Circumstances:

The pilot had just purchased the aircraft. He reported that when the landing gear was selected down, in the Maitland circuit, the nose gear failed to extend. All attempts to lower the landing gear using both normal and emergency procedures were unsuccessful. The aircraft subsequently diverted to Bankstown where an emergency landing was carried out with the nose gear retracted. It was later found that the nose gear door forward actuating linkage had travelled into an over centre position, preventing the nose gear doors from opening and the nose leg from extending. A mandatory service bulletin was issued by the manufacturer in October 1989 to improve the reliability of the nose gear door mechanism and to minimise the possibility of the nose gear not extending. The service bulletin was not the subject of an Airworthiness Directive in this country. No evidence was found to indicate the landing gear had been modified.

Circumstances:

About twenty minutes after DEPARTURE, the pilot advised Coffs Tower he was returning after observing a reduced engine oil pressure indication. Soon after, he reported oil fumes in the cockpit and requested a priority landing from a straight in approach to runway 03. The aircraft touched down heavily on the left main and tail wheel, collapsing the main landing gear and shattering the wooden propeller. The pilot reported the oil leak had emanated from an incorrectly assembled firewall fitting on the oil line to the oil pressure indicator. That fitting had been installed prior to the present owner purchasing the aircraft. The main gear is normally held in the locked down position by two mechanical latches. When the aircraft touched down heavily on the left wheel, one mechanical latch had slipped from the locked position. The other latch had not engaged due to misrigging.

Just after lift off, the pilot initiated a climbing left turn and the helicopter struck a powerline about 120 metres from the take-off point. Control of the helicopter was lost, it impacted the ground and rolled inverted. The occupants were able to evacuate the wreckage before it was destroyed by fire. The pilot was not aware of the existence of the powerline and did not see it during a pre-take off check of the DEPARTURE path. The nearest support pole indicating the existence of the powerline was surrounded by trees and the mottled background afforded a poor contrast for the detection of the wires.

Circumstances:

The pilot was taxiing for take-off from an agricultural strip when one main landing gear leg struck a tree stump, which was hidden by long grass, and collapsed. The pilot was not aware of the obstruction prior to the accident.

Significant Factors:

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

1. The pilot failed to ensure that the manoeuvring area was free of obstructions.
2. The pilot did not see the obstruction and therefore was unable to take avoiding action.

The pilot was carrying out various manoeuvres in the training area. After about an hour general flying, the pilot decided to conduct a practice forced landing approach to a disused strip on the island. At about 200 feet on final approach, the pilot moved the carburettor heat control to the cold position and applied full power to overshoot. The engine failed to respond normally, and produced only about 1500 rpm. The pilot exercised the throttle control without obtaining any further power increase, and he was then committed to a forced landing. Touchdown occurred in a cleared paddock and damage to the nose gear and propeller was sustained when the aircraft ran through a ditch. No fault was subsequently found with the engine or its associated systems. Reference to the appropriate chart indicated that atmospheric conditions were conducive to the formation of moderate to severe carburettor icing. Although carburettor heat was selected at the start of the forced landing practice, it was likely that some icing had already formed and was not dispersed by the time the throttle was re-opened. When the engine failed to deliver full power, the pilot had not re-applied carburettor heat in an effort to restore normal engine operation.

During mustering activities the aircraft was operating between 50 and 80 feet above the ground, when the engine suddenly stopped. The wind at the time was a quartering tailwind, and during the attempted autorotation the aircraft struck the ground in a tail-low attitude. The tail boom was severed, the aircraft bounced, spun to the right and came to rest with the landing skids collapsed. An inspection of the engine revealed that the magneto idler shaft had sheared due to overload caused by foreign objects fouling the magneto drives. The foreign objects were identified as crankshaft flange bolts which had been incorrectly torqued at overhaul.

The pilot reported that as he brought the aircraft into the hover in preparation for landing, it sank to the ground from a height of about 15 feet. The tailrotor blades struck a lygnum bush and the drive shaft sheared. The pilot indicated that the main rotor rpm had decayed, possibly from over-pitching during the latter stages of the approach. Operations had been conducted in gusty wind conditions. When the pilot noted that the main rotor speed had decayed to 2800 rpm, he applied more power but was unable to arrest the rate of descent.

Shortly after touchdown the pilot noticed a kangaroo on the side of the strip. He considered that more of the animals might be in the vicinity, and elected to carry out a go around. Full power was applied and the aircraft became airborne, but almost immediately afterwards the pilot changed his mind and decided to continue with the landing. When power was reduced again, the aircraft stalled and landed heavily. The nosegear subsequently dug into the surface of the strip and the aircraft overturned. After applying power to go around, the pilot had not monitored the airspeed and the aircraft had stalled at a low height above the strip.

The aircraft was engaged in the transfer of passengers from Cape Flattery to Cooktown. It was observed to overshoot from the first approach and to carry out a low level circuit subsequently landing with the gear retracted. The pilot reported that during the circuit following the missed approach, he was required to adjust the circuit pattern because of heavy rain in the area, and as a consequence flew a tighter than normal circuit. He also stated that during the circuit he was interrupted by radio conversations with another aircraft which was approaching Cape Flattery. An inspection of the aircraft revealed that the gear was in the locked up position and no damage had been caused to the main gear doors. No fault was found with the landing gear system that could have caused it not to extend when correctly selected down. The pilot believed that it was possible that when moving the gear selector lever to the down position he had not moved it fully down. He does not recall checking that the gear down indicator lights illuminated.

The pilot was conducting a cross country flight in company with a Thruster ultralight. Near their destination he lost sight of this aircraft. After several minutes of searching, he located the Thruster on the ground. However, during several low passes he could not see the pilot. Fearing for the pilot's safety he elected to land. Just as the Skydart was about to touch down the pilot saw some rocks ahead on the intended landing area. He applied full power for a go around but the left maingear leg hit a rock and was torn off. The pilot closed the throttle and landed adjacent to the other aircraft, which had also suffered landing gear damage during a forced landing. The other pilot was uninjured but had left the scene minutes earlier seeking assistance.