During the approach to land at Ord River Station the Pilot in Command (PIC) discovered that throttle movement was restricted within the range 18 to 23 inches of manifold air pressure. After considering the various alternatives the PIC elected to return to Kununurra and attempt a landing. The PIC sought advice from the company Chief Pilot before attempting a landing. Following a practice circuit, to determine the minimum approach speed obtainable, the Chief Pilot instructed the PIC to repeat the circuit and to close the mixture at 300 to 400 feet on final approach. The PIC flew a slightly modified circuit, which involved a longer, flatter final approach and closed the mixture, as instructed, at 300 feet on final approach. Shortly after closing the mixture the PIC realised that the aircraft would not reach the runway and she attempted a landing in a grass area short of and to the left of the threshold. During the landing the aircraft collided with a ditch which had been hidden from the PIC's view by the grass. Movement of the throttle was restricted because a throttle linkage pin, which had been fitted incorrectly, was binding against a loose induction air box. The bolts holding the induction air box in place had not been secured correctly at the last servicing. Three of the four retaining bolts were found lying in the engine bay. The PIC was inexperienced in commercial operations and the Chief Pilot was known to exercise "positive" supervision over the company's operations.

Circumstances:

The pilot was commencing a practice flight in preparation for a 600-kilometre soaring competition task. The weather was fine with a north-easterly wind of 15-20 knots and a temperature of approximately 40 degrees Celsius. Following line-up, the pilot was delayed for approximately fifteen minutes before his aero-tow became available. He then advised the tug pilot that a climb speed of 65 knots was acceptable. The subsequent tow initially appeared normal although observers at the airfield noticed some apparent roll instability. At approximately 1000 feet above ground level (agl) the tug pilot detected thermal activity and began a left orbit to regain the area of lift. With the turn almost completed the right wing was violently "kicked-up" as the aircraft re-entered the area of lift. The tug pilot corrected the upset checked that the glider was not affected and continued the left turn. Approximately five seconds after the upset at about 1300-1500 feet agl the glider released. Observers reported that the glider had banked steeply to the right while apparently still under tow. Following the tow release the angle of bank increased past the vertical the nose dropped steeply, and the glider entered a spiral dive from which it did not recover. It struck the ground in an almost vertical nose-down attitude. The investigation was unable to find evidence of any pre-existing structural or system defect. Pilot medical evidence is inconclusive. The reason the aircraft entered an abnormal flight manoeuvre at an altitude from which recovery should have been possible could not be determined.

Significant Factors:

The following factor was considered relevant to the development of the accident:

1. Control of the aircraft was lost following tow release. The cause of the loss of control was not able to be determined.

The aircraft was cruising normally at 7000 feet when the engine failed without warning. The pilot carried out checks and attempted to restart the engine without success. During the ensuing forced landing the pilot prematurely turned off the master switch, therefore, the wheels did not extend when he selected gear down. The engine failure was caused by the separation of crankshaft idler gear teeth due to high cycle low stress fatigue which had initiated from pre-existing overload cracks at the base of the teeth.

The pilot was requested to conduct an aerial survey in the Mount Bundey area, however, he evidently misunderstood the instructions and flight planned to Mt Bundey Station. This strip was 74 kilometres south-west of the passengers' expected destination. During the flight the front seat passenger, who was also a pilot, became concerned and questioned the pilot at length as to their route. Because of the confusion, and deteriorating weather conditions, the pilot decided to continue and land at the Station strip. A normal landing was subsequently carried out. The pilot then discovered that although the strip was 1100 metres long, a washaway had reduced the usable length to about 700 metres, and this was covered by long grass. After ascertaining the passengers' exact requirements, the pilot prepared for take-off. Acceleration was sluggish because of the long grass, and the stall warning was sounding continuously as the aircraft became airborne near the end of the strip. It failed to climb away, and collided with trees and fences before coming to rest. The aircraft Performance Charts indicated that a strip length of 840 metres was required for a safe take-off. It is likely that the pilot's performance was degraded because he was suffering the effects of a cold. The task had been allocated to him at short notice, and he was under some pressure from the passengers.

