In order to avoid thunderstorms in the immediate vicinity, the pilot requested take-off from a runway direction giving a slight downwind component. Light rain was falling at the time, but increased in intensity shortly after the aircraft commenced to roll. The initial stage of the take-off run was normal, but the aircraft then failed to accelerate. The take-off was abandoned at about 65 knots Indicated Air Speed, however braking effectiveness was reduced because of the wet runway conditions. A ground loop was attempted, the nosegear subsequently became detached and the aircraft slid sideways into the aerodrome boundary fence. No fault or defect was subsequently found with the aircraft engines, propellers or braking system which might have contributed to the development of the accident. A detailed engineering study revealed that under the existing conditions the wind velocity, rainfall rate and runway slope combined to prevent normal drainage off the runway. As a result, water tended to pool on the runway to a greater depth than anticipated. Quantitative estimates indicated that under these conditions, the rate of acceleration of an aircraft could be reduced by up to 50 percent. When the pilot abandoned the take-off attempt and applied the brakes, the depth of water present was such that the aircraft commenced to aquaplane.
