The pilot stated that he had just refuelled the aircraft. The subsequent engine start and take-off were normal. However, as the helicopter was accelerating through about 60 knots, the engine began to lose power, with decreasing RPM evident. As the pilot lowered the collective pitch control, the engine stopped. The pilot conducted an autorotation on to a road, but touched down in a high nose attitude and broke the right skid.

The engine had operated normally prior to the occurrence. The refuelling operation was the first from a newly opened drum but there was no indication of fuel contamination. Operation of the aircraft requires the fuel boost pump to be ON during take-off and landing and when flying below 140 metres above ground level. The pilot was not certain that he had switched the pump on before take-off. It is possible, therefore, that the engine failed due to fuel starvation.

During the landing roll the aircraft steering could not be controlled by the steering tiller. The tiller continued to drive to the full left position and directional control could only be maintained by differential braking. When the aircraft was stopped the nosewheel and tiller were locked in the full left position and taxiing was not possible. While arrangements were being made to disembark the passengers on the runway, the steering suddenly freed itself and the aircraft was then taxied to the terminal. The steering system could not be faulted on the ground at Albury but the nosewheel steering shut-off valve was changed as a precaution. The aircraft then operated the return flight to Sydney, but the problem recurred. The nosewheel steering control valve was changed and no further problems have been reported.

VH-KDB commenced descent to Whyalla at 55km and advised Adelaide Flight Service (FIS) and broadcasted on local MTAF. Adelaide FIS advised "no IFR traffic" and no response was heard on MTAF.

At 30km Whyalla, the estimated arrival time and intentions at Whyalla were broadcast and the pilots continued to monitor both radio frequencies (MTAF and Area).

At about 10km from Whyalla, when leaving 3000 feet on descent, opposite direction traffic was seen on climb straight ahead. Rate of descent was increased as an evasive action and the other aircraft passed overhead.

After passing, attempts were made to establish communications with the other aircraft on both MTAF and Area frequencies without success. A short time later, VH-LQD was heard on Area frequency, and it was established that this was the aircraft seen.

The pilot of VH-LQD, a foreign national, was flying a solo navigation exercise and although he had heard some transmissions, he had not associated them with conflicting traffic.

The crew of VH-JJT were making a straight in approach to runway 03 at Geraldton. They had made advisory calls on both the area and MTAF frequency and were in contact with four other aircraft in the Geraldton MTAF. As the aircraft joined the final approach a high wing, single engine aircraft was sighted departing from runway 08. Repeated attempts to contact the aircraft on the MTAF and area frequencies were unsuccessful.

While taking off from a forestry strip the aircraft performance achieved was less than expected. Concerned about terrain proximity after liftoff the pilot operated the dump lever. This did not prevent the landing gear from striking a log beyond the end of the strip. The aircraft continued to fly, and the pilot diverted to Albury Airport. During the subsequent landing roll, the right main landing gear leg collapsed.

Soft sand had been put on portions of the centre of the forestry strip, and it appeared this had adversely affected the take-off performance. A spreader was fitted to the aircraft to assist in distribution of the hopper load. When the dump was attempted, the spreader severely reduced the effectiveness of the dump and only about 20 per cent of the load was jettisoned.

Significant Factors

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

1. The presence of soft sand on the strip surface.

2. The pilot did not anticipate the effect the sand would have on the take-off performance.

3. Fitment of the spreader resulted in a severe reduction in the performance of the dump system.

Significant Factors

The following factors were considered relevant to the development of this incident.

1. The cannon plug on the rear of the landing gear indicator was not securely fastened.

2. The cannon plug disconnected from the indicator.

The aircraft was loaded to near the maximum permissible all up weight for the takeoff from the 1,000m strip which is 1,950ft above mean sea level. The strip is surrounded by low rolling hills which rise some 200 to 300 ft above the height of the strip.

The aircraft took off in the 040 degree direction, becoming airborne about half way along the strip. Flap 10 (degrees) had been selected for the take-off and was retracted once the aircraft was safely airborne. The pilot adopted the best climb attitude which held 60 knots. Initially the climb rate was 500ft per minute, but when the aircraft entered mild mechanical turbulence, this changed to a 300ft per minute descent rate. This situation continued until impact with trees on a ridge line some 1,000m beyond the departure end of the strip. The occupants were not injured and vacated the wreckage without assistance.