While conducting parachute dropping runs from 5000 feet the pilot heard a loud bang from the engine and saw an object ejected through the top engine cowling. The windscreen was immediately covered with engine oil and the engine lost power. The parachutists abandoned the aircraft, and the pilot made a forced landing in a field of young wheat. The field sloped downwards in the direction of the landing roll, and the aircraft nosed-over when the mainwheels intersected a shallow ditch while wheel brakes were being applied. Investigation revealed that the number 4 connecting rod had failed in fatigue across a big end arm. The fatigue had multiple origins on both the outside and inside of the arm, and propagated through approximately 95% of the cross- sectional area. The fatigue initiated from the inside of the big end bore revealed characteristics indicative of high cycle low stress fatigue, while the fatigue commencing from the outside of the arm propagated through high stress low cycle fatigue. The join between the two lines of propagation ran parallel with the bore. The other big end arm had 4 distinct fatigue initiations, one con-rod bolt had failed in overload with distinct signs of necking, while the other bolt remained attached to the cap and remaining part of the big end arm. The No.4 slipper bearing was reduced to a large quantity of severely deformed cold-worked fragments. Detailed metallurgical examination of the failed bearing did not disclose the cause of the failure. The oil filter was clogged with deposits and oil sludge. The bypass and pressure relief valve cavities contained similar deposits. The engine oil had the appearance of dirty used oil. However, laboratory analysis suggested that the oil had changed very little when compared with unused oil. The spark plugs were found to be oily, fouled and heavily deposited by carbon and lead. The aircraft had only flown 6 hours since the previous 100 hour inspection. This inspection should include the inspection of the oil filter, changing of the engine oil and servicing of spark plugs. The condition of the spark plugs was inconsistent with 6 hours of flight time. Approximations of the length of time for which the oil and plugs had been in use was not determined. Examination of the stripped engine disclosed that the oil passages were free, and no components showed signs of oil starvation. The cause of the bearing failure was not established. The aircraft had flown approximately 16 hours between a periodic inspection on 24.6.85 and the next periodic inspection on 1.10.87, and approximately 6 hours between the latter inspection and the accident on 3.10.87.

An aircraft maintenance engineer, who assisted the gliding group with maintenance aspects, was making a video movie of the glider operations. He was seen to be standing to the right-hand side, and well clear of the strip, near to the point where takeoffs were commenced. During the circuit by the particular glider, he moved to the edge of the strip to film the approach and landing. The colour of his clothing blended in with the high clumps of grass and general colour of the terrain, and the pilot did not detect his presence. When looking through the viewfinder of the camera, the photographer would have been led to believe that the glider was well clear of him. While panning the camera to film the landing run, he was struck on the neck by the wing of the passing aircraft.

Circumstances:

The pilot was conducting mustering operations at low level at the time of the accident. Shortly after the aircraft made a low pass to indicate the position of some animals, it was observed descending at a steep angle. The aircraft commenced rolling to the right just prior to ground impact and was destroyed by a post-impact fire. All essential aircraft systems appeared capable of normal operation prior to the accident. There was no evidence that the pilot had suffered any pre-impact illness or sudden incapacitation. Although all of the precise factors leading to this accident could not be determined, the sequence of events is similar to many other accidents investigated by the Bureau, where the loss of control at low level following a low pass has been due to inattention to aircraft operations by the pilot. It was disclosed during the investigation that although the pilot had a valid mustering endorsement, he had not received any training in recovery from stall/spin conditions, typical of a loss of control in a Cessna 150, at low level.

Significant Factors:

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

1. It is probable that the pilot did not pay sufficient attention to the operation of the aircraft during low-level mustering operations.

2. The aircraft probably stalled and entered an incipient spin.

3. The loss of control occurred at too low an altitude for any recovery attempt to be successful.

Recommendations:

This type of loss of control is a factor in many of the low-level accidents investigated by the Bureau. Training and exposure in incipient loss of control situations, particularly in Cessna 150 type aircraft, is not included in all mustering and associated low flying endorsement programs. The Civil Aviation Authority in Western Australia advised all local pilots of the desirability of obtaining this type of training. It is recommended that the Civil Aviation Authority extend this advice to all pilots in Australia who have approval to conduct fixed wing operations at low level.

Circumstances:

The pilot was to conduct solo training flights in a flying wing type ultralight aircraft. Directional control in this type of aircraft is achieved by yaw through the use of wing tip rudders. These rudders are spring loaded to the left and balanced by air loads in flight. During pre-flight assembly on the day of the accident, the control cable attachment to the left rudder was inadvertently positioned on the wrong side of a clamp near the wing tip rib. This allowed the cable, under some conditions to foul on the clamp. After assembling the aircraft, the pilot conducted some flights, until a heavy landing bent the main landing gear axle. The pilot used a steel pipe as a hammer to straighten the axle, but the shock loads from this operation dislodged the left hand wing tip rib and rear spar. Although an inspection was conducted, it did not discover the damage to the wing tip which would only have been apparent by removing the wing sail. On the subsequent flight at about 30 feet after take-off, the damaged left wing tip distorted due to aerodynamic loads, initiating an uncontrolled right roll. Attempts by the pilot to level the aircraft resulted in the incorrectly installed control cable attachment inducing further adverse distortion. The aircraft rolled to about 60 degrees, entered a rapid descent and clipped a parked aircraft before coming to rest in a nose down attitude. The engine which appeared to be operating normally was shut down by the pilot after the aircraft came to rest.

