Washington crash

Was a muted microphone the cause of the accident?

(Bild: AP)

More than two weeks after the fatal plane crash in Washington with a total of 67 fatalities, investigators have presented the first findings on the possible cause of the crash.

The US Transportation Safety Board (NTSB) announced on Friday that faulty instruments and communication problems could have been the reason for the collision between the passenger jet and the military helicopter. However, the final conclusion of the investigation could take up to a year.

Air traffic controllers warned helicopter pilot
Initial findings suggested that air traffic control had issued a warning to the helicopter pilot a few minutes before the accident, said NTSB chief Jennifer Homendy. The controllers had warned the helicopter crew of the "circling" passenger plane.

However, data taken from the wreckage of the helicopter showed that the message was muffled and the word "circling" was unintelligible. According to Homendy, the helicopter's voice recorder then appears not to have recorded the crucial instructions to avoid the passenger plane's flight path seconds before the collision.

Microphone could have been the source of the error
A radio message from air traffic control could be heard on both voice recorders 17 seconds before the collision, which "instructed the helicopter to fly past behind the passenger plane", Homendy continued.

However, voice recorder data from the helicopter indicated that this crucial part of the radio message may not have been received at all. It currently appears that the microphone button on the helicopter's radio was muted during the communication with the air traffic controllers.

Collision during landing approach
The passenger plane collided with the military helicopter on approach to Reagan Airport in Washington at the end of January. Both aircraft crashed into the Potomac River. The 64 occupants of the plane and the three-man crew of the helicopter were killed.