Circumstances:

The pilot was relatively inexperienced on the aircraft type and bush flying. She had flown into Lamboo Homestead airstrip during the morning to drop off her employer. She had then flown over to the newly graded strip at Old Lamboo where her employer's mustering team was camped. After approximately one hour on the ground, the pilot decided to do a circuit of the airfield with one of the mustering team as a passenger. She had not landed at this airfield before and did not consult the aircraft performance charts. The performance charts indicated that twenty degrees of flap was required and that the available take-off distance required to clear the obstacles at the threshold was marginal. The pilot elected to make a flapless take-off. When approximately 2/3 along the 700 metre strip, and the aircraft did not appear to be accelerating normally, the take-off was abandoned. The pilot expected that the aircraft would stop within the remaining distance, however, the aircraft did not stop as expected and continued beyond the end of the strip. The aircraft was substantially damaged before coming to rest approximately 110 metres past the prepared threshold. Subsequent investigation indicated that the pitot tube was partially blocked, and this had caused the airspeed indicator to under read.

Significant Factors:

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

1. The pilot attempted operation beyond experience/ability level.

2. The pilot did not use the aircraft performance charts to determine if runway length was adequate.

3. The pilot did not use the correct flap setting.

4. The pilot misjudged speed and obstacle clearance required and ran off runway.

5. The pitot tube was partially blocked causing the Air Speed Indicator to under read.

Information provided by the pilot indicated he had planned to land the aircraft in a paddock used by crop dusting aircraft. He contacted the owner of the paddock and determined that it met the requirements for his aircraft. The pilot was advised that a set of powerlines crossed the approach end of the paddock and he requested the owner to park his car underneath these powerlines to mark their location. When the pilot arrived over the strip a car was parked near the approach end where the pilot thought the powerlines were and he assumed the owner had acted on his request. After carrying out an Authorized Landing Area inspection during which he did not sight the powerlines the pilot made a normal approach. He kept well clear of the car but the aircraft collided with the powerlines on late final approach and touched down heavily. Information provided indicated that the owner of the paddock had parked his car more than 20 metres downwind of the powerlines for reasons which were not determined and this had given the pilot the wrong impression of their location. This accident was not the subject of an on scene investigation.

Circumstances:

Approaching top of descent at 10,000 feet, the pilot noticed smoke coming from under the instrument panel. The smoke rapidly increased in density until it was almost black in colour with a very strong petrochemical, choking odour. The pilot commenced a rapid descent and turned the aircraft towards the coast. He switched off all electrical services as flames appeared under the instrument panel. He extinguished these flames with the cockpit fire extinguisher and opened the cockpit window to provide fresh air. The pilot switched on the electrics to transmit a mayday call and talk to a company aircraft about 10 miles behind. However, flames reappeared so the electrics were again selected off. At no time did any circuit breakers operate. Passing about 7,000 feet in the descent, the engine failed without warning and could not be restarted. The pilot manoeuvered the aircraft for a wheels up landing on a dry tea tree swamp. On final approach, he unlatched the door to aid in emergency evacuation. The passenger in the right front seat attempted to exit the aircraft but was restrained by the pilot. This passenger had to keep her feet on the seat during the final 300 feet to avoid the flames. The pilot planned a high-speed approach to ensure he did not undershoot the intended landing area. On short final, he selected full flap and, probably due to the short circuit behind the instrument panel, full flap was obtained. He also opened the air vents which increased the intensity of the fire but gave him good vision. After striking some small trees on final, the aircraft slid about 90 metres before coming to rest. All occupants evacuated safely through the doors. The pilot estimated that the cabin was engulfed in flames within 30 seconds of the aircraft stopping. It is most likely that the fire started as a result of electrical arcing caused by the failure of insulation on the wire carrying electrical power from the starter relay to the ammeter. The fire burnt through the magneto wire insulation, grounding the wires and stopping the engine.

Significant Factors:

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

1. The insulation on the starter relay to ammeter wire on the cabin side of the fire wall rubbed through.

2. An electrical short circuit developed, resulting in arcing which started a fire under the right side of the instrument panel.

3. The fire spread to the left side of the instrument panel and burnt through the magneto wire insulation resulting in engine failure.

4. The aircraft landed in unsuitable terrain.

Circumstances:

