A near-miss incident at Ronald Reagan Washington National Airport on Wednesday between a departing flight and one that was landing has reignited safety concerns after Congress approved adding more flights to the airport.

The Federal Aviation Administration (FAA) has launched an investigation into the incident to determine how it occurred.

“An air traffic controller canceled the takeoff clearance for American Airlines Flight 2134 because another aircraft was cleared to land on an intersecting runway at Ronald Reagan Washington National Airport,” an FAA spokesperson told The Hill on Thursday.

Some legislators from Maryland and Virginia had sought to eliminate language authorizing five more flights at the airport from an FAA reauthorization bill over concerns it was already too crowded. The bill passed last month with the additional five-flights language intact, purportedly advancing with support from congressional members who wanted a more convenient way to fly home after sessions.

The near-miss incident on May 29 was the second at Ronald Reagan Washington National Airport (DCA) in the span of a month. According to the Metropolitan Washington Airports Authority (MWAA), the airfield is the smallest of three local fields, yet it is the most heavily used runway in the nation. MWAA was opposed to adding flights to the field.

“DCA operates at full capacity, with a takeoff or landing every minute, for much of the day,” said Airports Authority President and CEO Jack Potter, per MWAA. “Adding more flights to this already-packed schedule would lead to more delays, which would result from the need to accommodate the spacing between aircraft operations that is required to assure safety.”

Near-miss incidents happen more frequently than many people realize, according to an investigation by The New York Times. The news source cites FAA records indicating near-misses occur multiple times per week. One incident noted in the investigation involved a Dallas-bound flight in which an air traffic controller mistakenly put two jets close enough together in the sky that one of the planes’ collision warning systems was activated while traveling at 500 miles per hour.

NYT found that human error, often on the part of air traffic controllers, was almost always the cause of near-miss situations. Nationally, nearly every airfield is understaffed, leading to a more stressful workload that can significantly impact safety.

During former President Obama’s tenure, the FAA added “diversity, equity, and inclusion” requirements to its hiring of air traffic controllers, which has allegedly led to the bypassing of qualified candidates, according to Gary Leff with View From the Wing.

Leff added that there was no indication that DEI hiring practices have led to less-competent air traffic controllers, but it has contributed to a smaller field of qualified applicants to choose from. A lawsuit filed by applicants passed over has now become a class action suit and continues to make its way through the courts.