Loss of control

Circumstances:

The pilot was assessing a new powered trike hang glider which had greater performance capabilities than his own aircraft. He successfully completed several circuits before landing for a short period about one kilometre from the witnesses. The aircraft became airborne again, climbed to about 100 feet and performed a series of short climb and descent manoeuvers. It then entered a very steep angled climb, described by the witness as 80 degrees. At about 300 feet, the sound of the engine ceased, the nose pitched down, and the aircraft entered a series of three "tuck and tumbles", similar to an uncontrolled outside loop. On the third tuck and tumble, both wings failed and came together, and the aircraft fell straight to the ground. At some point, the emergency parachute handle was pulled but there was insufficient altitude remaining and the parachute did not deploy from the container. No pre-existing defects were found with the aircraft. The investigation determined that during the break-up sequence the seat area separated from the section containing the engine, which was still running at ground impact. Ground testing of the engine revealed no defects and the engine continued to run satisfactorily up to simulated angles of 35 degrees of climb. This, together with the 50 degrees freedom of movement for the control bar, would allow a very steep apparent angle of climb to ground observers. It is most likely that the pilot, once the aircraft attained this attitude, closed the throttle, and pulled back on the control bar. This probably initiated the tuck and tumble sequence. It was found that the parachute was attached to the engine, not the seat frame, and that the parachute's performance rating did not match the performance rating of the aircraft.

Significant Factors:

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

1. The pilot's experience was on considerably lesser powered and lower performing ultra-light aircraft. 2. Whilst attempting a very steep climb, the pilot applied incorrect recovery technique.

Recommendations:

1. It is recommended that the Civil Aviation Authority (CAA) and the Australian Ultralight Federation (AUF) review training standards and experience requirements for ultra-light pilots intending to upgrade to aircraft with significantly enhanced performance characteristics.

2. The AUF should encourage manufacturers of trike aircraft fitted with parachutes to ensure that the emergency parachute is attached to the seat frame and is compatible with the performance of the aircraft.

During the landing roll both mainwheels entered soft areas in the strip surface. The aircraft swung through 120 degrees to the left then slid sideways for 17 metres before the right maingear collapsed. The wing struck the ground and was bent upwards. The condition of the strip surface was unsatisfactory because the first 500 metres contained soft spots. The positions of the soft spots were not marked, nor was the strip threshold displaced. The pilot had used the strip previously but on this occasion he did not check its serviceability before the flight.

The pilot had been ridge-flying not far from the glider field, along a range of hills oriented north/south. The coastline was located just west of the range of hills, and a north-westerly wind was providing good lift along the ridge. When a sea breeze developed, the wind changed to a south-easterly and the pilot was unable to maintain altitude or reach the glider field. During the subsequent outlanding the glider sustained damage when the pilot induced a ground loop to avoid striking a fence.

At a height of about 150 feet after a normal take-off, the aircraft commenced to roll slowly to the right. Corrective control inputs appeared to the pilot to have little or no effect and the aircraft continued to roll, with accompanying nose drop and yaw. The right wing tip struck the ground, followed by the landing gear. The gear was torn off and the aircraft overturned, coming to rest across a drainage ditch. No fault was subsequently found with the aircraft which might have contributed to the loss of control. There was no evidence of wind shear or any other atmospheric disturbance. The pilot reported that the engine power, attitude and airspeed had been such that a normal climb should have been achieved. The reason for the accident has not been determined.

The pilot purchased the aircraft the week prior to the accident. He had no aeronautical experience prior to the acquisition and had not undertaken any form of training for ultalight flying. Whilst conducting taxy tests with the control column all the way aft to feel the effects of the controls the aircraft became airborne with less than full power set. After liftoff the airspeed decayed rapidly the aircraft became uncontrollable and dived into the estuary. It is a requirement of the regulations covering the piloting of ultralight aircraft that before acting as pilot-in-command of an aircraft that the pilot undergoes specified training. This accident was not the subject of a formal on scene investigation.

Circumstances:

The purpose of the flight was to carry out training in simulated forced landings. The aircraft was flown by the student to an airfield, and the instructor demonstrated a forced landing onto the airfield. During the landing roll the propeller is reported to have contacted the ground and thrown mud and water onto the aircraft windscreen. The aircraft was not inspected but was taxied back to the threshold and the instructor commenced a short field take-off. Acceleration to the mid-point of the strip was normal; however, from there on the ground was softer and acceleration reduced. The aircraft became airborne but touched down in the adjoining paddock before running through a fence. During the take-off run, the student, who was watching the airspeed indicator closely, noticed that the instructor attempted to fly the aircraft off the ground at 50 knots, the take-off safety speed being 59 knots. Wheel marks on the strip indicated that the aircraft became airborne 23 metres after the strip end. It settled back onto the ground 130 metres later and ran through the fence.

