A helicopter crashed after a pilot spotted an aircraft door was ajar and was forced to make an emergency landing.

The chopper - a Robinson R44 Raven II - came down in a field near the A299 Thanet Way in Herne Bay , leaving three people injured.

The private aircraft had a pilot and three passengers on board when it crash-landed near the junction of Heart in Hand Road and Margate Road just after 10am on July 26, prompting a huge emergency response.

An investigation into the incident has now been carried out by the government’s Air Accidents Investigation Branch (AAIB).

Its report reveals the 53-year-old pilot had flown the helicopter from Orsett near Thurrock to a friend’s house near Herne Bay that day with his wife and two other friends.

Upon arrival, the three passengers got out, and a friend of the pilot boarded the helicopter along with their two daughters.

The pilot kept the helicopter’s rotor blades running and remained at the controls, while the passengers switched over.

Once the three new passengers were on board and seatbelted in, the pilot took off to the west.

His plan had been to take his friend and their daughters on a short local flight.

But soon after take-off, he realised the left front door of the aircraft was not properly closed, and there was a gap of about half-an-inch between the door and the frame.

The pilot asked the passenger to try latching it, but the passenger inadvertently unlatched the door and to his alarm it opened a couple of inches.

The pilot decided to land in a field so he could close the door on the ground.

But while trying to resolve the problem in the air, the pilot had inadvertently turned the aircraft to the right meaning he was making a “downwind” approach to landing.

The helicopter struck the ground and rolled over, leaving the pilot and two passengers with minor injuries.

Concluding its report, the AAIB said: “The pilot decided to make a precautionary landing when he became aware that a door was not properly closed.

“However, he inadvertently made a downwind approach. During the later stage of the descent it is likely that the helicopter started to enter a vortex ring state leading to a high rate of descent which the pilot was not able to arrest.”

Analysing what happened, it added: “The accident highlights the hazard of passengers boarding with rotors running where it is harder for the pilot to confirm all doors are properly closed.

“It also demonstrates how easy it is for a pilot to be distracted from the primary task of flying the aircraft when a minor problem occurs in flight.”

The pilot and his front seat passenger were able to climb out of a door, and help the others exit.

Police, firefighters, the ambulance service, a Hazardous Area Response Team (HART) and HM Coastguard soon arrived at the scene.

The AAIB’s report found the aircraft suffered “substantial” damage in the crash.

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