In sunny conditions with clear visibility and a slight easterly wind drift, the pilot was spraying a paddock of thistles with a herbicide. He had inspected the job site on the ground two days earlier. Because of the mountainous terrain, the pilot flew a left hand racetrack pattern. The spray runs were flown at about ten feet above ground level. The fourth spray run was to the south and encountered clumps of trees. Near the end of the run, the outboard section of the right wing collided with a seven metre high tree removing about one metre of the top of the tree. Almost immediately the aircraft carried out a very steep climbing turn to the right and the engine noise diminished as if the pilot had closed the throttle. The aircraft then descended in a steep, nose down attitude. There was no witness to the aircraft's impact with the ground. Wreckage layout confirmed that it impacted the ground in a nose low attitude with wings almost level. There was no ground slide. For reasons unknown, the pilot did not dump the load of herbicide after hitting the tree. At ground impact the hopper burst out of the airframe and the fuel tank, containing an inner rubber liner, ruptured. The fuel ignited and the aircraft was destroyed by fire. Whether the aircraft became uncontrollable after the tree strike remains unknown. The aircraft was serviceable prior to impacting the tree despite confirmation of minor right wing damage after a previous tree strike on 27 October 1989 by the same pilot at a previous job site. A simulated spray run has since been flown over the same ground by an agricultural pilot flying instructor. The impacted tree was difficult to see because of a larger clump of trees in the immediate foreground. Also, it partially blended into a treed hill of similar hue about 500 metres beyond. There was no practical need to fly the run as low as ten feet and doing so would have been unnecessarily dangerous. It is possible that the pilot closed the throttle while mistaking it for the spray lever after the tree collision. The pilot had successfully flown sixteen hours of spraying operations in the same mountainous terrain during the week prior to the fatal accident.

The pilot and passenger were undergoing a full time flying training course to Commercial Licence standard, and had both recently obtained their restricted Private Pilots Licences (i.e. restricted to flight within the flying training area). On the day of the accident the pilot had spent the morning at lectures, and preparing for navigation exercises. After lunch he approached the Chief Flying Instructor and asked if he could take VH-FLF to the training area for an hour. This was approved and the pilot signed the flight authorisation sheet and entered the time 1340 hours on the sheet. There was no indication on the authorisation sheet that he intended to take a passenger, nor did he mention this to the Chief Flying Instructor. The pilot was later seen sitting in the aircraft, apparently awaiting the arrival of his passenger. There appears to have been no prior arrangement, other than a spur of the moment decision by the passenger, to go on the flight. The pilot called Archerfield Tower at 1351 hours and reported taxiing for the southern training area. At 1359 hours VH-FLF was cleared for takeoff. This was acknowledged by the pilot, and no further radio transmissions from the aircraft were heard or recorded. At approximately 1415 hours, witnesses heard the aircraft flying overhead. The aircraft was seen flying in a south-easterly direction in apparently normal flight, when the engine noise suddenly ceased. The aircraft was then observed descending in a steep spiral or spin from a altitude of about 2000 feet. The spiralling motion appeared to cease momentarily before the aircraft dived into the ground. The aircraft impacted the ground in a steep inverted nose down attitude. Indications are that the aircraft may have been recovered from the spiral briefly, before stalling and becoming inverted during the recovery at a very low height. No mechanical defects were found which may have affected the airworthiness of the aircraft, or which may have contributed to the development of the accident.

Circumstances:

The aircraft departed Narromine in company with three other gliders for a cross-country flight Narromine - Parkes - Condobolin - Narromine. Weather conditions were fine with good visibility but were otherwise difficult with weak and well-separated thermals being the only sources of lift. North of Parkes all four aircraft had descended to a low altitude. The other three pilots were able to use the weak lift to continue the flight but the pilot of VH-IUB decided that he was unable to continue and informed the other pilots by radio that he would land in a paddock. A south westerly wind of about five knots was blowing on the surface. The aircraft approached the paddock from the south west. In the latter part of the approach, at very low altitude, the pilot initiated a left turn to track away from trees at the edge of the paddock. During the turn the left wingtip struck the ground initiating a cartwheel motion. The fuselage impacted heavily in a steep nose-down attitude. The aircraft was destroyed and the pilot received fatal injuries. The pilot was a qualified glider pilot who had begun gliding ten years previously. However, he had only recently purchased the glider and resumed gliding after a layoff of several years. Stress and fatigue were possible factors in the accident, potential sources being a. the workload required to fly a cross-country route in conditions of poor lift; b. concern about the loss of an important horse sale; c. about sixteen hours driving, including caravan and glider trailer towing, in the 72 hours prior to the accident; and d. pressure to launch on the flight. Before DEPARTURE from Narromine the aircraft altimeters were set to read zero (QFE). Narromine Aerodrome is 782 feet Above Mean Sea Level (AMSL) and Parkes Aerodrome is 1069 feet AMSL. Consequently, an aircraft operating in the Parkes area, with Narromine QFE set on the altimeter subscale, would have approximately 300 feet less terrain clearance than at Narromine. A pilot lacking in currency, under a high workload, and possibly suffering from stress and fatigue, could fail to take this difference into account when considering the minimum altitude required for a safe outlanding. Examination of the wreckage did not reveal any defect that may have contributed to the accident. In March 1988, the wings were reprofiled from the original Wortmann FX67 airfoil sections to modified sections developed from research in USA. There is no evidence to indicate that the wing reprofiling resulted in the need for enhanced pilot skills for safe operation. The pilot was aware of the reprofiled airfoils.

