Circumstances:

The Facet Opal ultralight aircraft was of a tailless, flying wing design. This unique aircraft was designed, constructed, and operated under the provisions of Civil Aviation Orders, Part 95, Section 95.10. The aircraft arrived in the Lake Munmorah area after completion of the 300 nm flight at an average ground speed of about 100 knots. Upon arrival, the aircraft was observed to circle near Norahville and Lake Munmorah to alert relatives of the pilot's arrival. The aircraft took up a SW heading near Doyalson at the completion of the orbit. Witnesses reported sighting the aircraft at about 300 ft agl and travelling at about 100 kts. As the aircraft approached the Pacific Highway from the NE, it was observed to enter a level turn to the left. The angle of bank was estimated to be 20`-30` Almost immediately after the turn was commenced, the aircraft broke into three major sections as a result of structural failure. The wing, which broke into two parts at the centre section, tumbled to earth on a property on the E side of the highway. The cockpit and engine trajectories carried them over the highway, some 200 m beyond the wing ground impact points. The pilot received fatal injuries. One witness reported the aircraft's wing had flapped 'like the wings of a bird' immediately before the in-flight break-up. Weather conditions at the time were reported as overcast at 1500 ft, wind light and variable and visibility in excess of 10 km in fine drizzle. The conditions were suitable for flight under visual flight rules and not conducive to the formation of significant turbulence. It is therefore highly improbable that weather conditions were a factor in this accident. An examination of the wreckage revealed the main carry-through spar had failed in overload from an upward bending force. No evidence was found of any fault in manufacture or of pre-existing deterioration to the spar structure. The aircraft was designed and manufactured for an ultimate strength of approximately 8g+. A level turn of 20`-30` angle of bank would normally apply a loading of 1.06 to 1.16g. The wing was capable of producing aerodynamic loads in excess of 6g at an estimated cruising speed of 100 kts. The witness evidence concerning the flapping of the wings is consistent with the aircraft having entered an oscillating manoeuvre in pitch. Wing loads capable of causing structural failure could be generated in such a manoeuvre. The evidence indicated the aircraft entered an uncontrollable oscillating pitch manoeuvre during which the aerodynamic loads exceeded the structural strength of the wing. The reason(s) for the onset of such a manoeuvre, and the inability of the pilot to minimise the effects of the oscillation, could not be positively established. However, it is recognised that an aircraft with a tailless flying wing configuration that incorporates no sweepback has little damping in pitch and is therefore susceptible to overcontrolling in pitch.

Significant Factors:

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

1. For reasons undetermined, the aircraft oscillated severely in pitch.

2. The severity of the oscillation resulted in a structural failure of the main spar of the wing.

3. The pilot encountered circumstances beyond his control.

Circumstances:

Whilst conducting mustering operations at low speed and altitude over trees, the engine began to run rough. The helicopter was unable to sustain continued flight and the pilot elected to land. During the landing, the rotor blades struck trees and the helicopter landed heavily coming to rest on its side. The pilot was able to crawl to safety after switching the magnetos off, but he was unable to reach the fuel mixture control. The engine subsequently oversped to destruction. The investigations found that the left magneto had suffered an internal failure. The bush supporting the distributor rotor gear had become loose in its housing, allowing the rotor to become mis-timed. During the impact sequence, the magneto earthing wires were fractured which allowed the engine to continue to run despite the pilot switching off the magnetos.

Significant Factors:

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

1. Failure of distributor rotor block bush.

2. Mistiming of one magneto.

3. Forced landing in unsuitable terrain.

As the first student parachutist climbed out on the wheel strut for his parachute descent his main chute deployed prematurely. The parachute risers became entangled with the horizontal stabiliser causing increased drag damage to the stabiliser and a locked elevator. The entangled student and the other student and instructor safely evacuated the aircraft by parachute. The pilot who was also prepared to evacuate the aircraft carried out a series of handling checks and was able to establish a means of controlling the aircraft. He was able to land the aircraft safely on a salt lake with the parachute still attached. The parachutist was using a type of equipment which only requires a 10lb pull to activate the pilot chute. The static line to the pilot chute is tucked under an elastic band to prevent it trailing in the slip stream. If the line becomes loose from the band the slipstream can deploy the pilot chute which in turn will deploy the main chute. The instructor did not see the line work loose but it is probable that this is what occurred. This accident was not the subject of an on-scene investigation.

The pilot was conducting a local flight in the training area. He reported that while in cruise at 3500 feet above sea level, the oil pressure and RPM dropped. He carried out a trouble check but was unable to restore power. He carried out emergency landing procedures. During the landing, with a tailwind component, and only 10 degree flap selected, the aircraft overran the intended touchdown area, struck a fence and the nose gear folded under. The aircraft came to rest at the edge of a swamp. No fault was found with the engine. It was suspected that the loss of power was due to carburettor icing.

