Circumstances:

The aircraft had taken off from runway 29R when, at a height of about 80 feet, the engine suffered a substantial loss of power. A forced landing was carried out onto a cleared area, beyond the end of the runway. The nose gear collapsed as the pilot attempted to ground loop the aircraft to avoid fences. Investigation revealed a non-standard fuel strainer drain had been fitted in the fuel supply system between the fuel tank and the engine driven pump. Stress corrosion cracking caused failure of the strainer drain adapter fitting and allowed fuel to leak from the engine fuel supply. The diminished fuel supply was insufficient for the engine to maintain power.

Significant Factors:

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

1. Unauthorised modification of the fuel strainer drain system.

2. Stress corrosion failure of the fuel strainer drain adapter fitting.

3. Insufficient fuel supply to the engine to maintain power.

The pilot contacted Cairns Tower at 30 miles DME (Distance Measuring Equipment) inbound on the 153 radial (south-south-east of Cairns), and was subsequently cleared to make a visual approach at 2053 hours. At 2054 hours the pilot was given clearance to land on runway 15, and at 2056 hours he reported that he was making a missed approach because he had lost visual contact with the runway. The aircraft was given instructions to make a standard missed approach, and to intercept the localiser via the 15 DME arc (15 miles north of Cairns) for an ILS (Instrument Landing System) approach. At 2104 hours the pilot reported that he was "having a little trouble" and would like to go around again and make another approach from the 18 DME arc (18 miles north of Cairns). After subsequently being cleared for final approach on the ILS, the pilot then reported that he was "having trouble with radio aids" and would like to climb to 7000 feet. The aircraft was later cleared for a further instrument approach and landed at 2131 hours. The next day, checks with the company revealed that no aircraft unserviceabilities had been reported by the pilot and that the aerodrome ground radio aids were all functioning normally during the arrival of VH-TAI. No report had been made to the company by the pilot concerning any irregularities during the flight. A readout of the Flight Data Recorder was carried out to ascertain the track and altitude profile of the aircraft during the approaches at Cairns. This revealed certain irregularities including a Ground Proximity Warning "Pull Up" signal which operated for between 6 and 10 seconds at 2055 hours. This device is to warn the pilot when the aircraft is in danger of collision with terrain. The warning is considered to have been genuine as the terrain closure rate at this time was in excess of 6100 feet per minute, and the aircraft was in the vicinity of Earl Hill which is 722 feet above sea level. The weather at the time was overcast but fine at the aerodrome. There were rain showers in the area, and visibility was reduced to 4000 metres in rain showers. The two preceding aircraft had been able to make visual approaches. The crew declined to make themselves available to the investigators for interview, apparently under direction from their industrial association. This action by the crew hampered the investigation and resulted in the causal factors of the occurrence not being determined.

The pilot was operating on a Search and Rescue watch manned from the homestead. When the aircraft did not arrive by the appointed hour, the owner of the station conducted an aerial search and found the pilot by the disabled aircraft. The pilot reported that he was attempting to land beside the portable cattle yards when he backed off to avoid the dust clouds thrown up by the main rotor. In doing so, the tail rotor struck a tree obscured by the dust. An immediate landing was initiated but a heavy touchdown resulted. The tail rotor blades separated from the aircraft before the engine was stopped and the tailboom and skids were twisted from the impact with the ground.

The pilot carried out a normal circuit at his destination and obtained a gear green indication. A visual check in the engine cowl mirror also showed the nose gear to be in the fully extended position. The pilot also recalled seeing three greens on his gear check on final approach. Following a normal touchdown, the nose gear collapsed and the aircraft slid to a stop on the runway. The aircraft was subject to an identical occurrence at Kimba on 16 June 1988. The hydraulic power pack was found to be in a poor condition at overhaul. The poppet-valves and check-valves were worn. The nose gear is held in the down position by hydraulic pressure and by an over-centre lock. When the gear selector is placed in the gear down position, the down line is pressurized and the gear extends. When the pressure in the down line reaches system pressure the gear selector lever automatically returns to neutral and forms a hydraulic lock in the down line. However, with the worn valves in the power pack this pressure bled away leaving only the over-centre feature to hold the nose gear in the extended position. The Kimba strip has a rough surface. It is believed that the rough surface caused the over-centre mechanism to become unlocked and since the hydraulic pressure had bled away, the nose gear collapsed.

Circumstances:

The pilot was conducting spraying operations over a millet crop which was approximately 1.5 metres high. Towards the end of the spray run, the aircraft flew under two wires which were about 5.6 metres above the ground. Weather conditions were ideal with high overcast cloud and a light southerly wind. On the second spray run, the aircraft struck the powerlines. The aircraft's wire deflector cable was broken, and the wires then struck the vertical fin, one 50 millimetres from the top and the second 150 millimetres from the top. The wires then tore the tail fin off the aircraft, leaving the rudder trailing by its control cables. The aircraft was seen to pull up abruptly to a height of approximately 150 feet, turn left and head toward open paddocks one kilometre away. Shortly after, it descended rapidly into a crop about 300 metres short of open paddocks, coming to rest 19 metres from initial impact. Engineering examinations found that the elevators had been fouled by the trailing rudder. It is probable that the pilot experienced difficulties with elevator control, resulting in loss of control of the aircraft.

