Before take-off the pilot had been briefed on the operation of the aircraft by the owner. The owner had suggested the pilot make a short flight along the strip or that if he had the "feel" of the aircraft he could complete a circuit before landing. After becoming airborne the aircraft initially flew about 25 feet above the strip before entering a shallow climb. At a height of between 100 and 150 feet the engine noise suddenly ceased and pieces of the propeller were observed falling from the aircraft. The aircraft continued straight ahead for a short time before commencing a turn to the left. During the turn, the left wing and nose dropped and the aircraft struck the ground in a steep nose down attitude. Inspection of the wreckage revealed that one of the three propeller blades had disintegrated. The blade had failed due to the progressive propagation of spanwise splits along its length. Similar spanwise splits were also found in the other two blades. The splits were found to have originated from radial cracking at the hub of the blade which had been caused by local overstressing of the wood in the area of the blade retainers. Also, the widely spaced power strokes of the four stroke engine fitted to the aircraft would have contributed to the spanwise splitting of the propeller blades. The propeller manufacturer does not recommend the use of this type of propeller with the engine fitted to the aircraft. No other defects were found with the aircraft that could have contributed to the occurrence. Following the propeller failure, the pilot inadvertently stalled the aircraft while attempting to manoeuvre it for landing.

The pilot hovered the helicopter at about 20 feet above ground, in front of cattle, in an attempt to head them off. He became aware that an uncommanded descent had commenced and almost immediately the Low Rotor RPM Warning Horn sounded. He lowered the collective control in an attempt to regain control of the rotor rpm, however, the main rotor blades hit several small trees. A heavy landing resulted during which the tail boom was cut off by the main rotor and the skids were spread. The helicopter remained upright. At the time, the temperature was about 32 degrees Celcius the helicopter was hovering into a 15 knot wind. With the helicopter some 50 kilograms below maximum gross weight and a density altitude of 3000 - 3500 feet, an out of ground effect hover was within the machine's capability. However, the pilot said that he required maximum power to hover the helicopter. It is possible that the wind conditions changed momentarily, unnoticed by the pilot, or that during manoeuvring the power requirement exceeded the maximum available. The machine was flying at too low an altitude to allow a controlled recovery from an over-pitch situation. This accident was not the subject of a formal on scene investigation.

The pilot had landed and was taxying into the parking area on a slight down slope. He became aware that he had misjudged his distance from a fence post and applied a burst of power in an attempt to turn the aircraft and avoid the post. The lower right wing struck the post, causing the main spar to break. This accident was not the subject of a formal on-scene investigation.

The pilot reported that he was turning the helicopter at low level when he was confronted by trees which were higher than he thought. He had to manoeuvre the helicopter harshly to avoid the trees and in the process overpitched the main rotor blades, causing a loss of rotor RPM and thus helicopter performance. As the pilot attempted to land the helicopter in a cleared area, the tail rotor struck a fence. The helicopter yawed left, contacted the ground heavily, and came to rest lying on its side. This accident was not the subject of a formal on-scene investigation.

The company chief pilot, who holds an Agricultural 1 Rating, accompanied the pilot on the ferry flight. They surveyed the paddocks to be sprayed from the air before landing at a nearby agricultural strip where they discussed the order of work with the farmer and studied a local map. The pilot prepared a diagram of the paddocks and plotted wires and obstacles. The aircraft was then loaded with liquid chemicals and the pilot sprayed the first paddock while the chief pilot remained at the airstrip. Weather conditions were a light south westerly wind, with excellent visibility. After spraying the first paddock, the aircraft was reloaded. The pilot circled the second paddock before flying a spray run in a southerly direction between a highway and a railway line. During the run the pilot glanced at the boom pressure gauge and adjusted the setting. As he approached the railway line he commenced a pull-up during which the undercarriage struck a railways communications wire. The wire was about 4 metres above the ground and ran parallel to and just north of the railway line. Realizing that the aircraft had caught a wire, the pilot commenced a gentle, left turn starting at about 50 feet above the ground with the intention of landing as soon as possible in a safe area. During the turn, because of the drag of the wire, the aircraft vibrated and lost airspeed, despite the application of full power. After the turn the aircraft stalled from about 20 feet with wings level. The aircraft struck the ground in a slightly nose-low attitude and slid for 42 metres before coming to rest south of the railway line. Approximately 140 metres of wire was found trailing from part of the spray boom which had detached from the left wing and was located 5 metres behind the aircraft. The communication wires about 10 metres north of the railway tracks were the only significant obstruction near the crop. The steel poles supporting the wires were spaced reasonably close but the spray run was midspan such that the poles did not assist depth perception. The pilot could see the wires ahead at the end of the run. The wires were too low for the aircraft to fly beneath. It was the pilot's intention to fly over the wires. The pull-up was late and too shallow. The pilot had been given 17 hours flight training under close supervision by his employer immediately before commencing operational flying. At the time of the accident he was flying in a suitable area for an Agricultural 2 rated pilot with low experience.

Circumstances:

When nearing its destination after a flight of about three hours, the helicopter struck a set of power lines, eight metres above ground level, spanning a ridge line. Witnesses described flight path as "quite low and fast" compared to other helicopters they had observed approaching the Airport. Examination of the wreckage revealed wire strike damage to the upper surface of one blade, suggesting that the helicopter was in powered forward flight when it contacted the wires. A test run of the engine found it to be capable of normal operation.

Significant Factors:

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

1. The pilot crossed the ridgeline at low level.

2. The pilot did not see or avoid the power line. This accident was not the subject of an on-scene investigation.

The pilot reported that while mustering cattle he was attempting to turn an animal that had broken away from the mob. During this procedure the pilot attempted to climb the helicopter over a line of trees, however, the main rotor blades struck the top of one of the trees. The helicopter was landed and an inspection found that the main rotor blades required replacement.

