The aircraft departed Brisbane for Cairns at 0343 UTC, cleared at FL330. This level was coordinated by the Brisbane Sector 7 Procedural Controller to Townsville Control. At 0435 UTC, the Sector 3 Radar Controller contacted the Sector 7 Radar Controller requesting a level change for the aircraft to FL350. This was approved and the aircraft was recleared at FL350. However, the level change was not coordinated with Townsville Control who were still expecting the aircraft at FL330. At the same time, the level change was not recorded on the flight strip for the aircraft. The request from Sector 3 concerning the level change was not heard by the Sector 7 Procedural Controller as there is no facility for that person to monitor the radar controller's hotlines.

The helicopter was maintaining an altitude of 2,500 feet when a small vertical jolt, accompanied by a slight roll to the right, was felt by the pilot. A check of the aircraft instruments appeared normal, but application of collective pitch only increased indicated engine torque without any change to the main rotor system pitch setting. The pilot briefed the passengers for a precautionary landing, then carried out a successful run-on landing.

An inspection of the helicopter revealed that the main rotor drive scissors link had failed, and that sometime in the past the scissor crank had been installed upside down. Examination of the aircraft records did not indicate when the scissor crank had been fitted but showed that the failed scissor link had been recently installed, having acquired 65 hours time in service since new.

It was found that fouling had occurred between the scissor link and the incorrectly fitted scissor crank when the collective pitch control was raised towards the full up position. This caused bending stresses in the scissor link which eventually failed in flight. The fouling had not occurred prior to the installation of the new scissor link as the old scissor link had had some free play in its bearings allowing sufficient clearance between the two units.

The end of the broken scissor link jammed in the rotating swashplate and maintained some integrity between it and the main rotor head. The pilot's action in restricting collective movement during the emergency descent and landing, which kept the scissor link in contact with the swashplate, probably prevented a more serious problem from developing.

The pilot reported that during the take-off run the cabin door opened. The take-off was rejected, and the pilot closed the throttles and applied the brakes. The aircraft overran the runway, ran through a dirt and a fence before coming to rest.

The aircraft sustained damage to the landing gear, propellers and the fuselage.

The pilot of the accident aircraft released from an aerotow about 4 km south-west of the airfield at 1,800 ft above ground level and immediately encountered strong sink so decided to return for a landing.

At about 2km short of the airfield he realised that the glider would not reach the runway and turned towards a suitable open field for an outlanding. Strong sink was encountered throughout the approach causing the glider to undershoot and strike small fruit trees in an orchard at the edge of the field.

The day had been fine but very hot, with other pilots also reporting areas of strong lift and equivalent sink.

On first contact with Bankstown Tower the pilot advised that he had an unsafe landing gear indication. A flypast of the tower confirmed that the nose gear was only partially extended. Emergency services were called to attend. The nose gear leg collapsed during the subsequent landing.

An inspection later revealed that the left nose gear door actuating rod had separated from its attachment ball end due to excessive wear. The rod had become jammed in the nose leg shimmy damper, thus preventing the full extension of the nose leg. During repairs to the aircraft an internal leak in the nose leg actuator was detected. This was rectified by replacing the internal seals.

In subsequent cycling tests of the landing gear system, the nose leg failed to fully extend. The hydraulic power pack was dismantled and found to have been in poor condition, to the extent that normal operation may have been compromised.

Shortly after the pilot retracted the landing gear, on departure from Perth, he observed a light flash on the Master Warning Panel. The pilot decided to check the landing gear system before proceeding further. As he lowered the landing gear both hydraulic LOW FLOW lights came on. The left main gear, only, locked down. The pilot decided to leave the gear selected down and refer to the emergencies section of the aircraft manual before proceeding further.

An emergency was declared and the aircraft returned to Perth. The pilot activated the emergency gear lowering system and obtained a down indication on the right and left main landing gears but not the nose gear. The emergency system is a single shot nitrogen gas system operating through the normal hydraulic lines.

