During descent, approximately 20 kilometres from the destination aerodrome, the engine lost power. The pilot turned on the electric fuel pump, resulting in the engine briefly regaining power before stopping. By this time the aircraft was near the edge of a thunderstorm with associated rain and turbulence. The pilot attempted a forced landing onto a grass field but overshot the approach due to poor visibility and a tailwind. While manoeuvring to avoid obstacles, the left wing struck the ground, resulting in the aircraft landing heavily, collapsing both nose and right main landing gears. The pilot advised that the engine had lost power due to fuel exhaustion. He attributed this to the use of extra power during the flight to maintain altitude in the hot and turbulent conditions. The mixture had not been leaned to best economy due to an instruction to avoid high engine temperatures following recent maintenance work.