Circumstances:

The pilot reported that he was approaching to land in a clear area when the right skid struck an ant bed. The aircraft rolled and impacted the ground on its right side. The ant bed was partially hidden by long grass.

The purpose of the flight was to show the passenger the characteristics of a tailwheel aircraft. After a normal approach and touchdown the aircraft was observed to go-around and fly level at a low height above the runway. The aircraft was then seen to climb steeply, stall, and to impact the ground in a steep nose down attitude whilst rotating to the right. No fault was found with the aircraft that could have contributed to the accident. The pilot was inexperienced on the aircraft type and did not maintain adequate flying speed when manoeuvring the aircraft after take-off.

Circumstances:

The pilot reported that the helicopter was descending through 200 feet on approach to land in a clear area surrounded by trees 15-20 metres tall. Airspeed was 15-20 knots, engine power setting was about 15 inches Manifold Pressure, and the approach was being flown into a north-westerly wind of 5-10 knots. Without warning, as a result of what the pilot thought was a sudden wind change, the helicopter yawed slightly right and began to sink rapidly. The pilot noticed that the airspeed was indicating zero. The pilot managed to avoid the trees but could not prevent the helicopter landing heavily, damaging the main rotor blades and gearbox.

Circumstances:

The pilot stated that whilst aerial mustering he attempted to push a beast out from under a bush. The beast ran out from under the bush but headed away from the main mob. The pilot was attempting to turn the beast back towards the mob, when his passenger warned him of a power line which was in close proximity to the aircraft. The pilot stated that he flared the aircraft abruptly to try and avoid the power line, but the aircraft then began to sink, and the main rotor struck the power line. The aircraft then struck the ground heavily after falling about 30 feet.

The pilot decided to divert to a nearby aerodrome because the fuel gauges indicated a low fuel quantity remaining. Shortly after commencing the diversion the engine failed. During the ensuing forced landing the aircraft struck a fence post, overturned, and slid inverted for 120 metres. The engine had failed from fuel exhaustion. During the flight, which involved 3 landings, one refuelling and about 6 hours flight time, the pilot had not conducted a check of the aircraft fuel consumption. Although the fuel gauges indicated a higher than normal rate of consumption, the pilot did not land at suitable enroute aerodromes and the diversion was not made until a critical situation had developed. Subsequent examination of the engine and fuel system did not establish the cause of the excessive fuel consumption.

Circumstances:

The helicopter was being used to muster cattle from a paddock to a lane. One animal had stopped, and the pilot manoeuvred the helicopter towards this animal. This required a down-wind hover in gusty wind conditions and a high air temperature. The paddock was open, and the pilot did not consider it was a difficult operation. As the helicopter approached the animal, the pilot realised he had applied full anti-torque pedal and was over-pitching the main rotor. He lowered the collective pitch control, but the tail hit a dead tree, the tail rotor blades separated and then the main rotor blades struck the tree. The helicopter landed heavily, bending the skids. The pilot's acknowledged flying rate was high prior to the accident. This flying was mainly on cattle mustering operations in hot, dusty conditions. Such operational conditions, combined with the flying rate and the concentration and skill required, may have resulted in skill fatigue, which is characterised by insidious lapses in performance and judgement. At the same time, the pilot, considering the final muster to be relatively easy, might have become complacent and failed to give full concentration to the job.

Significant Factors:

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

1. Possible pilot skill fatigue due to a combination of hours flown and difficult operational conditions.

2. Possible complacency due to a perceived easy final muster.

3. The pilot overpitched the main rotor while operating down-wind in hot and gusty conditions.

Circumstances:

The pilot had positioned at Tindal from Victoria River Downs and embarked eight passengers for Delamere. On arrival at Delamere, the nose gear would not extend. Despite all attempts to extend the gear, the landing gear position indicator continued to indicate an unsafe position for the nose gear. The pilot elected to return for a landing at Tindal. A flypast of the tower revealed that the main gear wheels and nose gear doors were extended but the nose gear was still fully retracted. The pilot decided to land with the gear in that configuration. A successful landing was carried out and the runway under the aircraft was foamed when the aeroplane came to rest. A subsequent inspection revealed that the front right-hand nose gear door was installed incorrectly. This door had been installed in a position one hinge serration rearward of its correct position. That door then fouled the rear right-hand nose gear door which in turn prevented the nose gear leg from extending. On removal of the front right-hand nose gear door, the nose gear leg fell free and locked into the DOWN position. The aircraft logbook showed no entry for the removal and replacement of the nose gear door, but the aircraft showed evidence of having been recently repainted.

