The pilot stated that he allowed the engine temperature to stabilise for about two minutes at 2800 RPM after landing, then reduced power to about 2000 RPM for a further minute. At about the same time a severe bouncing started, the pilot disengaged the rotors and attempted to shut the engine down. The helicopter was affected by ground resonance and the pilot, who had already released his seat belt, was thrown to the floor of the helicopter.

While flying straight and level at 45 knots, the engine began to splutter. The pilot immediately used the hand fuel pump but his efforts were unsuccessful and the engine stopped as a result of fuel starvation. From the air the ground below looked suitable for a forced landing. However, at a low height it became apparent that the ground surface was rocky. During the landing roll the left mainwheel struck a rock. A subsequent examination of the fuel system discovered a piece of red, electrical, insulation tape within the fuel tank. This tape had blocked off the outlet pipe from the fuel tank to the engine. The pilot believes that the piece of electrical tape had probably originated from refuelling equipment and entered the tank during a refuel from drum stock.

A pilot who is based at Lake Evella was on scene soon after the accident occurred. He located the pilot-in-command who conveyed the following sequence of events. The takeoff was commenced from the threshold of the strip. The aircraft was being flown by the pilot under instruction. It lifted off further down the strip than the instructor expected, then commenced climbing at 80 knots. Very shortly after lift off the engine suffered a partial power loss. The instructor took control of the aircraft and checked fuel contents and saw that the mixture was rich. He then closed the throttle because he realized that he would have to land the aircraft on the remaining runway and overrun area and lowered full flap. He then assessed that he could not land in the available cleared area ahead so he turned right into wind and looked for a cleared area to land. The aircraft then flew into trees, striking several large trees before impacting with the ground at a low speed. The instructor said that he and probably the surviving passenger were thrown clear of the aircraft during the impact sequence, however, both were badly burned. The investigation focussed on trying to determine the reason for the engine malfunction. One possibility considered was that the take-off was commenced with the fuel selector in the OFF position. This was considered a possibility because the student pilot was trained overseas and may have been trained to switch the fuel selector off during the shutdown checks. The operator's normal procedure was to leave the fuel selector ON after engine shutdown. Another possibility was that the instructor may have turned the selector to the OFF position in order to check the thoroughness of the students pre-start checks. The fuel selector was badly damaged by fire, but it was determined that the selector, although displaced slightly from the BOTH position, was in a position where the fuel supply to the engine would not have been interrupted. A trial was made using the same model aircraft, in order to estimate how far into the take off run the aircraft would get if the engine was started with the fuel selector in the OFF position. The engine failed due to fuel starvation after one minute five seconds idling at 1000 RPM. It was considered that due to the distance of the tarmac area from the threshold of the runway used for DEPARTURE, the engine would have stopped before the take-off could have commenced. Therefore the hypothesis that the take-off was commenced with the fuel selector in the OFF position has been discounted. The engine was dismantled and examined in order to determine pre-impact serviceability. No defect that could have caused either a partial or complete engine failure was discovered. However, the investigation was impeded by the extensive post impact fire damage to the components of the engine. Parts of the air induction system and carburettor were destroyed, although some testing was possible. The magnetos were damaged to the extent that meaningful examination was impossible. Therefore a malfunction of one of the vital components of the engine cannot be discounted. The loss of power occurred when the aircraft was approximately 100 feet above ground level. From such a height it is not possible to turn back and land on the runway and in this case there was insufficient runway ahead to land. The strip is surrounded by trees which meant that there was no suitable area for a forced landing within gliding distance.

The pilot reported that as the aircraft climbed through about 300 feet after takeoff, the engine RPM suddenly dropped by 350-400. This was accompanied by rough running. The pilot decided to land in a gravel pit just beyond the airfield boundary. The aircraft was stopped after a ground run of 150 metres but received substantial damage due to the rough surface. The engine problem was probably caused by sticking valve(s). This accident was not the subject of an on-site investigation.

