Wirestrike

The pilot reported that had commenced the take-off run with no flap selected but felt that the aircraft was slow to accelerate to take-off speed. He then selected flap and the aircraft became airborne. There were trees and high ground beyond the end of the strip and the pilot turned the aircraft right to avoid this area.

As the aircraft turned, it struck a powerline and then impacted the ground in a nose down attitude. The pilot and passenger were uninjured. The pilot stated that the aircraft was about 100 lb under maximum weight with the centre of gravity within the envelope. He believed that the aircraft encountered wind shear and a downdraft leading to loss of performance. The ambient air temperature was 34 degrees C, with less than 5 kts wind at the time of the accident.

A Bell 206 helicopter was returning from a fire mapping operation along the Colo River at low altitude. Both the pilot and passenger were reported to be looking for wires when the helicopter main rotor struck a single wire that was strung steeply between two poles. The helicopter was operating approximately 300 ft above ground level.

The helicopter immediately landed to conduct an inspection for damage, before returning to the operating base. A detailed examination by a LAME was conducted at the base before the helicopter was returned to operational service.

The left wing of the aircraft struck a powerline from below during a pull up from a clean-up run. The aircraft rolled along its longitudinal axis and struck the ground inverted in an adjacent paddock. The cabin of the aircraft remained intact, consequently the pilot was not injured.

The clean-up spray run was flown at about 90 degrees to the previous spray runs and parallel to a high-tension power line running north-south. Immediately south of the paddock the power line converged at about 20 degrees and joined a power line at approximately 80 degrees to the high-tension line. The pilot said that the converging wire had not been an obstruction for his spray runs as the convergence started outside the field. He said that he saw the converging power line too late to avoid it.

The pilot of the AT502 aircraft was pulling up on completion of the spray run when the propellor came into contact with a power line. The aircraft made and uneventful landing at the agricultural airstrip from which it was operating. Post flight inspection found that damage had been sustained by two blades of the propellor and the upper skin of the left wing.

The pilot had completed a charter flight at Blackwater and was returning the aircraft to the company base at Emerald. Another company pilot, not endorsed on type, was the sole passenger.

Enroute to Emerald the pilot decided to do some low flying over a wheat crop. The aircraft struck a 3-phase power line about halfway across the paddock. The aircraft was arrested by the wires and came to rest upright in a fallowed part of the paddock. No one was injured.

The aircraft was being used to spread dressing on a property near Mindarie in South Australia. The landowner had not provided a map of the treatment area, instead, giving the pilot a preflight briefing that included drawing a diagram of the property with his heel on the ground. The property was located just to the north of a heavily wooded road running east to west. The property owner included the location of known powerlines in his briefing to the pilot.

The pilot began the job by performing the clean-up runs, filling in areas not suitable for the longer swath runs. He flew these runs primarily from the north-east. As he set up for the first swath run by flying east along the road before turning north to the property, the aircraft struck a powerline. The powerline was strung across the road to a derelict building.

The pilot reported that the powerline separated from a point near the disused building, and that approximately 30 m of line snapped back across the aircraft, damaging the left wing and aileron. The pilot landed the aircraft safely in an adjacent field. The pilot reported that the owner had not advised him of the location of the powerline because the owner was not aware of its existence. He also reported that he did not consider the likelihood of a powerline in that location due to the rundown nature of the building to which it was connected.

The pilot reported that he was entering the paddock for the final spray run, a clean-up run at right angles to his earlier spray runs. The right wing struck a power line at 40 ft above the ground, and was torn from the aircraft. After a rapid roll to the right the aircraft struck the ground in a semi-inverted attitude. The pilot vacated the aircraft, which did not catch fire.

The power line had been identified by the pilot during his initial inspection of the area. He had flown parallel to the line when spraying the paddock but forgot about it when he commenced the clean-up run. This was the first time the paddock had been sprayed this year, but the pilot had sprayed the area in previous years.

An emergency locator transmitter was carried in the pilot's bag. It was not used during the recovery from the accident.

This was the first occasion on which the pilot had sprayed the sugar cane paddock. A briefing and an area map were obtained from the property owner. The pilot conducted a power line inspection and found three lines, all that had been brought to his attention. During the first spray run he noticed sparks at the propeller as an unseen set of three wires was cut. He returned to the take-off point and found that only the propeller had been damaged. The wires struck had not been seen at all. The relevant poles were hidden in trees on each side of the paddock.

The pilot planned a flight from his base at Tooradin Vic, to Torquay Vic, accompanied by his son who also held a private pilot's licence.

The pilot advised that although he was familiar with the Torquay airfield layout he had not landed there before. Prior to leaving Tooradin he obtained airfield information from the Aircraft Owners and Pilots Association (AOPA) Airfield Directory and telephoned the operator for approval to land. He inquired about local conditions and was told that there were parachute operations at Torquay that day.

