When aircraft volume goes down, a supervisor can make the decision to combine two controller positions into one position. This happens routinely, and on Wednesday night at Reagan National Airport, it happened 40 minutes earlier than it normally does because the supervisor determined that the traffic was low enough to combine, according to a source with direct knowledge.
This position handles local arrivals into Reagan Airport and helicopter traffic when it's combined.
Before the explosion, the map below shows the paths the two aircrafts were taking.
The commercial pilot, marked in yellow, focused on the runway ahead of him, just seconds away from landing.
An air traffic controller spotted the Black Hawk nearby on its training mission and warned him to stay away.
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The Black Hawk pilot then confirmed, he spotted the plane, saying that they saw "visual separation," but that separation didn't happen.
"He was looking at something but apparently, it wasn't the same airplane," said aviation expert John Nance.
With all the updated technology, and aircraft warning systems, in those moments, experts say it all came down to line of sight, and preliminarily, human error.
"So, we have a thing called "see and avoid," Nance said. "It's been a problem in aviation since the very beginning. Sometimes even though we're responsible for seeing and avoiding, we don't have the right aircraft."
The 10-ton military helicopter collided with the 100-foot-long plane that weighed three times as much, plummeting into the Potomac River.
Officials with the NTSB are on scene, but an exact cause won't come quickly.
Their investigation could take a year to find exact answers.
"We are going to get to the bottom of this investigation, not in three years, not in four years, but as quickly as possible," said U.S. Secretary of Transportation Sean Duffy said in a White House briefing on Thursday.
We found that the NTSB has investigated 35 near-collisions in the air since 2008. Twenty-three of those involved commercial flights, and four resulted in accidents. Those accidents led to injuries and even death.
"The fact is we haven't had a major accident in the United States with an American air carrier in 16 years, and before that we wouldn't go for a year without a major accident," Nance said. "So, is it safe to fly? You're safer by far flying on a commercial airline than you are driving to the airport, and that is factual."
An internal operational report shows there were no staffing concerns inside the control tower.
The military is reviewing where and when the military does Black Hawk training.
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