Circumstances:

The pilot was engaged in mustering pigs for aerial culling. On spotting a group of animals, he flared the helicopter from about 50 knots to a slow speed and then banked hard to the left at low level. The main rotor blade tips struck long grass and the helicopter rolled over and came to rest on its left side. The area of operations comprised a virtual " sea of grass ", unrelieved by any trees or other vegetation. Judgement of height above the ground under such conditions is more difficult than usual. The manoeuvre flown by the pilot would have exacerbated the problem.

Significant Factors:

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

1. Featureless terrain.
2. Pilot misjudged height above the ground during a rapidly executed turn.

Circumstances:

The aircraft was on a night freight flight from Sydney to Melbourne, with a planned route via Canberra, Albury, and Eildon Weir, at 8000 feet. Over Canberra the pilot was cleared to climb to 10,000 feet. South of Canberra he amended his plan to proceed via Corryong due to unsuitable weather on the planned route. When the pilot transferred to Melbourne Flight Service frequency south of Corryong at 2329 hours, he advised the aircraft had a partial engine failure and to stand by. Subsequently at 2333 hours he said he had regained the engine. At this time, the aircraft was about 30 miles to the southeast of Albury. Approaching Eildon Weir, the pilot descended to cruise at 8000 feet and shortly after was cleared to commence descent into Melbourne. At 0027 hours when about 20 miles from Melbourne, while descending from 4000 to 3000 feet, he made a mayday call advising that he had a "dual engine failure" and requesting any available assistance. As the aircraft was too far from the lighted airfields at Melbourne and Essendon, the pilot was given radar headings towards Lilydale airfield. The pilot asked about lights at Lilydale and was advised that action was being taken to get them on. At 0028 hours he reported the right engine surging. He subsequently advised at 0029 hours that the altitude was now 1000 feet and when told Lilydale was 5 miles away said he was not going to make it. Radar contact with the aircraft was lost shortly thereafter. Apart from possible patches of ground fog the weather in the Melbourne area was fine, with no significant low cloud or wind. An on-site investigation revealed the aircraft had impacted heavily against the northern face of a road cutting. It was determined that both engines had lost power due to fuel exhaustion. A fuel stain found on the left wing was consistent with an inflight loss of fuel from the left main fuel tank cap. Further examination revealed that, although apparently fastened correctly, the fuel tank cap had been prevented from sealing due to interference from a wire clip attached to the fuel cap securing chain. This resulted in fuel being sucked past the tank cap during flight due to the difference between fuel tank and overwing air pressures. This in turn caused the floor of the bladder type fuel tank to be lifted, resulting in false gauge indications. The aircraft had departed Sydney with adequate fuel to complete the planned flight. It is probable that the engine partial power loss reported by the pilot at 2329 hours was due to fuel exhaustion in the left main tank, resulting from a combination of loss of fuel and normal fuel consumption. The pilot would have been able to regain normal engine operation by moving the left engine fuel selector to cross feed fuel from the right main fuel tank. However, because of the loss of fuel from the left tank, the endurance was significantly reduced. Continued use of fuel from the right main tank by both engines, would have led to total fuel exhaustion of the right tank at about the time the pilot reported the double engine failure. Inspection of other aircraft with similar tank cap systems indicated that it was not possible to lock the tank cap with the pin lodged under it. However, it was noted that the clip could inadvertently be caught under the cap and have force applied to it, such as was likely to cause the clip to become deformed in service. The pin attached to the left main fuel tank cap was found to have been deformed.

Significant Factors:

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

1. Design of tank clip and fuel tank system.

2. Undetected deformation of clip in service.

3. Clip inadvertently lodged under left main tank cap, probably during pre-flight inspection of the tank contents.

4. Undetected loss of fuel in flight and collapse of the left main fuel cell, leading to a false fuel contents indication and fuel exhaustion of the left main tanks.

5. Pilot decision to continue towards destination, rather than divert.

6. Double engine failure at night, following total fuel exhaustion.

The pilot reported that he was opening the throttle to gain height whilst flying over a cane crop at about 100 feet when the engine failed. The aircraft was landed in the cane crop and the landing gear was bent. The factory fitted swaging on the throttle cable at the carburettor end had come off allowing the throttle to close. This occurrence was not the subject of an on-site investigation and the above report is based on information provided by the pilot.

The pilot reported that he was flying at about 100 feet above ground level when the engine failed suddenly and completely over thick scrub. He decided to stall the aircraft into the foliage canopy, but the aircraft did not make contact with the main canopy other than small branches, and impacted the ground at a 60 degree nose down attitude from a height of about 40 to 50 feet. The nose section, undercarriage and fuel tank were totally destroyed on impact. Examination of the engine has not revealed any mechanical defect. The pilot believes he may have inadvertently bumped the "engine kill switch" to the off position with his knee. The Bureau has been advised by the Australian Ultralight Federation that this particular switch has since been fitted with a shroud to prevent inadvertent operation.

Following an aerial search for two people missing in the Dingo area, the pilot stopped the aircraft to let the observers deplane. He then taxied his aircraft along a grassed taxiway to the hangar. During this taxying, the left main wheel entered a deep hole, which had not been sighted by the pilot. The owner/pilot had recently had a "pop-up" sprinkler system installed along the taxiway. The work involved lengthy excavation. The aircraft had been taxied into a hole inadvertently left by the contractor. The pilot had been in the habit of leaving the aircraft near the strip while the work was in progress, but on this occasion he decided to hangar the aircraft to avoid any unnecessary risk of damage to the parked aircraft by stock. This accident was not the subject of an on-site investigation.

