This is the heart-stopping moment a medical helicopter crashed during takeoff in Illinois.

The terrifying incident took place on April 24 at around 9:20 pm during a training event with the Hartford Fire Department.

Authorities confirmed that the aircraft involved was an MMB–BK 117B-2 operated by Air Methods LLC.

An incident report from the Aviation Safety Network found that the crash occurred several hours after training was completed.

The pilot had conducted a ground reconnaissance, noting nearby trees and power lines.

The report added: 'The pilot, who was utilising night vision goggles with the helicopter's searchlight activated, brought the helicopter to an in-ground effect hover, and he balanced the torque indications for the two turboshaft engines.

'The pilot decided to use the power lines in front of the helicopter as a visual reference for the initial climb. During the initial climb, the helicopter inadvertently drifted rearward, and the tail rotor system impacted the tree.

Footage shows the aircraft spinning to the right before descending and coming to rest partially upright.

Moments after the impact, a fire broke out and partially engulfed the helicopter, reportedly injuring the pilot and two medical personnel.

The report continued: 'The helicopter sustained substantial damage to the fuselage, the main rotor system, the empennage, and the tail rotor system. The helicopter was not equipped with a crash-resistant fuel system, nor was it required by regulation.'

The National Transportation Safety Board (NTSB) released its final report on June 20, citing the probable cause as the pilot's failure to maintain directional control during the night takeoff from a confined area, resulting in a collision with a tree, loss of control, and impact with the ground.