The plane touched down on a concrete stairway and came to rest on its left side. Four of the five occupants made it through the initial impact, but no one survived the subsequent fire that the helicopter quickly caught after a significant fuel leak.
The collision happened around an hour after Leicester City and West Ham United’s Premier League match.
According to the AAIB investigation, the control system malfunctioned when a tail rotor bearing broke apart as a result of its ceramic balls sliding rather than rolling under pressure. Adrian Cope, AAIB senior inspector for engineering, responded when asked if this was “an accident waiting to happen”: “It was a process which built up consistently. Over time, the damage to that bearing accumulated. The inspection of the bearing was only necessary after 400 hours of operation, yet the accident occurred after only 331 hours of operation.
The lack of laws requiring maintenance checks to compare the state of worn bearings to their original design was one of the “contributory factors” for the crash, according to the AAIB.
The 209-page report excluded pilot mistake and drone involvement. “The AAIB has carried out an extensive investigation to establish why the accident occurred and how safety can be improved,” said Crispin Orr, the head inspector of air accidents for the AAIB.
A helicopter belonging to Leicester City owner Vichai Srivaddhanaprabha ahead of the Premier League match at King Power Stadium
Due to the fact that some important components were produced in those countries, authorities from Canada, France, Italy, and the US were also involved in the inquiry.
The European Aviation Safety Agency (Easa), whose criteria for aircraft certification are mirrored by the Civil Aviation  Authority in the UK, received eight safety recommendations from the AAIB to “address weaknesses or omissions” in the procedures for certifying helicopters. Design, validation, and monitoring of safety-critical components are the topics covered by these. As investigators learned of problems, the manufacturer and Easa made additional adjustments to the AW169 and AW189 fleets. In April of last year, a statue honoring Mr. Vichai was unveiled at the stadium.