The touchdown was reported as being smooth but during the landing roll, just after braking was commenced, the right mainwheel and strut came free of the aircraft. The strut bounced and struck the right horizontal stabiliser, severing a large section of it. The aircraft slewed to the right before running off the strip into trees. Inspection of the aircraft revealed that the bolt holding the landing gear strut to the inboard gear mounting assembly had failed. The failure resulted from fatigue, believed to have been initiated by a heavy loading applied to the bolt some time previously.

Circumstances:

The pilot was tasked to lift bundles of steel rods about 100 metres to the top of a small knoll. He briefed a fellow fixed wing pilot on hooking procedures and, as no lifting devices were available at Yalara, instructed him to wrap the load's chain twice around the hook to form a loop and prevent the load from slipping. The accident occurred on the second flight to the knoll. As the helicopter began to move forward, a partial power failure was experienced. The front of the load then dug into the ground and the rear swung up until it struck the tail rotor. The helicopter began to rotate to the left followed by a left roll. The pilot rapidly applied full right cyclic to level the helicopter before it struck the ground. During the sequence, the pilot attempted to release the load three or four times using the electric release button. He then reached for the manual release handle but was unable to operate it before the helicopter struck the ground. The helicopter had a history of recent, unreported engine chip detector warning light illuminations which included at least one precautionary landing. It also had a history of high engine oil consumption which was supported by the high level of sooting on the exhaust stacks. The absence of engine oil in the oil tank and the pilot's reported grinding feeling through the airframe indicate a malfunction with the engine. A specific reason for the power failure could not be determined, although the fuel system was found to be in a very poor condition and a section of the drive spline for the power turbine governor was missing.

Significant Factors:

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

1. The helicopter had a history of unreported engine chip detector light warnings and high engine oil consumption.

2. The pilot was tasked to conduct a hook operation without the correct equipment being supplied.

3. The helicopter suffered a partial power failure.

4. The load support chain jammed in the hook, and the load could not be released.

5. The helicopter's tail rotor struck the load, and the helicopter struck the ground heavily.

When the pilot was about 600 feet above the ground he realized that he was committed to an outlanding. He noted that the selected paddock had one set of powerlines parallelling his intended landing direction. On short final at about 100 feet above ground level the pilot saw a second powerline obliquely crossing the intended landing path. He turned right and carried out a landing in another paddock. The glider landed downwind and the pilot initiated a groundloop in an attempt to avoid a collision with a fence. The manoeuvre was not successful and the glider came to rest straddling the fence. The pilot had evidently delayed his planning for an outlanding until the glider was substantially below the minimum height of 2000 feet recommended by the Gliding Federation.

The helicopter was operating just above trees with little forward speed when the engine gradually lost power. The pilot was forced to attempt to land in an area covered with small trees. The engine stopped after the main rotor blades struck foliage and the helicopter fell heavily on its skids, which collapsed. The helicopter subsequently caught fire and was burnt out. Examination of the engine discovered that the number two big-end bearing had failed. It was also noted that the engine was internally damaged by pre-crash overheating and scoring. The reason for this damage could not be determined.

The pilot attached his harness hangloops to the retaining strap instead of the keel tube. During a tight turn after takeoff the retaining strap parted due overload and the pilot plummeted onto rocks from approximately 200 feet altitude. The pilotless hang-glider flew into a tree. The retaining strap is a non structural part of the hang-glider designed to stop the hangloops sliding back along the keel tube.

The pilot stated that he rounded out too low, touched down too fast, and the aircraft bounced slightly. He attempted to correct with back pressure on the control column, together with increased nose up elevator trim. The aircraft appeared to climb and the pilot eased the back pressure. The nose dropped, the aircraft touched down again in a flat attitude, and porpoising commenced. After three oscillations the nose gear moved rearwards and upwards, shattering the windscreen, and causing the propellers to contact the runway surface. Investigation revealed that there was an intermittent fault in the elevator trim switch, which caused the trim to move only in a forward direction, irrespective of the selection made by the pilot.

Circumstances:

The pilot had been spreading Graslan, a herbicide, about five kilometres from an agricultural airstrip. The aircraft was being flown back to the strip at about 300 feet above ground level when suddenly, the engine developed a severe vibration. The pilot diagnosed a propeller blade failure and shut the engine down before it shook itself out of its mounts. The pilot chose the clearest area available for the forced landing, a sloping paddock covered in windrows consisting of recently bulldozed trees. The aircraft encountered one such heap of timber during its 60-metre ground roll. Post flight inspection found a 21-centimetre tip missing off one of the two propeller blades. Specialist metallurgical examination of the fracture surface indicated that the loss of the propeller tip was due to metal fatigue. The fatigue failure was initiated from an improperly blended mark caused by previous foreign object damage.

