Earlier in the day the pilot had flown VH-MDI from a mining camp at Windy North to Broome. On arrival at Broome, at 0913 hours, the pilot was handed a completed flight plan by his Chief Pilot, and briefed for two flights to Koolan Island. The purpose of these flights was to convey nine or ten passengers from Koolan Island to Derby. The aircraft was subsequently refuelled to full tanks and departed Broome at 0956 hours arriving at Koolan Island at 1103 hours. After loading five passengers and their luggage, the pilot taxied the aircraft for take-off from runway 23. Runway 23 is 810 metres in length and has an overall uphill slope of 1.17 percent. The wind at the time was a direct crosswind of between 10 and 15 knots. The aircraft became airborne approximately 54 metres before the end of the runway. It was observed to descend into a small ravine off the end of the runway, then climb steeply and strike power lines before impacting the ground in a near vertical nose down attitude. Following the impact, the aircraft cartwheeled once and burst into flames. Investigation disclosed that the take-off had been commenced from a point approximately 50 metres in from the threshold of the runway. The all-up-weight at the commencement of the take-off exceeded the maximum permitted for the runway selected by about 320 kilograms, given the prevailing conditions. Examination of the wreckage did not reveal any evidence of mechanical defects which could have contributed to the accident. This was the first time the pilot had flown a Cessna 210 type aircraft into Koolan Island although he had been checked on island operations in a different aircraft type by the Chief Pilot.