Loss of control

Circumstances:

The aircraft had a recent history of directional control problems while operating on water. On two earlier flights on the day of the accident, while landing in strong wind conditions, the aircraft had slewed sharply left when the left pontoon contacted the water. The final landing took place in light wind conditions. On this occasion, as the left pontoon entered the water, the nose of the aircraft dipped, and the aircraft flipped over. Due to accident damage, it was not possible to make an accurate determination as to the cause of the control problem. However, repair work had recently been carried out on the aircraft after it struck a submerged object while landing.

Significant Factors:

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

1. The pilot attempted a landing on water knowing that the aircraft had a directional control problem.

2. The pilot lost directional control of the aircraft on landing.

The aircraft had an amphibious capability and began the flight via a water takeoff. The landing was to be made on a beach on the other side of the island. The aircraft was observed flying parallel to the beach a few hundred metres from the shoreline and at an estimated altitude of 200-400 feet, when it rolled right and suddenly spiralled into the water. Some witnesses indicated that they heard the engine noise interrupted just before the aircraft rolled while others said that the noise remained constant. No abnormality was found in the aircraft or its engine which might have contributed to the accident. There was positive evidence that the engine was delivering power when the aircraft struck the water. The pilot indicated that he was winding down the landing gear as he flew parallel to the beach. This may have distracted him, allowing the airspeed to decrease. The flightpath of the aircraft into the water was typical of the post-stall behaviour of Drifter aircraft.

The pilot took-off with the intention of completing a circuit of the airfield. Once airborne, the pilot observed that the wind was stronger than anticipated, and he decided to abandon the circuit and land immediately in a clear field below the aircraft. During the downwind approach and when the aircraft was about 15 to 20 feet above ground level, the nose dropped suddenly. The pilot endeavoured to correct the situation by opening the throttle and attempting to raise the nose, however, this was ineffective and the aircraft collided with the ground. The pilot had recently purchased the aircraft, and although he had been advised to obtain some training before attempting to operate the aircraft he had declined to do so. The aircraft was not fitted with an air speed indicator, and assessment of speed was based on aircraft attitude in flight and speed across the ground.

On arrival at his destination the pilot is reported to have overflown a house near the strip before entering a steep climb to an altitude of about 300 feet. The aircraft was then observed to enter a steep left turn and dive into the ground. The pilot received head injuries in the accident and had only limited recall of the events of the day. However, it appears likely that the aircraft was stalled during the steep turn and entered a spiral/spin from which the pilot was apparently unable to recover. This accident was not the subject of an on-site investigation.

Circumstances:

The pilot inspected the strip from the air and elected to land towards the west because of high ground and obstacles on the opposite approach. The aircraft bounced on landing and then floated for some distance before braking could be applied. The pilot remained confident adequate strip remained to stop the aircraft. There was, however, a slight hump in the strip and as the aircraft reached it the pilot saw a fence about 100 metres ahead. He applied heavy braking which had little effect on the loose surface. To avoid the fence, the pilot attempted to ground loop the aircraft. The left main landing gear leg entered a small ditch and was torn from the aircraft. On exiting the aircraft, the pilot noted that he had landed with a tailwind of about 5 knots.

At the conclusion of an aerobatic sequence, the pilot positioned the aircraft for a landing on the grass flight strip. At the time, there was a crosswind of about 8 knots with occasional gusts. Towards the end of the landing roll the aircraft groundlooped and the left maingear collapsed. The pilot stated that he did not believe the aircraft could groundloop at such a slow speed and was therefore not ready when the aircraft weathercocked. He did not attempt to apply full power, which is the recommended procedure in this aircraft, to correct such a swing.

Circumstances:

The pilot had been engaged in sheep spotting for a period of approximately three hours and was returning to the refuelling pad. Enroute, he observed a motorcycle stockman, and landed the aircraft in a cleared area nearby, to advise him of the location of a mob of sheep he had spotted earlier. The pilot advised that after he had landed, he left the engine running at between 70 and 80 percent rotor/engine speed.

Circumstances:

After flying to the resort, the pilot landed the helicopter and picked up a photographer for local area photography. He reported that the initial runs were flown at 500 feet above ground level. During some of these runs the wind changed in direction from north to east and was about 10 knots in speed. The pilot noticed on some occasions, when the wind was a tailwind, it caused control difficulties. On one pass, at about 200 feet above the ground and travelling forward at about 30 knots, the helicopter was again affected by a tailwind. The pilot was unable to prevent it yawing to the right. The rotor rpm decayed, collective was lowered, and the aircraft was flared at about 100 feet, but the sink rate could not be arrested. The helicopter struck the ground at a high rate of descent but remained upright. Evaluation of the flight indicates that the pilot was flying very slowly with a tailwind. He lost directional control, and insufficient power was available to sustain rotor rpm. The pilot later flared the aircraft too high to enable a landing at a safe rate of descent.

Significant Factors:

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

1. The wind was variable in direction.

2. The aircraft was being operated at slow speed and with a tailwind.

3. The pilot lost directional control.

4. The pilot misjudged the height to begin the flare for landing. This accident was the subject of an on-scene investigation.

Circumstances:

The helicopter was flying at about 25 knots and a height of about 75 feet, 10 feet to the left of power lines. The passenger was surveying the wires. As the helicopter approached a tree line, the pilot increased collective. However, rotor RPM decayed, and the helicopter descended rapidly, hitting the ground and rolling over.

Significant Factors:

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

1. The pilot overpitched the main rotor, resulting in a loss of rotor RPM.

2. Insufficient height was available for the rotor RPM to recover before the helicopter struck the ground.

At the conclusion of an aerobatic flight, the pilot intended to practice a number of circuits and landings. Two touch-and-go landings were completed, and the pilot positioned the aircraft for a full-stop landing in 10 knot crosswind conditions. Towards the end of the landing roll, the aircraft commenced to ground loop to the left. The pilot applied corrective rudder and brake, but was unable to arrest the swing. He then applied full power, with the intention of becoming airborne and passing between trees which lined the side of the strip. The aircraft lifted off, but then collided with a tree, fell to the ground, and came to rest inverted. The particular type is known to be difficult to control directionally. It was considered possible that the pilot had relaxed his concentration after the aircraft had touched down.