Loss of control

At 1627 hours the wreckage of VH-EQU was located in an area of relatively dense timber 137 metres beyond and 91 metres to the left of the end of Runway 14 at Batchelor. The aircraft had struck the ground at a relatively low speed whilst in a steep nose down, left wing down attitude. The evidence indicates that the aircraft sustained a substantial, but unexplained, loss of power at a low height after take off.

The unmarked area being used as an agricultural airstrip was situated on a narrow ridge aligned north/south. There was high ground to the north and wide deep valleys in all other directions and it was necessary for landings to be made to the north and take-offs to the south. The strip was 365 metres long and it curved 15 degrees to the left at a point 243 metres from the southern end. It sloped down at 2.75 degrees for the first 152 metres and then rose at a 4 degree angle to the loading area which was near level. The central section was about 11 metres wide and the surface of short grass and bare earth was smooth.

The aircraft touched down at about the point where the longitudinal slope changed and in the long grass to the right of the central section. The aircraft ran parallel to the southern portion of the strip and the pilot attempted to steer it left into alignment with the northern section. Although the heading of the aircraft was changed to the left, the wheels skidded on the surface, the path of the aircraft did not change and it failed to follow the curve of the strip. As the aircraft approached a gully where the ground fell away steeply, the pilot applied full engine power in an attempt to "go around". The aircraft became airborne at low speed as the ground fell away but it then descended, struck the steeply sloping ground and overturned. It came to rest at a level about 100 feet below that of the northern end of the strip.

VH/ULC had been constructed by the pilot and was classed as an amateur-built aircraft. Being an amateur/built aircraft, a flight test schedule was required to be completed before a Certificate of Airworthiness could be granted.

The pilot flew the aircraft several times and on the day of the accident had completed a flight of approximately two hours duration. After the aircraft was refuelled to capacity the pilot made it known that he intended to carry out a further flight and after starting the engine the aircraft was seen to taxi out and takeoff from runway 03 into a 10 to 15 knot headwind. At a height of about 300 ft after takeoff, the engine noise was heard to stop suddenly and the aircraft was seen to turn towards the right. It then descended rapidly and struck the ground in a near vertical nose down attitude. Subsequent examination of the wreckage failed to reveal any evidence of a pre-existing.defect or a reason for the engine's sudden loss of power.

Aircraft bounced several times on takeoff pulled into air in stalled condition. Prop pitch found faulty.

Unauthorised flight by student pilot lost control after takeoff. The car arrived at the southern end of the airstrip as the aircraft commenced to take off towards the north. After a short ground roll, the aircraft became airborne and climbed steeply to a height of about 150 feet. It then commenced a steep climbing turn to the left and, after turning through some 90 degrees, the nose dropped and the aircraft dived to the ground and overturned after impact. Shortly after impact a fierce fire broke out and extended to the surrounding scrub.

Attempts were made to obtain photographs of VH-MJO with sharks in the background but these were unsuccessful. It was then decided that VH-KWN would descend to 500 feet to photograph the school of sharks, while VH-MJO remained clear of the other aircraft. The pilot of VH-KWN extended flap to 30 degrees and reduced speed from about 70 knots to 55-60 knots, using just sufficient engine power to maintain 500 feet altitude. Two left hand racecourse orbits were flown around the sharks and, during the third orbit, while on a north-easterly heading, the pilot had a discussion with the photographer regarding the positioning of the aircraft and then looked out to the right to check the location of the other aircraft. As a further left turn was initiated the pilot looked at the aircraft instruments and noticed that the altitude had decreased to 300 feet and that the airspeed was also low. The port wing dropped and the stall warning was heard to operate. Despite the initial application of corrective aileron, and the subsequent application of right rudder, forward stick and engine power, the aircraft lost height rapidly and struck the water in a nose down, port wing low attitude.

The main rotor blades made contact with objects on the deck of the barge and three bystanders were struck by flying debris. The helicopter then fell into the water and subsequently the pilot swam clear of the wreckage. The cause of the accident was that the helicopter was operated in unsafe proximity to the barge.

Mr. Armstrong purchased the aircraft in June, 1972 and later that year, assisted by two other persons also not authorised to perform such work, modified and fitted to the aircraft a long range fuel tank of unknown history. This work was not recorded in the aircraft log book as is required. The aircraft subsequently underwent a major inspection followed by some 60 hours flying before again being delivered to the owner during September, 1973. Mr. Armstrong then flew the aircraft on various occasions totalling some 11 hours although, being the holder of a student pilot licence, he was not authorised to pilot any aircraft unless he was under the supervision if a flight instructor.

The aircraft was crulstng in a southerly direction at an altitude of 4500 feet above mean sea level in clear weather conditions north of Mansfield when there was a substantial loss of engine power and smoke issued from the engine and entered the cabin. The pilot checked the engine controls and selected the mixture control to the idle cut-off position. He made a distress radio call to the Melbourne Flight Service Unit and reported that he had a suspected engine fire and intended to make a forced landing two miles north of Mansfield. A field to the left was selected by the pilot as being suitable for a forced landing and he planned to fly down the western side of the field and make a left turn of about 180 degrees to land to the north into a light northerly surface wind. As the aircraft descended the undercarriage was selected down and a left hand turn was commenced but, as the turn progressed,the pilot decided that the field which he had selected was unsuitable and that he would now land in the field adjacent to and to the west of that originally selected. At this stage the starboard wing dropped and, despite recovery action taken by the pilot, the aircraft veered to the right until it was heading some 45 degrees to the right of the intended final approach path at a very low height. The aircraft then struck the upper limbs of a large gum tree at a height of about 50 feet, passed through the upper section of the tree and dropped steeply' into a nearby small dam coming to rest in a level attitude in water some four feet in depth. Subsequent investigation indicated that the engine power loss was the result of an in-service failure of the No. 4 cylinder connecting rod big end bearing as a result of which the connecting rod had fractured and penetrated the crankcase.

The aircraft was engaged in the transport of men and materials In connection with the installation and maintenance of conveyor belting. The flight had commenced at Maitland, New South Wales, on the previous day and, prior to departure, the pilot had loaded the aircraft with a quantity of heavy, low volume materials. With one passenger on board, the flight to Groote^Eylandt had been uneventful. At Groote Eylandt the main and wing tip fuel tanks were replenished for the final stage of the flight to Gove. Before tlie aircraft began its departure from Groote Eylandt, two more passengers, their baggage and further materials of trade were loaded on board and distributed by the pilot. The weather was fine and clear and the wind was calm.

After the engines were started, the aircraft taxied to the eastern end of the 6,240 feet long bitumen runway and Phen commenced a take off into the west. Following a ground run of about 3000 feet the aircraft became airborne and entered a gentle climb. The nose of the aircraft was then seen to rise, the climbing angle increased abruptly and the aircraft climbed steeply to a height of some 300 feet. At this point the port wing went down very quickly until the aircraft was banked almost vertically. The ncse then dropped and the aircraft entered a flat, left hand spin from which it did not recover.

The aircraft struck the ground at a position 150 feet to the left of the runway centreline and 4480 feet from the eastern end of the runway. The undercarriage was found to have been down at impact and there was no fire. It has been calculated that, before the flight began, the loaded aircraft weighed 4433 pounds, which is 705 pounds in excess of the maximum permissible gross weight and the centre of gravity, with the undercarriage down, was located 3.9 inches aft of the rear limit specified for the aircraft type. This loading configuration could lead to the aircraft entering an uncontrolled nose pitch up condition with insufficient stabilator control available to correct the situation. There was no defect of the airframe or engines which could havo contributed to the loss of the control experienced.