The aircraft was being used for a pleasure flight from Sydney to Lord Howe Island, NSW, Australia for the owner and some friends. The captain calculated the landing distances required for both runway 28 and 10 at Lord Howe Island, based on weather reports obtained at briefing, which indicated a strong northerly wind component. An updated report received some 30 minutes before descent confirmed the wind as 290 degrees at 7 knots. Approaching the island and becoming visual, the crew noted the windsock near the western end of the runway to be indicating a slight headwind component in the 10 direction and decided on a straight in approach to runway 10, to avoid an approaching squall/shower. The aircraft touched down firmly a short distance beyond the threshold. Speed brakes were immediately extended and wheel braking applied. About four seconds later the captain called for the drag chute to be deployed. Although the co-pilot correctly activated the handle, it became obvious that the chute had not deployed as no increase in retardation occurred. When the captain realised that the aircraft could not be stopped on the runway remaining he attempted to turn the aircraft towards a clear grass area to the right. However, the aircraft was aquaplaning on the wet surface and did not respond to steering inputs for some distance. The aircraft left the bitumen tracking to the right. It collided with a gable marker, passed through a fence, continued down an embankment, across a road, through a second fence and came to rest approximately 90 metres from the runway end and 70 metres to the right of the extended centreline. The left main and nose gear legs were torn off. Significant Factors: The following factors were considered relevant to the development of the accident 1. Inadequate pre-flight planning and preparation by the flight crew. The runway distance required was in excess of the distance available on either runway. 2. Adverse runway and weather conditions – wet surface and downwind component. 3. Improper sealing of drag chute canister. 4. Inadequate maintenance of the drag chute system. 5. Improper operation of wheel brakes.