At a hearing in Washington Wednesday, Senators heard from FAA officials who revealed a disturbing new detail about the midair collision between an Army helicopter and American Airlines flight in January that killed 67 passengers.

The FAA said a hotline between the Defense Department and air traffic controllers at Reagan National Airport was down and had not been working in three years — and the FAA had no idea.

That made it difficult for controllers to know when Army helicopters were flying in some of the nation's busiest airspace.

Military flights have since been restricted around the airport.

RELATED STORY | Newark experienced another outage impacting flight radar, FAA says

Meanwhile, parents of the co-pilot who died on that American Airlines plane were on hand for another hearing about aviation safety in the House of Representatives.

Transportation Secretary Sean Duffy pushed for billions of dollars of new funding to modernize the nation's air traffic control system after radar outages caused delays and cancellations at Newark Liberty Airport in New Jersey.

He also faced questions about recent staffing cuts.

"We see thousands of qualified federal workers and contractors, including air traffic controllers, made up of women people of colors and veterans pushed out of highly skilled jobs," said Rep. James Clyburn.

"No one from air traffic control has been allowed to take a deferred resignation offer," Sec. Duffy said. "We have preserved all of our safety critical mission, including air traffic controllers."

Duffy says they are right now testing new fiber lines at Newark Airport that should help prevent further issues with the radar. But he also said flights will need to be reduced into that major airport while work is ongoing.