WASHINGTON, Jan. 28 (Xinhua) -- U.S. National Transportation Safety Board (NTSB) on Tuesday blamed "deep, underlying systemic failures" for the deadly midair collision in Washington D.C. in January 2025, as it released its findings after a yearlong investigation.

"Deep, underlying systemic failures - system flaws - aligned to create the conditions that led to the devastating tragedy," NTSB Chair Jennifer Homendy said.

The fatal collision between an Army Black Hawk helicopter and a passenger jet near the Ronald Reagan Washington National Airport on Jan. 29, 2025, is the deadliest air accident in Washington, D.C. since 1982, killing all 67 people on board.

"Having a helicopter route crossing runway 33 with only 75 feet (23 meters) of vertical separation ... separating a helicopter and a civilian aircraft, nowhere in the airspace is that ok," Homendy told reporters, noting that the tragic collision was "100 percent preventable."

Homendy harshly criticized the Federal Aviation Administration (FAA) for not acting on the concerns of air traffic controllers at the airport, despite receiving reports of more than 80 serious close calls in recent years between helicopters and passenger aircraft.

Investigators cited multiple factors that likely contributed to the collision, including the placement of a helicopter route in congested airspace, critical equipment failures and human errors, the National Public Radio (NPR) reported, noting that the final report is expected in a few weeks.

NTSB investigators said a single controller was handling both local and helicopter traffic on the night of the deadly collision, and the supervisor on duty should have separated the helicopter and landing responsibilities after the controller complained about being overwhelmed earlier in the shift, the NPR reported.

The investigation also found that air traffic controllers at the airport relied heavily on "visual separation," expecting helicopter pilots to spot approaching aircraft and avoid them. However, on the night of the collision, the Army Black Hawk was on a training mission using night-vision goggles, which can hinder pilots' ability to see dimmer objects or details in the surrounding environment. ■