Loss of control

The pilot had intended to carry out aerobatic practice in the Dry Creek Aerobatic Training Area. After DEPARTURE, the pilot requested, and was cleared to operate in the Dry Creek area up to an altitude of 3500 feet. The aircraft was then observed to be spinning and crashed into a salt evaporation pan. The investigation revealed no pre-existing defects with the aircraft or its systems which may have contributed to the pilots inability to effect recovery from the spin. However, it was found that, at the time of the accident, the weight of the aircraft exceeded the maximum allowable by about 26 kilograms. The pilot was a member of a local aerobatic club and had accumulated some 30 hours of aerobatic flight. He had been assessed by his instructors and other experienced club members as a competent aerobatic pilot. The circumstances surrounding the entry to the spin and reasons for the pilots apparent inability to recover from the manoeuvre could not be determined.

The helicopter was being used as an platform for test equipment. Part of the test equipment included an aerial that was mounted vertically below the helicopter. This aerial could be retracted and stowed in a horizontal position for landing by operating a control which was positioned in front of the technician. On this occasion the pilot inadvertently attempted to land the helicopter with the aerial extended. Just prior to touch down the helicopter began to vibrate, the pilot lowered the collective and the helicopter rolled onto its right side. Following the completion of each test it was normal for the technician to raise the aerial prior to landing. On this occasion, the technician became engrossed with the transmission of test data and forgot to retract the aerial. The pilot was concentrating on the landing and neglected to ensure that the aerial had been retracted. Normally if a landing is attempted with the aerial extended a weak link in the system fails and the aerial is retracted by a spring. However, it is believed that because the helicopter touched down with little forward speed the weak link did not fail at the required time in the landing sequence.

Prior to DEPARTURE, the pilot had obtained a weather briefing, which indicated that deteriorating conditions were forecast. This forecast proved to be accurate and the pilot was forced to carry out a number of diversions to remain in visual contact with the ground. The fuel state of the aircraft also became critical, and in the face of further deterioration in the weather conditions, the pilot attempted to land on a racecourse. A normal touchdown was made, but the aircraft slid off the banked track and collided with the inside guard rails.

The pilot had been conducting a series of solo circuits and landings. On the seventh circuit, a normal approach was flown but the aircraft ballooned slightly as the flare was commenced. The aircraft was then seen to climb abruptly to a height of about 20 feet, and shortly afterwards the left wing dropped. Full power was applied, but descent continued and the left wing tip struck the ground. The aircraft slewed rapidly to the left and the nose struck the side of a ditch. During his training, the pilot had experienced some inconsistency in the control of the landing flare. On this occasion he had evidently applied rearward pressure to the control column, and had not relaxed this pressure before the aircraft stalled.

The glider was being launched via an aero-tow. It became airborne after a short ground run and climbed to a higher than normal altitude. The pilot attempted to correct the situation but the glider bounced twice on the strip, breaking off the tail skid. As the glider climbed away it continued to oscillate in a position above the tug aircraft. The tow rope was released when the glider was about 120 feet above ground level and the pilot, believing that there was insufficient runway remaining to land, attempted to turn back for a landing on the strip. During the turn the glider entered a spin subsequently striking the ground in a nose low attitude. The pilot was inexperienced on the aircraft type, having not flown the type for about two months. On the day there was a gusty wind blowing and it was the opinion of experienced local pilots that a landing straight ahead after rope release would have been possible.

The pilot was requested, by the passenger, to land the helicopter on the mud flats to the north of Kununurra. He decided to make a run on landing as he believed he may have difficulty in hovering the helicopter. As the aircraft approached the touchdown point, the pilot allowed it to yaw into wind, but it contacted the ground still moving sideways. The left skid caught in the dry mud and the helicopter rolled onto its side. The pilot was inexperienced in the operation of helicopters and had experienced difficulty in hovering the aircraft when he departed Kununurra that morning. The approach to land on the mud flat was poorly planned and the pilot misjudged the altitude of the aircraft during the turn into wind.

Circumstances:

The purpose of the flight was for the pilot under check to obtain a tailwheel undercarriage endorsement. Prior to take-off, the pilot under check was briefed that due to the instructor's seating position, he was unable to apply full rudder pedal travel. Therefore, rudder control would have to be exercised by the pilot under check. During a demonstrated short field landing by the instructor, the pilot under check did not take control of the rudder on the ground as briefed. Directional control of the aircraft was lost despite calls by the instructor for the pilot to check the swing and use brake. The aircraft left the strip and was substantially damaged. The reason why the pilot under check did not take control of the rudder pedals during the landing was not determined, as he refused to co-operate with the investigation.

The pilot was carrying out a period of solo circuits as part of a check on the aircraft type. Following the third circuit, the aircraft was observed to approach and land normally into the 10 to 15 knot headwind. During the subsequent landing roll, while still travelling at about 30 knots, the aircraft veered suddenly to the left. The pilot applied full right brake and rudder and then both brakes in an attempt to stop the aircraft. However, before the aircraft stopped it struck one of the boundary fence posts. An inspection of the aircraft did not reveal any mechanical defects that could have contributed to the occurrence, and the pilot was unable to explain the reason for the loss of directional control. This accident was not the subject of an on-site investigation.

Whilst mustering cattle near a holding yard, the helicopter was being held in the hover in a 15-20 knot headwind. Because some of the cattle broke away, the pilot turned downwind to herd them back. As the aircraft rolled out of the turn it began to descend and the pilot attempted to arrest the sink by increasing collective. However, the helicopter continued downward and impacted heavily on the ground resulting in the tail boom being sheared off. It then bounced into the air and began to yaw rapidly but the pilot quickly and firmly placed it back onto the ground. When the helicopter came to rest the occupants were able to extricate themselves from the wreckage. The pilot misjudged the performance that could be expected from the helicopter. When the machine was turned downwind, the sudden loss of lift resulted in a descent from which the pilot was unable to recover before the aircraft collided with the ground. The pilot reported that he believes he overpitched the main rotor during the recovery attempt.

The pilot had only recently arrived in the area and had not operated from this strip previously. On his first take-off from the strip he decided to employ a short field technique and lifted the aircraft off the ground at 50 knots. The aircraft became airborne after a ground roll of about 250 metres but after travelling a further 110 metres the wingtip struck the ground, the aircraft landed heavily and ran off the side of the strip. The pilot continued with the attempted take-off and the aircraft travelled a further 325 metres before the take-off was abandoned when the aircraft struck trees. The Pilot's Operating Handbook gives the climb speed after a short field takeoff as 57 knots. The prevailing wind at the time was a crosswind from the right and the pilot believes he may have encountered some tailwind component during the take-off. This combined with a lower than recommended climb speed probably resulted in the aircraft stalling before contacting the ground. After the aircraft had run off the strip it was travelling downwind over soft ground and thus would have required a higher groundspeed than that probably expected by the pilot before it became airborne.