Loss of control

The aircraft had previously had to be flown with the control stick displaced to the right of centre in order to maintain a wings level attitude. The aircraft owner advised a visiting ultralight pilot of the problem, who offered to attempt rectification. After conducting a flight to experience the problem first hand, the pilot adjusted the right wing warping wire and conducted another test flight. The adjustment had improved the trim problem but still not completely provided a fix. The pilot then readjusted the right wing warping wire to its original condition and added a D-shackle to the left wing warping wire to increase its length. Another test flight was carried out and it was found that the aircraft could only be maintained in level flight when full right rudder and full right control stick were applied. The aircraft was struck by a wind gust and the left wing dropped, as no further control was available to correct this situation, the pilot pulled a wing warping wire. Unfortunately he pulled the right wire instead of the left wire and was unable to correct his error before the aircraft struck the ground. A subsequent inspection of the wreckage found that the right wing warping wire was 19 millimetres longer than the left. Also, all the dimensions of the right wing were slightly larger than that of the left wing, resulting in the right wing area being about 80 square centimetres greater.

While conducting a cross-country flight, the pilot encountered deteriorating lift conditions, and an outlanding became necessary. The pilot reported that while he was on short final approach to the selected paddock he encountered strong lift, which caused him to overshoot the target touchdown point. During manoeuvring for another approach, the glider stalled and struck the ground in a very steep nosedown attitude. When it was apparent that the aircraft would overshoot the target touchdown point, the pilot had carried out a steep turn to re-position for final approach. During this manoeuvre the spoilers, flaps and landing gear had been left extended. The pilot had evidently not monitored the airspeed and the glider had stalled and probably entered an incipient spin. There had been no requirement for the steep turn to be undertaken, as a landing straight ahead was available.

The pilot was participating in a 500 kilometres cross country gliding competition. Atmospheric conditions were not favourable for prolonged soaring flight, and none of the other participants was able to cover any significant distance. However, this particular aircraft departed on the planned track, and the next reported sighting was about 3 kilometres from the accident site. At this time the aircraft was circling at approximately 300 feet above the ground and tracking to the north-west. No further sightings were reported, and the wreckage of the aircraft was subsequently discovered in a paddock 102 kilometres from the DEPARTURE aerodrome, on the intended track. Investigation revealed that the glider had initially contacted the ground with the leading edge of the right wing, while the aircraft was in a steep nose-down attitude and spinning to the right. There were no known witnesses to the accident, and it could not be established whether the pilot had been attempting to outland or to find a thermal at low level. There was no evidence of any pre-existing mechanical defect which might have contributed to this occurrence. It was probable that control of the glider was lost during a manoeuvre at low speed and height above the ground, however the reason for the loss of control was not determined.

The purpose of the flight was to convey the three passengers to Casino for business. Prior to departing Scone the pilot telephoned Sydney Operational Control Centre Briefing Office and submitted a flight plan which indicated that the flight would be conducted in accordance with Visual Flight Rules (VFR) and proceed via Upper Bowman and Taree at 7000 feet above mean sea level (amsl) to Port Macquarie and then Casino.

The pilot also indicated when submitting the flight plan that no radio navigation aids were fitted to the aircraft. The pilot then received a briefing on the weather conditions that could be expected along the route to be flown. The winds were given as generally southerly at about twenty knots with the cloud as scattered stratus between 1000 and 2500 feet and areas of broken strato-cumulus between 2000 and 6000 feet amsl. At 0740 hours the pilot advised Sydney Flight Service (FS), by radio, that the aircraft had departed Scone at 0733 and was climbing to 7000 feet. At 0809 the pilot reported the aircraft's position at Upper Bowman, cruising at 7000 feet and estimating Taree at 0829. Twelve minutes later the pilot of another aircraft also bound for Taree contacted VH-UDX and asked the pilot to confirm the aircraft altitude as 7000 feet. The pilot of VH-UDX replied that his aircraft was at 6500 feet on descent to 5000 feet and that he had run into a bit of "murk". When questioned further by the other pilot and Sydney FS the pilot reported VH-UDX was at 6000 feet in cloud and requested the visibility at lower altitudes. The pilot was advised that the cloud base at Williamtown was 3000 feet and he then reported that he intended to back track to Scone. The pilot was then requested to activate the transponder fitted to the aircraft and VH-UDX was subsequently identified by radar 18 nautical miles south-west of Taree at 0828 hours. The pilot was advised of this position and reported his heading, which indicated the aircraft was tracking towards Scone. During the next few minutes Sydney FS obtained information from the pilot relating to fuel endurance; estimate for Scone; altitude and cloud conditions.

