WASHINGTON () The National Transportation Safety Board will begin a three-day hearing Wednesday to investigate the deadly midair collision over Washington, D.C., that killed 67 people in January.

The hearings will include NTSB board members, investigators and witnesses for organizations involved in the crash. Panelists are expected to focus on military helicopter routes in the Washington area, collision avoidance technology and training for air traffic controllers at Ronald Reagan National Airport, among other subjects.

Aviation officials will question witnesses and investigators about how the actions of the Federal Aviation Administration, its air traffic controllers, and the Army may have contributed to the nation’s deadliest plane crash since 2001. It’s likely too early for the board to identify the cause of the crash.

On Jan. 29, an American Airlines regional jet traveling from Wichita, Kansas, collided with a military Black Hawk helicopter while landing at Reagan National near D.C. Those who died include 64 people who were on the jet and three who were on the UH-60 Black Hawk.

The incident was the first in a string of crashes and near misses this year that have alarmed officials and the traveling public, though statistics show flying remains the safest form of transportation.

DOT chief Sean Duffy ‘concerned’ about aviation near-misses

Although the final NTSB report won’t be released until sometime next year, in light of a spate of recent aviation near-misses, Transportation Secretary Sean Duffy told on Tuesday, “Of course I am concerned. The FAA is concerned. The American people are concerned.”

Duffy told he and his agency are “leaning into” the incidents and looking for solutions: “What is key, we are not ignoring it.”

Culture of near misses led to crash: Father of co-pilot

Investigations have shown the FAA failed to recognize a troubling history of 85 near misses around Reagan Airport in the years before the collision, and that the Army’s helicopters routinely flew around the nation’s capital with a key piece of locating equipment turned off.

Tim Lilley, whose son Sam Lilley was the co-pilot on the American Airlines jet involved in the crash, has demanded answers about the Army’s risk management practices. Speaking to “ Live” on Monday, Lilley criticized what he calls a culture of normalized risk and near misses within military aviation.

“I want to find out when it became commonplace to do dangerous acts in the 12th, like asking for visual separation, when it was a really bad idea,” he said. “We want the Army to analyze data.”

He added, “These 64 victims, they’re not casualties of war. They’re casualties of a culture that decided near misses were okay, because there was many, many near misses that led to this thing.”

Lilley also criticized the Army for what he called a lack of accountability, saying it has hidden behind the NTSB investigation for six months without owning its role in the crash.

Kevin Bohn and the Associated Press contributed to this report.