Circumstances:

During the flight over the Simpson Desert, the pilot realised that the ground features were difficult to relate to his map. Large areas were covered in flood waters which distorted the usual ground features. While still outside the 40 nautical mile rated coverage of the Birdsville Non-Directional Beacon.

The pilot was carrying out a period of circuit practice. After touchdown on the fourth circuit the aircraft commenced to porpoise. The pilot applied forward elevator in an attempt to control the aircraft. The aircraft subsequently touched down heavily on the nosewheel, causing the nosegear to collapse and the propeller to strike the runway. The pilot lacked recent experience, and had not considered going around when the aircraft began to porpoise.

One of the pilots was undergoing practice in engine failure emergencies at night. The helicopter was equipped with a "Nightsun" light, which was used to illuminate the ground below the aircraft. Fixed lights were also installed at the edges of the helipad. During the third practice autorotative descent, the Nightsun light was inadvertently extinguished when the aircraft was about 300 feet above the ground. It was turned on again by the time the aircraft had descended to about 100 feet, and the remainder of the descent and flare appeared to be normal. However, after touchdown the aircraft became airborne again, before touching down on the heels of the skids while moving slowly forward. The aircraft rocked forward and the main rotor severed the tail boom just forward of the tail rotor assembly. The surface of the helipad had been softened by recent rain ,allowing the heels of the skids to dig in slightly. This probably accentuated the rocking movement which led to main rotor blade contact with the tail boom. The type of manoeuvre being performed requires a high level of skill. Should a slight error of judgement occur, there is little opportunity for any corrective action to be successful.

Circumstances:

The pilot reported that when he selected the landing gear up after take-off, it remained down, and the three green lights remained illuminated. After checking the circuit breakers, several more attempts were made to retract the landing gear without success. During the subsequent landing, the landing gear collapsed, and the aircraft settled onto its underside. The only fault revealed during examination of the landing gear system was varying resistance in the right landing gear safety switch (the squat switch). This intermittent fault could have prevented the landing gear from retracting. The pilot reported that he conducted a smooth landing because of the nature of the problem. Despite that, it could have been sufficient to free the switch and allow the retraction cycle to begin as the oleos were compressed but before the safety switch was made. However, this could only have happened if the landing gear selector was in the up position.

Significant Factors:

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

1. There was varying resistance in the right landing gear safety switch causing intermittent operation.

2. The aircraft was landed with the landing gear selector in the up position.

The aircraft was carrying out a survey in a remote area. When last light occurred the aircraft was still some distance from the base camp. The pilot decided to follow a road into the camp. Enroute the engine lost power and an autorotational decent was carried out for a landing on the road. During the landing the left skid struck a low dirt bank and the tail rotor struck the dirt bank on the opposite of the road. Throughout the survey the pilot had used a higher than normal cruise power setting, but had not recalculated the endurance for the higher fuel usage. The engine failed after the fuel became exhausted.

The pilot was carrying out a check of the station windmills prior to commencing mustering operations. About 15 minutes after DEPARTURE he reported that an acrid smelling gas entered the cabin. He turned off the radios, the master switch and closed the cabin air vent and diverted to the nearest suitable strip. Enroute the acrid smell intensified and as the pilot was having trouble breathing he decided to land the aircraft in a nearby clearing. The throttle was closed in an endeavour to reduce the fumes but reapplied when this was not successful. However, the engine did not respond and the aircraft was landed short of the cleared area. During the landing roll the aircraft collided with trees. Following the last engine start the starter relay contacts remained closed due to internal corrosion, this resulted in the motor continuing to operate. The continuous operation of the starter produced enough heat to melt the non-standard engine earth strap at the attachment point to the firewall. Earth was then made through the tachometer cable and magneto switch leads, which overheated and burnt causing the magnetos to earth and the engine to subsequently fail.

The pilot hired the aircraft, a type he had not flown for four years, for a trip to what he believed to be an authorised landing area (ALA). However, he did not check the strip condition prior to DEPARTURE for the ALA. During the takeoff run at the ALA, the aircraft entered thick grass located to the left of a ten metre cleared area along the strip centreline. The acceleration of the aircraft was retarded and the pilot, realising that the aircraft would not accelerate to takeoff speed in the distance remaining, abandoned the takeoff. The aircraft stopped 64 metres beyond the end of the strip after colliding with two fence lines and a road shoulder.

The pilot reported that during the flare in preparation for a landing on runway 03, the aircraft was hit by a gust of wind. The aircraft touched down on the right mainwheel, which was bent backward, and the right wingtip contacted the ground. At the time the wind velocity was 330 degrees at 10 knots and the pilot had been unable to use the more into wind runway because it was unserviceable. He was also generally inexperienced on the aircraft type and in particular in operating the aircraft in crosswind conditions. This accident was not the subject of an on-site investigation.

The pilot had been advised by the property owner to land on a strip about two kilometres from the homestead instead of the usual strip. The available strip length was 1400 metres which was adequate for the operation. The pilot reported that when the aircraft became low during the later stages of the approach, he applied power, but realised that the main wheels would probably pass through tall grass near the threshold. Just prior to touchdown, the pilot heard and felt a loud bang. Immediately after touchdown, the aircraft adopted a left wing low attitude before the propeller blades of the left engine and left wing tip contacted the ground. The aircraft slewed through 90 degrees to the left and ran off the strip. The investigation revealed that when the landing gear was allowed to pass through the long grass in the undershoot area, it struck a concealed mound of earth, seven metres prior to the threshold. The impact caused the left oleo leg to become detached from the aircraft.

A group of pilots had travelled from a property strip to a nearby dam in order to complete training exercises on a float-equipped Bell 47 helicopter. VH-SRE was not fitted with floats but had been used to ferry some of the pilots to the area. At the conclusion of the training operation the pilot arranged to ferry VH-SRE back to the property strip. After take-off a practice autorotation was conducted over the dam and was followed by some unauthorised low flying in the vicinity. On arrival at the strip low level runs were performed along the strip with torque turns at each end. Control of the aircraft was lost during the third of these turns and the aircraft struck the ground in a steep nose-down attitude. Fire broke out on impact and engulfed the wreckage. The subsequent investigation did not reveal any evidence of a pre-impact defect or malfunction of the aircraft which might have contributed to the accident. Several of the pilots who observed the flight reported that the final manoeuvres performed were outside the normal operating parameters of the helicopter, and were conducted at an unsafe height above the ground. It was, however, not possible to establish which of the pilots was flying the aircraft at the time of the accident.