Loss of control

Shortly after the student had made a normal touchdown, a sheep ran across the strip in front of the aircraft. The instructor had not been looking forward, and he was taken by surprise when the student applied a considerable amount of nosewheel deflection in an effort to avoid the animal. The aircraft ran off the side of the strip and struck an earth run-off water vane. It was reported that the strip was 37 metres wide and this width is less than that required for a training authorised landing area. This accident was not the subject of an on-site investigation.

Before commencing spraying operations, the pilot discovered that the left maingear tyre was deflated. The tube was patched, however about half way through the spraying task the pilot noticed that the tyre was partially deflated. Air was added to the tyre, and the operation was continued. On the last landing for the day the left gear commenced to vibrate and the aircraft veered to the left. The pilot was unable to maintain adequate directional control, and the aircraft entered the crop at the side of the strip before ground looping to a halt. The left main tyre was found to be flat.

The pilot and his passengers had arranged to fly to Wagga Wagga to attend an agricultural seminar. He had flown the aircraft from his home base to spend the night at Melrose, with a friend, before departing the following morning. Prior to DEPARTURE, the pilot obtained a weather forecast for the route to be flown. He then submitted flight details that indicated the flight would be conducted in accordance with visual flight rules. The aircraft was later observed to take-off and head towards the north-east. Approximately 40 minutes after the aircraft departed the wreckage was sighted by a passing motorist. Ground marks indicate that the aircraft had struck the ground while heading in a north-westerly direction. Both the forecast and actual weather conditions at the time of DEPARTURE and the time of the accident indicated the presence of low cloud, poor visibility and rain in the area. These conditions were below those required for flight in accordance with visual flight rules. An inspection of the wreckage revealed that the aircraft had struck the ground at a relatively low forward speed between two areas of rising terrain. No fault was found with the aircraft that could have contributed to the occurrence.

Two photographers chartered the aircraft to fly them to a white tropical beach. Enroute to Hope Island, the passengers asked the pilot to land near a beach at the mouth of the Daintree River. After making a water landing on the river, the pilot found that he could not get his passengers and their photographic equipment to the shore because the hull of the aircraft grounded on a sandbank, some 50 Metres from the beach. A decision was then made to takeoff from the water and land on the beach. During the landing , the pilot lost control of the aircraft when one of the mainwheels ran through shallow water. The aircraft nosed over and came to rest inverted.

The pilot had diverted to Wellington because of thick bushfire smoke on his intended track. Take-off was initiated after the smoke had cleared, however shortly after becoming airborne the aircraft sank towards the ground. The pilot subsequently advised that although the engine was developing full power he was unable to prevent the sink from continuing until the aircraft struck the ground heavily, 210 metres beyond the boundary fence of the strip. The 05 strip was used for take-off into a north-easterly breeze. However a witness about 2 kilometres away, along the take-off path, reported that the wind there was from the south. It is likely that at about 200 feet agl the aircraft experienced a head to tail wind change. The pilot attempted to regain airspeed by lowering the nose but the low altitude and rising ground ahead prevented sufficient airspeed to be recovered.

Circumstances:

Well before the flight was due to depart, the company agent at Mabuiag Island endeavoured to warn the operator that the strip was wet and unsuitable for operations. This attempt to communicate failed due to a local fault in the Telecom system. The pilot was aware of a previous recent accident where a pilot landed short of the runway lip. When he arrived, he assessed the strip as suitable and landed well into the strip. By the time that he discovered that the strip was slippery, it was too late to go around. When it became obvious that he could not stop within the confines of the strip by using normal braking, he attempted a ground loop. The aircraft slid sideways off the end of the strip onto a beach.

