In a tragic turn of events that unfolded on January 29, a collision between a commercial airliner and an Army helicopter near Washington, D.C., resulted in the most catastrophic plane crash on American soil since 2001. As the National Transportation Safety Board (NTSB) prepares to hold a hearing on the matter, it seems unlikely that a single cause will be pinpointed for the accident that claimed 67 lives.

Instead, the NTSB will outline a series of contributing factors unearthed during their investigation, offering recommendations aimed at averting future disasters. In a proactive move, the Federal Aviation Administration has already cemented temporary restrictions into permanent regulations, ensuring that planes and helicopters will no longer share airspace in the vicinity of Reagan National Airport.

Families of the victims, however, are hopeful that these recommendations won’t be shelved like many in the past. Tim Lilley, whose son Sam served as the first officer on the ill-fated American Airlines flight, stresses the importance of action from Congress and the administration. Lilley, a pilot and former Black Hawk helicopter operator in the Washington area, argues for a more data-driven approach to aviation regulation.

“Instead of writing aviation regulation in blood, let’s start writing it in data,” Lilley asserts. “The data clearly indicated the potential for this accident. It was entirely preventable.”

Throughout the past year, the NTSB has highlighted several critical missteps that led to the crash. These include a poorly conceived helicopter route near Reagan Airport, the Black Hawk helicopter flying 78 feet above its designated altitude, previous FAA warnings that went unheeded, and the Army’s decision to disable a key system that would have enhanced the visibility of the helicopter’s location.

The D.C. plane crash was the first in a number of high-profile crashes and close calls throughout 2025 that alarmed the public, but the total number of crashes last year was actually the lowest since the COVID-19 pandemic hit in 2020 with 1,405 crashes nationwide.

Experts say flying remains the safest way to travel because of all the overlapping layers of precautions built into the system, but too many of those safety measures failed at the same time last Jan. 29.

Here is some of what we have learned about the crash:

The helicopter route didn’t ensure enough separation

The route along the Potomac River the Black Hawk was following that night allowed for helicopters and planes to come within 75 feet (23 meters) of each other when a plane was landing on the airport’s secondary runway that typically handles less than 5% of the flights landing at Reagan. And that distance was only ensured when the helicopter stuck to flying along the bank of the river, but the official route didn’t require that.

Normally, air traffic controllers work to keep aircraft at least 500 feet (152 meters) apart to keep them safe, so the scant separation on Route 4 posed what NTSB Chairwoman Jennifer Homendy called “an intolerable risk to flight safety.”

The controllers at Reagan also had been in the habit of asking pilots to watch out for other aircraft themselves and maintain visual separation as they tried to squeeze in more planes to land on what the Metropolitan Washington Airport Authority has called the busiest runway in the country. The FAA halted that practice after the crash.

That night a controller twice asked the helicopter pilots whether they had the jet in sight, and the pilots said they did and asked for visual separation approval so they could use their own eyes to maintain distance. But at the investigative hearings last summer, board members questioned how well the crew could spot the plane while wearing night vision goggles and whether the pilots were even looking in the right spot.

The Black Hawk was flying too high

The American Airlines plane flying from Wichita, Kansas, collided with the helicopter 278 feet (85 meters) above the river, but the Black Hawk was never supposed to fly above 200 feet (61 meters) as it passed by the airport, according to the official route.

Before investigators revealed how high the helicopter was flying, Tim Lilley was asking tough questions about it at some of the first meetings NTSB officials had with the families. His background as a pilot gave him detailed knowledge of the issues.

“We had a moral mandate because we had such an in-depth insight into what happened. We didn’t want to become advocates, but we could not shirk the responsibility,” said Lilley, who started meeting with top lawmakers in Congress, Transportation Secretary Sean Duffy and Army officials not long after the crash to push for changes.

The NTSB has said the Black Hawk pilots may not have realized how high the helicopter was because the barometric altimeter they were relying on was reading 80 to 100 feet (24 to 30 meters) lower than the altitude registered by the flight data recorder.

Investigators tested out the altimeters of three other Black Hawks of the same model from the same Army unit and found similar discrepancies.

Past warnings and alarming data were ignored

FAA controllers were warning about the risks all the helicopter traffic around Reagan airport created at least since 2022.

And the NTSB found there had been 85 near misses between planes and helicopters around the airport in the three years before the crash along with more than 15,000 close proximity events. Pilots reported collision alarms going off in their cockpits at least once a month.

Officials refused to add a warning to helicopter charts urging pilots to use caution when they used the secondary runway at Reagan the jet was trying to use before the collision.

Rachel Feres said it was hard to hear about all the known concerns that were never addressed before the crash that killed her cousin Peter Livingston and his wife Donna and two young daughters, Everly and Alydia, who were both promising figure skaters.

“It became very quickly clear that this crash should never have happened,” Feres said. “And as someone who is not particularly familiar with aviation and how our aviation system works, we were just hearing things over and over again that I think really, really shocked people, really surprised people.”