Circumstances:

The aircraft was conducting a scenic flight over an area of Lake Eyre North, where the surface of the lake is 30-40 feet below sea level. Weather conditions were fine. High cloud and calm conditions resulted in a glassy lake surface with diminished horizon definition. Passengers on the flight reported that the pilot had mentioned the possibility of flying below sea level, and later when approaching the lake, he remarked that it would be "tricky" without a horizon. He gave no indication that the aircraft was experiencing any difficulties which would affect its ability to maintain flight. The aircraft contacted the lake in a near level attitude, and in cruise configuration. The nearest landfall was twelve kilometres distant, and after several hours the passengers were reached and assisted by a rescue party. Rescue attempts by helicopters were abandoned when unable to safely hover due to the illusory effects created by the glassy surface. The passengers had not been provided with the required flotation safety equipment for this particular flight.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The pilot attempted to cross the lake at an extremely low level.

2. The pilot had insufficient experience to recognise the danger of the prevailing conditions.

3. The pilot was unable to maintain an adequate definition of the lake surface, due to visual illusions created by the glassy water surface conditions.

Recommendations:

1. It is recommended that the Civil Aviation Authority publish an article in the Aviation Safety Digest addressing the dangers inherent in low flight, particularly the visual illusions created by areas of water during calm conditions.

2. It is recommended that the Civil Aviation Authority publish an article in the Aviation Safety Digest to emphasise the requirement for the carriage of flotation equipment in accordance with CAR 258 and CAO 20.11 with respect to areas of water other than ocean. This accident was not the subject of an on-scene investigation.

Shortly after takeoff and while climbing through 2000 feet at approximately 90 kts in light to moderate turbulence, the aircraft encountered unforecast, unavoidable severe turbulence. The aircraft suddenly rolled approximately 75 degrees to the left, and the pilot applied full right control wheel rotation and full right rudder. Control was regained, but during the latter part of the flight the pilot noticed a change in the directional flight characteristics of the aircraft. The turbulence appeared to have been associated with the development of localised "dust devils" or "willy-willies", which had not reached the visible stage. Subsequent examination of the aircraft revealed distortions in the right wing and empennage, consistent with the aircraft having suffered excessive inflight loads. The horn balance of the right elevator was bent, and the internal balance weight was loose. Weather conditions at the time of the occurrence were scattered cumulus, base 5000 feet; visibility 40 kms; surface wind, a gusty south-easterly; and temperature 25 degrees. The Manoeuvering Speed, Va, was estimated to be 100 kts for the weight of the aircraft at the time the turbulence was encountered.

The pilot was making an approach in light wind conditions to a 600 metre long strip. Undulations on the surface were such that the slope in the landing direction varied from about 7 up to 4 down. The pilot was using a short-field landing technique. Touchdown occurred just prior to the threshold, and the aircraft bounced. Full power was applied, but the aircraft then touched down heavily 100 metres in from the threshold. The noseleg broke at the fork, the propeller struck the ground several times and the aircraft came to rest at the edge of the strip. The strip did not meet the published requirements for an ALA suitable for Private category operations. The premature touchdown short of the threshold may have resulted from visual illusions associated with the strip slope. The aircraft had stalled during the attempted recovery from the bounce after initial touchdown.

The pilot attempted to takeoff on an access track to a cattleyard. A southerly wind of about 15 knots necessitated take-off to the south, towards the yard. The aircraft was near gross weight and short-field technique was used. At a position 411 metres from the brakes-release point, the right brake caliper assembly struck a 1.65 metre high section of fence which formed the cattleyard. The right wing sheared off outboard of the fuel tank when it hit an adjacent 3 metre high fence cap. The aircraft then impacted the ground in a steep nose down attitude and slid inverted for a short distance before coming to rest. The aircraft had been airborne for 155 metres prior to the first impact. The pilot did not consult performance charts and underestimated the distance required for the aircraft to safely complete the take-off at this weight. There was sufficient room available for the pilot to taxi the aircraft at least a further 300 metres along the track to the north before attempting the take-off. A properly constructed, serviceable airstrip was located within 500 metres of the cattleyard.

The pilot had recently completed the construction of the aircraft, and had taken it to the aerodrome in order to make the initial taxi runs and short hops along the strip. Wind conditions were light, favouring operations into the east. The engine proved difficult to start until minor maintenance was performed, after which the pilot taxied the aircraft along the strip towards the western end. He then turned the aircraft and, to the surprise of those present, commenced a take-off. Witnesses reported that the aircraft made two or three low orbits of the aerodrome, at times disappearing from sight behind trees. The accident occurred as the aircraft was approaching from the south, when the wings were seen to fold before the aircraft dived to the ground. The left wing was discovered to have failed at the point where it was attached to the fuselage, and had separated in flight. The reason for the structural failure has not been determined.

The aircraft was being flown for the first time. The pilot stated that after take-off the aircraft felt very nose heavy and that he had difficulty in maintaining a nose-up attitude after lift-off. When he attempted to reset the the elevator trim the friction nut broke. The back pressure that he was required to hold with the control column reduced as the airspeed increased. During the subsequent approach the pilot found he had insufficient elevator control available to flare the aircraft. On touchdown the aircraft bounced and a go-around was carried out. The pilot made several other landing attempts but on each occasion the aircraft bounced. On the final attempt the aircraft bounced a number of times before the right canard collapsed and the aircraft ran off the runway. The aircraft had been correctly loaded, with the centre of gravity 14 aft of the forward limit. The angles of incidence on the wing and the canard were found to be about 0.3 degrees outside the design specifications. It was apparent that there was a critical relationship between these angles, the centre of gravity position and the amount of pitch control available. The aircraft manufacturer subsequently recommended a modification to the control system.

The pilot reported that he had difficulty obtaining effective braking during the landing roll, due to a grassed, wet strip surface. He was able to initiate a groundloop near the end of the landing roll but the aircraft drifted sideways off the side of the strip prior to the upwind threshold. Very heavy rain had fallen during the previous night and up until 30 minutes prior to the landing, and there were areas of standing water on the strip. The airstrip was not suitable for the intended operation.

The pilot received a request at 5am from a neighbouring property to fly a seriously ill person to a hospital some 150 kilometres away. During the approach to the property strip the pilot realised that the aircraft was too high and too fast so he attempted a sideslip to lose altitude. The aircraft floated the full length of the strip before the pilot decided to go around. During the go-around the aircraft stalled at about 50 feet above the ground after the pilot had commenced a steeply banked climbing turn to avoid trees.

The pilot reported that the aircraft encounted turbulence late on the final approach. This resulted in a heavy landing during which the left maingear and nosegear were deformed. Turbulence was generated by a hill, on the upwind side of the strip, which acted to inhibit the gusty 25 knot wind blowing at the time. This accident was not the subject of an on-site investigation.

The pilot had held a Private Pilot Licence which had expired about six months prior to the accident. A witness reported that after the aircraft touched down it bounced about three times before landing in a nose down attitude which resulted in the nosegear strut failing in overload. The landing was attempted in a 10 knot crosswind and the pilot reported that the aircraft was affected by a wind gust during the landing sequence. The pilot was not in recent flying practice and had not flown for about five months prior to this trip.