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 Flap 10 (degrees) had been selected for the take-off and was retracted once the aircraft was safely airborne.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.

The departure was from runway 27. Prior to take off the crew were told to "maintain heading 260." After take-off, the crew initiated a right turn. This was observed by the Melbourne Departures controller and the turn was stopped on a heading of 310. There was no loss of separation.

Significant Factor

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

1. Aircraft flight crew error over implementation of after take-off heading instruction.

During the take-off run on runway 34 the first officer, who was flying the aircraft, called "failure" at approximately 120 knots. This was below V1, and the captain rejected the take-off. The Master Caution Air Conditioning lights were illuminated. The auxiliary power unit bleed air was supplying the left pack which was running in high mode. The pack tripped off as a result of high temperatures.

Autobrake was used in the rejected take-off selection and operated until down to a slow speed in the deceleration. The outboard left main wheel tyre deflated due to overheating. Both left main gear wheels and the left outboard brake unit were subsequently changed. Take-off should not be rejected from high speed for a Master Caution. However, when the first officer responded by calling "failure" the captain was obliged to reject the take-off.

Significant Factors

1. Master Caution Air Conditioning lights illuminated during the take-off roll.

2. The first officer incorrectly called "failure" for the caution light illumination.

3. The captain was obliged to reject the take off on the basis of the first officers call.

The aircraft took off in company with another Cessna 152. Whilst turning to avoid higher terrain north of Kooralbyn, the pilot lost sight of the other aircraft against the setting sun. He rolled his aircraft to maintain physical separation from the other aircraft. In the process he lost control of his aircraft.

The pilot next noticed the ground rushing up to meet him and rolled off bank and pulled back on the elevator control. The aircraft passed underneath a powerline and the left wing tip struck the lower of the three wires. The collision with the wire caused the aircraft to flick roll through approximately 180 degrees. The aircraft narrowly missed the ground and trees before the pilot regained control.

Despite the obvious visual damage and control difficulties the pilot elected to fly the aircraft to Archerfield. An emergency was not declared, and the aircraft was landed safely at the destination.

Post flight inspection revealed that about one and a half metres of the leading edge was stripped of the metal skin back to the front spar.

The pilot was not endorsed to fly in formation with other aircraft.

Shortly after commencing descent from 6,000 ft, the pilot reported that the right engine began to run roughly, which was followed soon after by a loud bang and the appearance of flames around the engine. The pilot shut down the engine, feathered the propeller and turned off the fuel, magnetos and alternator. However, these actions had no effect on the intensity of the fire.

Because it was still dark at ground level, the pilot elected to continue the 40 km to the planned destination. The intensity of the fire appeared to diminish as the flight continued and finally self-extinguished just prior to landing.

Inspection of the engine found that the #1 piston to crankshaft connecting rod had separated at the crankshaft end and had broken a hole through the lower forward crankcase. Engine oil being drawn through the broken section of the crankcase ignited when it came into contact with the hot exhaust manifold. The ensuing fire, being fuelled by a quantity of oil from the crankcase, caused substantial damage to the engine cowls, engine bay, lower right wing and landing gear door panels.

Metallurgical examination of all of the connecting rods and bearing shells from the engine revealed that the #1 connecting rod had failed as a result of fatigue which had initiated at multiple sites on both sides of the connecting rod.

The examination found the presence of aluminium oxide particles in the engine lubrication system. It was concluded that these particles had acted abrasively on the bearing shells which resulted in the breakdown of the hydrodynamic oil film during engine operation. This in turn caused overheating and the eventual breakup of the bearing shells.

The engine had been in service for a total of 4,623 hours and was overhauled 427 hours prior to the failure.

Aluminium oxide beads of the type found in the engine are used in most maintenance workshops and overhaul facilities as a bead blasting medium.

The overhaul facility which carried out the last overhaul of the failed engine advised that they do not use any form of bead blasting to clean internal engine components or crankcases. The facility did use aluminium beads in their bead blast machine, but it was used only to clean external engine parts.

It was not determined how the aluminium oxide beads entered the oil system.

SIGNIFICANT FACTORS

1. Aluminium particles were introduced into the engine lubrication system at an undetermined stage of its life.

2. The aluminium particles interfered with the proper lubrication of the connecting rod bearings.

3. The engine failed as a result of overheating of the bearing shells which led to the breakup of the #1 connecting rod.

4. The fire resulted from the released engine oil being ignited by hot engine components.

The pilot made a normal approach for landing on runway 23. He selected the landing gear down and obtained three green lights.

On the landing roll the nose gear leg collapsed.

Later, retraction checks were carried out on the aircraft. These did not reveal any defects in the system. The reason for the collapse of the nose gear leg has not been established.

Significant Factors

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

1. The nose gear leg collapsed for undetermined reasons.

The aircraft was cleared via Kinglake and Epping for a landing on runway 27 at Melbourne. The aircraft proceeded south of the cleared track and did not comply with heading change instructions from Melbourne Tower to get the aircraft back on track. The aircraft was transferred back to approach control where it was vectored and descended for a landing on runway 34. There was no breakdown in separation.

Investigation determined that on the approach to Melbourne there was confusion in the cockpit between the two crew members. En route the captain had asked the first officer to request runway 34. This had not been done. From some distance out the captain was planning to land on runway 34 but the first officer was basing his actions on a landing on runway 27. It was established that the ILS selectors were tuned to 109.3 which is the runway 27 ILS frequency but it was not established exactly how communication between the captain and the first officer broke down to the extent that they both thought they were going to land on different runways.

Significant Factors

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

• There was confusion between the captain and the first officer as to which runway they were going to land on.