At the time of the accident the wind direction and strength was judged to be 060 degrees at 15 knots.

It is most probable that the aircraft encountered a downdraft in the lee of the hills to the north-east of the strip which negated the climb performance of the aircraft.

Shortly after the aircraft was established in cruise, the crew noticed that the right engine low oil pressure light was illuminated and that the corresponding oil pressure indication was zero. As the engine shutdown procedure was being carried out, a smell of smoke was noticed, and the right engine fire extinguisher was activated. The aircraft was returned to Melbourne and landed without further incident.

An analysis of the flight data recorder readout showed that oil pressure began to fall during the take-off at Melbourne, and some 13 minutes later had fallen to the low oil pressure warning light setting of 13 lbf/sq in. The pressure continued to fall to zero over the next 3 minutes 20 seconds. The engine ran with zero oil pressure for a further 2 minutes and 40 seconds before the number 3 bearing failed leading to rapidly rising EGT and decaying N1 and N2. The engine was then shut down by the crew.

The crew did not notice the gauge indications during the climb and initial cruise. A check of oil pressure indication during these phases of flight is not required by the aircraft checklist. The engine monitoring instruments are located on the pilots' centre console and are not connected to the aircraft master caution system.

An inspection found that the engine oil tank cap had not been correctly secured and was displaced out of its holder. The non-return valve was also missing from the base of the cap holder. With the oil tank cap not sealing and with the non-return valve not fitted to the cap holder, the engine oil tank was vented to atmosphere, was unable to pressurise, and oil was able to escape from the tank. The lack of oil tank pressurisation also caused a loss of positive inlet pressure to the oil pump resulting in a loss of pump performance which starved the engine bearings of oil and led to the failure of the number 3 bearing. The smoke smell detected by the crew would have been generated during this failure sequence.

For this incident to occur there had to be two problems. First the oil tank cap had to be unsecured and secondly the non-return valve had to be missing. All engine manufacturers have addressed the problem of unsecured oil tank caps by fitting non return valves to the tanks. This particular installation was the original fitment when the engine was delivered new to the operator, and it is therefore likely that the non-return valve was not fitted on manufacture. The engine oil tank cap was not locked into place correctly after the engine oil quantity was checked prior to departure. The reason for this was not determined.

Significant factors

The following factors were considered relevant to the development of the incident.

1. The engine oil tank cap was not properly secured and became dislodged.

2. The engine oil tank filler non-return valve was not installed.

3. The engine low oil pressure warning is not connected to the aircraft master warning system.

4. The reduction in engine oil pressure indication was not noticed by the crew.

Safety Actions

1. The operator carried out a fleet inspection to check for the installation of the non-return valve.

2. The engine manufacturer was notified of the findings.

3. The operator has revised the preflight check to ensure that the cap is correctly secured.

4. The operator has issued an Engineering Instruction that requires that the presence of the oil tank non-return valve be checked each time engines are inspected in the operator's engine facility.

5. Consideration is being given to connecting the engine low oil pressure warning to the aircraft master warning system.

During descent the aircraft suffered a loss of power. The pilot was forced to land into an unsuitable area resulting in the aircraft being damaged when it ran into a fence.

The weather was conducive to the formation of carburettor ice at the time of the accident.

The carburettor heat flapper valve was found to be stuck in the open (cold air) position. This valve normally closes when the throttle is retarded giving "automatic" protection against ice build up. The flapper valve shaft had suffered from a lack of lubrication.

Significant factors

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

1. The weather was conducive to the formation of carburettor ice.

2. The carburettor heat valve was inoperative.

3. The engine suffered from a loss of power over an area unsuitable for a forced landing.

The aircraft was engaged in sheep spotting operations when the engine began to run roughly, causing severe vibration. The pilot shut down the engine and carried out a forced landing on flat scrubby ground. The aircraft collided with shrubs during the landing.

The reason for the rough engine running was not determined.