The pilot was engaged in dropping sweets at a Children's Christmas party. As the pilot was completing the third run over the area at an altitude of about 50 feet, the cord on the sweet bag became tangled. The pilot diverted his attention from the operation of the aircraft as he freed the cord. The aircraft descended and the left wing struck a tree, it continued on colliding with a power line before coming to rest on the verandah of a house.

The pilot was conducting a soaring flight when deteriorating lift conditions made an outlanding necessary. A paddock was chosen and the pilot carried out a standard approach pattern, aiming to land into wind. He noted a powerline pole on a hill some 500 metres away, but could not see any other poles near the intended landing area. However, as he was about to turn onto final approach, he noticed a single powerline directly ahead of the aircraft. There was insufficient time available to take any avoiding action, and the wire struck the aircraft canopy. The aircraft subsequently impacted the ground and cartwheeled to a stop 87 metres beyond the point of collision with the wire. The powerline struck by the glider was particularly difficult to see from the air. The pole on the hill was prominent, but the other pole was situated amidst a group of farm buildings. The distance between the poles was one kilometre. The pilot had been at a lower height than normal for a turn onto final approach, however there was little doubt that the intended landing would have been successful had the wire been avoided.

Circumstances:

The pilot had not flown for over four months and planned to sell the aircraft. On the day of the accident, he decided to conduct a check flight before the arrival of a prospective buyer. The aircraft took off into a very light breeze and remained in the circuit area for a short time. It then departed to the east, climbing to about 300 feet. It was then seen to commence a left, level (yawing) turn, both wings seemed to come together at the same time and the aircraft fell in a level attitude to the ground. During the sequence, the engine was heard increasing and decreasing power. It was determined that the left wing spar failed under load at about 1.6 metres from the keel tube. Following this failure, both wing spar tubes failed at the attachment points. No pre-existing fault could be found which could have initiated the left wing spar outboard failure. No other fault was found which could have contributed to the accident. Extensive engineering analysis has shown that at a weight of 160 kilograms, wing spar failure could be expected at about 2.3g. Brochures and other literature on the aircraft claim the airframe will withstand up to 8g.

Significant Factors:

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

1. For undetermined reasons, the left wing spar failed 1.6 metres from the keel tube.

2. Both wing spars buckled at the keel attachment points.

Circumstances:

The aircraft was approaching 1000 feet, on departure, when it began to vibrate significantly. The pilot declared an emergency and carried out a precautionary landing in open country. An inspection of the aircraft disclosed that two of the three main rotor blades had begun to delaminate along their trailing edges, and the foam core of one blade had begun to break up. Subsequent inspections of the blades indicated that all three had suffered a foliage strike on their lower surface. The strikes had caused sufficient damage to the blade material to allow delamination to occur; however, they had not been sufficiently heavy to damage the blades' leading edges or penetrate the skin except where the blade body joins the trailing edge insert. It was evident from the strike marks that the blades had been positioned at a high angle of attack at the time of the strike. Debris found in the skin fracture indicated that the strikes had occurred some time prior to the delamination but not more than two to four flying hours. The light nature of the strikes indicates that the pilot and crew were possibly unaware that a strike had occurred. The high angle of attack on the blades indicates that the strikes occurred either during an approach to land or whilst the aircraft was manoeuvring at low level in the vicinity of tall trees.

At the conclusion of a local flight the pilot carried out a practice touch and go landing, and then positioned the aircraft for a full stop landing. Wind conditions at the time were light. Shortly after touchdown the aircraft commenced to veer to the right. The pilot was unable to stop the swing, and elected to go around. However, the aircraft was no longer aligned with the strip and during the attempted go-around the aircraft struck an embankment and a small tree. The pilot closed the throttle and the aircraft came to rest about 100 metres to the right of the strip.

The pilot had initiated a climb from a baulked landing. On application of the power he found that the engine was not responding correctly. He elected to turn towards the takeoff area in order to reduce the distance of the aircraft from shore. During the turn the aircraft stalled and side-slipped into the water from about 100 feet above the surface. Examination of the engine disclosed a binding throttle cable which prevented the throttle slide from opening fully when full power was demanded.

The pilot reported that the engine stopped following the failure of the ignition coil. During the subsequent approach to land, the aircraft struck a powerline before impacting the ground heavily. The pilot received a fractured vertebrae. One landing gear leg and the wooden propeller of the aircraft were damaged. The pilot stated that the powerline was difficult to see against the backdrop of the rolling hills, and that the supporting poles were situated one and a half kilometres apart and hidden behind the terrain.

The pilot had arrived at the strip the previous day to continue learning to fly the gyrocopter. He flew one circuit during which the craft was observed to porpoise a number of times. After landing, the pilot complained to his adviser that there was something wrong with the aircraft. The adviser then flew the craft and reported that it behaved perfectly. He counselled the pilot that he was overcontrolling in the pitching plane and suggested flying low runs along the strip as practice to overcome the problem. The pilot did this a number of times and showed good pitch control. On the morning of the accident, the pilot flew some further strip runs, again showing good control. He then began flying circuits at about 50 feet above ground level. On the third circuit, as the gyrocopter was turning base with about thirty degrees bank applied, the following sequence occurred in rapid succession - nose pitch-up 15`, nose pitch-down 20`, nose pitch-up 40`, nose pitch-down 50`. The gyrocopter remained in this latter attitude until ground impact. Although the pilot had owned the gyrocopter for some six months, he had flown it only once previously. This was some six weeks before the accident when other instances of pitch control difficulties occurred. There was no evidence of any fault with the gyrocopter. The engine sounded normal up to the time of impact and the shattered propeller blade was evidence of the engine being under power at impact. The gently undulating terrain over which the craft was seen to fly might have given the pilot the illusion that he was descending as he flew the base turn. The porpoising of the gyrocopter as described by witnesses was indicative of the pilot overcontrolling in the pitching plane. When the craft pitched nose down the second time, the airflow through the rotor disk would have been reversed from the normal upwards flow to a downwards flow. Once this condition arises, recovery to normal flight is impossible. It was noted during the investigation that there was no part of the gyrocopter in the pilot's normal forward field of view which could assist him in judging the in-flight attitude of the craft. Such information is particularly important for control in the pitching plane, especially during the learning phase.

The pilot was taking part in a gliding race. About 3 kilometres from the destination the pilot realised that he would not reach the aerodrome and that an outlanding would be necessary. He selected a small paddock with trees on the approach boundary, but sink was encountered and he found he was unable to clear these trees. The aircraft stalled either just before or coincident with colliding with the tree tops. The right wingtip then struck the ground 22 metres beyond the trees and the glider rotated through about 140 degrees to the right before the fuselage impacted heavily with the ground. The decision to outland was left too late.

The student pilot was being checked on the Motorfalke powered glider. At about 50 feet above ground level after takeoff, the instructor shut the engine down to simulate an engine failure. The student elected to land the glider straight ahead on the remaining runway, and the instructor being satisfied with the students initial actions directed his attention to stopping the propeller in the horizontal position. The student fully opened the spoilers and a high rate of descent was set up. The instructor took control of the glider but was unable to arrest the high rate of descent and a heavy landing resulted.