Wirestrike

Prior to commencing operations in the area the pilot carried out an aerial reconnaissance to check the location of powerlines. He stated that he had almost completed the second load when he had the feeling that he was running out of chemical. He believes that he momentarily looked at his instruments to check for pressure and load remaining and temporily forgot about the presence of the powerlines. He subsequently saw the powerlines as the aircraft was approaching the end of the run, just before they were struck by the canopy of the helicopter. Control was maintained with difficulty, and when the pilot noticed that the aircraft was trailing wires he decided to land. The landing in a cleared paddock was heavy, causing the skids to collapse, and the main rotor to flex downwards, striking the tailboom and severing the tail rotor. The pilot stated that the powerlines were difficult to see because of wire sag and the backdrop of trees and buildings. This accident was not the subject of an on-site investigation.

Spraying operations were planned to be conducted on two paddocks. A briefing on the operation was passed to the pilot by telephone by one of the owners of the property the previous evening. The briefing indicated that a particular power line was strung outside the boundary of the smaller of the paddocks, clear of the likely swath run approach path. Based on the information supplied, the pilot drew a map of the area. In fact, the line cut across the corner of the paddock. Before commencing operations, the pilot carried out an aerial inspection of the area. However, he failed to detect the actual position of the power line. While descending for the first run over the paddock, the aircraft struck the line. The impact partially severed the left wing, and a fire broke out behind the engine firewall. The pilot was able to complete a semi-controlled landing in the adjacent paddock, and the fire was extinguished by the ground party.

The pilot had arranged to take each of his guests on a scenic flight of the local area. On the second of these flights, the passenger took along a video camera. The aircraft was observed flying at a low altitude and subsequently struck the top wire of a 10 metre high three strand power line. The aircraft then continued towards rising ground, climbed over a row of trees before descending rapidly into the ground. A fire broke out and consumed the fuselage of the aircraft. An inspection of the wreckage revealed that only the underside of the rear of the aircraft had struck the wire. It is considered unlikely that this impact would have adversely effected the control of the aircraft, other than to reduce its airspeed. The inspection did not reveal any other defect that could have contributed to the occurrence. It is probable that as the aircraft was climbed over the trees it stalled and that there was insufficient altitude available for the pilot to recover the aircraft. Both occupants survived the impact but were apparently unable to evacuate the aircraft and died in the subsequent fire.

Approaching the destination, the pilot noticed that rain had recently fallen on the strip. The pilot stated that he overflew the strip but wished to ascertain the amount of rain that had fallen before attempting to land. He reported that an inspection run was conducted, however, a strong tailwind component existed and the resulting groundspeed was too high to enable an adequate inspection to be made. A procedure turn onto a reciprocal heading was carried-out, and the aircraft placed in the approach configuration. This inspection run was intended to be flown at a height of about 200 feet above the ground, and additional engine power was introduced as required to compensate for downdraughts. During the inspection the aircraft struck a power line about 20 feet above a road, and subsequently landed heavily on the sloping roadside. Information available at the accident site indicated that the pilot was either landing or preparing to land on the road.

After helping to herd cattle to a yard, the pilot turned the helicopter and accelerated away adjacent to a creek. The helicopter struck a powerline, which crossed the creek at right angles, and impacted the ground on its right side. One of the main rotor blades bounced backwards into the cabin and almost severed the pilot's right foot. The powerline was difficult to see against the background of the surrounding countryside. The pilot, who has no memory of the accident, was aware of the location of the powerline but now believes he must have temporarily forgotten about its presence.

The pilot was spraying a crop of potatoes. The rows in the paddock ran north-south and there was a powerline running from just outside the paddock at the south-western corner to about one swath width inside the paddock at the north-western corner. Spraying of the bulk of the paddock had been completed, with runs aligned with the rows. The runs were shortened on the western edge to avoid flying under the powerline. There was an easterly drift in the breeze, which the pilot assessed as 2 to 3 knots. He started a cleanup run along the western edge tracking from north to south, intending to use the drift to carry the spray under the wires into the corner of the paddock. The pilot selected an aiming point at the far end of the paddock so that the helicopter would fly parallel to the powerline. During the run the helicopter became entangled in the wires and crashed before catching fire. The pilot had made no allowance for drift in selecting the aiming point. This accident was not the subject of an on-site investigation and information on the occurrence was provided by the pilot.

Towards the end of a spraying run the pilot noticed that the aircraft was drifting towards a power line running roughly parallel to the aircraft track. He attempted to counter the drift but the aircraft moved underneath the wire. The main rotor struck the line as the pilot attempted to manoeuvre clear and also avoid trees at the end of the spraying run. After striking the wire the helicopter swung through 180 degrees and the tail boom collided with a tree. Although the pilot had gained considerable experience on helicopters, most of this had been obtained cattle mustering. He evidently did not realise that a hazardous situation was developing in time to take safe avoiding action.

Circumstances:

At 2000 feet, during a navigation exercise, the instructor initiated a practice forced landing. When the instructor was satisfied with the student's performance, the student initiated a go-around at about 200 feet above the ground. At about the same time the front of the helicopter contacted a powerline. The helicopter pitched up severely and lost speed rapidly. The single wire snapped after damaging the main rotor mast cover and bending control rods to the main rotor. The instructor took over and immediately carried out an autorotative landing. The wire had a span of approximately 600 metres between two hills. It was difficult to see. This accident was not the subject of an on-scene investigation.

The aircraft was one of a group attending a vintage aircraft fly-in. It had been engaged on a photographic flight in company with another aircraft, in an area west of the Hunter River. During the return to the strip, the two aircraft became separated. The subject aircraft was observed to descend to a low height over the river, while apparently tracking for a right base leg position. It subsequently collided with powerlines and trees before falling to the ground about 1.5 kilometres from the strip. The powerlines consisted of three cables strung on individual poles. The span which crossed the river was about 645 metres in length, and the height of the cables at the point of collision was 35 metres above the river level. The weather at the time was fine, with no restrictions to visibility. However, the wires were difficult to see against the background, and the pilot had not been aware that there were any powerlines in the vicinity.

Circumstances:

As part of their commercial pilot training scheme, the flying school sent five trainees supervised by two instructors, in two aircraft to further their experience by operating from a remote aerodrome. The two aircraft arrived at Longreach Aerodrome before noon on the day of the accident. The instructor in charge of the operation had apparently decided to take two trainees flying in the local area. The flight was authorised for radio navigation aid training. The aircraft was later seen over a period of time, flying at heights judged as 100 feet and lower over the flooded Thomson River. Later, some two kilometres north-west of the Thomson River, two stockmen saw the aircraft flying parallel to the Winton Road towards Longreach township when suddenly the wings separated from the fuselage which then crashed to the ground. The aircraft had flown into a subsidiary powerline strung across the main road. Two steel wires had struck the windscreen and had sliced both wings and centre support section away from the fuselage. The span of the wire struck was 239 metres. The point of impact was 8.2 metres above ground level and 67 metres from the main feeder powerline which parallels the far side of the main road. At the time of the accident, the wind was calm, the sky was clear of cloud, and the sun was directly behind the aircraft. Although the visibility was excellent, tests conducted exactly 24 hours after the accident revealed that the wires would not have been visible to the pilots in time to avoid a collision.

Significant Factors:

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

1. The pilots were engaged in an unnecessarily hazardous operation - low flying.

2. The pilots were unfamiliar with the local area.

3. The pilots did not see the subsidiary power line in time to take collision avoidance action.