Significant Factors:

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

1. The strip was unsuitable for the operation.

2. The condition of the strip was not checked prior to the commencement of the takeoff.

3. The pilot did not abandon the takeoff.

4. The pilot mishandled the aircraft controls during the take-off.

Circumstances:

The pilot was undertaking a 300 kilometre triangle cross-country task. A witness reported seeing the aircraft circling at about 400 feet above ground level (agl) before starting to fly a straight path. The aircraft was then seen to begin circling again at a much lower altitude after which it straightened up and flew in the direction of the home airfield. The glider was then observed to nose over and strike the ground without any apparent attempt at recovery. An inspection of the aircraft on site by a club official showed that the airbrakes were fully extended and the flaps were at plus ten degrees when the aircraft impacted. The pilot reportedly could not recall circling at a low altitude, but he believes that he was attempting to land prior to the accident. A probable explanation of the accident is that the pilot allowed the aircraft to stall at a height insufficient for recovery.

A witness, who lives alongside the airstrip, observed the aircraft flying in a north-south direction, about 300 feet above ground level and about 300 metres to the east of his position. The witness took particular notice of the actions of the aircraft and watched as it porpoised three times before diving steeply into the ground. Inspection of the wreckage revealed no defect which may have contributed to the accident. Weather at the time was fine, wind was light and variable, and the aircraft was being flown over flat pastureland. Investigation revealed that the pilot suffered from epilepsy, had heart disease, and that this was his first flight for over one year.

Circumstances:

The pilot had held a Private Pilot Licence for several years, for conventional aircraft only. He bought the gyroplane as a kit and assembled it late in 1988. His brother later bought a similar kit, and this was mostly assembled by the pilot. In the period 31 January-2 February the pilot received 3.5 hours of dual instruction in a two-seat version of the type. The flights consisted of take-offs and flights along the strip. No circuits were carried out. The instructor assessed that the pilot was tending to overcontrol the aircraft and recommended additional training. There was no evidence to indicate that the pilot carried out any further flying. On the day of the accident the pilot carried out a series of taxy runs and short hops along the strip. Following these he flew about six separate circuits, climbing to about 100 - 120 feet, landing and taxiing back to the start point on each occasion. The pilot's brother's machine had never been flown and the pilot suggested that he fly it for him. Two take off runs with brief lift off and landings were made. The pilot then flew several circuits and landings. Late on downwind on the final circuit the aircraft started to porpoise, with increasing amplitude. On about the fourth of these the nose went down, and the aircraft subsequently struck the ground in an inverted attitude. Inspection of the wreckage did not reveal any signs of pre-existing defects. For operation of these machines, it is necessary to ensure that they are flown under a positive gravitational loading. If this is not done the aircraft quickly becomes uncontrollable and may turn upside down. The porpoising manoeuvres seen just before the accident are known to lead to a negative gravitational loading situation if not quickly corrected. Advice provided to the investigation was that the appropriate control action was to reduce engine power to idle and hold the control stick central. In his limited training the pilot had not progressed to the stage of having the recovery technique demonstrated to him. It is possible that with his low experience level he may not have appreciated the dangers of the porpoising situation. While the machine in the accident and the one owned by the pilot were similar, there were some differences. The pilot's own machine was fitted with fairings, a windshield and a horizontal stabiliser. Persons experienced in the operation of gyroplanes consider that with a horizontal stabiliser the machines are more stable and less susceptible to porpoising and negative gravity situations.

Significant Factors:

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

1. Pilot did not obtain sufficient training on gyroplane operations.

2. Aircraft had different design and therefore, different flight characteristics to model previously flown.

3. Probable onset of porpoising, precise reasons undetermined.

4. Pilot unable to regain control possibly due to lack of knowledge and/or experience.

During a Police search for an offender in scrub country, the helicopter was required to hover at about 100 feet over level ground in light wind conditions. After about 12 minutes in the hover with the co-pilot at the controls, it became necessary to re-position the aircraft slightly to the right and rear. To maintain adequate observation of the search area the pilot in command took over the controls and elected to back the aircraft into the new position. Whilst backing-up a slight descent developed. Power was increased but without effect. The pilot then applied full power and forward cyclic control in an effort to arrest the sink and fly away, but descent continued until the aircraft struck the ground heavily. The right maingear was broken and the fenestron shroud sustained damage. After the impact the aircraft bounced back into the air and the pilot maintained a low hover while the extent of the damage was assessed. He then flew the aircraft to the base camp and carried out a successful landing on fuel drums, which supported the right side of the aircraft. The initial slow descent during the back-up manoeuvre was probably the result of the pilot having just assumed control of the aircraft, coupled with a diversion of visual attention while moving towards the required position. The reason for the final, rapid descent could not be established. The aircraft manufacturer had no information relating to previous uncontrolled descents under the conditions which existed at the time, and therefore no procedures had been developed to counter the phenomenon.