Loss of control

Circumstances:

The pilot was conducting mustering operations and had the aircraft configured with 10 degrees of flap. While manoeuvring in a tight left turn at about 100 feet above ground level, the aircraft suddenly flicked inverted and had rolled through almost 360 degrees when it struck the ground. The pilot had about 40 hours mustering experience. This accident was not the subject of an on-scene investigation.

Circumstances:

The pilot had previously experienced difficulty with directional control on landing. He had been given additional training in crosswind landing techniques on the day prior to the accident and had performed to a satisfactory standard. On the subject flight, the pilot carried out a normal approach and touchdown with a slight crosswind from the right. During the ground roll while still travelling at about 25 knots, the pilot lost directional control and the aircraft ground looped to the right. During the ground loop the left wheel broke off and hit the left wing strut.

Circumstances:

During the final approach over a station dam, the helicopter lost height suddenly in a strong down draft. The right skid hooked under a power line which resulted in the loss of control of the helicopter which crashed upside down at the water's edge. A strong South-Westerly wind pattern was established over the area. The approach path was downwind from a stand of large trees.

Circumstances:

Shortly after touching down on runway 22, the aircraft was affected by a localised whirlwind. Despite corrective action, the pilot was unable to prevent the aircraft from entering a ground loop. The left mainwheel ran off the sealed surface causing the aircraft to yaw sharply, resulting in substantial damage to the tail section.

The aircraft was observed approaching to land on Runway 21. It bounced on landing and then rocked from one mainwheel to the other before veering off the left side of the strip and running through a fence. The pilot reported that the wind was straight down the strip and that on touchdown the aircraft swung left suddenly. He was unable to control the swing. A witness on the ground reported that the wind at the time was from the south-east at 15-20 knots but favouring Runway 21. He saw the aircraft bounce a few feet before touching down again on one mainwheel and then the other and then veer off the strip. No fault was found with the wheel brakes which might have caused the swing. This accident was not the subject of an on-site investigation.

The aircraft had been operating for two hours without any apparent problems. Shortly after lift off, following a refuelling stop, the pilot was unable to maintain directional control and the aircraft began yawing rapidly to the right. The pilot attempted to land the aircraft in a clear area, however, one skid dug in and the aircraft rolled over. A fractured tail rotor drive shaft intermediate flexplate was the only mechanical defect found during the investigation. The specialist engineering investigation established that the flexplate failure was caused by the main rotor blades contacting an external object. The only main rotor strike evident at the accident site occurred when the aircraft rolled over following the landing. Damage to the tail rotor control rods indicated that full left peddle had been applied at the time of the flexplate failure. Aircraft weight, power requirements, wind conditions and take-off and DEPARTURE techniques were not conducive to loss of tail rotor effectiveness, however, loss of tail rotor effectiveness will cause the aircraft to yaw to the right. The reason for the initial yaw was not determined. The aircraft rolled over when the pilot was forced to make an emergency landing on unsuitable terrain whilst he was attempting to recover from a difficult control situation.

After six dual check circuits the pilot commenced his second solo flight from the 18 strip. The surface wind was 150`/15 knots. At about five feet above the ground on the first landing the aircraft started veering to the left. The pilot commenced an overshoot but the left wing dropped and the aircraft continued to veer left. The throttle was closed but the pilot was unable to prevent the aircraft running off the strip into the trees. This accident was not the subject of an on-site investigation.

Circumstances:

Neither pilot had landed at Porepunkah before. They obtained details of the strip which was at an elevation of 935 ft and had an average downslope of 1.25 percent to the north. There were trees just beyond the southern end of the strip. Because of the trees the landing distance available to the north was 740 m whereas to the south 840 m were available. Accordingly, it was recommended to land to the south in light northerly wind conditions. On arrival over the strip the pilot noted the wind was a light northerly. He therefore elected to land to the south. On the first approach the pilot found he was too high on final and made a go-around. A second approach was made with full flap selected. After touchdown, the aircraft floated and touched down again three or four times. By this stage, the aircraft was some two thirds of the way along the strip and power was applied for go-around. The aircraft swung 30 degrees left with the left wing low. Alarmed because he thought the left wing would hit the ground, the pilot closed the throttle. After touching down firmly, the aircraft ran off the side of the strip, went through two fences, then over a road, finally colliding with a tree before coming to a stop.

Significant Factors:

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

1. The pilot was inexperienced in landing on sloping strips and in downwind conditions.

2. The pilot did not initiate a timely go-around when the aircraft continued to bounce along the strip.

3. The pilot lost directional control on the attempted go-around.

Circumstances:

The pilot reported that he had flown to the destination area but was experiencing difficulty in locating the strip. He located an area that he thought might be the strip and carried out an inspection from a low height with full flap selected. About halfway along the paddock the pilot decided that the area was not the strip he was looking for and applied power to climb and retracted the flaps. The aircraft stalled and struck the ground in a nose down attitude.

Significant Factors:

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

1. The pilot made an improper decision to conduct the inspection using full flap.

2. He did not maintain adequate airspeed.

3. He retracted the flaps prematurely during the go around. This accident was not the subject of an on-scene investigation.

Circumstances:

As the aircraft was making an approach into a confined area, it was struck by a local wind condition known as "willy willy". The aircraft began to rotate in a clockwise direction, and the pilot was unable to obtain a response from any of the controls. The aircraft touched down heavily, causing damage to the right hand skid and the tail rotor.

Significant Factors:

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

1. The pilot lost control of the helicopter when it was affected by a "willy willy".
2. The aircraft collided with the ground before the pilot was able to regain control.