The Examiner-of-Airmen was flight testing a pilot for his commercial helicopter licence. At 3000 feet above sea level the Examiner closed the throttle without warning, to simulate an engine failure. The Examiner had preselected what he considered to be a suitable clearing within autorotative distance for the practice forced landing. The terrain was undulating, tree covered but with scattered clearings. Ground level averaged 1500 feet above sea level. The candidate was not expecting a simulated emergency; he was not holding the collective lever. However, he performed a normal entry into autorotation straight ahead. The main rotor RPM initially reduced to the bottom of the green arc (390 RPM). Instead of reducing to idle RPM, the engine stopped when the throttle was closed. The Examiner immediately took over control of the helicopter and turned right into wind and towards the clearing. Rotor RPM was soon established in the middle of the green arc (at about 450 RPM) but there was no response to the throttle. During the descent towards the clearing, the pilots unsuccessfully attempted to restart the engine. During the autorotative descent the helicopter undershot the clearing. At the tops of 15 metre high trees, about 20 metres short of the clearing, the Examiner flared the helicopter and applied some of the collective pitch to reduce the rate of descent. As the helicopter settled through the trees with about 20 knots forward speed, he pulled the remaining collective pitch. At about five metres above ground level the helicopter settled on to saplings at the edge of the clearing. The saplings cushioned the descent and diminished the forward speed. The main rotors struck the ground, and the helicopter came to rest on its right side about eight metres into the clearing. The two pilots were wearing a full harness. Both inertia reels locked (as designed) at ground impact. Both harnesses severed at the point where the straps exit the reels. The investigations determined that both reels had been installed upside down before the Australian Certificate of Airworthiness was issued in 1988, despite the existence of a detailed CAA Airworthiness Directive warning that erroneous installation could jeopardise restraint in an accident. Engineering bench tests and subsequent engine ground runs revealed that fuel injector servo fuel flow at engine idle setting was excessively rich. The fuel injector servo had been fitted to the helicopter six days before the accident, and the helicopter had successfully carried out several simulated engine failures in training during that period. There is little doubt that the engine stopped as the result of a "rich cut" when the Examiner closed the throttle to simulate an engine failure.

Significant Factors:

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

1. The fuel injector fuel flow was excessively rich at engine idle.

2. The engine stopped during the simulated engine failure because of a "rich cut".

3. It is more difficult for a pilot to judge a helicopter's autorotative glide distance over undulating terrain than over flat terrain.

4. The Examiner-of-Airmen misjudged the range capability of the helicopter's autorotative descent.

Circumstances:

The aircraft was approximately 40 minutes into the flight when the pilot noticed a substantial loss of oil pressure. He initiated a diversion to the nearest suitable aerodrome, but several minutes later, following an increase in RPM, the engine failed. A small quantity of oil appeared on the windscreen and the cabin filled with smoke. The propeller continued to windmill during the descent, causing moderate to severe vibration from the rotating engine. A successful wheels-up forced landing was carried out into a cleared area. Inspection of the engine revealed a hole in the top of the crankcase adjacent to and rear of the oil filler neck which was caused by the failure of the number four connecting rod. The screws attaching the oil filler neck flange to the crankcase were found to be excessively loose, allowing a gap between the flange and the crankcase. There were no other apparent oil leaks. The aircraft had undergone a major inspection and top overhaul 108 hours prior to the accident and had flown 5 hours since the last periodic inspection. There was no reason to remove or loosen the oil filler neck at either of these inspections or during the salvage operation. Before further inspection of the engine could be carried out, it was discovered that the filler neck had been retightened. This caused metal fragments which had been suspended in the oil to become embedded into the gasket material. This confirmed that contaminated oil had exited the engine through this aperture. The pilot stated that he had checked the oil level and the security of the oil cap prior to the flight without noticing any looseness of the filler neck. The oil filler neck may have been loose during the earlier part of the accident flight but was held in position by the screw threads catching and interfering with the holes in the filler neck flange. The pilot's twisting action on the cap, as well as vibration and crankcase pressure may have caused the filler neck flange to lift off the crankcase, probably with the gap between the flange and crankcase being positioned in such a way that a capillary action was created by the airflow, causing the hot oil to be drawn from the crankcase. The oil then flowed with the cooling air between cylinders number four and five to both the underside and lower left-hand surfaces of the fuselage via the nose wheel well, all of which were thickly coated in oil. There was an insignificant amount of oil, with relatively dry carbon and sludge deposits in the crankcase breather outlet and associated plumbing, indicating that the oil had not escaped from the engine via that route. As the oil level in the engine decreased, oil pressure also decreased, and with insufficient oil flow and pressure to operate the propeller governor, normal rotational loads on the propeller moved the blades towards the fine pitch position increasing the engine RPM. Oil starvation caused overheating of the crankshaft, allowing the babbit alloy of the connecting rod bearings to melt. The number four connecting rod bearing was the first to fail, with separation of the bearing cap allowing the rod to flay about, causing the hole in the top of the crankcase. The small amount of oil thrown onto the windscreen indicated that most of the oil had already escaped from the engine prior to the failure.

Significant Factors:

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

1. The engine developed a serious oil leak.

2. The oil filler neck to crankcase attachment screws were excessively loose, probably allowing oil to escape from the engine through the gap between the oil filler neck and the crankcase. The reason why the screws were loose could not be determined.

3. The number four connecting rod failed due to oil starvation. This accident was not the subject of an on-scene investigation.

