Loss of control

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.

The pilot reported that the take-off on runway 17 proceeded normally until immediately after the gear was selected up. At this point the aircraft pitched up and rolled to the left. The pilot pushed the auto-pilot release button on the control column and heard the release annunciator sound, however he noted that the yaw damper and auto-pilot annunciators were illuminated. He also noted the elevator trim wheel moving and shortly thereafter the stick shaker began to operate at an aircraft speed of about 115 knots. The aircraft was manoeuvred for a successful landing on runway 26. It was determined that water had entered the auto-pilot computer via a faulty seal on the electronics compartment door. Prior to take-off the pilot armed the flight director system in the indicated air speed and heading modes. During the take-off run the auto-pilot engaged, wound the elevator trim nose up and commanded a left turn. The pilot managed to overpower the auto-pilot inputs by applying extremely high forces to the control column, but in doing so was unable to withdraw one hand from this task to trip the circuit breaker controlling power to the auto-pilot.

The pilot lived alone on his property and was last seen on 29 April when he indicated to a friend that he planned to fly his aircraft the following day if conditions were suitable. He had not flown the aircraft before, but was believed to have made taxy runs and short hops during the previous weeks. Two days later the pilot's brother reported that he was missing and that the aircraft was not at the property. The wreckage was located the following afternoon by a search aircraft. An inspection of the wreckage indicated that the aircraft had struck the ground inverted, at a low forward speed, and that the engine was not developing power at the time of impact. No fault was subsequently found with the engine, and it was considered that it had probably stopped shortly before impact, under negative "g" conditions. The pilot was inexperienced, and the particular aircraft was known to be difficult to control in pitch. It was likely that the pilot experienced handling problems which he was unable to correct before the final 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.