UK Air Accidents Investigation Branch (AAIB) claim that the aircraft did not respond to pilot commands in a preliminary report, and started to turn right “contrary to the pilot’s left pedal command”.
The accident on 27 October, which also claimed the lives of four others onboard, continues to be investigated after Mr Srivaddhanaprabha’s private helicopter crashed outside the King Power Stadium roughly 40 seconds after takeoff.
Investigators are yet to determine why the pilot lost control with the AAIB stating that the “cause of the apparent loss of yaw control has yet to be determined”, but added that “investigation of the tail rotor system is being carried out as a priority”.
Footage of the incident appears to show that sections of the tail rotor may have fallen off in mid-air.
The aircraft reached an altitude of approximately 430ft before plummeting to the ground in a car park next to the Stadium and was “rapidly engulfed in an intense post-impact fire”, the AAIB said.
The Leicester City owner, employees Nursara Suknamai and Kaveporn Punpare, pilot Eric Swaffer and his partner, Izabela Roza Lechowicz – who was also a professional pilot – were all killed in the accident.
Following the crash, the European Aviation Safety Agency ordered that safety checks should be carried out on the tail rotors of AW169 helicopters and similar models.
The first flight of the day for the helicopter involved in the crash was from Fairoaks airport in Surrey, with one pilot and one passenger.
Three additional passengers boarded in London, before the helicopter flew to Leicester City’s training ground, where it was shut down.
All five passengers went to the stadium, where Leicester were playing West Ham United in a Premier League fixture.
The pilot and a passenger returned to the training ground to make the short flight to land on the centre circle of the stadium’s pitch.
Soon after taking off 50 minutes later, at 8.37pm, the helicopter crashed.
Additional reporting by PA