What caused the deadly D.C. plane crash between an American Airlines jet and Army Black Hawk helicopter?

S E E D E D   C O N T E N T

By Elizabeth Chuck, Jon Schuppe and Melissa Chan

The skies on Wednesday night were clear. The pilots were in communication with air traffic control, and officials said American Eagle Flight 5342 was on a standard descent to the runway in the busy airspace above the nation's capital. Yet somehow, the passenger jet and an Army helicopter collided midair, bursting into flames and plunging into the Potomac River in the first major fatal commercial plane crash in the United States in 16 years.

Federal investigators are now searching for answers in what is expected to be a lengthy process. A number of factors, both technological and human-driven, could have played a role in the deadly accident, aviation experts say, including whether multilayered systems designed to stop collisions functioned properly.

"Everything, unfortunately, lined up for this accident to happen," said Kenneth Byrnes, a pilot and chairman of the flight training department at Embry‑Riddle Aeronautical University.

The National Transportation Safety Board is leading the investigation, which will also involve the Federal Aviation Administration and the Army. The painstaking process will include the collection of evidence from the scene, reviews of radio traffic and data on aircraft flight paths, communications with air traffic controllers and interviews with those controllers. Such investigations can take a year or longer to reach a conclusion, and the NTSB is the only agency authorized to provide an official cause for the crash.

"We look at the human, the machine and the environment," NTSB Chair Jennifer Homendy told reporters Thursday. "We will look at all the humans that were involved in this accident. We will look at the aircraft. We will look at the helicopter. We will look at the environment in which they were operating in. That is standard."

Officials cautioned that it is still too early to speculate about what led to the crash that killed all 64 on board the American Eagle jet and all three crew members on the Army Black Hawk helicopter.

Aviation experts say that the focus for investigators will likely be on several elements, including an automated system that should have warned the plane's pilot that another aircraft was close by; the pilots' communications with air traffic controllers; and any visual obstructions that could have prevented the pilots from seeing each other. They will also investigate any missteps by the pilots, though two aviation experts told NBC News that there was nothing pointing in that direction.

The disaster — the first major fatal commercial plane crash in the United States since 2009 — happened just before 9 p.m. ET Wednesday as the American Eagle jet, a regional aircraft owned by American Airlines, was descending into Ronald Reagan Washington National Airport, where airline pilots routinely navigate tight and crowded airspace.

While commercial jets have a safety system called the Traffic Alert and Collision Avoidance System, or TCAS, that gives pilots verbal cues when they are in danger of colliding with another aircraft, most military helicopters are not equipped with the same technology, said Jimmie Cummings, a spokesperson for the Army Combat Readiness Center. He said the chopper in the crash did not have it.

Regardless, there are limitations to TCAS. One is that the system reduces the number of alerts it issues as a plane descends in order to avoid false alarms from other aircraft on the ground. The American Eagle's last recorded altitude was at 375 feet, according tothe aircraft tracking websiteFlightAware.

John Halverson, a veteran pilot who said he has extensive experience landing at Reagan National airport, noted that FlightAware data appeared to show a by-the-book approach and descent. He added that pilots at that point in the landing process are focused on the runway and their instruments.

"They were in the slot. They were exactly where they needed to be," he said.

Communication between the aircraft and air traffic controllers also was routine. Transportation Secretary Sean Duffy told reporters that both the passenger jet and the helicopter had experienced pilots and "standard communication" with the air traffic control tower when they crashed.

"Everything was standard in the lead-up to the crash," he said. "Obviously something happened here."

According to a preliminary FAA safety report on the collision, at the time of the crash, one controller at the tower was focused on both helicopters and airplanes, a source with knowledge of the situation told NBC News. Usually, the tower has a separate controller who deals exclusively with choppers. FAA guidelines allow for the combined position.

Jeff Guzzetti, a former accident investigator for the FAA and the NTSB, said any dialogue with air traffic control will be a primary focus of the investigation.

"You can be sure that the air traffic control communications are going to be scrutinized by the NTSB, that controller is going to be interviewed, and the radar data is going to be looked at by NTSB," he told the "TODAY" show on Thursday. "There's going to be a lot of human factors involved."

Though officials stress that air travel has never been safer in America, Wednesday's accident has raised concerns, particularly in high-traffic areas like the nation's capital. Reagan National airport presents unique challenges — limits on where commercial flights are allowed to fly, skies congested with military aircraft and plenty of light on the ground, said Shawn Pruchnicki, a former airline pilot and an assistant professor at the Center for Aviation Studies at the Ohio State University.

"Reagan is just so saturated with lights. It's very easy to lose sight of an airplane in that flood of lights," he said.

The aviation experts said there is also a possibility that the aircraft were in each other's blind spots — which planes and helicopters have, just like cars. The fact that the two aircraft were so close to the ground would have meant they had limited time to maneuver around blind spots.

"Helicopter pilots can't be just constantly leaning forward or backward, because you could become disoriented," Pruchnicki said. "So there could have been a visual obstruction for them as they were trying to find this jet, and they ran out of time."

A report this month by the Army Combat Readiness Center found that in fiscal year 2024, the Army had the highest number of serious accidents, including fatalities, in a decade. Of the 15 incidents, only one involved a Black Hawk. The report noted that pilots might not be getting enough flight hours.

Jimmie Cummings, a spokesperson for the center, said it was difficult to explain the spike. He declined to comment on the flight-hours issue, however. "We're really not doing things differently. We do all we can to promote safety but, at the end of the day, what we do is dangerous," Cummings said.

The American Eagle jet that was involved in a collision over the Potomac River on Wednesday night pictured in 2022 near Ronald Reagan Washington International Airport. David Liebowitz

The American Eagle jet, which was carrying 60 passengers and four crew members from Wichita, Kansas, was on a normal approach to Reagan, officials said. The chopper, an Army Black Hawk with three crew members from nearby Fort Belvoir, Virginia, was conducting a training flight — a common practice in the busy airspace above Reagan.

"This was not unusual with a military aircraft flying over the river and aircraft landing at DCA," Duffy said, referring to the airport. "If you live in the area, you'll see that frequently with those two aircraft working together."

Dean Winslow, a retired Air Force colonel and onboard physician, said Black Hawks "are not incredibly maneuverable" and would have difficulty avoiding an airliner. "It would have been very difficult to see and avoid," Winslow said.

The Army pilots aboard the helicopter had night vision goggles, Defense Secretary Pete Hegseth said on X. Winslow said night goggles can help view terrain and obstacles, but also can restrict a pilot's field of view, "like looking through soda straws."

Radio traffic recordings indicate that one of the last communications that took place was a controller asking the helicopter pilot if they saw the plane, and directing the chopper to pass behind it.

Seconds later, the helicopter slammed into the plane, a fireball lighting up the sky.