The inquiry set-up by Honda to establish the cause of Daijiro Kato's death at the season opening Japanese Grand Prix has declared that mechanical failure was not to blame - and that the former 250cc world champion's fatal accident was probably triggered by a loss of rear grip.

The six-month investigation - chaired by Professor Ichiro Kageyama of Nihon University's College of Industrial Technology - believes Kato was pushing hard to catch the race leaders and that his rear tyre began to slide when he braked hard for the chicane, at a speed of 170km/h.

"According to the on-board data, we conclude that the engagement of the front brake abruptly changed the load on the rear wheel, which lifted almost entirely off the ground, causing a lateral skid," declared the Daijiro Kato Accident Investigation Committee report. "From data on the change in suspension and acceleration sensors that followed, we can confirm that the vehicle entered a high-side like condition."

While the Japanese was able to partially control the slide - by reducing his braking - the bike began to kick ever more violently, shaking from side-to-side (oscillating). This instability also caused a loss of balance and Kato was thrown over to the left side of the bike, taking his right foot off the footpeg - and removing any chance of using the rear brake - in the process.

These factors combined are believed to have resulted in the #74 veering sharply left into the trackside tyre wall, on lap 3 of the April 6 event.
After the initial contact, Kato travelled along the tyre wall, still on his bike, before eventually hitting a new section of foam protection which - together with the closeness of the barrier - contributed significantly to the extent of his injuries.

"Kato veered (from his planned direction) in a straight line at approximately 170 km/h from the centre-left side of the racing course... after which the front left side of his bike struck the tyre barrier at approximately 150 km/h at an incident angle of 16.5 degrees. Kato and the bike progressed forward together along the surface of the tyre barrier, then crashed into the side of the adjacent foam barrier at approximately 140 km/h," said the report.

"Kato remained mounted on his bike as it travelled along the tyre barrier, but when his bike struck the adjacent foam barrier he was momentarily caught between the compressed foam barrier and the bike.

"As the foam barrier was unable to completely absorb the motorcycle's substantial kinetic energy at that point, the bike flipped forward into the air, springing up higher than the top of the foam barrier, and landing in the grassy area to the left side of the course 48 metres forward from where it initially struck the tyre barrier.

"After impacting the foam barrier, Kato was separated from his bike. He plunged head first into the foam barrier, and was then thrown into the air. Rotating horizontally through the air in the manner of a discus, he landed face up in the centre of the course 33 metres forward and to the right of the point where he first struck the tyre barrier."

In summary, if anything is to blame for Kato's death, the report said it was the lack of consistent barrier protection and limited runoff area (2-2.5 metres) available:

"If (Kato) had been able to decelerate sufficiently once he left the course (if there had been more runoff), the incident might have ended as a simple course departure," stated the report. "Further, if there had not been a (1.2m) gap between the two barriers, Kato would not have crashed into the side of the foam barrier, which would have changed the extent and type of injury he received."

The accident left Daijiro in a coma with serious head, neck and chest injuries. Almost exactly two weeks later it was announced that he had lost his fight for life but the report states: "It is also our judgment that Kato may have experienced clinical brain death immediately after receiving his injuries."

Former GP rider Kyoji Namba, a committee member, also explained that lesser riders would have been thrown off long before the bike finally veered into the barrier - had Kato not been able to control his machine for so long he may have survived.

A mechanical failure was dismissed since Tohru Ukawa (and others) suffered a similar type of 'weave' - the shaking motion which triggered the accident. Ukawa had an identical factory spec RCV, and experienced side-to-side oscillation at the same part of the racetrack, but his machine recovered as it wasn't on the very limit.

"It can be seen from the fact that other competitors experienced 'weave mode' in the same race in which Kato's accident occurred that it is a common oscillation phenomenon. In the case of this accident, however, Kato's vehicle was operating at its performance limits," confirmed the inquiry.

The Suzuka circuit has been removed from the 2004 MotoGP calendar while safety modifications are made.

However, question marks still remain as to whether Kato's immediate treatment after the accident was acceptable. Despite the 26-year-old lying unconscious on the racetrack, the event wasn't red flagged and marshals instead quickly carried the unconscious Telefonica rider away on a stretcher.

"Four rescue workers took hold of Kato, who lay collapsed face up in the middle of the course, held him by the right shoulder, the torso and both legs, and moved him sideways just a few dozen centimeters onto the stretcher. It certainly appears that sufficient care was taken to immobilize his head and neck area," said the report. "However, when the stretcher was moved Kato's head drooped markedly, and it cannot be denied that this might have additionally injured his neck."

Since those shocking scenes, the MotoGP riders - led by Valentino Rossi - have insisted on a red flag being shown immediately if any rider is left unconscious after an accident.

 

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