiest hubs. Officials say they are trying to resolve the issues, but concerns remain.

The delays are the latest problem to plague the airport, where radar and radio communications have recently malfunctioned.

Pakistan said it had fired missiles at military sites in India after accusing India of targeting at least three of its air bases. India said it had targeted the bases in response to a wave of Pakistani attacks.