Jan. 27 (UPI) -- The Federal Aviation Administration ignored warnings about dangerous air traffic conditions at Ronald Reagan Washington National Airport ahead of the deadly mid-air collision that killed 67 people a year ago, National Transportation Safety Board officials said Tuesday.

Air traffic controllers were overworked and commonly dealt with near-collisions that likely numbed them to the dangers of the many close calls that they encountered at the airport, according to the NTSB officials.

The NTSB conducted a hearing after investigating the crash over the past year and determined the FAA ignored several complaints and warnings of dangers to air traffic made by air traffic controllers and others at the airport.

"We have an entire tower who took it upon themselves to try to raise concerns over and over and over and over again, only to get squashed by management and everybody above them with [the] FAA," NTSB Chairwoman Jennifer Homendy said during a Tuesday morning hearing at the NTSB's headquarters in Washington, D.C.

A pilot aboard the Army helicopter confirmed seeing the airliner when asked by the controller, but simulations created by the NTSB suggest it was very hard for the helicopter and airliner pilots to see one another.