After establishing level flight with an external sling load, the pilot felt a bump from the rear of the helicopter. He corrected the accompanying pitch change and then a second bump was felt. The load was jettisoned and immediately the helicopter began yawing to the right. The pilot was unable to regain control before the helicopter struck the ground. The pilot had not flown helicopters for two years and although he had recently completed a check flight, slung operations were not covered. On this operation the pilot was substituted for another pilot who was unavailable. The load carried on this run was identical to loads previously carried, but much lighter. The pilot elected to use the same cruise speed as for the heavier loads. The load became unstable and encountered the tail boom. Upon its release the load slid back and was struck by the tail rotor, breaking off one blade and snapping the drive shaft.

During the fifth touch-and-go landing of a period of solo circuits the student pilot applied right rudder in anticipation of the expected swing as take-off power was applied. The aircraft immediately swung to the right and the student, becoming confused, applied further right rudder pressure. The aircraft left the runway and impacted a ditch outside the flight strip. The pilot was not using the sash component of his seat belt and he suffered a facial laceration when he struck the instrument panel during the impact.

It was reported that shortly after the takeoff roll had been commenced the left wing contacted the ground. The glider groundlooped and skidded off the runway. Visibility had been reduced at the time of the accident by dust generated by the tug aircraft.

The pilot, who was inexperienced in total hours and hours on the aircraft type, landed the aircraft firmly. A bounce occurred but the pilot persevered with the landing. After the aircraft had bounced a further three times the nose wheel collapsed and the aircraft slid to rest on its nose.

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.