Circumstances:

The pilot had hired the aircraft to conduct a flight to a destination 240 kilometres from the DEPARTURE airport. The aircraft had been operating that day on a charter flight and was late returning. This caused the pilot to become anxious as the weather was forecast to deteriorate. He was informed by the operator that fuel had been arranged for the aircraft on its arrival, and it would be replenished to the indicator tabs in the fuel tank filler necks. This would give the aircraft an endurance of 240 minutes, the return flight time being estimated as 110 minutes. The pilot duly submitted a flight plan indicating this endurance. When the aircraft landed the refueller set out to refuel it, but the tanker broke down. When the pilot arrived at the aircraft, he assumed that it had been refuelled. He carried out a rushed pre-flight inspection including a check of the fuel tanks, although he did not consciously notice if the level was up to the tabs. The flight to the destination was uneventful, but at no time did the pilot seriously consult the fuel gauges in the aircraft. The next morning the pilot prepared for DEPARTURE, but as the airstrip was located on a claypan and there was a chance of further rain that would render the area unserviceable, he again rushed the pre-flight inspection. He was still able to see a level of fuel in the tanks but again failed to cross reference this with the fuel gauges. Approaching Alice Springs, the engine began to run roughly and lose power. The pilot was unable to restore power and carried out a forced landing in the only suitable area. On landing the aircraft bounced heavily then collided with a tree. The pilot believed that the aircraft had suffered a fuel blockage and was surprised to learn that the aircraft had not been refuelled before his DEPARTURE. He then accepted the fact that he had run out of fuel. This accident was not the subject of an on-scene investigation.

Significant Factors:

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

1. Pilot anxiety/apprehension at deteriorating weather conditions.

2. Inadequate pre-flight inspection on two occasions.

3. The pilot did not monitor the fuel gauges during flight.

4. Fuel exhaustion, resulting in the pilot being forced to land on unsuitable terrain.

Circumstances:

The purpose of the flight was for the pilot-under-instruction to gain endorsement for constant speed propeller and retractable landing gear operations. This was only the second flight on type for the pilot-in-command and the first for the pilot-under-instruction. The pilots stated that the pre-landing checks had been completed and that the landing gear down and locked light was illuminated. The light was rechecked on final approach to the runway. The pilots reported that the touchdown seemed normal, but the aircraft soon adopted a left wing low attitude. The propeller then contacted the runway surface and the aircraft settled on to its underside before skidding to a halt. A thorough examination of the landing gear system revealed no fault. The type and location of abrasion damage to the nosewheel doors, and the lack of damage to the main gear fairings and brake assemblies, indicated that the doors were closed when the underside of the aircraft contacted the runway, i.e. the landing gear was in the retracted position. It was noted that the red and green post lights on the instrument panel which indicate high and low vacuum pressure were of the same type as the landing gear position lights. The green vacuum light was seven centimetres from the green landing gear down light in approximately its two o'clock position. It was considered possible for the crew to have mistaken one light for the other.

Significant Factors:

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

1. Neither pilot was familiar with the aircraft type.

2. The landing gear was not extended.

3. The pilots possibly mistook the green vacuum light for the green landing gear light on the instrument panel.

4. The aircraft landed with the landing gear retracted.

Circumstances:

The aircraft was being prepared for a normal push-back DEPARTURE from the Sydney freight apron position V2. A towing tug was connected to the nose gear and number two engine was running at idle power. The aircraft was cleared to be pushed back to taxiway GOLF where the other engines would be started. The aircraft brakes were released but as the tug took the weight for the push back, there was a loud report, and the nose of the aircraft collapsed onto the cabin roof of the tug. The nose wheels folded back under the fuselage and arrested its fall, saving the tug cabin from further collapse. The engine was immediately shut down and the crew departed the aircraft to assess the damage. Investigation revealed the nose landing gear oleo outer cylinder, fabricated from 7079-T6 alloy, had failed at the upper end of the cylinder bore. The failure was initiated by a fatigue crack in the radius at the bore end forward quadrant. The radius in the vicinity of the crack was found to be .039 inches, marginally less than the manufacturer's minimum dimension of .040 inches. Extension of the crack due to stress corrosion was extremely rapid and may have occurred whilst the aircraft was parked at Sydney. Because of numerous reports of cracking in this area, the manufacturer issued a service letter recommending that operators consider replacement of nose landing gear cylinders fabricated from 7079-T6 alloy with cylinders of 7075-T3 or 7049-T73 alloy at overhaul.

