Investigators discovered that air traffic control instructions were not successfully transmitted to the Army Black Hawk helicopter crew before the fatal collision which killed 67 people during a crash near Ronald Reagan National Airport.
Chairwoman Jennifer Homendy from National Transportation Safety Board revealed that the Black Hawk crew was potentially unable to receive essential instructions for following the jet due to transmission errors. History records this aircraft accident as the deadliest plane disaster within the United States since the year 2001.
The helicopter pilot crew who were performing their scheduled maintenance check using night vision goggles may have faced contradictory altitude information during the accident. The black box onboard the helicopter showed an impact altitude of 278 feet while the crew possibly received different altimeter readings on their pressure instruments. 
Aviation specialists pointed out that transmission signals which overlap and stack on top of each other lead to blocked communications. Retired airline pilot John Cox established that two minutes prior to the accident the helicopter took over visual separation responsibilities from the jet thus making its operators primarily responsible for avoiding the collision.
Only seconds before its collision the American Airlines jet executed a sudden evasion under the command of pilot Jonathan Campos. The fatalities included teenage figure skaters together with schoolchildren and hunters of the group. The Army conducted deceased crew identification and named Capt. Rebecca M. Lobach and Staff Sgt. Ryan Austin O’Hara together with Chief Warrant Officer 2 Andrew Loyd Eaves.
Parties involved in the examination focus on understanding potential issues with the altimeters. Subsequent analysis from the NTSB will take longer than one year to produce their final report about this disastrous accident.
