Chilling audio has captured the moments before a tragic plane crash in Philadelphia.
On Friday evening, an air ambulance carrying six people crashed moments after take-off, killing a seventh person who was in a car below.
AP reports that at least 19 people have also been injured in the tragedy, but officials have warned that it could be days — or longer — until the total number of dead and injured can be determined across the huge impact area.
Terrifying footage was captured on cameras in the area showing the moment the Learjet 55 plummeted to the ground before flames erupted and onlookers panicked.
The air ambulance had been transporting a child home to Mexico and had been due to stop in Missouri before continuing on to Tijuana.
She had been treated Shriners Children's Philadelphia and the plane had left Northeast Philadelphia Airport at 6.06 PM local time, heading to Springfield-Branson National Airport in Missouri.
However, the aircraft then quickly vanished from radar after climbing to an altitude of 1,600 feet, and was reportedly only airborne for around 40 seconds before falling from the sky.
Footage from the scene showed a mushroom-shaped fireball shooting into the sky as the plane impacted the ground in the densely populated area.
Audio from an air traffic control tower at Northeast Philadelphia Airport has been shared revealing the heart-stopping moment they realized the plane had disappeared from the radar.
In the clips, operators can be heard trying to make contact with the pilot, with one asking: "What’s going on down there?"
Another responds: "We have a lost aircraft. We’re not exactly sure what happened. So, we’re trying to figure it out.
"The field is going to be closed so no inbounds-outbounds."
Jet Rescue Air Ambulance, the company operating the plane, said the aircraft was a Learjet 55 carrying four crew members and two passengers, which were revealed to be a pilot, copilot, physician, paramedic, pediatric patient, and her mother, who were all Mexican nationals.
A spokesman for Jet Rescue Air Ambulance shared the identities of the victims to CBS as Captain Alan Alejandro Montoya Perales, co-pilot Josue de Jesus Juarez Juarez, Doctor Raul Meza Arredondo, Rodrigo Lopez Padilla, Valentina Guzman Murillo, and Lizeth Murillo Ozuna.
The seventh victim, who was in the car, has not yet been named.
The young patient had been in the US for life-saving medical treatment and had been on her way home after completing it and being released.
John Anderson, a retired pilot from Philadelphia, told Fox News Digital that he believes the reason for the crash may have been a takeoff stall, having viewed the footage of the way it fell to the ground less than a minute after taking off.
Anderson explained: "The plane was out of the crew’s control. It was not controlled flight into terrain (CFIT). May have been a mechanical malfunction of the stabilizer, elevator, trim or even a load shift rearward within the cabin."
He also speculated that it there was a stretcher on board the medical flight, it may have "rolled rearward" if it was not properly secured.
"This would cause the nose to raise and stall the wing," he explained. "In that case, the nose will drop with the angle in the video.
"Because it was right after takeoff and the initial climb, I would say it was likely a wing stall. There could be a number of factors that would cause a stall. Could have been a runaway trim, malfunctioning stabilizer."
The incident happened just two days after another major crash claimed the lives of 67 people.
Last week, there was a deadly mid-air collision between a Black Hawk military helicopter and an American Airlines passenger jet in Washington DC.
The two aircraft collided near Reagan National Airport, with both landing in the Potomac River, and all 64 people on board the plane and three soldiers on the helicopter were killed in the incident.
Investigations are underway into both collisions to establish why the tragic crashes occurred.