Circumstances:

The pilot had hired the helicopter to fly a friend to his property situated about 2500 feet above sea level. On arrival the pilot landed next to the homestead and removed the passenger door so that his friend could take aerial photographs. The weather was fine, with a 10-knot wind from the north-west, and a temperature of 30 degrees Celsius. The density altitude was 5500 feet. After flying the helicopter around the property boundary, the pilot considered that it may be more advantageous if they climbed higher from where a more panoramic view of the property could be obtained. A climb was made in an easterly direction, at a slow forward speed, to about 500 feet above ground level, at which point the helicopter began to pitch and fishtail from side to side before descending rapidly. This was witnessed by a farmer working nearby, who said that he did not hear any change to the normal sound of the helicopter before it disappeared behind a ridge. The helicopter contacted the tops of the trees at a very slow forward speed and low main rotor RPM. During its descent through the trees to the steeply sloped forest floor the helicopter struck, and broke off, a large branch which entered the cabin resulting in a fatal injury to the pilot. The helicopter came to rest on its side, 19 metres from the initial contact point with the trees. The pilot had only recently qualified for his Private Pilot Licence (Helicopter) and had not received instruction in the methods for conducting helicopter survey or photography operations. There was no evidence that the helicopter was not capable of normal operations prior to the accident. Investigation found that the helicopter, which had been relatively heavy but within limitations, was operating at a high-density altitude and a slow forward speed while climbing in a downwind direction. The subsequent loss of translational lift and true airspeed (TAS), combined with a reduction in engine performance due to the conditions, required the pilot to use considerably more power and collective pitch than normal to commence and maintain the climb. When the helicopter's operation became erratic, the pilot told the passenger they would fly out of the situation and mentioned autorotation. He was observed by the passenger to be making rapid movements of the controls with his hands and feet. The circumstances of the accident were consistent with the pilot probably allowing the main rotor speed to decay due to overpitching of the rotor system, then using large left pedal inputs to prevent the helicopter from turning. The increase of tail rotor pitch further assisted decay of the main rotor speed. The low inertia rotor system used on this type of helicopter makes it susceptible to rapid rotor speed decay, but it can be regained quickly if there is no delay in effecting recovery action. The speed and height of the helicopter placed it in the avoid area of the height-velocity curve, and the action by the pilot of entering an autorotation failed to restore the main rotor RPM. If the helicopter had been allowed to weathercock into wind, then flown away towards the lower cleared terrain, a successful recovery may have been accomplished. As the helicopter descended rapidly towards the trees, the natural reaction of the pilot would have been to pull up on the collective pitch lever in order to arrest the descent, causing a further reduction to the remaining main rotor speed. This was evident by the lack of rotational damage to the main and tail rotor blades, however this action probably reduced the helicopter's vertical descent speed sufficiently to prevent more serious injuries to the passenger. When the rotor speed decreases below 95 percent a warning horn sounds and an amber light illuminates. During the descent, the passenger could not remember hearing a horn blowing but had seen lights flashing on the instrument panel. When the problem commenced, he may not have registered any noises but did notice the warning light. There are several warning lights in the Robinson R22 helicopter, and each associated system was checked and found serviceable. The type of operation, and prevailing weather conditions, would have required the manufacturer's performance criteria to be observed, and a considerable amount of attention given to flying the helicopter.

Significant Factors:

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

1. The helicopter's performance was affected by the hot weather and high-density altitude conditions.

2. The pilot had not received training to perform aerial photography.

3. The pilot climbed the helicopter downwind at a low forward speed.

4. The pilot did not adequately compensate for the prevailing weather conditions, probably due to diverting his attention to photographic considerations.

5. The pilot overpitched the rotor system and then did not effect a successful recovery of the main rotor speed.

Circumstances:

The student helicopter pilot was at an early stage of his training, however, he was a very experienced fixed-wing pilot. Before conducting some circuits, he was given practice in hovering. After this the instructor took over to demonstrate the manoeuvrability of the helicopter with the rotor disc steady. During this hovering the height increased to about 30 feet before the aircraft began to spin rapidly in an anticlockwise direction and dive towards the ground. The low rotor rpm warnings sounded during the descent. Impact evidence showed that the helicopter had struck the ground at a high rate of descent while travelling forward slowly. No signs of engine malfunction were found.

Significant Factors:

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

1. The instructor did not maintain directional control of the aircraft.

2. The instructor did not maintain adequate rotor rpm.

3. The instructor was operating outside the safe flight envelope.

The pilot was engaged on a survey flight for the owner of Coolibah Station, the operator of the helicopter. While flying at approximately 500 feet above ground level(agl) a turn downwind was initiated. The helicopter was close to maximum all up weight and it started to lose altitude. The pilot started to apply more power but the helicopter continued to sink and the rotor rpm decayed. The pilot saw a gap in the trees and attempted to land in it, however, the mainrotor hit a tree. The helicopter then slid along on the skids for approximately 10 metres before they dug into the ground and the helicopter nosed over. The pilot was engaged in conversation with the passenger and allowed himself to become distracted. He may have commenced recovery action too late. However, the helicopter was descending downwind which are conditions which predispose towards settling-with-power. Settling-with-power happens when the mainrotor is settling in its own downwash and additional power will not stop the descent. The pilot's statement that he was applying more and more power but that the helicopter kept sinking indicates that settling-with-power was likely. Part of the technique for recovery from settling-with-power is to increase indicated airspeed before increasing power. This accident was not the subject of a formal on scene investigation.