The acknowledgement came during the second day of testimony held to discuss the collision of a commercial plane and Army helicopter in January that killed 67 people.

The National Transportation Safety Board will question witnesses Thursday about air traffic control training, a key part of the investigation into January’s deadly midair collision at Ronald Reagan Washington National Airport.

Air traffic control managers told the National Transportation Safety Board that F.A.A. leaders rebuffed efforts over the years to address hazardous conditions that played a role in the Jan. 29 crash.