(AP) — Long-standing concerns about military helicopters flying in crowded airspace and worries over short staffing among federal aviation workers emerged Thursday as key factors in investigators’ inquiry into the fatal midair crash between an Army helicopter and a commercial airliner earlier this year.

During the second of three days of witness testimony and public inquiry by the National Transportation Safety Board into the January midair crash over the Potomac River, the board focused on air traffic control.

The NTSB heard Thursday that it was common for pilots to ask to use visual separation — basically relying on their eyesight — just as the Army Black Hawk’s pilot agreed to do the night of the crash. FAA officials also said controllers relied heavily on pilots using visual separation as a way to manage the complex airspace with so many helicopters flying around Washington D.C.

But Rick Dressler, an official with medevac operator Metro Aviation, told the board it is difficult to identify other aircraft in the night sky around Ronald Reagan National Airport, especially if an onboard locator system was switched off, as Army choppers routinely did.

Dressler said that he and other civilian helicopter pilots in the area have long been concerned about the Army and Air Force helicopters flying around Reagan airport.

“I don’t like saying this. I’ll say it again on the record,” Dressler, a former Army aviator and retired Air Force officer, said. “I’m speaking for my group there. We we are all very uncomfortable when those two units are operating.”

Clark Allen, an FAA training manager in the Washington area who worked in the tower at Reagan National Airport, said it was common for visual separation to be used daily between helicopter pilots and commercial traffic.

The Department of Defense referred questions about Thursday’s testimony to the Army, who did not immediately respond.

The Air Force also did not immediately respond to questions about Dressler’s remarks.

The American Airlines jet arrived from Wichita, Kansas, carrying, among others, a group of elite young figure skaters, their parents and coaches, and four union steamfitters from the Washington area.

The collision was the nation’s deadliest plane crash since November 2001 and was the first in a string of crashes and near misses this year that have alarmed officials and the traveling public, despite statistics that still show flying remains the safest form of transportation.

It’s too early for the board to identify what exactly caused the crash. The board’s final report won’t be released until sometime next year.

Staffing worries

James Jarvis helped evaluate the operations at Reagan airport for several years. He said that at one point when his group visited the airport for an evaluation in 2022, the airport was so far out of compliance on more than 33 different items that the audit was stopped so Jarvis and the other experts could help the facility identify where to improve.

Jarvis said that he was concerned about staffing levels at the airport dating back to 2016 or 2017 — particularly the lack of support staff. That meant that the air traffic control staff couldn’t focus on what they needed to because they had to take care of things that support staff would normally handle and might not have had the time needed to manage training. And he said controller staffing levels were always on the low side.

“That was a concern of mine,” said Jarvis who works for FAA contractor Leidos. “At one point I was told to quit bringing it up.”

Final moments on Black Hawk

Communications from on board the helicopter moments before the collision were released as part of the board’s investigation.

The Black Hawk’s crew had been communicating with the airport’s control tower, although the helicopter pilots did not fully hear the controller’s instructions.

The Black Hawk pilots told the tower twice in the minutes before the crash that they had the American Airlines passenger plane in sight and would maintain proper separation. But when the controller instructed the pilots to “pass behind” the jet, the crew didn’t hear that instruction because the Black Hawk’s microphone key was pressed at that moment.