Significant Factors:

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

1. The pilot lacked recent experience.

2. The pilot could have been suffering the effects of stress and fatigue.

3. The pilot misjudged the altitude required and the approach direction during an outlanding.

The forecast for the flight indicated that there was scattered cloud along the flight planned route, with additional cloud around the ranges. The pilot was advised that the weather conditions would be least favourable close to the DEPARTURE aerodrome, with conditions improving as the flight progressed to the south. Approaching the ranges on the Queensland border, the aircraft was climbed to 9000 feet to overfly what the pilot expected would be a small area of cloud. However, the cloud was found to be more extensive and the pilot descended to regain visual contact with the ground. He then found that he was unable to fly out of a valley because of cloud and rain, and elected to carry out a precautionary landing in a paddock. During the landing roll the nose gear was torn off because of the rough surface conditions. An amended area forecast was issued about five minutes before the aircraft departed Archerfield but this was not relayed to the pilot. The amended forecast indicated broken cumulus cloud between 2500 feet and 10000 feet in addition to broken strato-cumulus between 4000 feet and 9000 feet in the area of the accident.

Circumstances:

The pilot reported that he was attempting to land on a short, one-way strip in a quartering tail wind. While on short final the wind speed increased. The aircraft drifted left and sank low on the approach path, finally striking a rock fence just short of the threshold. The left landing gear assembly and the right wheel and axle were dislodged in the impact. The aircraft came to rest some 30 metres from the fence to the left of the strip. The pilot advised that the strip did not meet the requirements of an Authorised Landing Area (ALA) in terms of slope, length, and obstacles. He was not experienced in operating in tail wind conditions into one-way strips and had only landed at this particular strip once before but in different wind conditions.

Significant Factors:

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

1. The pilot was attempting to land on a short sloping strip in hilly terrain. He was not familiar with the strip nor with landing on a steep upslope.

2. The pilot used a flat, low approach technique rather than the correct short field approach procedure.

3. A possible increase in the tail wind was not detected in time to stop the aircraft descending onto a rock fence. This accident was not the subject of an on-scene investigation.

The helicopter was being used to drive cattle across a creek, when one beast broke out of the herd. During an attempt to drive it back, the pilot misjudged the clearance between the main rotor disc and the foliage of a large tree. After the tree strike, the machine was still controllable to the extent that it was landed without any further damage. Post-flight inspection revealed that all three main rotor blades were damaged.

Circumstances:

The aircraft was engaged in joy flights at an agricultural field day. Operations were being conducted from a paddock with a downslope of 7 toward the north. Part of the paddock had been slashed for a helipad, leaving a thick layer of loose hay on the surface. The pilot had been using the slipperiness of the loose hay to assist in obtaining translational lift, by turning and sliding the skids down the slope. He reported that the wind had been variable from the north-west. On the last take-off, the helicopter became airborne but failed to climb above about 10 feet. The rotor RPM began to decrease, and the helicopter started to descend. The pilot started "milking" the collective and noticed that the wind had swung to a westerly and increased to about 15 knots. He considered turning into wind but was concerned that he would either have to land in the long grass adjacent to the pad, or that he would have problems outclimbing the heavily populated exhibition area to the west. He was also concerned that he would not be able to outclimb a set of powerlines to the north over which he had normally flown on climb out. He elected to land down the slope in a north-north-westerly direction. He flared for landing and the helicopter touched down gently, slightly tail first. As it rocked forward onto the skids the tail rose up into the main rotor disc. Part of the tail frame and tail rotor drive shaft were severed. The helicopter came to rest approximately 50 metres from its parking position at the top of the pad.

Significant Factors:

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

1. The wind component change immediately after lift-off.
2. The pilot overpitched, resulting in low rotor RPM.
3. The helicopter landed with the tail up-slope.

As the pilot rotated the aircraft for takeoff he heard several bangs and felt there was an accompanying power loss, so he aborted the take-off. When it appeared he would be unable to stop in the strip remaining he deliberately ground looped the aircraft. The nosewheel leg was damaged and the propeller struck the surface of the strip, necessitating an engine strip - the propeller was not damaged. An inspection of the aircraft did not find any fault with either the engine or the braking system. The blacksoil strip was found to be very soft and it is considered that the retarding action of the strip caused the pilot to believe a power loss had occurred. The bangs heard by him were probably caused by clods of dirt hitting the fuselage.

When approaching Lake Nash the pilot had selected the fuel boost pumps to low in accordance with the manufacturer's operating handbook. He started to smell fuel so he turned the pumps off. After landing he shut down and unloaded the appropriate freight. On start up he did not smell any fuel but, at about 40 knots on the takeoff run, the left wing tip exploded and the aircraft caught fire. The pilot brought the aircraft to a stop off the strip and evacuated the aircraft. He was unable to recover any of his documents before the aircraft was totally destroyed by fire. Examination by an engineer indicated that the fire may have started in the left wheel well area and that fuel vapour in the wing had exploded through the wing tip.

During circuit training, the aircraft suffered a complete engine failure. The pilot was unable to reach the flight strip and landed the aircraft amongst trees. One of the two pistons of the two stoke engine had seized in the cylinder, probably due to lack of lubrication.