The helicopter crash which killed the chairman of Leicester City and four other people
The Air Accidents Investigation Branch found to be disconnected, resulting in the helicopter becoming unstable and preventing the pilot from controlling it.
Leicester City chairman Vichai Srivaddhanaprabha, two of his staff Nursara Suknamai and Kaveporn Punpare, pilot Eric Swaffer and Mr. Swaffer's girlfriend Izabela Roza Lechowicz were killed when the aircraft crashed into a car park close to the King Power stadium on 27 October.
Found the pilot's pedals became disconnected from the tail rotor and caused the aircraft to make an uncontrollable right turn before it spun and fell, hitting the ground in a ball of flames.
Had become disconnected and there was a "build-up of black grease" on one component.
The failure led to the tail of the rotor blades being changed "until they reached the physical limit of their travel", investigators said.
The report stated: "The initiating cause and exact sequence of the failure that resulted in the loss of the tail rotor control is being investigated as a priority."
The report said: "The tail rotor actuator control shaft became disconnected from the actuator lever mechanism.
"The disconnection stopped the feedback mechanism for the tail rotor actuator from the operating and the rotor actuator from responding to the yaw control inputs."
This loss of the feedback mechanism meant the continuous rotation of the tail of the rotor blades "until they reached the physical limit of their travel".
"This resulted in an uncontrollable right yaw."
It went on: "Sufficient force and torque has been applied to the cast of the pinion.
"Unscrewed" from the nut, disconnecting the shaft from the actuator level mechanism, and causing the nut to become welded to the pin carrier. "
More follows …