http://www.atsb.gov.au/media/4548260...-051_final.pdf
What the ATSB found The ATSB found that while coordinating a landing clearance with air traffic control and flying a low level circuit with a close downwind and base in turbulent conditions, the pilot inadvertently allowed the airspeed to decay. In the subsequent turn (downwind) to adjust the circuit the aircraft aerodynamically stalled, descended steeply, and impacted the ground.
The aircraft was prone to aerodynamically stall with little or no aerodynamic precursors and it was not fitted with a stall warning device, increasing the risk of inadvertent stall.
Safety message Flying in an air display is different to normal operations and places additional demands on a pilot. Pilots who participate in air displays should consider the demands involved and to the extent possible ensure that the complete sequence, including landing, is planned and rehearsed.
Although amateur-built aircraft operated in the experimental category are not required to be fitted with a stall warning device (preferably with aural output), owner-pilots should consider the benefits of such devices as a last line of defence against stalling.