The pilot hired the aircraft to make a short local pleasure flight with some friends on board. The aircraft was parked at the southern end of the airfield, pointing north and aligned with the centre of the 1300 metre grass strip. The pilot reported that he started the engine and completed normal engine runup and pre-takeoff checks. He then manoeuvred the aircraft out of the parking position to check for other aircraft on final approach. A takeoff into the north was then commenced. After what the pilot considered was a normal ground roll, the aircraft became airborne. He initially allowed it to accelerate close to the ground before commencing to climb. At an altitude of about 100 feet above the ground and an airspeed of about 60 knots, the engine began to run very roughly. The pilot landed the aircraft back on the strip and commenced braking. He then became aware that the aircraft was not going to stop before the fence at the northern end of the strip. Accordingly, he applied power in an attempt to fly over the fence. This attempt was not successful. The aircraft hit the top wires of the fence and an adjacent gorse hedge, coming to rest 50 metres further on with the nose gear detached. An examination of the engine revealed a number of faulty spark plugs. An opinion was obtained from an engine specialist that the condition of the plugs was consistent with the rough running reported by the pilot. Weather conditions had not been conducive to the formation of carburettor icing.