Circumstances:

The pilot had purchased the aircraft some time prior to the accident and did not fly it until he had completed a full training course on gyroplanes of some 7-8 hours. Since completing the training, the pilot had flown about ten hours on type, mainly on windmill inspections on the property. The witnesses to the accident reported that the pilot had taken off on a windmill inspection and they had seen him return about 15 minutes later. As they watched from about one kilometre away, they saw the pilot approach the landing area at about 400 feet above ground level and commence a turn. The aircraft was then seen to nose over and continue in a dive until it struck the ground and exploded on impact. The South Australia Rotor Club was co-opted to assist with the investigation and through their assistance it was learned that this type of gyroplane was fitted with a large pilot cabin that extended some two feet in front of the rudder pedals. Other pilots have reported that this fitment induced severe pitch down in flight and/or severe yawing due to the imbalance of the air loads on the cabin compared to the correctional force available from the moments of an unmodified empennage. In effect, the anti-yaw moment from the rudder and fin is insufficient and the aircraft is without an effective horizontal stabiliser for effective anti-pitch control. A reduction of power at the onset of any perceived instability would be instinctive and would also reduce a pilot's ability to control the yaw due to the reduced propeller wash over the rudder and fin. The conclusions drawn from the investigation were that the pilot experienced a pitch down and/or yaw in flight that resulted in the imposition of negative g forces. These forces caused the retreating main rotor blades to dip and strike the fin and rudder. At the same time, the propeller would have disintegrated on contact with the rotor blades as they dipped into its arc. The blade strikes were such as to stop the main rotor and put the aircraft beyond the control of the pilot.

Significant Factors:

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

1. Faulty design. The aircraft was unstable when fitted with a large forward cabin.

2. An uncommanded DEPARTURE from controlled flight caused the main rotor blades to strike the propeller and empennage.

3. The rotor blades were stopped in flight rendering the aircraft uncontrollable.

Recommendations:

1. That the Civil Aviation Authority, in conjunction with the Australian Sports Rotorcraft Association (ASRA), advise all gyroplane operators of the design instability of the Wasp Air Buggy II when fitted with a large cabin.

2. That the CAA, in conjunction with the ASRA, devise and/or approve a suitable modification to the empennage of gyroplanes in conjunction with the fitment of large cabins.

3. That the short period oscillation of gyroplanes operated in Australia be examined. i.e. fit or replace the horizontal tailplane. A number of accidents in Australia can be attributed to DEPARTURE from controlled flight as a result of excessive pitching, (porpoising).

Circumstances:

The pilot reported that he had made a normal landing on the grass runway 14. The wind was a light crosswind from the left. During the ground roll the aircraft began to swing to the left. Application of right rudder was not effective, and the aircraft ground looped to the left. During the ground loop the right hand gear leg broke off and the right wing contacted the ground. At the time of the accident there was a thunderstorm developing nearby and strong thermal activity was reported in the circuit area by another pilot. The loss of directional control was probably caused by a sudden wind gust associated with the unstable local conditions.

Circumstances:

The glider was lined up short of the normal launch point. During the winch launch the wing-walker apparently released the into wind wing early. The wing dropped and the glider veered into the gusting crosswind. The pilot abandoned the launch however the glider continued to weathercock and ran into the retrieval vehicle before being brought to a halt.

The pilot had recently purchased the glider, and had previously made two short flights in it, for endorsement and familiarisation purposes. On the day of the accident he had trailered the glider to the launching strip, and had then assembled and rigged it for flight. A normal winch launch was carried out, with the glider releasing from the winch at about 1000 feet above the ground. It was then observed to be circling in a thermal, while gaining a further 500 feet of altitude. The angle of bank at this time appeared to be moderately steep. A witness then observed that the nose of the glider dropped and the aircraft commenced to spin to the left. It spun rapidly in a steep nosedown attitude, with occasional pitch oscillations, and recovery was not effected prior to impact with the ground. The subsequent investigation did not reveal any apparent faults or defects with the aircraft which might have led to the development of the accident. In addition, there was no medical evidence to indicate that the pilot was incapacitated or unfit to perform his duties as pilot in command. Although the pilot had received training in spin recognition and recovery techniques, he was possibly unaware that a spin could occur during an apparently normal thermalling turn. It could not be established when he had last performed spinning manoeuvres.