Significant Factors:

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

1. Fatigue fracture of propeller blade.

2. Improper maintenance by maintenance personnel.

3. Forced landing on unsuitable terrain.

About ten minutes into the helimustering flight, the engine stopped with a loud bang. A downwind autorotational approach from a low altitude was attempted. The pilot used most of the rotor's energy in stretching the glide to a small, natural clearing. The helicopter then fell from tree top height (about 30 feet) onto rocky, sloping ground. It rolled over and slid several metres down the 14 degree slope. The No 1 connecting rod had failed and breached the engine crankcase. The connecting rod had failed from fatigue initiated overload. The fatigue was initiated from a galling spot on the inside of the big-end which occurred as a result of the relaxation of the bearing nip. It is probable that the relaxation of the bearing nip was caused by repeated engine overspeeds.

Circumstances:

About twelve minutes after departure and while cruising at 1200 feet above the ground the engine speed reduced from 5200 to 2000 rpm. This was accompanied by a mechanical knocking noise and severe vibration. The pilot immediately shut down the engine down to prevent possible damage. He carried out an emergency landing into the most favourable area within gliding distance. On touchdown the aircraft decelerated rapidly nosed over and came to rest inverted. It was not apparent from the air that the grass in the paddock was about half a metre high. The crankshaft had fractured at the centre pin between the bearing and the helical gear. The fracture was caused by fatigue attributed to extensive cracking. It was not possible to determine if the cracking had been present since manufacture or initiated from a propeller strike event some 60 hours prior to the failure when the engine was installed in a different aircraft. No logbooks are required for this type of engine hence the complete history of the engine could not be determined. 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. Engine crankshaft failed due to fatigue.

2. Long vegetation in emergency landing field.

Recommendations:

It is recommended that the Civil Aviation Authority consider a requirement for airframe and engine logbooks for this category of aircraft particularly those with the potential for commercial operations such as flying training.

The purpose of the flight was to convey the three passengers to Casino for business. Prior to departing Scone the pilot telephoned Sydney Operational Control Centre Briefing Office and submitted a flight plan which indicated that the flight would be conducted in accordance with Visual Flight Rules (VFR) and proceed via Upper Bowman and Taree at 7000 feet above mean sea level (amsl) to Port Macquarie and then Casino.

The pilot also indicated when submitting the flight plan that no radio navigation aids were fitted to the aircraft. The pilot then received a briefing on the weather conditions that could be expected along the route to be flown. The winds were given as generally southerly at about twenty knots with the cloud as scattered stratus between 1000 and 2500 feet and areas of broken strato-cumulus between 2000 and 6000 feet amsl. At 0740 hours the pilot advised Sydney Flight Service (FS), by radio, that the aircraft had departed Scone at 0733 and was climbing to 7000 feet. At 0809 the pilot reported the aircraft's position at Upper Bowman, cruising at 7000 feet and estimating Taree at 0829. Twelve minutes later the pilot of another aircraft also bound for Taree contacted VH-UDX and asked the pilot to confirm the aircraft altitude as 7000 feet. The pilot of VH-UDX replied that his aircraft was at 6500 feet on descent to 5000 feet and that he had run into a bit of "murk". When questioned further by the other pilot and Sydney FS the pilot reported VH-UDX was at 6000 feet in cloud and requested the visibility at lower altitudes. The pilot was advised that the cloud base at Williamtown was 3000 feet and he then reported that he intended to back track to Scone. The pilot was then requested to activate the transponder fitted to the aircraft and VH-UDX was subsequently identified by radar 18 nautical miles south-west of Taree at 0828 hours. The pilot was advised of this position and reported his heading, which indicated the aircraft was tracking towards Scone. During the next few minutes Sydney FS obtained information from the pilot relating to fuel endurance; estimate for Scone; altitude and cloud conditions.

The last communication received from the aircraft was at 0838 when the pilot acknowledged an instruction to call Williamtown Approach (for radar assistance). Further communication attempts were unsuccessful. At about 0840, residents of Gloucester heard the sound of an aircraft engine, apparently at high power, moving from the west to the north of the town. They could not see the aircraft. At the time there was dense cloud overhead, base about 800 feet above ground level (elevation 350 feet amsl), with drizzle. The aircraft appeared suddenly, descending steeply from the base of the cloud. The nose rose momentarily then the left mainplane folded back against the fuselage, separated and dropped away. The empennage separated from the fuselage. The fuselage with the right wing attached struck the ground in a park on the western edge of the town. The left wing, empennage and some other debris landed several hundred metres to the north east of the main wreckage.

Subsequent investigation did not reveal any pre-existing fault with the aircraft that could have contributed to the accident. The weather conditions that were encountered by the pilot were substantially as forecast and relayed to the pilot during the pre-flight briefing.