Circumstances:

The left hand fuel filler cap locking tongue had been replaced during the periodic servicing 20 hours prior to the accident. The new tongue did not have a positive feel when pushed to the closed position and the cap did not seal correctly. The pilot was aware that the bladder type fuel cells could trap water which might not be apparent during a normal fuel drain. About one week before the accident and following heavy rain, the pilot rocked the aircraft, during his fuel drain check, to remove all the trapped water. On the day of the accident the pilot refuelled the aircraft, to full tanks, from an un-opened 200 litre drum. A subsequent check of the drum disclosed some water although in insufficient quantities to enter the standpipe of the hand pump during refuelling operations. The pilot carried out a normal fuel drain check which indicated that the system was free of water. He did not rock the aircraft as there had not been any significant rainfall since his previous check. At 150 feet above ground level, shortly after take-off and following flap retraction and power reduction, the engine stopped. The pilot carried out a turn through 170 degrees in an attempt to land in the only reasonable area. The nosewheel collapsed on touchdown and the aircraft overturned. An inspection of the aircraft's fuel system disclosed water contamination in the main fuel filter bowl, in the fuel lines to the carburettor and in the carburettor. No other defects found which may have been factors in the accident. It is probable that water entered the fuel tanks, via the defective fuel cap and remained trapped in the tank despite the checks carried out by the pilot. Water subsequently entered the engine fuel system during the manoeuvers following take-off.

Significant Factors:

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

1. The fuel filler cap was still unserviceable following replacement of the locking tongue.

2. Water in the fuel system that was not detected during the pre-flight inspection.

3. Engine stoppage caused by water contamination of the fuel system.

4. Unsuitable terrain for a forced landing.

The pilot conducted a daily inspection of the helicopter prior to meeting another company pilot to fly two helicopters to a mustering camp. After start he reported by radio to the pilot of the lead aircraft that he was ready to depart. Ground witnesses saw the two helicopters depart in company. The lead pilot proceeded to Hell's Gate and landed but the second aircraft did not arrive. The second helicopter was found one day later about 7 km from Doomadgee and on the extended centre-line of the runway. Examination of the wreckage indicates that the helicopter struck the ground inverted and with a high rate of descent. No pre-existing defects were found in the helicopter. No evidence to indicate that the pilot was other than healthy or suffered from any incapacitation was found during a post-mortem examination. While the factors associated with the cause of this accident were not determined, one possibility is that the pilot suffered a flicker induced seizure. This phenomenon can be caused by the passage of sunlight through the main rotor creating a strobe effect in the cockpit. It may have resulted in control inputs, by the pilot, which could have caused the helicopter to become inverted and crash.

Circumstances:

The aircraft had been refuelled from drums at a refuelling point located at one end of the lagoon. The refuelling point was surrounded by tall trees, so the pilot decided to hover taxi out over the lagoon and to execute a take-off from a more open area. The take-off had to be initiated with a slight tailwind, and the pilot intended to turn and to depart upwind after the aircraft had obtained translational lift. As the pilot initiated the take-off, the aircraft experienced a tailwind gust and began to lose height. In an attempt to check the descent, the pilot overpitched the main rotor. The right skid contacted the water surface and the aircraft simultaneously pitched forward and rolled to the right before coming to rest on the lagoon bed. The two occupants evacuated the aircraft without injury.

Significant Factors:

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

1. The aircraft experienced a tailwind gust as the pilot initiated the take-off.

2. The pilot overpitched the main rotor while attempting to counter height loss from the gust.

3. Loss of lift resulted in the right skid contacting the lagoon surface. This accident was not the subject of an on-scene investigation.

Circumstances:

The aircraft was established in normal cruise flight when the pilot thought he could smell burning oil. A check of the engine instruments did not indicate any problem, but he elected to return to Essendon. The Essendon Terminal Information Service recording advised runway 35 was in use wind from the north at 15-30 knots and a temperature of 28 degrees. The flying conditions were moderately turbulent, and the pilot made the approach with 10 degrees of flap and at 75 knots. Observers in the Tower reported the aircraft touched down well into the runway heavily nosewheel first and bounced two or three times before coming to rest. Subsequent ground inspection of the aircraft revealed that the bolt attaching the upper portion of the nose gear leg to the aircraft had been sheared by straight overload forces. This had allowed the upper part of the nose leg to be forced into the engine bay under pressure. The engine firewall was also buckled.

Significant Factors:

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

1. Strong gusty wind conditions.

2. The pilot misjudged the landing flare and touchdown.

3. The pilot was possibly distracted by the perceived engine problem.

Circumstances:

A night take-off was initiated from runway 21. The runway was wet, with patches of standing water on the surface. Light rain was falling, with a south-easterly surface wind of 10 to 15 knots. The crosswind component was close to the maximum specified for this type of aircraft. Just prior to reaching rotation airspeed the left mainwheel apparently entered a pool of standing water, and the pilot reported that at the same time the aircraft was subjected to a strong wind gust. The aircraft swung to the left and the pilot was unable to maintain directional control. The pilot thought that the aircraft may have commenced to aquaplane, and he closed the throttle immediately. There was no attempt made to apply brakes. The aircraft departed the runway to the left, crossed the grass flight strip, and continued for approximately 85 metres, before colliding with a levee bank and coming to rest in a drainage ditch. No evidence of aquaplaning was subsequently found. This accident was not the subject of an on-scene investigation.

Significant Factors:

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

1. Patches of standing water on the runway which were not visible to the pilot.
2. Loss of directional control following penetration of standing water and/or sudden wind gust.
3. The pilot did not apply braking in an attempt to slow the aircraft prior to the collision with a ditch.