Collision with terrain

A witness reported that as the aircraft approached a ridge line about 5 kilometres from the DEPARTURE point he observed a marked "wing wobble". This was then seen to cease briefly, then recommence. Shortly afterwards, the aircraft collided with the top of the ridge line and cartwheeled down the slope before coming to rest against a tree. An inspection of the aircraft did not reveal any fault that may have contributed to the occurrence. At the time of the accident the wind velocity was north-westerly at about 15 knots and thus was blowing across the ridge struck by the aircraft. It is likely that the aircraft, while being flown at a low altitude, was affected by mechanical turbulence in the lee of the ridge line and collided with the ground.

During the pull up at the end of a clean up run, a small note pad fell to the floor of the cockpit. The pilot leant forward to retrieve it but almost immediately the aircraft struck the ground. The note pad was used to record spraying details that were not critical to the operation of the aircraft.

The pilot was returning to land after a period of thermalling flight, when severe turbulence was encountered. The pilot's head hit and broke the canopy, and he then had problems with his vision. Heavy sink was also experienced. The pilot stated his last recollection of events was making a left turn towards the airfield at about 150 feet above the ground, and then regaining consciousness in the wreckage. Investigation revealed that the glider had touched down on a 5 metre wide strip between areas of cane growing to about 1.7 metres in height. The left wing caught in the cane and the aircraft slewed violently before coming to rest with the wing completely torn out of the fuselage.

The pilot departed the property strip with the apparent intention of flying to a position near a town some 16 kilometres to the North. Witnesses in the town subsequently observed the aircraft as it arrived in the area. It was evidently performing normally as the pilot completed a level turn and took up a southerly heading. The aircraft then entered a descent, which was described as being similar to a landing approach except that the engine was operating at high power. The aircraft then disappeared from sight behind a hill and the wreckage was subsequently sighted by the pilot of another ultralight aircraft. It was determined that the aircraft had struck the ground in about a 20 degrees nose-down attitude. The pilot had been restrained by a lap-type seat harness and the flexing of his body during the impact had resulted in the stretching and dislocation of his thoracic spine. Specialist medical opinion indicated that the accident would probably have been survivable had the pilot been restrained by a full harness. The area where the accident occurred was not suitable for a normal landing. The investigation did not reveal any defect or malfunction with the aircraft, or any pre-existing medical condition with the pilot that might have accounted for the accident. The precise causes of the occurrence could not be determined.

At the conclusion of night spraying operations the pilot departed for Mungindi. Witnesses at the town saw the aircraft overflying at a low height and heading towards the aerodrome, which is about 7 kilometres from the town. Engine noise was then heard to cease and sounds of impact followed. The aircraft had struck the ground 5 kilometres from the aerodrome, and a post-impact fire had engulfed the wreckage. No fault could be found with the aircraft or its systems that could have contributed to the accident. Specialist medical opinion indicated that the pilot had suffered a heart attack before the fire occurred. It was not possible to determine to what extent, if any, the pilot was able to control the aircraft prior to impact.

The pilot had recently finished modifying his Benson style Rotorcraft and he was attempting to have it ready to participate in the annual Sports Aircraft Association of Australia fly-in at Serpentine which was planned for the weekend following the accident. The pilot had not flown since he commenced work on the modifications over twelve months prior to the accident. The Technical Committee from the Rotorcraft Club of WA Inc. inspected the aircraft and its modifications on the day before the accident and they required some changes to be made before the aircraft was flown. Some of the committee members also advised the pilot that he should have an experienced, current pilot with him when he test flew the aircraft. A friend, who was not a Rotorcraft pilot, accompanied the pilot to the Club's flying area on the afternoon of the accident and helped prepare the aircraft for flight. The aircraft became airborne after spending some time taxying around on the ground. The pilot carried out a number of turns. In one turn, the aircraft was also seen to climb and descend, before entering what appeared to be a controlled, steep descent. The aircraft did not completely recover from the descent before it collided with the ground and the pilot was killed. The accident occurred after sunset and just prior to official last light on the dry bed of a salt lake. An inspection of the wreckage did not disclose any faults with the aircraft that may have contributed to the accident. The engine was delivering power at the time of impact.

