India, Jan. 30 -- The deadly Washington DC plane collision between a US passenger plane and a military helicopter on Wednesday raised serious concerns over the response, or lack thereof, from air traffic controllers at the time of the tragic crash.

According to The Associated Press, audio from the air traffic control tower around the time of the crash captured the grim moment.

Less than 30 seconds before the crash, an air traffic controller asked the helicopter if it had the arriving plane in sight: "PAT25, do you have the CRJ in sight?"

When there was no response, the controller issued a second call, directing the helicopter to "pass behind the CRJ."

However, no response was received, and the two aircraft collided seconds later.

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