When he arrived in the Torquay area, the pilot listened out on the appropriate frequency and heard another pilot announce that that he was landing on runway 18. The pilot joined crosswind for a landing on runway 18, and while in the circuit observed the marked taxiway and worn take-off area at the threshold of runway 18.

On final approach to land, the aircraft collided with powerlines placed along the road adjacent to the threshold of runway 18. One powerline passed over the fuselage, damaging the horizontal and vertical tail surfaces. The other powerline broke the cockpit canopy and snagged on the roof structure. This powerline was pulled from the pole and stretched, allowing the aircraft to travel 70 metres before settling onto the ground in a level attitude. The pilots stayed in the aircraft until electrical power was disconnected. The aircraft was substantially damaged.

The "Special Procedures" section of the Torquay entry in the Airfield Directory did not mention the power line. AOPA advised that the details contained in the directory were supplied by the airport operator. The operator advised BASI that he had not brought the line to the attention of the pilot when he telephoned for permission to land.

There were two thresholds in use on runway 18 at Torquay, one for take-off and one for landing. Because of the powerlines, the airport operator had placed displaced landing threshold markers some 150 metres into the 805-metre strip in an endeavour to establish an approach gradient that would give adequate clearance over the powerlines. The markers were white and may not have established an effective contrast with the airfield surface under the prevailing dry conditions.

The take-off threshold was adjacent to the fence line with taxiway markers and runway edge markers delineating the take-off area.

The powerlines were made of steel which had a light-grey galvanised finish. The lines were fitted with 200-mm diameter orange marine buoys, the upper sections of which had bleached white. Power supply company records show that the orange marine buoys had been fitted some 8 years prior to the accident. The power supply company manuals did not contain standards for marker buoys, nor was there any requirement to check for ultraviolet degradation during the 3-yearly powerline inspection cycle.

The markers pre-dated the formulation of the Australian Standard for powerline marking.

The accident occurred in bright but overcast lighting conditions at the end of a hot dry summer so that the airfield surface was light brown in colour. The dry background, the oxidised wires, the degraded orange markers, and the displaced landing threshold markers were all of a similar colour to the airfield surface. Therefore, the powerlines would have been very hard to detect.

Because the pilot had not been warned of the existence of the powerlines he would have had a lowered expectation of their presence.

After the accident the pilot said that he considered the use of separate landing and take-off thresholds confusing, especially when the latter was neither adequately marked nor mentioned in the airfield directory.

Safety action

1. The operator is ensuring that all pilots who telephone for landing approval are thoroughly briefed on the existence of the powerline and the use of the displaced landing threshold.

2. The operator has enlarged the property and extended the runway. This has allowed the displaced threshold to be placed approximately 300 metres from the fence line and the powerline.

3. The operator has revised the entry in the AOPA airfield directory to include details of the powerline and the displaced threshold.

As a result of the investigation into this occurrence, the Bureau has made the following recommendations:

R970153: The Bureau of Air Safety Investigation recommends that the Electricity Supply Association of Australia make known to its members the circumstances of the accident and make appropriate use of the applicable Australian Standard (AS 3891.1) when marking powerlines.

R970177: The Bureau of Air Safety Investigation recommends that the Australian Airport Owners Association make known to its members the circumstances of the accident. The association should also recommend to its members that they contact their local electricity supplier if they believe any powerlines affecting their airfields are not marked in accordance with the Australian Standard.

R970178: Windsock Productions, publishers of The Country Airstrip Guides, gathers information regarding aerodrome and landing areas by asking operators to fill in a survey form and return it to them. The Bureau of Air Safety Investigation recommends that Windsock Productions amend that survey form to include, as examples, a detailed list of possible hazards, obstacles and special procedures an operator needs to consider when completing the form.

R970179: AOPA, which publishes the Airfield Directory, gathers information regarding aerodrome and landing areas by asking operators to fill in a survey form and return it to them. The Bureau of Air Safety Investigation recommends that AOPA amend that survey form to include, as examples, a detailed list of possible hazards, obstacles and special procedures an operator needs to consider when completing the form. The Bureau also recommends that AOPA inform its members of the circumstances of this accident.

Sequence of Events

The pilot was conducting aerial inspections of local roads affected by recent flooding. On board with the pilot were two council inspectors. The pilot reported that the helicopter struck a powerline as he was positioning for a closer look at a damaged section of roadway. The helicopter then impacted the ground coming to rest on the side of the road.

One passenger received minor injuries, the pilot and second passenger exited the helicopter without injury.

The helicopter was fitted with a Pointer 3000 Emergency Locator Transmitter which activated automatically.