Significant Factors:

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

1. Incorrect installation of the front right-hand nose gear door.

2. A fouling of the nose gear doors prevented the nose gear leg from extending.

3. Inadequate supervision of maintenance.

The aircraft departed Sydney on 8 August 1987, with the pilot and eight French tourists, for a twelve day Air Safari. The trip was uneventful until about 35 km west of Mt Isa, when the left engine failed during the descent. The pilot did not attempt to lower the landing gear and flap until the aircraft was on final approach. However, the landing gear did not extend. A go-around was carried out and on the subsequent circuit the pilot attempted to release the hydraulic hand pump so that he could manually pump the gear down. He was unable to release the handle. This fact, combined with an indication of rising temperatures on the operating engine necessitated a reduction in power on that engine, with a resultant loss of aircraft performance. The pilot then decided to carry out a "wheels-up landing" on the grassed area adjacent to the main runway. During the approach and landing the cowl flaps on the operating engine remained closed. An inspection of the aircraft revealed that the engine failed due to the separation of the induction system when the number 3 cylinder hold down bolts broke. These bolts failed as a result of fatigue probably as a result of the studs either not being torqued correctly at installation or becoming loose in service. The landing gear failed to extend by the normal method due to too low a hydraulic pressure possibly caused by low fluid level in the reservoir. It was found that the hydraulic hand pump handle required a two-handed effort to release it. This was due to it being clogged with dirt and old grease.

Circumstances:

The pilot had engaged in gliding activities for more than thirty years. These activities were interrupted in December 1987 when he underwent coronary by-pass surgery. On receipt of a medical clearance from his coronary specialist, the pilot resumed flying gliders in February 1989. He had since accumulated 31 flights of which 18 were solo. On the day of the accident, the pilot arrived at the airstrip at about 0930 hours and during the day assisted with glider launch and recovery operations. Late in the afternoon the pilot was authorised by the duty officer for a solo flight. After a winch launch in a northerly direction in light wind conditions, the glider was observed to perform several steep turns before positioning for a right hand downwind leg for a landing in a northerly direction. The pilot reported his position by radio on the downwind leg in accordance with the gliding club's standard procedures. The flight was witnessed by numerous club members who were generally located at the southern end of the airstrip. They reported the approach appeared normal until the glider was established on base leg. The turn onto the final approach was delayed such that the glider lined up on the western side of the strip which is reserved for winch launches. Soon after, when the glider was at an altitude of about 150 feet above ground level, it commenced a turn to the left. The glider levelled out on a south-westerly heading and then entered a climb, from which it apparently stalled, and dived from view behind trees. The wreckage was found in timbered country about one kilometre from the southern end of the gliding strip. The wreckage distribution suggested the glider had rolled inverted and dived near vertically into the ground. A technical examination revealed no evidence of any pre-existing fault or defect. The manoeuvres following the turn onto final approach were consistent with the pilot being incapacitated. The autopsy revealed the pilot had suffered a heart attack.

Significant Factors:

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

1. The pilot was incapacitated when he suffered a heart attack.

2. Loss of control in flight due to pilot incapacitation.

The pilot had been operating the glider at this strip for several days, being launched for each flight by an aero-tow aircraft. The grass at the strip was about 15 centimetres long, and was relatively dense. The weather conditions for this flight were fine, with a light and variable wind. On takeoff, as the tug aircraft and glider accelerated the right wing tip of the glider contacted the grass. An attempt by the pilot to raise the wing was unsuccessful and the glider groundlooped. During this groundloop the tow line back-released. The particular glider was equipped with a belly tow point, with no provision for a tow point on the nose. With the wings level, there is about 30 centimetres clearance from the wing tips to the ground. This accident was not the subject of an on-scene investigation.