The aircraft was flying above an overcast cloud cover. Whilst tracking towards Leonora, the last NDB station fix was lost, and the pilot could not establish contact with Leonora NDB or any other stations to determine his position. The pilot was eventually able to fix his position and landed safely at Leonora. The pilot was not aware that the ADF equipment in the aircraft was not in good condition.

The pilot was landing the aircraft on an agricultural strip when the left hand spray boom became entangled in the oat crop growing on the edge of the strip. The pilot was unable to maintain directional control and the aircraft ground-looped off the strip.

The pilot of the outbound aircraft, VH-WJQ, reported that he had passed a single engined light aircraft which was tracking inbound at the same altitude of 7,500ft. The inbound aircraft, VH-PDF, just before the incident, was still on the area frequency and had not yet obtained a clearance into the control area. The Approach Radar Controller noticed a transponder return, indicating an aircraft inbound at 6,200ft.

There was no need to advise the pilot of the outbound aircraft as the indicated vertical separation was 1,300ft. When the inbound aircraft came onto the control frequency to ask for a clearance, it became apparent that this aircraft was also at 7,500ft. The controller realised that the transponder of VH-PDF was suspect and asked the pilot to switch the height mode off. The pilot of VH-PDF did not see the outbound aircraft.

VH-EXF which had been operating on a low-level training exercise was cleared by Darwin Approach for a visual approach and instructed to track to a left base for runway 36, and to contact the tower. The aircraft joined left base at about 800 feet AMSL and contacted the tower as instructed.

After completing prelanding checks the pilot became aware of another aircraft on a converging track at a similar attitude. The separation between the aircraft was about 200 metres horizontally and less than 100 feet vertically. The other aircraft, VH-AHX, had just become airborne from runway 18 and was making a right turn, as instructed, onto a heading 240 degrees and climbing to 1000 feet.

Two helicopters were engaged on frost prevention activities during the night. One helicopter was on the ground, its engine running with the pilot standing some distance away. The second helicopter was approaching to land to refuel. The pilot reported that he approached his selected landing point and entered the hover, facing east into the sun which had just risen. After touchdown, the main rotors of both helicopters collided and resulted in the destruction of both aircraft.

Significant Factors

1. The landing pilot misjudged the clearance between his rotor disc and that of the helicopter on the ground during landing.

2. Sun glare may have affected the landing pilot's vision.

VH-OGI, a Boeing 767, was tracking for left base runway 19 at Brisbane when the TCAS (Traffic Alert and Collision-avoidance System) alerted the crew of the presence of another aircraft. The Boeing 767 was on descent to 1,500ft and passing 2,000ft when the TCAS Traffic Alert indicated the unknown aircraft was 900ft below and ahead. The crew levelled the Boeing 767 and notified the Approach Controller who was monitoring the airspace by radar.

A short time later, the Boeing crew saw a high-winged light aircraft about half a mile left and indicating 600ft low on their TCAS which gave a TCAS Resolution Advisory at the same time. They took no further avoiding action because they had sighted the light aircraft in question. The area of the reported confliction consists of a control area step which commences at 1,000ft, with uncontrolled airspace below.

The applicable separation standard is 500ft vertically, and with the jet being cleared down to 1,500ft other traffic could be operating quite legitimately up to 1,000ft. This was the case in this instance. There was no breakdown in the separation standards. The incident was initially reported as a confliction due to the alleged penetration of the control area by the light aircraft. The Approach Controller at Brisbane did not have a height readout capability on his radar equipment. However, his colleague at Coolangatta does and was asked for an altitude readout on the light aircraft.

The Mode C label attached to the light aircraft read 1,600ft. Later, it became evident that this was incorrect. A system limitation is that when two aircraft are in close proximity, typically less than one nautical mile, the Mode C information from the two aircraft can be corrupted or switch altitude labels between aircraft. This apparently occurred on this occasion.

The TCAS operated effectively and within its parameters. The jet was in a descent, virtually pointing at the light aircraft at a lower altitude. The system could not predict that the crew were about to level off at an altitude which would have given an adequate separation from the lower traffic.

At about 40 kts during the take-off run the nose of the aircraft lifted off the runway and then sank, allowing the propeller to strike the runway. The aircraft skidded to a stop with the landing gear partly retracted. The pilot then noticed that the landing gear lever was in the "up" position. The pilot stated that he had not selected the landing gear up during the take-off run and was unsure of the lever position prior to commencing the take-off.

The pilot had been spraying a plantation of fully developed banana trees which had vertical irrigation sprinklers protruding about 1 m above the canopy. The next area to be treated was in a hollow and consisted of half-grown trees with the sprinkler heads protruding about 2.5 m. The pilot reported that as he attempted to arrest the rate of descent after flying down into the hollow, the left wing struck one of the sprinkler heads. The aircraft immediately rolled left and struck a number of other sprinklers. The pilot was unable to regain control, and the aircraft struck the ground. The engine was torn from the airframe and both wings separated during the impact sequence. The cockpit area remained largely intact. There was no fire.

The pilot reported that, before starting the engine, he completed a routine daily inspection and found no defects. Approximately three minutes after startup, as the engine was being accelerated for take-off, the pilot heard a loud noise and felt the aircraft start to vibrate. The throttle was closed and the engine shut down.

Inspection found that one of the stainless-steel abrasion strips from a tail rotor blade had delaminated causing a serious imbalance of the tail rotor drive system. The out of balance situation caused the tail rotor gearbox to separate from its mounting. The particle separator (airbox) was also damaged by the abnormal flexing of the tail rotor drive.