The pilots of a Black Hawk helicopter that collided with a passenger jet near Washington Reagan National Airport in January never heard an air traffic controller's instruction to pass behind the jet, the National Transportation Safety Board said in a hearing Wednesday on its investigation into the crash that killed 67 people.

Roughly 15 seconds before the collision, the controller asked the Black Hawk if it had the jet in sight as it was on approach to land. Three seconds later, the controller instructed the helicopter to pass behind the airliner, but the helicopter crew had keyed its microphone at the same time as the controller and never heard the instruction, according to the Black Hawk's flight recorder.

MORE: FAA administrator: 'Clearly, something was missed' that led to DC plane crash

The new details were part of the six-month NTSB investigation into the crash. The NTSB released thousands of pages of documents -- including new video from the end of the runway showing the crash -- about its investigation into the January collision between American Airlines Flight 5342 and the helicopter that was on a training flight.

Umit Bektas/Reuters - PHOTO: Relatives of victims attend a National Transportation Safety Board (NTSB) investigative hearing at NTSB headquarters in Washington, D.C., July 30, 2025.

The altimeter testing report in the docket showed that there were likely discrepancies between the barometric altitude and the radio altitude. A test flight over the Potomac found that the barometric altitude was consistently lower by about 100 feet than the radio and geometric altitudes over the water. The barometric altimeter was also obscured in the helicopter flight.

The crash killed all 64 passengers and crew on the airliner and all three in the helicopter. Investigators said in the hearing the helicopter crew had no idea they were about to crash, but the pilots flying the airliner used expletives two seconds before the crash and pulled the plane up.

Families of the victims of the crash sat in the audience of the hearing, some of whom wore pictures of their loved ones around their necks or on buttons. They broke down in tears as officials played the video with newly released surveillance footage of the incident.

During the three-day hearings, the NTSB is expected to question the Army, Federal Aviation Administration officials and others, and present its finding on the crash investigation. The NTSB will focus on a variety of topics in the hearings.

Umit Bektas/Reuters - PHOTO: National Transportation Safety Board Chairwoman Homendy attends a National Transportation Safety Board (NTSB) investigative hearing, in Washington

The investigation showed that the helicopter was flying higher than it was supposed to because there were likely discrepancies between its altitude measured by barometer and radio. A test flight over the Potomac River found that the barometric altitude was consistently lower over water by about 100 feet than its radio and geometric position.

More information was also disclosed about Capt. Rebecca Lobach, who was flying a training flight with an instructor pilot.

In February 2022, Lobach failed a night vision goggle annual examination, but passed other night vision goggle examinations after that, according to investigators. Another pilot who evaluated her in 2022 said her performance was “well below average” and she had “lots of difficulties in the aircraft.” He reverted her to the lowest readiness level and trained her for a month before she improved and demonstrated full readiness.

Other commanders and officers she worked with did not express concerns.

MORE: DC plane crash recalls similar event in 1982

On the eve of the investigative hearings, Republican Sen. Ted Cruz introduced legislation called "The Rotor Act," which would require all aircraft, including military, to transmit ADSB location when flying -- a system that allows aircraft to transmit its location to other aircraft as well as to air traffic controllers.

All aircraft flying above 18,000 feet are required to have ADSB, but certain aircraft, including military aircraft, are exempt from transmitting ADSB location for security reasons.

Umit Bektas/Reuters - PHOTO: Relatives of victims attend a National Transportation Safety Board (NTSB) investigative hearing at NTSB headquarters in Washington, D.C., July 30, 2025.

Transportation Secretary Sean Duffy said the NTSB recommended to the FAA to require ADSB on all aircraft nearly two decades ago.

"ADSB, and I can't stress this enough, is a game-changer, a game-changer when it comes to safety and will provide, as we said in 2008 immediate and substantial contribution to safety. This will save lives. This legislation will save lives," Homendy said.

MORE: Pilots warned of safety concerns at Reagan National Airport for decades

Umit Bektas/Reuters - PHOTO: A victim's relative wears an image on her neck during a National Transportation Safety Board (NTSB) investigative hearing at NTSB headquarters in Washington, D.C., July 30, 2025.

The helicopter crew might have had bad information from their altimeter, which measures height, as the pilots had differing altitudes in the seconds before the crash, the NTSB said in its preliminary report in February.

"We are looking at the possibility of there may be bad data," Homendy said at the time.

One helicopter pilot thought they were at 400 feet and the other thought they were at 300 feet.