At the completion of the student's second flight the instructor believed the glider was too high downwind and used speedbrake in an attempt to recover. As a result the glider got into an undershoot situation. The instructor attempted a landing outside the aerodrome to avoid hitting the boundary fence but a heavy touchdown resulted damaging the landing gear and wheel well area. This accident was not the subject of an on-site investigation.

Circumstances:

The aircraft was about to be flown to Maitland as part of a multi-stage charter flight. After boarding, the pilot attempted to start the left engine, but the starter was apparently not engaging the ring gear. He started the right engine and again unsuccessfully tried to start the left engine. The pilot said that he then left the aircraft, with the right engine running, and attempted to move the left propeller to enable the starter to engage. As he turned the propeller the engine fired and commenced to run, the propeller grazing his right hand. The aircraft started to move forward, although the parking brake was reported to have been on. The pilot said he tried to board the aircraft but was unable to prevent it continuing ahead about six metres into a wooden fence. Substantial damage was sustained to the left wing, left propeller, and nose cone. The three passengers on board were not injured. The front seat passenger had no aviation knowledge and is not believed to have contributed in any way to the accident. The pilot said he subsequently found the left engine magneto switches had been on when he moved the propeller.

Significant Factors:

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

1. An apparent malfunction of left engine starting system.
2. The pilot left the aircraft unattended while one was engine running.
3. The pilot exercised poor judgement during his attempt to start the other engine.

The aircraft was cruising at 1500 feet above the ground when the engine began to vibrate and the RPM dropped from 2400 to 1900. Even with full power selected the aircraft could not maintain height. The pilot planned a forced landing on to a stretch of trotting track. On final approach he realized that the aircraft was overshooting the planned touchdown point. He used the available engine power and landed in a 250 metre wide paddock adjacent to the trotting track. Braking was not fully effective on the damp grass surface. In the latter part of the roll despite an attempt to veer the aircraft to the left the aircraft penetrated a stock fence at very low speed. The underside of the mid-section of the left wing was damaged as it contacted a fence post which swung the aircraft to the left. Number one cylinder was found to have no compression. About half of the head of the exhaust valve had broken free and been ejected through the exhaust port. The exhaust valve had achieved 603 hours time in service since installation as a new item. There may have been a flaw in the exhaust valve since manufacture. The valve failure was considered to be an isolated occurrence.

The pilot in command was a Training Captain and he occupied the right seat, operating the radios and navigation equipment. The other pilot was part way through his training for Captaincy on type and was flying the aircraft. After take off the crew were initially given radar headings by Melbourne Departures Control. At 0706 hours they were instructed to resume their own navigation. Some four minutes later while the Captain was making his normal public address announcement to the passengers concerning seat belts the Departures controller asked the crew to "-- just confirm tracking direct ---." The crew reaction to this was to ask themselves if they had made an error. The pilot in the right seat made a careful check of the navigation equipment, confirmed that all was in order and then advised the Controller of this. While nothing was found to be wrong this unexpected query from Departures Control remained in the minds of the crew. At 0710 the crew were instructed to change to frequency 128.5 MHz and call Melbourne Control. This instruction was acknowledged. No call was received from the aircraft crew and further calls directed to them on various frequencies did not obtain a response. The aircraft was tracked on radar continuously and when it was approximately 150 miles from Brisbane the crew contacted Brisbane Air Traffic Control and asked for a clearance to descend. Communications were normal for the remainder of the flight. Monitoring of the communications recording for the departure from Melbourne showed that the instruction to call on frequency 128.5 MHz tapered off so that the "five" was very difficult to hear. Advice from the crew was that they had tuned their equipment to 128.4 MHz. This was one of several Sydney Air Traffic Control frequencies and the crew heard periodic radio transmissions to and from other airraft, which indicated to them that all was normal. When the crew changed to 128.4 MHz they called on that frequency and thought they obtained a response. The aircraft was operating under full radar coverage which meant that the crew were not required to make any position reports to Air Traffic Control. The procedure under such an environment is for the crew to be told to change from one frequency to another. As this was a training flight considerable in flight time was devoted to training tasks, in particular cross checking of radio navigation aids against the aircraft's main navigation system. Attempts were also made to contact the crew on the emergency frequency of 121.5 MHz, without success. Monitoring of the Sydney frequency 128.4MHz did not reveal any calls from the aircraft, which was to be expected as it would have been beyond the range for two way communications with the aircraft at the time. However, it is possible that the crew heard part of a transmission from another enroute aircraft communicating with Sydney on this frequency. No calls were made to the aircraft on 128.4 MHz, which was not one of the frequencies that would have been used on that flight.

The pilot was practising circuits. The engine lost power at about 90 feet in the climb after the fourth take-off. Thinking his foot may have slipped off the throttle, the pilot lifted his foot and pressed down on the throttle again. The engine responded with full power. With the sudden increase in thrust the Trike adopted a steep nose high attitude. Two or three seconds later the engine stopped. The Trike stalled, rolled to the right and began to sideslip. The pilot tried unsuccessfully to recover from the stall. The engine failed because of fuel starvation. A plastic fuel funnel extension was later discovered in the fuel tank. The funnel extension had blocked off the fuel outlet from the tank. The funnel extension was completely unfamiliar to pilot. It is probable that the funnel extension entered the tank during refuelling by a previous owner of the Trike. It is likely that the funnel extension had been present in the fuel tank for a considerable time. This accident was not the subject of a formal on-site investigation.