The lessons F1 learned from Berger's fiery Imola crash

Everyone feared the worst as they watched the fire engulf the car, with the speedy arrival of fire marshals within seconds of the incident a significant factor in the Austrian driver's survival.

Berger, who had been left unconscious thanks to the ferocity of the crash, escaped with second-degree burns to his hands, bruises and cracked ribs. It was another wake-up call for F1 though.

For although the carbon-fibre monocoque, first introduced by John Barnard at McLaren in 1981, had absorbed the energy (believed to be as high as 100G) in the impact, the side exposure of the fuel tank had resulted in almost a full tank of fuel catching alight.

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After the race, Ferrari's attention turned to finding out the cause of the accident, in order that it could prevent further occurrences.

It turned out to be a failure of the front wing, which had subsequently folded under the wheel and turned it into a sledge, driving straight-on into the wall.

Barnard and his design team hadn't really factored-in Berger's exuberant kerb hopping driving style, with their calculations more or less focused on the forces being transferred in a downward direction, rather than the upwards trajectory it was forced when colliding with the kerbs.

Ferrari's technical director also cited as a factor the rule maker's decision to ban flexible front wing endplates [5], with the teams still using stiff versions for their aerodynamic effect: making them more susceptible to striking the ground and incurring damage.

Ferrari 640 front wing with John Barnard corrections

Photo by: Giorgio Piola

In preparing for the next race in Monaco, Ferrari made alterations to the wing's carbon lay up to strengthen the affected area. Its rapid response wasn't enough though, as Mansell's penchant for using the front wing as a guide, clipping the Armco barriers with it, resulted in a similar failure during practice.

Another hot fix later, which resulted in metal being inserted in the wing support tube, was readied for qualifying and latterly improved upon for the subsequent races.

Berger's accident proved to be a defining moment for F1 though, as the fire – live on the world television feed - led to regulatory changes going forward, with fuel tank and chassis changes the focus of the sport's efforts.

The designs used then had been a hangover from the less safety focused decades that preceded them, when fuel tanks were still allowed to occupy the space alongside the driver. This was a significant factor in this accident and one that was to be changed in the following years.

As part of an overhaul prompted by the Berger crash, the fuel tank would need not only to be wholly enclosed within the monocoque's structure, but a new bladder construction, impervious to incursion, had to be homologated to a strict safety level too.

The FT5 bladder is a standard still in use today. It is a pliable and lightweight construction of Kevlar fibres that are tightly woven and then coated with an advanced elastomer, allowing them to be inserted through a small window in the monocoque.

Side-by-side here we can see the differences in the 640, 641 and 642 chassis and their fuel tanks.

The carbon-fibre monocoque of the Ferrari 640 was made from a male mould, a process that Barnard had used with his first carbon car at McLaren and adopted once again for Ferrari. The construction of the monocoque helped to soak up the massive loads the car underwent in the crash.

The stillborn 639 underwent plenty of changes as the car morphed into the 640 for the ‘89 season.

This exploded view of the 640 shows the chassis and fuel tank relative to the rest of the car.

This cutaway of the 641 gives a comparison of how the chassis and fuel tank differs in design to the 640.

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