The pilot had borrowed the aircraft to fly to Medlow Bath to visit his brother who resided on the Blue mountains. He was accompanied by his father and a friend. The pilot had not previously flown from the Medlow Bath airstrip but had inspected it from the ground. After landing, the pilot and his passengers spent about 90 minutes on the ground. The wind appeared to be light and variable so the pilot decided to take off in the 24 direction. He said he lifted off at an indicated airspeed of 50 to 55 knots, but after the aircraft became airborne it did not accelerate or climb. The tailplane struck the branches of trees at the south-western end of the strip. Because the terrain fell away sharply at the end of the strip, the pilot said he lowered the nose of the aircraft in an attempt to increase airspeed. However, the left wing dropped and the aircraft entered an uncontrollable descending turn to the left. The aircraft impacted scrub covered terrain about 300 metres from the end of the strip. A passenger suffered a fractured arm as a result of ground impact. The pilot did not have the owner's permission to operate into the airstrip.