The last communication received from the aircraft was at 0838 when the pilot acknowledged an instruction to call Williamtown Approach (for radar assistance). Further communication attempts were unsuccessful. At about 0840, residents of Gloucester heard the sound of an aircraft engine, apparently at high power, moving from the west to the north of the town. They could not see the aircraft. At the time there was dense cloud overhead, base about 800 feet above ground level (elevation 350 feet amsl), with drizzle. The aircraft appeared suddenly, descending steeply from the base of the cloud. The nose rose momentarily then the left mainplane folded back against the fuselage, separated and dropped away. The empennage separated from the fuselage. The fuselage with the right wing attached struck the ground in a park on the western edge of the town. The left wing, empennage and some other debris landed several hundred metres to the north east of the main wreckage.

Subsequent investigation did not reveal any pre-existing fault with the aircraft that could have contributed to the accident. The weather conditions that were encountered by the pilot were substantially as forecast and relayed to the pilot during the pre-flight briefing.

Circumstances:

The pilot purchased the aircraft in kit form from the manufacturer when he was visiting the USA in June 1989. He completed a training course in the dual seat version comprising approximately 30 hours of dual instruction and was certified competent for solo flight on 10 June 1989. After returning to Australia, he assembled the aircraft with the assistance of an aircraft engineer and began flying it on 20 September 1989 and had flown approximately 5 hours since then. On the day of the accident, the pilot had been practising take-offs and landings at the Tully aerodrome, and after about an hour of flying stopped for a break and to check the fuel. During the break he said that he would fly for another half hour and then stop to refuel and have something to eat. During the next flight, the aircraft was seen proceeding along the runway and carrying out "S" turns to reverse direction. During the commencement of a turn to the right, whilst heading towards the southern end of the strip, the aircraft was seen to adopt a steep nose down attitude, and dive towards the ground. The aircraft impacted the ground inverted, adjacent to the strip on a heading of 200 degrees magnetic and travelled 15 metres after initial impact before coming to rest. There was no evidence to suggest that the aircraft was operating abnormally prior to the accident sequence, and no defects were found which may have contributed to the development of the accident. The aircraft pitched nose down suddenly, and the rotor blade struck the tailfin with considerable force before ground impact. The behaviour of the aircraft is consistent with that which may occur when a gyrocopter is subjected to zero or negative "g", causing normal inflight forces to become unbalanced, and the gyrocopter to become uncontrollable. The weight of the aircraft is removed from the rotor, and the engine thrust may then turn the aircraft upside down. This could be caused by levelling off from a climb too abruptly at a low forward speed and allowing the airflow through the rotor to be reversed.

Significant Factors:

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

1. The pilot was inexperienced and was teaching himself to fly the gyrocopter without the supervision of an instructor. His previous training was thorough, but its effectiveness was diminished by lack of continuity during the following 3 months.
2. The loss of control is considered to be due to misapplication of controls leading to a zero or negative "g" situation. The possibility of a wind gust or willy willy causing an upset was considered, but there was no such observation by witnesses, and the wind at the time of the accident was light and variable.
3. The longitudinal stability of the aircraft is dependent on the balance of forces, in the absence of a horizontal stabiliser. The aircraft was not fitted with a horizontal stabiliser which would have improved longitudinal stability and reduced control sensitivity.

Recommendations:

1. The Civil Aviation Authority should consider the introduction of two place gyroplanes for use in a training role. At the moment there is no avenue in Australia for such training and the number of accidents involving inexperienced pilots is significant. It is recommended that CAO 95.12 be amended to include dual place gyroplanes, and that a syllabus of training be specified similar to the FAR 61.85 requirements.
2. The Civil Aviation Authority should consider the establishment of a scheme, to assist the Australian Sport Rotorcraft Association to set up a training and checking system, which would be available to members in specified areas of each State where this activity is popular.