The glider was winch launched to a height of 900 feet above the ground. The pilot was unable to find any strong lift, and when the glider had descended to 600 feet the pilot rejoined the circuit for landing. Some sink was experienced on the downwind leg and the glider was only about 200 feet above the ground when the base turn was made. During the turn onto final approach, the right wing of the glider struck the ground. The aircraft swung sharply to the right and subsequently landed heavily. There was no other traffic in the area and the pilot could have modified his circuit and landed on a cross-strip. It was likely that he had attempted to land the aircraft close to the winch launch cable to facilitate the next flight.

The aircraft reported departing Bundaberg for Monduran Dam on a no SAR flight at 1135 hrs EST with three persons on board and an endurance of 270 minutes. The purpose of the flight was to complete the endorsement of the pilot under check and to assess the suitability of an area of water on the coast to where the passenger, who was the regular pilot of the aircraft, was to fly the aircraft the following day. The pilot in command had flown 27 hours in the previous three months, of which 9 were on type. The pilot under check had flown only one hour in the last three months. This flight had been in VH-BSL. At approximately 1200 hrs, the aircraft was observed in the Lake Monduran area. It flew two left hand circuits, landing into wind towards the dam wall each time. After the second takeoff, it turned left and was seen heading north from the lake. Nothing further was heard or seen of the aircraft. Following an extensive search, the wreckage was located six days later lying inverted in 15 metres of water approximately 2 km WNW of the dam wall in the area of the junction of the main east-west channel and a north-south channel of the lake. Both floats had separated from the aircraft and the right float was severely torn for about half its length. There was substantial water impact damage to the windshield frame/cockpit roof area and to the upper leading edge surfaces of both wings. No fault was found with the aircraft or its systems which might have contributed to the accident. It could not be determined who was manipulating the controls of the aircraft at the time of the accident. Evidence was obtained that it was the habit of the check pilot to have pilots undergoing endorsement or check to fly two circuits landing into wind and then to carry out crosswind landings. The check pilot and the pilot under check had previously operated at the dam and alighted on to both the east/west and the north/south channels. Having been observed to fly two into wind circuits and then head north and not be sighted again, it is possible that the aircraft then commenced crosswind operations onto the north/south arm of the lake, landing in a southerly direction with a crosswind from the left. Information from the Bureau of Meteorology indicated that the surface wind in the area at the time of the accident was 090` magnetic at 15 knots. This information was confirmed by witnesses at the dam wall who observed white caps on the surface of the dam. The north/south channel of the lake was bounded on its east side by steep hills rising to 70 metres above water level. The effect of this high ground was to partially blanket the north/south channel from the easterly wind. The position of the wreckage was in the area where the wind shadow effect would have ended and where the wind would have blown at full strength along the main east/west channel of the lake. The crosswind limitation for the aircraft as stated in the flight manual was 8.7 knots. Commenting in early 1988 on an enquiry regarding the raising of this limit, the aircraft manufacturer emphasised the 8.7 knot limit and advised that any test work to raise the limit should proceed cautiously starting at or below the current (8.7 knot) limit. If the aircraft was conducting crosswind operations in the north/south channel, and suddenly encountered a 15 knot crosswind on exiting the wind shadow area, the control difficulties confronting the pilot could have been significant. The aircraft wreckage was intact except for the floats which had been torn off by water impact forces. The right float was severely damaged while the left was intact. The forward tip of the right float had been severed by the propeller. The remaining forward section had then been forced upwards and outboard and had broken off. This weakened the float support structure, causing it to fail, and allowing the remaining section of the right float to strike the right side of the fuselage just aft of the cabin. Damage of this type an magnitude was most probably caused by the nose of the right float digging into the surface of the lake at relatively high speed. For this to occur, the aircraft was banked to the right at float impact - a possible consequence of encountering a strong crosswind from the left. There was no evidence that the aircraft had hit a submerged object.