Circumstances:

The aircraft was on a flight from Port Macquarie, NSW to Moorabbin, VIC with an intermediate stop at Wangaratta, VIC. When nine kilometres north-east of Moorabbin, at an altitude of about 2500 feet, the engine stopped without warning. The pilot was unable to restart the engine in the time available and forced landed the aircraft onto a road. The left wing was substantially damaged when it collided with roadside obstructions. Investigation showed water was present in the right wing fuel collector tank, the fuel pump, the fuel control unit and in the fuel manifold valve. The aircraft was found to have had a history of water ingress into the fuel system. The wing upper access panels had previously been removed and resealed, and the fuel filler caps had been replaced. The pilot had fully refuelled the aircraft two days prior to the accident and during those two days torrential rain fell at the Port Macquarie airfield where the aircraft was parked. On the morning of the accident the pilot reported that he did not find any water when he checked the fuel system drains. The latter part of the flight had been through moderate to severe turbulence and it is suspected that water sitting within the wing fuel tank had been agitated and found its way into the engine supply system. It was not determined how the water entered the wing fuel tank, however, it is possible that some water had been present prior to the tank resealing, some weeks prior to the accident, and some may have entered the tank during the two days prior to this flight. At the accident site the left fuel tank was found to contain 53 litres of fuel while the right tank was virtually empty. Based on calculations of flight time versus known fuel consumption rates, there should have been about 117 litres of fuel remaining in the fuel tanks. The cause of the loss of fuel was not established. However, the pilot has advised that fuel has been stolen from aircraft based at Port Macquarie. Because the aircraft had not been flown since the pilot refuelled it, he did not visually check the tank contents prior to DEPARTURE from Port Macquarie. Although all the fuel could not be accounted for and the right tank was near empty, these facts were not considered factors in the accident. During his attempt to restart the engine, the pilot did not follow the procedure specified in the Pilot's Operating Handbook in that the throttle was fully open, the electric fuel pump was on, and the mixture rich. This would have severely limited the chances of a successful restart. (The throttle should have been half open, the electric fuel pump off and the mixture lean.) After a basic examination of the aircraft at the accident site, the engine was started without any problem.

Significant Factors:

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

1. The engine lost power due to water contamination of the fuel system.

2. The pilot did not use the correct procedure to attempt to restart the engine.

3. The pilot's attempt to restart the engine was not successful.

4. The pilot was forced to land on an obstructed roadway.

5. It is likely that the turbulence flown through during the latter stages of the flight caused the water in the fuel system to enter the engine.

The helicopter was carrying 360 litres of water based Herbicide and about 90 litres of fuel when it took off the second time that morning. Flying activity had commenced later than planned due to local fog and low cloud in the area to be sprayed. A level area on the bank of the creek was used for loading and the pilot availed himself of the open space over the creek to accelerate before commencing a climb out to the treatment area. This technique involved an immediate loss of ground effect as the helicopter moved off the elevated creek bank. The aircraft failed to achieve translational flight and the pilot "sensed" a power loss as it descended towards the fast flowing creek. The left skid fractured when it struck a log protruding from a low island. The impact rotated the helicopter through 180 degrees causing the pilot to lose sight of the only reasonable landing area on the opposite bank. The helicopter settled and balanced on sloping ground whilst the engine wound down due to fuel starvation caused by a fuel feed line separation in the initial impact. As the rotor system slowed down, the helicopter fell onto its damaged left side. The pilot was using a pad that was not suitable for the operation. The pad was limited by a fence line at one side which was high enough to prevent operations over it at high all up weights and a creek at the other side which caused an immediate loss of ground effect as soon as the helicopter moved off the pad. Trees and high terrain prevented other take-off options. The pilot was using the potential energy of pad height above the creek to gain airspeed quickly and early translational flight. On this occasion he did not obtain translational flight and the helicopter descended into the creek. The pilot overpitched the main rotor blades causing a loss of RPM and power. The engine and fuel components were examined in detail and no mechanical reason for a power loss was discovered. The helicopter was fitted with a spray system that was not authorised for the type in Australia, the performance combination of helicopter and spray system was unknown.

