A search operation is underway after a Belgian Army pilot mysteriously fell out his military helicopter without a parachute during an airshow.

The co-pilot of the Agusta A-109 had been watching three troops jump from the aircraft near Liège, Belgium - but then turned back to see the pilot was no longer in his seat and his door open.

With the helicopter flying at 3,900ft, its nose lurched forward and the co-pilot was forced to grab the controls to stabilise it.

A search operation (pictured) is underway after a Belgian Army pilot mysteriously fell out his military helicopter without a parachute during an airshow.

The reason for the pilot's fall, which happened during a regiment open day demonstration at Amay, remains a mystery.