Washington plane crash: What air traffic audio tells us about helicopter pilot's actions moments before mid-air collision

The audio shows how the helicopter, using the code Priority Air Transport 25 (PAT-25), specifically asked for visual separation from the CRJ (Canadair Regional Jet) passenger plane.

That means the helicopter's pilot requested permission to proceed, taking responsibility to look out for the plane and avoid it.

New audio reveals how the helicopter acknowledged the presence of the passenger jet before the crash

The request was in response to a question by air traffic control (ATC) asking whether they could see the passenger jet.

• ATC: "PAT-25, do you have the CRJ in sight? PAT-25, pass behind the CRJ."
• PAT-25: "PAT25 has the traffic in sight [unintelligible], request visual separation."
• ATC: "Confirmed."

The helicopter made this same request again a short while later, after air traffic control again alerted them to the presence of the CRJ passenger jet.

• ATC: "PAT-25, there's traffic just south of the Wilson Bridge, CRJ is at 1,200ft setting up for Runway 33."
• PAT-25: "Requesting visual separation."
• ATC: "Visual separation approved."

It is not clear if the helicopter was responding to the wrong aircraft.

Another jet nearly hit a helicopter just 24 hours earlier

The mixing of helicopters and passenger jets around the airport had also led to confusion just 24 hours earlier.

On the evening of 28 January, a different American Airlines jet, flight 4514, had to take evasive action to avoid a helicopter near the airport.

At 8pm, local time, on 28 January, American Airlines Flight 4514 was coming in to land.

It was descending rapidly, and had already reached just 1,700ft.

It then received a warning from air traffic control.

"Helicopter over Georgetown, northbound, 300 feet".

Seconds later, the helicopter veered directly into the plane's flight path and climbed to 600ft, flight tracking data shows.

We don’t know whether the suspected helicopter continued to gain altitude, because its data cut out at this point.

What we do know is that, 15 seconds later, the pilot of American Airlines 4514 stopped descending and began climbing rapidly – gaining 1,800ft in just over a minute.

He then veered off to the right, aborting his landing.

“We had an RA,” the pilot told air traffic control, using the code for the automated alert sounded by aircraft to avoid mid-air collisions.

“Brickyard 4514 is going around.” 

The plane landed safely on its second attempt.

The suspected helicopter was next spotted 40 seconds later at an altitude of 1,600ft, having veered off in the opposite direction to the plane.

Staffing was 'not normal'

As part of its investigation into Wednesday’s crash, the US National Transportation Safety Board is looking into various areas, including staffing at the airport’s air traffic control tower.

Sky's US partner network NBC revealed that an air traffic controller left work early on the day of the crash. That allegedly left just one person to monitor both airplane and helicopter traffic.

Air traffic controllers are only allowed to operate alone after 9.30pm. The accident took place at 8.47pm.

The Federal Aviation Administration's (FAA) preliminary report into the crash said staffing at Reagan Washington National Airport was "not normal" in advance of the accident.

Across the US, FAA data does show a decline in the number of air traffic controllers over the years.

The context, however, is an even larger decline in air traffic - meaning there arguably isn't a need for as many air traffic controllers as in the past.

It also remains unclear whether air traffic control staffing levels affect passenger safety. Fatal air accidents are, thankfully, rare - but that means it's hard to spot patterns in the data.

A more common occurrence is runway incursions - where a plane, in the grounds of the airport, goes where it isn't supposed to be.

The vast majority of runway incursions have no safety consequences at all, but it's a useful proxy to measure the number of mistakes on the ground.

The chart below shows the number of runway incursions per million flights has actually been falling, and last year was the lowest it's been since the pandemic.

A board member of the National Transportation Safety Board said that staffing is likely to be only one small part of the investigation.

Investigators may also be examining the altitude of the helicopter involved in the crash.

Maps published by the FAA show that helicopters are required to stay below 200ft in the area around the airport, but flight tracking data suggests the helicopter may have been flying at 300ft in the moments before the crash.

New CCTV obtained by CNN shows plane and helicopter collision over Washington DC0:35

"With military traffic, quite a lot of the time they can negotiate these restrictions," says Marco Chan, a senior lecturer in aviation operations at Buckinghamshire New University and an experienced pilot.

"If air traffic controllers know what's going on with traffic in the vicinity, they can allow them to go beyond the minimum or maximum altitude."

Investigators will need to determine if the data is accurate, and whether the helicopter had received prior authorisation to breach the altitude limit.

The videos of the collision are strikingly, shockingly clear.

The reasons are, so far, not.

-SKY NEWS