Collision with terrain

While taking off from a forestry strip the aircraft performance achieved was less than expected. Concerned about terrain proximity after liftoff the pilot operated the dump lever. This did not prevent the landing gear from striking a log beyond the end of the strip. The aircraft continued to fly, and the pilot diverted to Albury Airport. During the subsequent landing roll, the right main landing gear leg collapsed.

Soft sand had been put on portions of the centre of the forestry strip, and it appeared this had adversely affected the take-off performance. A spreader was fitted to the aircraft to assist in distribution of the hopper load. When the dump was attempted, the spreader severely reduced the effectiveness of the dump and only about 20 per cent of the load was jettisoned.

Significant Factors

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

1. The presence of soft sand on the strip surface.

2. The pilot did not anticipate the effect the sand would have on the take-off performance.

3. Fitment of the spreader resulted in a severe reduction in the performance of the dump system.

The pilot was taking his passenger for a flight to demonstrate the aircraft. Following preflight and pre-take-off checks the take-off was commenced from runway 28. The aircraft accelerated normally until 60 knots when the aircraft was established in a 400 feet per minute climb. As the aircraft crossed the upwind threshold it began to sink. The pilot checked the performance and found that the airspeed was 60 knots, and the engine was developing full power. He lowered the nose of the aircraft to the straight and level attitude and the aircraft maintained level flight. However, as the nose was raised again to outclimb trees ahead, the aircraft again began to sink. The pilot turned the aircraft to the right towards a clear area but was unable to avoid the trees.

The aircraft came to rest upright in an area covered by 15 foot high regrowth. The pilot was able to extricate himself from the wreckage but because of his injuries could not free the passenger.

The pilot had not operated from Mareeba prior to this flight and was unaware that local pilots do not normally use runway 28 for take-off because of downdraughts near the upwind threshold.

At the time of the accident the weather was fine and clear with a temperature of 22 degrees Celsius and no wind.

The aircraft was flying over the Grampians Mountain ranges, the highest peak of which is nearly 4000 feet. The pilot reported that he had diverted slightly to the north of track to avoid the higher peaks of the first range but also to keep clear of a storm to the south and to keep below cloud. As the flight proceeded, the pilot realised that the aircraft was not going to clear the rising ground. He attempted to turn away from the rising ground but realised that the aircraft was going to sink into the trees in the heavily timbered terrain. The pilot lowered flap and stalled the aircraft into the tops of the trees, estimated to be between 20 and 30 metres high.

The aircraft was destroyed as it fell through the trees to the ground. The two occupants spent the night at the site. Early the next morning, when there was no longer any sign or smell of fuel, they turned the radio on and made a call to Melbourne, after which search and rescue procedures were commenced.

The pilot initially believed that the engine had suffered some form of power loss. The wreckage was inspected by an aircraft engineer who reported that damage to the propeller was consistent with the engine delivering significant power at the time of propeller impact. The Bureau of Meteorology advised that there were active thunderstorms in the area at the time with the possibility of severe downdrafts. In addition, conditions were conducive to the formation of carburettor ice. However, an eyewitness reported that the wind was calm, and the sky was clear at the time of the accident.

The accident was not formally investigated by the Bureau, and it was therefore not possible to determine significant factors that could be supported by sound evidence.

Shortly after lift-off, at about 50 feet, the right engine surged and lost power. The pilot was unable to control the yawing effect and attempted a landing beyond the departure end of the airstrip. During this attempt the engine surged to power once but as this exacerbated his control difficulties the pilot closed both throttles. The aircraft cartwheeled after striking the ground with the left wingtip. The aircraft came to rest in a paddock beyond the 1,000 metre airstrip.

The fuel selector for the right engine was found in the auxiliary position. The pilot later commented that he probably missed the fuel selection out of his pre-take-off checklist. He said that he had been in the habit of using a memorised checklist for the operation of the aircraft and at times he had forgotten to switch the tank selection from auxiliary to main tank prior to landing, as required by the operating instructions in the aircraft flight manual. The pilot also commented that he felt uncurrent in asymmetric operations.

Examination of the right engine did not reveal any defects which could cause a power loss.

Significant Factors

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

1. The pilot did not follow flight manual operating instructions for the operation of the aircraft fuel system.

2. The pilot relied on a memorised checklist.

3. The pilot was uncurrent in asymmetric operations.

The pilot advised that at the time of the incident he was carrying out a last +fly around; of his property which had recently been sold. The pilot's three year old son was the only other passenger on board. While manoeuvring at low level the pilot's attention was diverted into the cockpit for a period of time, assisting his son who had become ill. During this period of distraction the pilot had inadvertently allowed the aircraft to descend. He recalls looking outside the aircraft again just as it impacted the ground. The pilot confirmed that the aircraft's engine and flight controls were operating normally at the time. The pilot received serious injuries to both ankles in the accident. The passenger received only minor cuts and bruising. The aircraft was damaged beyond economical repair.