Significant Factors:

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

1. A fatigue crack developed in the bore top radius of the nose landing gear cylinder.

2. The marginal dimension of the bore top radius may have contributed to the development of the initial fatigue crack.

3. Stress corrosion then developed the crack at a rapid rate to final failure.

Recommendations:

A recommendation to improve the strength of towing tug cabins is being prepared.

After selecting gear up on DEPARTURE, the pilot noticed the gear unsafe light did not go out. He assessed that it was probably a false indication and continued with the local flight. On return for landing, the right main landing gear leg would not extend by the normal or the emergency systems. The pilot elected to land with the landing gear retracted. After conducting a trial approach and overshoot on runway 31, he made a shallow approach for the same runway from 6 to 7 km out. The wind was from the north-west at 10 to 15 kts. His intention was to touch down near the threshold. Full flap was selected on long final, and airspeed was reduced to 60 kts, 15 kts below the normal approach speed. On late final sudden sink was experienced and the aircraft struck the ground about 120 m short of the runway. It then slid into a large drainage ditch along the airfield boundary. The right landing gear leg failed to extend because the bolt joining the upper and lower torque links had fractured. This bolt had become corroded and seized in the bushes through lack of lubrication. Bolt failure allowed the upper torque link to catch on a section of the landing gear bay, thereby preventing the gear leg from being extended. The pilot indicated that he elected to conduct the approach at a lower-than-normal airspeed because he wished to minimise the resulting ground slide.

Significant Factors:

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

1. Mechanical failure to the right main gear torque link bolt, due to lack of lubrication.

2. Landing approach conducted at a lower than recommended airspeed.

The pilot was hovering the helicopter at about 60 feet above ground level and about 30 feet above a large tree, when the engine began to lose power and the aircraft commenced to vibrate. The pilot was unable to maintain height with the power that was available and he lowered the nose and flew clear of the tree. At this stage the rotor RPM began to decrease. The pilot selected the only clear area and attempted to land the aircraft. He used the collective pitch control in an attempt to cushion the landing but overpitched the main rotor blades at approximately 10 feet above the ground. The aircraft landed heavily, bounced forward 5 metres and collided with a large tree. The technical inspection revealed that the most probable cause for the loss of power was the breakdown in performance of the spark plugs of number 4 cylinder, due to a build-up of lead fouling. The reason for the fouling in this cylinder and not in the others was not determined. There is an inherent danger in stock mustering with helicopters in that there could be an engine failure or loss of power at a low altitude which will preclude an autorotational descent. On this occasion there was a narrow safety margin for the operation due to the ambient temperature and the aircraft weight, which meant that any loss of power required a forced landing.

The pilot was departing a confined pad amongst some small trees. He made a vertical take-off to about 20 feet and then commenced forward movement. The aircraft then began to descend and the pilot increased the collective pitch. The blades entered an overpitched condition and during the subsequent attempted landing the main rotor struck a tree. The pilot had flown in and out of the DEPARTURE pad a number of times, on the day of the accident, without encountering any difficulty. Immediately prior to the accident he had refuelled the aircraft to what he believed was approximately half tanks. Subsequent investigation indicated that the tanks were three quarters full. Temperature at the time of the accident was about five degrees above that for the pilot's earlier flights. The pilot was aware that a power check should be carried out at each lift off but he did not check the excess power available on this occasion. When the aircraft moved from the hover into forward flight there was insufficient power available to maintain rotor rpm when the pilot increased the collective pitch angle to stop the descent. It is possible that the terrain and wind conditions may have caused some mechanical turbulence which could have added to the amount of power required to transfer from the hover to forward flight.