Significant Factors:

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

1. Incorrect assembly of the left hand rudder cable.

2. Shock load damage to the left hand wing tip structure during straightening of the landing gear axle.

3. Inadequate inspection of the aircraft for damage.

4. The damaged left hand wing tip distorted with increased aerodynamic loads. This accident was not the subject of an on-scene investigation.

The pilot was attempting a normal night takeoff in light drizzle, with 7 to 10 knots of crosswind at the time of the accident. As the aircraft lifted off heavy rain started to fall. The aircraft appeared to accelerate normally to 120 knots. As the pilot completed the after takeoff checks he noted that the aircraft was descending at 200 feet per minute instead of climbing, although the nose of the aircraft was 10 degrees above the horizon. The pilot raised the nose still further and reduced the speed to 110 knots, however, this did not stop the aircraft from descending. At 510 feet indicated on the altimeter, the airfield elevation, the pilot levelled the aircraft and prepared for ground impact. The aircraft touched down, gear up, 3 km from the DEPARTURE end of the runway and slid to a stop in flat marshy country. The meteorological station at Forrest reported that during the aircraft's takeoff, the intensity of the rain increased and the surface wind swung around to give a 30 knot tailwind. During test flights prior to and after the accident the pilot-in-command was assessed as having slow cross reference skills and poor attitude control. It is possible that the pilot's performance contributed to the accident.

Circumstances:

The commencement of parachuting activity on the Corowa Drop Zone was delayed due to extensive cloud in the vicinity of the Corowa aerodrome. About mid- afternoon the cloud base had lifted sufficiently to permit descents from the minimum safe height. The aircraft took off carrying four parachutists. Their intention was to exit the aircraft for a "Hop and Pop" jump in which the main parachute deployment sequence is commenced immediately after leaving the aircraft. The four parachutists jumped at several second intervals, from a height of 2200 feet above ground level. Three parachutists main canopies opened normally, the fourth did not. The fourth parachutist, was observed to fall in a face down attitude until he struck the ground, fatally injured by the impact. During his fall, the pilot parachute from the main canopy system was seen to deploy and remain attached to the harness. There was apparently no attempt made by the parachutist, to initiate cut away action (to disconnect the main canopy from the harness) or deploy the reserve canopy. A specialist examination of the equipment revealed the line from the pilot parachute passed under the right leg strap preventing deployment of the main canopy. The reserve canopy and its deployment system were in a serviceable condition. The fatally injured parachutist was attempting his 42nd descent, held an "A" licence and was considered to be relatively inexperienced. He was using borrowed equipment which differed significantly from that on which he carried out the majority of his training. He had completed 39 descents with a harness/container system that incorporated a ripcord main canopy deployment and "single operation system" reserve canopy deployment. The borrowed equipment consisted of a throw away pilot chute main canopy deployment system, and a "two stage" reserve deployment arrangement. It was reported the parachutist was trained to use the borrowed equipment. The parachutist incorrectly fitted the borrowed equipment so that the right leg strap passed over the line from the pilot chute to the main canopy. Although the pins which secure the main canopy within the container were checked by another parachutist before the aircraft was boarded, the routing of the pilot chute line was not the subject of a deliberate check. (The reason why the parachutist did not deploy his reserve parachute was not determined). The descent was conducted from the minimum safe height above ground level and in the event of a complete failure of the main canopy to deploy, a rapid response was required to identify the nature of failure and deploy the reserve parachute. 

Significant Factors:

1. Parachutist lack of experience with this equipment.

2. The parachutist incorrectly donned the parachute equipment.

3. Prior to boarding the aircraft, a complete check of the parachutist’s equipment by an independent person, was not conducted.

4. The main canopy failed to deploy because the line from the pilot's chute passed under the right leg strap. 

Recommendations:

The following recommendations were made to the Australian Parachute Federation during the course of the investigation

1. All parachutists should have their complete equipment checked prior to boarding aircraft.

2. Inexperienced parachutists be discouraged from using borrowed equipment with unfamiliar operating systems.