When Congress pushed ahead last year with adding 10 new daily flights to Washington D.C.’s Reagan National Airport, the Federal Aviation Administration had data showing an unnerving number of near misses in the already-crowded skies — something lawmakers apparently did not know.

The FAA, which manages the nation’s airspace and oversees aviation safety, had data on dozens of incidents that experts said documented a safety concern. That data didn’t prompt any action before January’s deadly midair collision between an American Airlines jetliner and a military helicopter that killed 67 people.

“Why someone was not paying attention to those numbers and those events are questions yet to be answered,” said James Hall, a former National Transportation Safety Board chair during the Clinton administration. “What not to do is to ignore that many incidents.”

Data collected by the FAA shows close calls were far more frequent than travelers and outside aviation experts knew at Reagan National, which was built to handle 15 million passengers a year, not the 25 million traveling through it annually.

Now, safety experts and family members who lost loved ones in the Jan. 29 crash are asking why action wasn’t taken earlier.

The NTSB said airplane pilots were alerted to take evasive action to avoid hitting helicopters at least once a month from 2011 through 2024, citing data compiled by the FAA, and that there were 85 near misses when aircraft were within a few hundred feet (meters) of each other during recent years.

“How does that happen in this day and age and somebody doesn’t do something about it?” asked Doug Lane, whose wife, Christine Conrad Lane, and their 16-year-old son, Spencer, died in the crash.

Pilots have long worried about the congested and complex airspace around Reagan National, near the heart of the capital, where flights must maneuver around military aircraft and restricted areas. It was no secret there had been previous close calls, but the numbers found by the NTSB were alarming.

FAA officials have not yet addressed who inside the agency saw the data and whether it prompted discussions about possible changes. Messages seeking comment were not immediately returned Thursday.

Current NTSB Chairwoman Jennifer Homendy and Transportation Secretary Sean Duffy, who oversees the FAA, both said they were angry that the number of close calls were not recognized earlier by the FAA.

“If someone was paying attention, someone was on the job, they would have seen this,” Duffy said. He also announced he will move forward with banning some helicopter flights around the airport, a move that was temporarily made after the crash.

Safety advocate Mary Schiavo, a former inspector general of the U.S. Transportation Department, said that while there was plenty of blame to go around for the midair collision, the FAA was shockingly complacent.

“They literally wait for a disaster,” she said. “I can’t even fathom how the families of those lost in this crash can even deal with this. I mean this would be so maddening to hear.”

In Kansas, some officials also argue the FAA’s data should have been readily accessible to the public. State Rep. John Carmichael, from Wichita, where the airliner’s flight started, said Thursday that it’s not enough for people to get data through Freedom of Information Act requests when that can take months.

“The public absolutely needs to know about statistics like that because we all put our lives in the hands of pilots and air traffic controllers every time we get on a plane,” said Kris Kobach, the state’s attorney general. “I’m hopeful that the Trump administration will make this kind of information available to the traveling public.”

Commercial passenger airlines are authorized to make a total of 864 landings and departures from Reagan National from 6 a.m. to midnight each day, or 48 an hour, according to the airport’s website. Of those, 64 have been added by Congress since 2000. Local airport authorities have objected to the increases.

The crowded airspace around Washington drew attention last year when Congress debated an aviation safety bill that allowed 10 more flights a day at Reagan National, despite strong objections from Virginia’s Democratic senators, Tim Kaine and Mark Warner.

Squeezing in more flights would only increase the risks, they warned, calling a near miss between two planes on a runway last April a “flashing red warning light.”