Circumstances:

Shortly after the aircraft departed the television station helipad, the pilot became concerned about a decay in the power available. He carried out a precautionary landing on a suburban road adjacent to, but on the opposite side of a fence from the helipad. One of the two passengers disembarked, and the pilot carried out a power check which appeared normal. The pilot elected to reposition the helicopter back on to the helipad. Shortly after lift off the power again decayed, and the pilot attempted a precautionary landing back onto the road. The main rotor blades made contact with the tail boom during the second landing. Although some minor faults were found in the engine fuel system none of them were significant enough to cause the loss of power reported by the pilot. No other faults were found which may have contributed to the accident. The reason for the loss of power was not determined. The pilot's decision to attempt a return to the pad was influenced by the apparently normal power check, following the first landing, and his concern about the possibility of a vehicle/aircraft collision if the aircraft remained on what was a major access road with visibility restricted by a curve.

Significant Factors:

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

1. An undetermined problem within the engine system caused a loss of power during a critical stage of the take-off.

2. The pilot's decision to attempt a second take-off with a suspect engine led to the aircraft reaching a position from where a successful forced landing could not be achieved. The pilot made his decision based on the facts that were available to him at the time. A more prudent decision might have been to arrange for roadblocks to be put in place as soon as possible and wait for an engineer to inspect the aircraft.

Circumstances:

The pilot was expecting to make an early morning DEPARTURE but was confronted with adverse weather conditions and low cloud. He was advised by another pilot that these conditions were expected to improve later that morning, but he decided to depart immediately and assess the weather as the flight proceeded. After flying in a westerly direction for several minutes it became obvious to the pilot that visual flight could not be maintained, so he elected to return for a landing. Re-entering the circuit area the low cloud and poor visibility required the flight to continue close to the ground, and the pilot misjudged the turn onto final. He abandoned the landing and joined a low left hand circuit for the reciprocal runway. While turning onto a close final leg, the left hand wing contacted a six metre high telephone wire located across the approach path approximately 300 metres from the runway threshold, causing the aircraft to lurch violently to the left and impact the ground heavily.

Significant Factors:

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

1. The flight was initiated and continued in adverse weather conditions. This accident was not the subject of an on-scene investigation.

The pilot was to conduct a charter with passengers from Sydney to Wollongong, Nowra, Canberra and return to Sydney, departing Sydney at about 10.00am. Earlier that morning he positioned the aircraft at Sydney and had it refuelled. When the passengers arrived he explained that the weather in the various destinations was very poor and that there was a possibility they may not be able to land. However, he was prepared to give it a try. As the passengers were pressed for time, they could not afford to take a chance with the weather and so they decided to drive. They told the pilot that if he could land at Wollongong later that day they would continue the flight with him. However, they impressed on him that there was no pressure for him to depart immediately as they would not be in Wollongong for several hours. After driving for a short time, the passengers decided that the weather did not appear as if it would improve, and believed that it would be better to complete the journey by car. They contacted the charter company by phone to cancel the charter, but the pilot had already departed. The flight to Wollongong appears to have proceeded normally where the pilot reported commencing an NDB approach, and would call again at a specified time. This was the last message received from the pilot. Witnesses on the ground at Wollongong, and on a yacht 20 nautical miles to the east of Wollongong reported hearing an aircraft flying at approximately 1000 to 2000 feet in the low cloud and rain. There were no other known aircraft in the area. Later that day a helicopter discovered wreckage debris in the sea, which was confirmed as being from the aircraft. The search was discontinued due to very poor weather and visibility, and cancelled two weeks later when further efforts failed to locate any trace of the aircraft.

Circumstances:

The pilot reported that following a normal landing, as the aircraft turned left onto the taxiway, the right main landing gear collapsed. Subsequent inspection revealed the right main down lock bell crank pivot bolt had failed in shear, and the forward pivot lug had failed in bending overload. This is consistent with what would be likely to result from excessive down lock tension. After repairs had been effected, an engineering report determined that the down lock tension was significantly higher than specification. However, the engineering report was not conclusive as the original components could not be used for testing.

Significant Factors:

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

1. Probable misrigging of the right main gear down lock. This accident was not the subject of an on-scene investigation.

The aircraft struck a bird while cruising at 1500 feet. The bird shattered the windscreen and struck the occupants of the aircraft before coming to rest in the rear of the cabin area. The pilot reported that loss of the windscreen reduced aircraft performance to the extent that, while flying at about 1000 feet with cruise power set, the indicated airspeed was 65 knots compared to the normal 90 knots. The bird was later identified as a wedge tailed eagle. It had a wingspan of almost two metres.

The aircraft is a prototype designed for long distance and altitude record attempts. The pilot reported that after touchdown the nosegear retracted and this also resulted in the maingear collapsing. The gear collapse resulted from undetected stiffness in the nosegear downlock mechanism. A number of modifications to the system are to be incorporated.