Transportation safety officials believe that the crew of an Army Black Hawk helicopter that collided with a passenger jet near Washington DC last month may have been using night vision goggles and possibly depended on incorrect flight data just before the tragic incident.
Initial analysis of voice recordings and other black box information retrieved from the crash site indicated that the helicopter pilot and instructor voiced inconsistent altitude readings prior to the impact, while some altitude data from the Black Hawk appeared flawed, according to National Transportation Safety Board (NTSB) officials.
“We are encountering contradictory information in the data, which is why we have not released the altitude data for the entire route of the Black Hawk,” NTSB Chair Jennifer Homendy stated during a press briefing.
Ms. Homendy expressed confidence that at the moment of the crash, the helicopter was flying at an altitude of 278 feet—higher than it should have been for that area. “However, I want to emphasize,” Ms. Homendy added, “that does not necessarily reflect what the Black Hawk crew was perceiving.”
One of the altitude data sources for the helicopter, which depends on atmospheric pressure but is typically not used directly by pilots, was deemed invalid by investigators.
“This altitude is calibrated based on what we call standard atmospheric pressure, and we have determined that this parameter is invalid. This constitutes erroneous data,” said Sean Payne, the head of NTSB’s vehicle recorder data division.
The NTSB is currently investigating the mid-air collision on January 29 between the helicopter and an American Airlines Bombardier jet that resulted in 67 fatalities, marking the deadliest air disaster in the US in over two decades.
The Black Hawk crew, who were engaged in a nighttime training flight but were considered seasoned pilots, were thought to be using night vision goggles that might have complicated the differentiation between the American Airlines jet and the city lights on the horizon, according to Ms. Homendy.
Ms. Homendy also mentioned that the on-site part of the inquiry into the tragedy has now concluded.
In the upcoming week, Ms. Homendy indicated that wreckage will be transported from Ronald Reagan Washington National Airport to a secure site for more thorough analysis.
Investigators will conduct laser scans of mockups of the Black Hawk cockpit to make detailed comparisons with the wrecked helicopter and will examine whether various altimeters and other recovered data systems were operating as intended or if they had been intentionally switched off.
