Collision with terrain

The aircraft was being taxied on an apron between several hangars. Painted guide lines were provided to allow obstacle clearance, however the pilot had difficulty seeing the lines over the nose cowling. As the aircraft passed a parked aircraft on the right, the left wing struck a power pole. The pilot had evidently not followed the marked guide lines. The pole struck had a weathered appearance, and was not easily distinguished against the grey colour of the hangar wall. The pilot also commented that he was distracted by the presence of the parked aircraft.

The pilot had only limited flying experience and had not flown at all for more than 12 months. He had owned the aircraft for about 5 years. On the day preceding the accident, the pilot carried out a number of short hops along the strip in the aircraft, but did not attempt to conduct a circuit. Other pilots who were watching reported that the aircraft porpoised during the hops, although the type was regarded as being stable and easy to fly. On the following morning, the pilot commenced a flight in company with two other aircraft. Shortly after take-off, he turned left and tracked towards the north, while the other pilots flew south. His aircraft was last observed to be flying at about 50 to 100 feet above the ground. The wreckage of the aircraft was discovered about 15 minutes later. The subsequent investigation failed to reveal any defect or malfunction of the aircraft which might have led to the accident. Weather conditions were fine and warm and were not considered to have been a factor. Although it was probable that the pilot had mis-handled the flight controls, the precise reasons for the accident could not be determined.

Witnesses reported that after take-off in hot and gusty crosswind conditions the aircraft did not climb away normally. It passed over the boundary fence at a low height and then remained at about tree-top height for about one kilometre. The aircraft was then seen to turn sharply to the left before disappearing from view. It was subsequently discovered to have struck the ground while in a steep nose-down attitude, and been completely destroyed by a post impact fire. No evidence was found of any pre-impact defect or malfunction of the aircraft which might have contributed to the accident. The take-off had been attempted with the aircraft approximately 20 above the maximum allowable weight. It was considered that the combination of aircraft weight and ambient weather conditions caused a significant reduction in the aircraft climb performance. The available performance was insufficient to allow the aircraft to clear rising ground beyond the aerodrome boundary.

After completing an instrument flight at night, the pilot reported his arrival in the circuit area of the destination aerodrome. The aircraft did not land and a search was commenced. The burnt out wreckage was located the following morning. A detailed techical examination of the wreckage did not reveal any evidence of a defect or malfunction which might have contributed to the accident. operation, the pilot did not hold an Instrument Rating. Weather conditions at the destination were suitable for visual operations, but it was a very dark night with no ground lighting other than the runway lights. There was a strong crosswind in the landing direction and moderate turbulence in the area. The post-mortem examination of the pilot indicated a significant level of blood alcohol concentration. It was likely that the pilot lost control of the aircraft while manoeuvring to land in difficult conditions.

The pilot had just completed a low-level turn to down wind when the helicopter began to sink. He applied power and collective control but was unable to arrest the sink and the tail rotor struck the ground. The helicopter then rotated 3-4 turns to the right and dropped heavily onto its skids. The pilot shut down the engine. Fire broke out and the passenger was struck by the still rotating main rotor as he ran around the tail to reach the boom-mounted fire extinguisher. The investigation did not reveal any fault with the aircraft that might have contributed to the accident. The reason for the helicopter sinking after the turn could not be positively determined.

At the time of the accident, weather conditions were fine but it was a very dark night. The stars were obscured by a high overcast and there were only a few ground lights. The horizon was not visible. The take-off was into the southeast. Shortly after becoming airborne the aircraft entered a left turn and then began to descend. This continued until the aircraft struck the surface of a salt lake, in an inverted attitude. No contributory faults could be found with the aircraft or aircraft systems. The pilot was inexperienced in night operations and on this occasion there was a lack of external visual cues available. It is probable that the pilot became disorientated during the turn after take-off and lost control of the aircraft.

Circumstances:

The aircraft was conducting cattle spotting operations from an estimated height of between 90 and 150 metres above ground level. The pilot was relatively new to the task and was being guided by the passenger, who was in radio contact with the ground mustering party. The procedure was for the aircraft to spot and then fly directly over cattle as a guide to the ground party. Following the first flight of the day, the aircraft was refuelled from a newly opened 200 litre drum of aviation gasoline. The aircraft then took off normally and flew over one group of cattle before heading north-east towards another area. A short time later, a high revving engine noise was heard followed immediately by the sound of impact. The aircraft had impacted the ground 48 degrees nose down and slightly right wing low on a heading of 158 degrees Magnetic. The fuel tanks ruptured on impact, and the wreckage caught fire. The extent of the fire damage was such that a thorough examination of the wreckage was not possible. However, of the components that were able to be checked, no fault was found which might have prevented normal operation of the aircraft. The engine was operating at impact, and the flaps were at 15 degrees. The steep nose down attitude of the aircraft at impact is typical of what might be expected as a result of the aircraft stalling at low level and the pilot having insufficient height to effect recovery. While there is no proof of this occurring, there were circumstances existing which could have contributed to its development. These included the sun being on a Magnetic bearing of 40 degrees and an elevation of 25 degrees above the horizon at the time of the accident, indicating that the pilot could have been affected by sun glare as the aircraft headed north-east. During the refuelling stop, the passenger remarked on the turbulent conditions at the operating height of the aircraft. If the aircraft was operating at comparatively low speed (and the flap setting probably indicates this), then the turbulent conditions could have upset the aircraft to the extent that it stalled, with the sun glare preventing the pilot detecting the upset.

Factor

The following factor was considered relevant to the development of the accident:

For reason(s) which could not be positively established, the pilot lost control of the aircraft at a height from which recovery to normal flight could not be effected.

Circumstances:

During a flight from Orange to Camden, the pilot was unable to proceed beyond the Hartley Valley due to low cloud on the ranges. He attempted to return to Orange but found that route was also blocked by deteriorating weather conditions. In decreasing light, the pilot began a search and located a paddock where he conducted a precautionary landing, during which the main landing gear and wing struck a fence, causing substantial damage. The area forecast had indicated extensive areas of low cloud, with reduced visibility associated with drizzle, over the mountain ranges.

During a sheep mustering operation the aircraft was being orbited at about 200 feet agl and with 15 to 20 degrees of bank applied. During the orbiting the left wing struck the ground, the aircraft nosed-over and the engine was torn from its mountings. In the previous week the pilots normal sleep pattern had been broken. On the morning of the accident, he arose before dawn after having about five and a half hours rest. He had moved two large mobs of sheep into another paddock, which requires a high degree of concentration, and was orbiting whilst waiting for the last small mob to pass through the gate. It was at this stage, when the task required less concentration, that the pilot said, that he relaxed and fell asleep.

Circumstances:

The pilot had previously undertaken a dual instructional flight during which he received instruction in, and practised, approaches simulating a jammed tail rotor pedal control. The pilot was then authorised for a solo flight which was to include practice of "jammed pedal" approaches. During one such approach, the skids contacted the ground while the helicopter was not in straight, balanced flight. The helicopter rolled onto its side in an uncontrolled dynamic rollover. Following the accident, the flying school amended its operations manual to preclude solo students practising "jammed pedal" approaches and landings.

Significant Factors:

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

1. The student pilot misjudged the height of the skids above the ground.

2. The helicopter was not in straight, balanced flight.