Circumstances:

The pilot reported that he was making his first flight in his ultralight which he had just completed building. After a 30-minute flight around his farm he made a landing approach to a grass strip. The intention was to overfly the strip and make a left circuit. However, as he crossed the threshold, he judged that he was in the right "slot" for a landing and the approach was continued. But when the aircraft was in the flare, he sensed the heading to be 10 degrees right of the strip direction. Because of lack of recent flying experience, he decided at that point that the safest thing to do was to abandon the landing attempt and go around. Confident that he had plenty of reserve power he did not use full throttle for the go-around. As power was applied, the right wing dropped gently, not responding to aileron. The pilot assumed a control malfunction and was not prepared to open the throttle any further. The aircraft continued to turn to the right, now heading toward a power line that was running parallel to the landing strip. The pilot instinctively applied backstick to clear the power line, but the aircraft continued the uncontrolled gentle turn to the right. The pilot said that "resigning himself to the inevitable" he began closing the throttle. The aircraft gently descended into a stubble paddock. The pilot advised that he later realised that a mild stall had developed on the right wing and had proper stall recovery technique been applied, the situation would have been corrected. The pilot subsequently critically self-analysed the accident and identified a number of factors that resulted in him being under significant stress while performing this first flight in his aircraft. In hindsight he believed that he should not have flown the aircraft at all until he had completed some dual flying.

Circumstances:

The pilot stated that after becoming airborne he lowered the nose of the aircraft to gain airspeed, but the aircraft sank back onto the water, then veered to the left. The pilot closed the throttle and attempted to steer the aircraft away from the riverbank. The floats struck a rock retaining wall and the aircraft nosed over. The take-off attempt was towards the lee of trees near the riverbank. The local wind conditions produced approximately five knots of crosswind component from the right. The aircraft may have encountered a sudden decrease in headwind component during the take-off causing it to sink back onto the water. Loss of directional control may have occurred because the aircraft was not correctly aligned at touchdown.

FACTORS

1. The aircraft sank back onto the water after becoming airborne possibly due to an unexpected wind gust.

2. The pilot was unable to maintain directional control after the aircraft touched the water.

After completing a dual instruction period of crosswind take-offs and landings the pilot prepared for solo exercises in the training area. At about 45 knots during the take-off roll the aircraft unexpectedly became airborne. The pilot had been correcting for the left crosswind and when the aircraft touched down again its heading altered sharply to the left. Attempts to regain control were unsuccessful and the pilot abandoned the take-off. Damage to the nosegear was sustained when the aircraft entered a ditch before coming to rest off the side of the strip. The wind at the time of the attempted take-off was gusting close to the crosswind limit for the aircraft type. After the aircraft ran off the strip, soft wet ground reduced braking effectiveness, and the pilot was unable to prevent the entry into the ditch.

The pilot, who was an experienced glider pilot and instructor, was taking part in a gliding competition. Only 2 of the 12 competitors were able to complete the exercise, the remainder being required to outland. Almost 4 hours after being launched, the aircraft was sighted in a right hand circling descent, apparently being manoeuvred for an outlanding. At low level, the angle of bank was seen to suddenly increase and the nose dropped. The right wing struck the ground and the aircraft cartwheeled before coming to rest about 34 metres from the point of initial impact. It was evident that the aircraft had entered an incipient spin at too low a height above the ground to enable the pilot to recover control of the aircraft. The reason for the loss of control could not be determined.

The pilot was attempting to complete a solo flight of at least one hour duration as part of the qualification for the issue of a C Gliding Certificate. Witnesses reported that during the winch launch, the glider lifted off too early, and then assumed the climb attitude before sufficient airspeed had been obtained. The pilot stated that she released from the winch cable when she became aware that the airspeed was too low. At about the same time the right wing dropped and the aircraft turned through about one and a half revolutions before impacting the ground with the right wingtip. The pilot had attempted to correct for the wing drop with aileron control inputs, which were ineffective at the low airspeed.