The root cause of the longest halt in flight departures to U.S. airports since 9/11 remains unclear after a Saturday press conference by U.S. transportation officials.
Routers and networking equipment appeared to be involved in the technological disruption that grounded flights across the country, but a definitive cause has not been established as of Saturday afternoon.
The inability to pinpoint the reason for the infrastructure malfunctions led the Federal Aviation Administration to take actions that resulted in the grounding order, Bryan Bedford, administrator of the Federal Aviation Administration, told reporters.
"Because of our lack of identifying the root cause, we were unwilling to take any risk that this propagation could actually result in a sensor losing connectivity with aircraft," he said.
"What we saw was instability. We couldn't explain the instability," Bedford added.