New Delhi, Nov. 15 -- Federal aviation officials received repeated warnings that efforts to modernize the United States' air traffic control network could disrupt its operations, The Washington Post reported after a nationwide ground stop halted departures for more than four hours on November 13.

The Post's report said government reports had outlined the risks in the months and years before the shutdown. The findings put the handling of the transition from aging equipment to newer systems under scrutiny as investigators work to establish what went wrong.

Maintenance work comes under scrutiny

Transportation Secretary Sean Duffy said Saturday that the disruption began while contractor L3Harris was updating telecommunications infrastructu...