The National Transportation Safety Board (NTSB) continues its public hearings on Thursday regarding the midair collision that occurred in January between an Army Black Hawk helicopter and a passenger plane, which resulted in the deaths of all 67 individuals on board both aircraft.

During the first day of the hearings, investigators focused on several aspects that might have led to the crash, including prior warnings about helicopter activity that the FAA had received years before the unfortunate event over the Potomac River.

While it is premature for the board to determine the exact cause of the accident, the final report is anticipated for release sometime next year. Wednesday’s discussions revealed how narrow the margin for error was for helicopters following the Black Hawk’s route during the evening of the deadliest plane accident since November 2001.

This January crash was the first in a series of incidents and close calls this year that have concerned authorities and the public, even though flying is statistically still the safest mode of travel.

FAA didn’t add warning to helicopter charts, official says

NTSB Chairwoman Jennifer Homendy mentioned that in 2022, an FAA working group had expressed worries about helicopter traffic near Reagan airport and the potential collision risks, yet the FAA did not place a caution warning on helicopter charts advising pilots to be vigilant when that runway was active.

“This is the very event that this would have been the cautionary note for,” she said.

During the initial day of proceedings, video footage and animations illustrated the helicopter flying beyond the 200 feet (61 meters) altitude limit before it hit the plane.

Investigators said Wednesday the flight data recorder showed the helicopter was actually 80 feet to 100 feet (24 to 30 meters) higher than the barometric altimeter the pilots relied upon showed they were flying. So the NTSB conducted tests on three other helicopters from the same unit in a flight over the same area and found similar discrepancies in their altimeters.

Dan Cooper with Sikorsky helicopters said that when the Black Hawk helicopter involved in the crash was designed in the 1970s, it used a style of altimeter that was common at the time. Newer helicopters have air data computers that didn’t exist back then that help provide more accurate altitude readings.

Chief Warrant Officer Kylene Lewis told the board that she wouldn’t find an 80 to 100 foot discrepancy between the different altimeters on a helicopter alarming because at lower altitudes she would be relying more on the radar altimeter than the barometric altimeter. Below 500 feet (152 meters), Lewis said she would be checking both instruments and cross referencing them.

Army officials said a discrepancy of 70 to 100 feet (21 to 30 meters) between the Black Hawk’s altimeters is within the acceptable range because pilots are expected to maintain their altitude plus or minus 100 feet.

Concern about distances between planes and helicopters

The greater concern is that the FAA approved routes around Reagan airport that included such small separation distances between helicopters and planes when planes are landing.

“The fact that we have less than 500 foot separation is a concern for me,” said Scott Rosengren, who is chief engineer in the office that manages the Army’s utility helicopters.

During the two minutes before the crash, one air traffic controller was directing airport traffic and helicopters in the area, a task that involved speaking to or receiving communications from several different aircraft, according to the NTSB’s History of Flight Performance Study.

The air traffic controller had spoken to or received communications from the Black Hawk helicopter, an airplane that was taking off, an Air Force helicopter, an airplane on the ground, a medical helicopter and an inbound flight that was not the American Airlines plane that would crash.

“All aircraft could hear the controller, but helicopters could only hear other helicopters on their frequency and airplanes only other airplanes,” the report stated. “This resulted in a number of stepped on transmissions as helicopters and airplanes were not aware when the other was communicating.”

Stepped on transmissions are those that are unheard or blocked because of other transmissions. The NTSB report provides a list of 29 separate communications between the airport tower and other aircraft during approximately the 1 minute and 57 seconds before the collision.

Previously disclosed air traffic control audio had the helicopter pilot telling the controller twice that they saw the airplane and would avoid it.

The animation ended with surveillance video showing the helicopter colliding with the plane in a fiery crash.

Investigations have already shown the FAA failed to recognize a troubling history of 85 near misses around Ronald Reagan National Airport in the years before the collision, and that the Army’s helicopters routinely flew around the nation’s capital with a key piece of locating equipment, known as ADS-B Out, turned off.