Circumstances:

The pilot was conducting spraying operations in a large wheat paddock. The aircraft was being flown about two metres above the crop and the pilot intended to pass to the right of a large tree near the end of the particular swath run. The aircraft suddenly swung violently to the left as the wheels entered the crop. By the time the pilot managed to pull the aircraft clear, it was heading for the tree. While attempting to manoeuvre the aircraft, the pilot was unable to prevent it from striking the ground.

Significant Factors:

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

1. Contact with the crop on spray run, reasons undetermined.

2. Aircraft struck the ground during pilot attempt to avoid a tree.

The pilot and his four passengers had planned a trip to Sydney and return for the Anzac Day long weekend. In preparation for the trip the pilot obtained a flight check in a Beech Bonanza aircraft. On the morning of the accident the pilot obtained weather forecasts for the route to be flown, prepared a flight plan for the trip and submitted it to the Briefing Officer at Moorabbin Airport at 0755 hours. The flight plan indicated that the aircraft would proceed to the first nominated reporting point at Mangalore outside Melbourne Controlled Airspace and at an altitude below 5000 feet above mean sea level (amsl). When the pilot submitted the flight plan he was advised by the Briefing Officer that the route through the Kilmore Gap was not suitable for flight under visual meteorological conditions (VMC). The pilot agreed to delay his DEPARTURE until conditions improved in the Kilmore Gap. The pilot and passengers then proceeded to the aircraft and after loading, the aircraft was taxied for take-off. The DEPARTURE time from Moorabbin was reported by the pilot as 0900 hours. No request for any update of the weather situation in the Kilmore Gap area had been received from the pilot before DEPARTURE. Shortly after DEPARTURE the aircraft was identified on Melbourne radar after having inadvertently entered Melbourne Control Zone. The pilot was instructed to maintain the aircraft's present altitude and heading, until about four minutes later at 0908 hours when the pilot was cleared to resume his own navigation after reporting he had Yan Yean reservoir in sight. At about 0918 hours VH-DAJ was observed over Kilmore at an altitude of approximately 600 feet above ground level (agl), heading in a north-westerly direction. Shortly afterwards the pilot was asked by Melbourne Flight Service for his appreciation of the weather in the Kilmore Gap. In reply the pilot advised he was unsure of the aircraft's location and was going to carry out a 180 degree turn, he also requested the aircraft's bearing from Melbourne. The pilot was then advised that the aircraft was not within radar coverage and asked if the aircraft could be climbed to 4000 feet amsl and remain in VMC, to which the pilot replied that the aircraft was not in VMC at that time. The pilot was then advised that three minutes earlier his aircraft had been 30 nautical miles north of Melbourne and that if he turned to the south the aircraft would be expected to come within radar coverage shortly. Two minutes later Melbourne Flight Service asked the pilot the direction and the altitude at which the aircraft was flying. The pilot answered that the heading was "one two zero" and then that the aircraft's level was "two thousand", this was the last transmission received from the aircraft. Weather in the area at the time was reported as low cloud and rain. The search for the aircraft was hampered by the weather. The wreckage was finally located by a motor bike rider later in the afternoon. The initial impact had been in a slight right wing low attitude on a heading of approximately 135 degrees at a height of 2180 feet amsl on the slopes of Mt William, the top of which is 2639 feet amsl. After the initial impact the aircraft had rolled inverted before striking the ground again, 70 metres beyond the initial point of impact. Fire broke out and engulfed the wreckage. The investigation did not reveal any fault with the aircraft that would have contributed to the accident. Witnesses in the area reported that the position VH-DAJ struck the ground was shrouded by cloud at the time of the accident.