An air and ground inspection confirmed that the nosewheel was trailing behind the normal locked position. The aircraft was held for approximately two hours to burn off fuel before the pilot made an emergency landing on runway 29 at Perth Airport. As the aircraft touched down, on its main wheels, the pilot shut the engines down and activated the engine fire extinguishers, as a precautionary measure. The nose landing gear folded up as the nose was lowered to the runway.

A post-accident inspection indicated that one of the hydraulic lines, in the right-hand landing gear extension system, split allowing the hydraulic fluid, used to activate the normal extension system, to escape. The split line also allowed the gas from the emergency extension system to escape. There was insufficient residual pressure in the system in either the normal or emergency modes to lock the nosewheel into the correct down position.

The possibility of a line failure is a known problem on the Cessna 441 aircraft. Fatigue cracking can occur at a bend in the line due to expansion and contraction of the bend resulting from pressure changes in the system. The operator had an inspection process in place aimed at disclosing any cracking prior to it becoming a safety problem. An inspection of the line, conducted prior to the flight, did not disclose the crack. The crack's location on the bend, longitudinal rather than transverse, probably prevented a hydraulic leak from becoming apparent until the crack was opened up, on the accident flight, by the system pressure.

Safety Actions

The operator is in the process of replacing all the suspect landing gear hydraulic lines on all its aircraft regardless of their condition. They will continue to inspect the lines on a regular basis in accordance with the program already in place and have indicated that they will be replacing the lines, which are normally an 'on condition' item, at more regular intervals.

The CAA will notify all operators of Cessna 441 aircraft of the details of the occurrence and of the action taken by the operator.

The pilot landed the helicopter in long grass leaving the engine at idle power.

Hot exhaust gas emissions from the exhaust tail pipe ignited the dry grass, engulfing the helicopter in flames. The pilot attempted to take-off, but the engine appeared not to respond.

Both the pilot and passenger received minor burns as they vacated the helicopter, which was damaged by fire.

The helicopter exhaust system appeared to have been modified with an extension welded to the tail pipe which directed the hot exhaust gases towards the ground. There did not appear to be any reported problems with the engine.

The helicopter on a ferry flight late in the afternoon failed to arrive at its destination. A search found the injured pilot and damaged helicopter the next morning only 4km from the departure point. The pilot had activated the ELT, but it failed to transmit.

The pilot stated that a vibration had developed shortly after departure, and he slowed the helicopter to nearly a hover at about 150 ft above ground level to determine its origin. He planned to land once clear of trees but as he manipulated the anti-torque pedals the helicopter went out of control and crashed heavily on its right side. Due to head injuries suffered during the accident the pilot had difficulty in remembering any details of the accident subsequent to slowing down.

Inspection revealed that marks on a tail rotor blade indicated that it had impacted something while rotating. The tail rotor drive shaft pin, connecting it to the universal joint, had sheared allowing the shaft to spin in the universal joint.

It was not possible to determine whether the connection between the universal joint and the drive shaft failed because of the tail rotor strike, or whether the tail rotor blade was damaged after the connection had failed.

Engineering evidence tends to indicate that something was struck by the tail rotor blades while they were under power. The item may have been similar to an item of clothing or cloth large enough to fail the tail rotor drive path by overload but not hard enough to dent the tail rotor blades. Nothing that fits this description was found in the immediate vicinity of the crash site.

The aircraft was engaged in an agricultural operation. The pilot having surveyed the property from the air and received on-site information from an agent on the ground by UHF radio, was aware of the many wires and other obstacles in the area.

On the initial swarth run the pilot failed to notice a single wire earth return line suspended between 15 and 18 metres above the ground, with a span of about 1000 metres. The aircraft struck the wire with the landing gear, decelerated rapidly and impacted the ground in a steep nose-down attitude.

During a winch launch the pilot noted that the glider was accelerating slowly. He considered abandoning the launch but because there was 6000 feet of runway he decided to persist until the winch driver realised that more power/speed was required. The speed slowly increased to 50 knots at which point the pilot made a gentle rotation. As soon as the glider started to rotate the speed fell off dramatically.

The pilot said that he lowered the nose immediately and then saw the ground approaching at a steep angle. He managed to get the aircraft to a level attitude but was unable to prevent it touching down very heavily resulting in substantial damage.