Terrifying footage shows spectators running for their lives as a Red Bull helicopter hits an airport building before bursting into flames.

The aircraft was the main act during the summer opening of a 1,300ft-long, 376ft-high suspension walkway connecting a Roman fortress with a 700-year-old castle in Reutte, a town in the mountainous western Austrian state of Tyrol.

Amateur footage shows the Bell AH-1 Cobra, a helicopter of Vietnam War fame, hovering a few feet above the tarmac at the private-use Reutte-Hoefen Airport.

Amateur footage shows the Bell AH-1 Cobra, a helicopter of Vietnam War fame, hovering a few feet above the tarmac at the private-use Reutte-Hoefen Airport

Dangerously close: Instead of going down vertically as it lands, the helicopter moves sideways towards the terminal building

But instead of going down vertically as it lands, the helicopter moves sideways towards the terminal building.

The giant rotor blades then hit the side of the building with a terrifying clatter.

Spectators including the person filming are seen running and diving out of the way for their lives as debris whizzes past.

After the cameraman stopped filming, the helicopter toppled over and burst into flames.

The giant rotor blades then hit the side of the building with a terrifying clatter

Luckily, pilot Siegfried Schwarz managed to escape unharmed and no spectators were injured.

Mr Schwarz is reportedly one of the most highly respected helicopter pilots in Austria and has piloted numerous helicopters in his 30-year-long career.

In the 1990s he was the chief instructor at the mountain rescue helicopter unit.

Since then, he has been employed as aviation manager and chief pilot by soft drinks firm Red Bull's 'Flying Bulls', a private aviation team owned by the company's co-founder, billionaire Dietrich Mateschitz.

A terrified woman is seen running for her life as debris whizzes past. Luckily, no one was hurt

On the website of the team, Mr Schwarz described the crashed helicopter as 'especially dear to him', admitting that the accident was down to a 'parking mistake'.

However the experienced pilot refused to talk to the media about the crash.

MailOnline has contacted Red Bull for comment.