Significant Factors:

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

1. There was insufficient clearance between the crop and the powerline for the aircraft to safely fly under.

2. The aircraft struck the wires which resulted in the rudder trailing by its control cables.

3. The trailing rudder interfered with elevator control, probably causing the pilot to lose control.

Circumstances:

The aircraft was loaded with approximately 80 litres of fuel and 220 litres of spray. The pilot had intended to taxi to the far end of the 570 metre long paddock in order to take-off into wind but at the last moment he noted that the wind was very light. He elected to take-off from his current position with a rear quartering wind. Full power was applied and the aircraft accelerated normally. Approximately 50 to 100 metres from the boundary fence the pilot rotated but the aircraft failed to become airborne. He commenced to dump the load, but the aircraft remained on the ground. The aircraft then ran through the boundary fence and collided with a small embankment collapsing the main gear. The pilot then noticed that the wind strength had increased to approximately eight knots which increased the tailwind component. A performance analysis estimated that under the prevailing conditions reported by the pilot the aircraft required 500 metres for take-off. Although it was possible for the aircraft to take-off in the available paddock length it is obvious that a small error in estimated wind velocity or paddock slope would have increased the take-off run to more than was available. It is likely that this was the case. This accident was not the subject of a formal on-scene investigation.

Significant Factors:

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

1. The take-off was made with a tailwind stronger than that estimated by the pilot.
2. The take-off distance available was insufficient for the planned operation.

Circumstances:

The student was authorised to conduct solo circuit practice in generally light easterly wind conditions. During the session, the wind began to swing through more than 90 degrees, with associated strong gusts. In the landing flare on the circuit prior to the accident, a wind gust lifted the left wing and rolled the aircraft to the right. Experiencing considerable difficulty, the student regained control and climbed the aircraft for another circuit. Being unsettled, the student forgot that he could seek advice from his instructor through Perth Flight Service. He elected to terminate the session with his next landing. Again, as the student flared the aircraft for landing, a strong gust lifted the left wing, rolling the aircraft to the right. Before he could correct the roll, a second gust struck the aircraft. Despite recovery efforts the student realised he was losing control and attempted to go-around. The aircraft with a bank angle of 50 degrees, stalled and contacted the ground right wing tip first, coming to rest 95 metres from the runway centre line.

Circumstances:

On completion of temporary repairs following a forced landing accident in a paddock, a permit to fly was issued authorising a ferry flight from the accident site to a nearby strip. During the take-off roll the pilot was unable to maintain directional control and the aircraft crossed a drain before striking a fence and overturning. An inspection of the aircraft did not reveal any defect which could have contributed to the loss of directional control. Following the landing accident the property owner had rotary-hoed the paddock to a depth of 10 centimetres. Using a motor vehicle, the pilot compacted a 2.5-metre-wide strip along the centreline of the paddock, which sloped approximately 3 degrees down to the north. At the time of the take-off to the north the wind was from the north-east at 5 knots. The pilot selected a take-off power setting of 53 percent of the maximum power available which effectively increased the take-off ground roll required by approximately 170 metres. The investigation revealed that after a 50-metre ground roll the left main wheel entered the rotary-hoed area. The aircraft then veered further to the left before striking the fence and overturning.

Significant Factors:

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

1. The strip width was inadequate for the safe operation of the aircraft.

2. The pilot did not maintain directional control during the take-off.

3. The pilot delayed abandoning the take-off.

The pilot reported that he was delivering the aircraft to the new owner. The normal strip at the property was unserviceable so the use of another strip had been arranged. No mention was made by the owner of a powerline crossing near the end of the strip. The aircraft struck the powerline on late final approach and fell to the ground tail first. This accident was not the subject of an on-site investigation.

This was to be the first trip away for the pilot since having the area restriction lifted from his Private Pilot Licence. He obtained an area weather forecast which included predicted winds of 35 knots, scattered stratus cloud, base 1000/2500 in showers, visibility reduced to six kilometres in showers, with turbulence moderate and occasionally severe. A Visual Flight Rules plan was submitted for a flight from Romsey to Ararat and return. The aircraft later departed and the flight to Ararat was completed satisfactorily. After several hours on the ground the pilot departed on the return leg, deciding that he would call at Ballarat for fuel. Melbourne Flight Service passed him details of the amended area forecast which included details similar to the forecast earlier received and included advice that there would be widespread moderate turbulence and occasional severe turbulence. The Ballarat Terminal Area Forecast was also passed and this gave a surface wind from 290 degrees at 15-35 knots. After landing at Ballarat and obtaining fuel the pilot departed for Romsey. There was moderate turbulence enroute and this became noticeably worse near Mt Macedon and continued for the remainder of the flight. On overflying the airfield the pilot estimated the wind was a south-westerly to westerly and the strength varied from 20-30 knots. He elected to approach for strip 21 but on the landing flare found the crosswind was too strong and made a go-around. The pilot then decided to make an approach for strip 33, intending that if the crosswind was too strong he would divert to Melton. Again on the landing flare the crosswind was too strong and he applied full throttle for a go- around. It appeared to the pilot that the aircraft was not climbing as well as on the first go around; he reduced the flap setting from two stages to one stage and lowered the nose to try and gain airspeed. The aircraft descended and drifted well right of the strip, striking a small tree abeam of the upwind end of the strip. The right wing was dislodged by the tree impact, the aircraft then fell to the ground. Inspection of the aircraft did not reveal any evidence of pre-existing defects which might have contributed to the accident. The engine had continued operating up to the time of the accident. An analysis of weather data was made by the Bureau of Meteorology. This indicated a surface wind from 290 degrees at 15-20 knots with possible gusts to 40 knots. Also, moderate/severe turbulence, windshear, possible downdrafts and a high probability of rotor turbulence associated with the strong low level westerly flow over Mt Macedon to the west of the airstrip. It was not possible to state with certainty the reason for the poor climb performance on the second go-around but the most likely explanation was an encounter with severe weather conditions and windshear.