Circumstances:

The aircraft was loaded close to its maximum all-up weight and departed from runway 24. The take-off was normal, and the aircraft was airborne within 500 metres. After take-off, a right turn was commenced which is normal procedure to avoid the rising terrain. The aircraft was apparently performing normally and climbing at about 65 to 70 knots. However, approaching a row of pine trees, it began to lose height. Despite the pilot maintaining the aircraft in the climb attitude, and using full engine power, the aircraft continued to lose height until ground impact. Although fire rapidly developed after impact the pilot successfully assisted the passengers to evacuate. No pre accident defects were found with the aircraft which could have contributed to the accident. At the time of the accident, a low pressure of 995 hPa was situated over the area. This combined with the surface temperature of about 28 to 30 degrees Celsius to produce a density altitude of 4650 feet at the airfield which is 1850 feet above sea level. The weather pattern was also producing gusty winds and mechanical turbulence over the surrounding hills. A combination of high-density altitude and high aircraft all-up weight resulted in a best achievable rate of climb of about 400 feet per minute. This was reduced by the effects of downdrafts, turbulence, and the turn, with the result that the aircraft could not outclimb the terrain.

Significant Factors:

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

1. High density altitude.

2. High aircraft all-up weight.

3. Turbulence and downdrafts over the surrounding hills.

4. Pilot's low aeronautical experience level.

The pilot was cooling the engine down at 2500 RPM after completing a circuit and normal landing. Suddenly, a hard, high frequency bounce developed and the helicopter bounced left skid low followed by a 45 degree yaw to the left. The pilot had tightened the control frictions after landing and he attempted to release these as he fought for control of the helicopter. He was unable to release the control frictions and the cyclic control grip was broken during his attempts to restrain the movement of this control. The engine stopped without input from the pilot and the aircraft came to rest. The period of ground resonance had been about 5 seconds. During the preflight inspection the pilot had noticed that the front left landing gear was slightly under-inflated, although he considered it to be within normal limits. However, the correct landing gear damper inflation is critical in the prevention of ground resonance in this type of helicopter and the Pilot's Flight Manual contains a caution to this effect. Incorrect or unequal landing gear damper pressure can markedly alter the resonance response of the undercarriage system of the helicopter. If a rotor head vibration is induced, for whatever reason, and it is in sympathy with the resonance response of the undercarriage system, then ground resonance will occur. The cause of the rotor vibration that initiated this occurrence of ground resonance could not be established.

An unidentified aircraft was heard to depart Kalgoorlie at approximately 0430 hours, and VH-UQR was subsequently reported to have been stolen. Some four hours later the aircraft was sighted, flying at low level, by a number of witnesses in the Margaret River area. The engines were reported to be not operating normally. The aicraft then disappeared from sight behind trees and was heard to crash. The wreckage was located in a heavily wooded area. An inspection of the site indicated that the aircraft had collided with the ground following a high speed descent at an angle in excess of 30 degrees. Neither engine was producing power at the time of impact. The investigation indicated that the fuel supply had been exhausted at the time of the accident. Although the aircraft was almost totally destroyed there was no evidence that aircraft components or systems contributed to the accident. Neither pilot was qualified to fly, or had any known flying experience, on the Cessna 310 or any other multi-engine aircraft type. The factors leading to the theft of the aircraft were not established.

Circumstances:

The aircraft departed with full fuel tanks and had been airborne for approximately 25 minutes when the engine lost power. The pilot sustained back injuries in the subsequent forced landing. The investigation revealed that a threaded union which connected a drain line to the bottom of the carburettor fuel bowl had unwound, causing the bowl to drain. The engine then lost power due to fuel starvation.

Significant Factors:

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

1. For reason(s) which could not be established, a drain line connected to the bottom of the carburettor fuel bowl had become loose, allowing fuel to leak from the bowl.

2. The engine lost power due to fuel starvation.