Wirestrike

Circumstances:

The pilot, accompanied by two employees, was carrying out an aerial inspection of a harvesting operation in a large open paddock. The aircraft had approached from the north, flying at approximately 150 feet above ground level, and carried out a right hand orbit. It then proceeded for a short distance in a southerly direction, before entering a steep descending turn to the left towards a three wire powerline positioned north-south across the paddock, the spans of which were approximately 30 feet above ground level. Approaching the powerline the aircraft was observed to climb rapidly, and a noise like a breaking stick was heard as the left hand wingtip contacted the centre wire of the powerline. The aircraft continued to climb steeply to about 80 feet above ground level. It faltered momentarily before stalling and impacting the ground 100 metres east of the powerline. The aircraft impacted on its left hand wing and nose. It bounced a further 25 metres while turning inverted and became engulfed in a ball of fire which reduced it to ashes. In 1988 the pilot received a serious head injury which resulted in the Civil Aviation Authority not renewing his pilot licence pending additional information from the pilot regarding his medical condition. The pilot did not provide sufficient information but continued to fly up to the time of the accident.

Significant Factors:

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

1. The pilot was conducting a low flying operation.

2. The pilot probably saw the powerline too late to avoid it.

3. The aircraft stalled at a height from which it was too low to effect a recovery.

ACFT STRUCK TWO POWER LINES ON FINAL APPROACH WITH PROP.ONE WIRE SLID UP WINDSCREEN & SLICED OFF CANOPY ROOF.OTHER SNAGGED LDG GEAR & TILTED ACFT TO VERTICAL NOSEDOWN ATT.HIT GND,OVERTURNED & BURNED.

PLT WAS NOT TRN FOR PWR LINE INSPECTIONS.AN APPROVED PLT INSTRUCTED HIM NOT TO FLY BELOW 300 FT.LATER ACFT WAS OBSERVED OVERFLYING PWR LINES AT 100 FT & 25 FT JUST PRIOR TO ACFT STRIKING PWR LINES.

WHILST ENGAGED IN KANGAROO CULLING OPS ACFT STRUCK POWER LINE & CRASHED.PLT FLD TO EXERCISE NECESSARY DEG OF VIGILENCE REQ IN LOW LEVEL OPS AS HE WAS AWARE OF LINE HAVING OVERFLOWN IT EARLIER IN DAY.

ACFT STRUCK A TWO WIRE POWER LINE WHILST LOW FLYING,THEN STRUCK GROUND NOSE DOWN AND CARTWHEELED

ACFT STRUCK PWR LINE DURING CLEAN UP RUN ALONG EDGE OF CROP-CRASHED AND BURNED-WIRE AND CROP DAMAG

VH-BOA was one of two aircraft operating from an agricultural strip near Namban. The strip was orientated approximately north/south and the agricultural load, a mixture of superphosphate and clover seed, was located at the southern end. Weather conditions were fine with a light surface wind from the south-east. Prior to commencing operations it was agreed between the two pilots that VH-BOA would treat the areas to the east of the strip whilst the other aircraft worked to the west. The possibility of expediting operations by VH-BOA had not previously landed on this area but he had inspected, on the previous day, the surface which in the northern section of the area, he did not detect a 260 metre long double wire span in the southern sector which crossed the approach path at an angle of 30 degrees. At the completion of their first spreading flights both aircraft returned to the strip at the same time. The pilot of VH-BOA then decided to land on the alternative area. An immediate approach to land from the south was commenced. The pilot's attention was primarily directed towards sighting a slight contour bank which he knew bordered the cleared area. The aircraft was at a height of about 20 feet and an airspeed of some 55 knots when it struck the power line. One wire broke but the other caught under the right door latch. The aircraft rapidly decelerated and fell to the ground.

After the interim completion of agricultural spraying operations, the property owner asked the pilot to disperse one load of insecticide over a neighbour's property. The adjacent property owner had requested this work to be done. As the pilot hover-taxied an Agusta-Bell 47G-3B1 helicopter towards a water replenishing point on the neighbour's property, the cockpit bubble and one main rotor blade of the helicopter struck an unseen single strand high-tension power line partially concealed by a shed. The pilot was able to maintain control of the helicopter and landed safely. The helicopter sustained minor wire impact damage to one main rotor blade, the main rotor mast, and one tail rotor blade. The pilot and passenger escaped without injury. The water tanks were near a shed which partially concealed the wire which was at an angle of about 45 degrees to a height of 60 to 70 feet AGL. The wire also blended into the background foliage. The pilot had visited this section of the neighbour's property about 2 years ago. No wires were noted during this visit. The owner of the adjacent property had not briefed his neighbour to inform the pilot about a new wire that had been erected near the water tanks. Consequently, the pilot had not been adequately briefed by the other property owner as to the presence and location of the recently erected wire which was in close proximity to the water tanks.

The operator and pilot reported that the helicopter struck a single-wire-earth-return (SWER) power line at the beginning of a swath run during a spraying operation. The orientation of the cane paddock being sprayed was north-east / south-west with a major power line running through the north-eastern corner. A SWER power line running east -west joined the main power line over the paddock. The pilot had sprayed the western edge of the paddock, flying the helicopter over the main power line on each spray run. As the pilot moved his spray effort further east on each swathe run, he concentrated on missing and flying over the main power line. On one pass he lost awareness of the SWER line and during descent onto the crop the mast of the helicopter struck the line. The helicopter rolled into the crop. The pilot was not injured

The pilot of the Hiller 12E helicopter had been tasked with spraying insecticide on a paddock of soybean plants. The pilot familiarised himself with the property layout and obstacles before starting treatment of the area. The paddock to be sprayed was crossed at its mid-point by powerlines running east-west. The southern boundary of the paddock was marked by a wire fence, a road and another set of powerlines.

The pilot reported commencing a spray run along the northern boundary but found that his GPS navigation system was not working. He landed on the western side of the paddock to re-enter data into the GPS system. On carrying out another run, the pilot found the system was still not operating, so he moved the helicopter away from the paddock to the south. He then elected to return to the paddock by flying over the powerlines. The pilot reported that at this time, he was mentally occupied with the problem with the GPS and forgot about the powerlines at the southern edge of the paddock. The helicopter spray gear contacted the powerlines, causing the helicopter to pitch nose down and contact the ground. The helicopter came to rest inverted, and the pilot climbed out of the wreckage, receiving only minor injuries. The helicopter did not catch fire.

A significant factor in this accident was the preoccupation of the pilot with the GPS navigation equipment at a time when he was flying close to obstacles.