The pilot had arranged to take some friends for a flight and to have a flight check with a flying instructor beforehand. Initially the instructor was unhappy with the pilot's circuit planning and landings. The pilot was given some information on the aircraft and a circuit diagram and another check was scheduled for the following day. On the next day the instructor gave the pilot a substantial briefing prior to the flight. The pilot's flying had improved significantly and the instructor assessed him as competent to fly the aircraft. After a scenic flight in the local area the aircraft joined the circuit on right downwind for runway 12. Surface wind at the time was 120` at 15 knots. The aircraft was observed to touchdown aligned with the centreline, near the runway threshold, and a short time later was seen to bank left. It touched down on the grass within the left hand side flight strip heading about 40` to the left of the runway direction. At around this time the pilot elected to go-around and he applied full power. From this point the aircraft made a gentle left turn until it was tracking 330`. Initial impact with the ground occurred when the aircraft was descending at an angle of approximately 15` and banked at least 30` to the left. Indicated airspeed at this time was 35 knots. The aircraft landed heavily on the nosegear and rolled backwards before coming to rest 20 metres from the point of initial impact.

Because of the load carried the pilot could not take a full load of fuel. The aircraft was not equipped with a calibrated dipstick or a ladder. Due to the position of the tank caps on top of the high wing the absence of these items of equipment made it difficult for the pilot to make an accurate visual assessment of the fuel contents. After checking the tanks the pilot arranged for 30 litres of fuel to be added to the right tank. The reported fuel gauge indications at engine start were 30 US gallons (113 litres) in the left tank and 35 US gallons (132 litres) in the right tank. His planned fuel consumption rate was 60 litres an hour, indicating a total endurance of just over four hours. The flight plan time for the flight was slightly under three hours. The flight proceeded normally initially and the pilot said he used a power setting of 23-24 inches of manifold pressure and 2400 RPM. The cruise fuel flow was set to 90 pounds per hour (57 litres). Near Henty while cruising at 4000 feet the pilot became concerned when the total indicated fuel contents had fallen to 25 US gallons (95 litres) and he advised Melbourne Flight Service that he would land at Mangalore which was on his planned track. Not long afterwards the total gauge indications fell to under 10 US gallons (38 litres) and he told flight Service he was diverting to Shepparton, with an estimate of 0950 hours for arrival there. At about 10 miles from Shepparton the engine misfired and the pilot changed the tank selection from right to left. He entered the circuit at Shepparton on mid downwind at about 1800 feet and tracked for left base runway 18. On base leg the engine failed completely and the pilot realised he could not reach the runway. He selected a grass area into wind and touched down firmly while tracking approximately west. The nose wheel detached on the soft surface and the right main gear leg was damaged as the aircraft slid to a stop. Inspection of the fuel tanks revealed there was no fuel left in either tank. Testing of the fuel flow gauge showed it was accurate. No evidence was found to show that there had been any fuel leakage or loss in flight. Having regard for this it was likely that on DEPARTURE Bankstowm the fuel contents were somewhat less than the pilot thought. A calibration check of the fuel gauges showed significant errors. At an indicated contents of 30 US gallons the left tank held 22.5 gallons, and when the right gauge indicated 35 US gallons the right tank contents were 26.4 gallons.

The pilot was herding a bull along a shallow valley and he decided to hover behind it. He entered the hover about 20 feet above the trees from a slight descent and with some right lateral movement. The heading of the helicopter was westerly in a wind from the south at 10 knots. The pilot then initiated a pedal turn into wind. The helicopter stopped turning when nearly into wind and the pilot added almost full left pedal to complete the turn. The helicopter then began to rotate smoothly and rapidly to the right, and the pilot applied full left pedal in an attempt to stop the yaw. As the application of full left pedal had no effect, the pilot closed the throttle but there was no perceptible reduction in the rate of turn. The helicopter rotated through at least 360 degrees before striking the trees and crashing on its side. The on site investigation did not reveal any mechanical defects or anomalies that would have contributed to the loss of tail rotor control.

The flight was intended to provide a dual check for a pilot to satisfy company and insurance requirements, and to enable a test flight to be carried out, following extensive maintenance on the aircraft. After a normal takeoff, the aircraft made a brief flight to the training area before returning for landing. The landing gear was selected down and normal safe gear down indications were obtained (three green lights and no warning horn). The safe indications were again confirmed during the final approach phase. The aircraft touched down normally on the maingear, but as the nose was lowered, the nosegear collapsed. The subsequent investigation revealed that the nosegear actuator had been incorrectly assembled. The nosegear downlock switch had been adjusted to compensate for the error in the actuator. This resulted in the failure of the nosegear to fully extend to the locked position, while providing a false gear down indication in the cockpit.