The pilot was taking off from the 020 degree grass strip but was using only the last 700 feet of the available 2200 feet. Partial engine failure occurred when the take-off roll was well established. The engine surged. The pilot applied carburettor heat, full rich fuel mixture and full throttle without regaining full power. The pilot continued the take-off and became airborne. He advised that he had to turn to avoid trees. The aircraft stalled from somewhere between 50 and 100 feet. The wings were damaged. The engine was pushed back into the firewall and the undercarriage collapsed.

The owner subsequently advised that no fault has been found with the airframe, engine or fuel system. He believes that the likely cause of the loss of engine power was carburettor icing.

Significant Factors

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

1. The engine suffered a partial engine failure probably because of carburettor icing.

2. The pilot did not reject the take-off.

The club was carrying out joy flights in VH-WVQ and earlier in the day another pilot had flown these. A second pilot then took over this task. He flew his first flight with an adult passenger and no operating anomalies were noted. For his second flight a 12 year old boy was carried in the front seat, along with 13.5 kilograms of ballast.

On aero tow take off the pilot noted the stick had to be pushed fully forward to lift the tail. He said the handling felt a little "strange" in the air, but he elected to continue. Release was at 2800 feet, and he commenced circling in the Gap area to try and obtain lift. Positive two stages of flap was set, with a speed of 42 knots and 30 degrees of bank.

Lift conditions were poor; they were just maintaining height. At about 300 feet above a ridge the glider stalled with the left wing going down and the tail also dropping slightly. Recovery seemed slow even though the stick was pushed completely forward. It became impossible to avoid trees and on contact these pulled the wings backward. The glider came to rest in the trees with the canopy dislodged and the nose pointing down at the ground some 30 feet below.

The pilot was unable to prevent the passenger from undoing his belt and attempting to get out onto a branch. In the process the passenger slipped, then managed to briefly hold on to the branch with a hand before falling to the ground. He was injured but managed to walk to a nearby road where a motorist picked him up. The pilot got out of the aircraft onto a branch but could not get down to the ground which was still some 25 feet below. He remained there until rescued about 1.5 hours later.

It was a fine day with virtually no surface wind. Other glider pilots who flew either before or at about the time of the accident said that lift conditions were poor and intermittent. One of those who flew in the Gap area commented that he had to circle close to the mountain to get lift. As his turn took him out from the side of the mountain he lost the lift, with the variometer indicating -1. Post accident calculations indicated that the position of the centre of gravity was at 38.7 per cent Mean Aerodynamic Chord (MAC). The approved range was 22-40.6 per cent MAC.

Significant Factors

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

1. The conditions were unfavourable for obtaining adequate lift for prolonged flight.

2. The pilot continued the flight in marginal lift conditions.

3. The pilot allowed a severe stall to develop at a low height above the terrain.

The pilot reported that he was making an aerial inspection of the Benambra airstrip prior to landing. He overflew the strip at about 150 feet above the ground and then commenced a left turn at a bank angle of about 45 degrees. While turning, the pilot said he was looking at obstructions in the vicinity of the airstrip and neglected to monitor the airspeed. He felt the aircraft shudder and then it stalled. He managed to level the wings but was unable to arrest the descent. The aircraft struck the ground in a flat attitude in swampland immediately to the north of the strip.

The pilot said that the day was hot and the aircraft was heavier than usual, in that there were three persons on board. Usually he is the sole occupant. The elevation of the airstrip is 2250 feet.

Significant Factors

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

1. The pilot became distracted while manoeuvring in the circuit area and as a result the airspeed decayed and the aircraft stalled.

2. The pilot was operating the aircraft in a circuit area at a higher density altitude and higher weight than what he normally operated at.

The aircraft was conducting joy-flights near a Rock Festival. The pilot aborted a take-off attempt when it became clear to him that he would not obtain translational lift in time to clear trees at the end of the selected take-off area. He chose to air-taxi to a more suitable pad. To get to the pad, he had to air-taxi between two large trees. Whilst passing between the trees the pilot concentrated on rotor clearance and did not notice a wind gust which moved the aircraft towards the tree on the left. The main rotor hit a branch, forcing the pilot to take immediate recovery action. The aircraft landed heavily.

The aircraft struck an obstacle during an attempted forced landing.

Inspection found that the engine had stopped when the fuel on board had been exhausted after 40 minutes flying. The pilot reported that the tanks were half full prior to departure. This should have been sufficient fuel for about two and a half hours flying. No evidence was found of any fuel leaks.