Circumstances:

The aircraft was being pushed back from the parking bay of the operating company. The despatch engineer, who was on headset to the flight deck, was located near the nosewheels prior to commencement of pushback. When pushback commenced, he walked on the right side (looking to the rear of the aircraft) of the nosewheels, slightly leading them in the direction of travel and approximately one metre from them. Shortly after pushback commenced, the tug driver initiated a turn such that the nosewheels turned towards the despatch engineer. At this point, the despatch engineer was seen to stumble and fall into the path of the oncoming nosewheels, one of which ran over his right lower leg. The tug driver immediately applied the brakes, selected reverse gear, and pulled the aircraft off the engineer's leg. The investigation determined that the injured engineer had been in the employ of the company for one year at the time of the accident. He had done approximately six months on-the-job training in tarmac duties including pushback procedures. He was considered competent to do pushbacks of all aircraft in the fleet. The investigation did not determine what caused the engineer to stumble and fall. Company procedures for receipt and despatch of aircraft are published. Included in those procedures is a warning that "the despatch engineer must remain on one side of the aircraft, clear of nosewheels, whilst the aircraft is moving". The procedures also include advice that "the aircraft will normally be pushed back to a nominated despatch area with the despatch engineer walking beside the tractor and adjacent to the driver". The despatch engineer was aware of these published procedures. The reason he did not follow the procedures was not determined.

Significant Factors:

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

1. The despatch engineer was too close to the nosewheels during pushback.

2. The despatch engineer stumbled and fell into the path of the nosewheels resulting in his right lower leg being crushed.

Recommendations:

The major part of this investigation was done by the Safety Department of the operating company. As a result of that investigation the company made a number of recommendations which are summarised as follows

1. Issue instructions to ensure that all personnel involved in despatch of aircraft keep at least three metres away from the nosewheels and always stay behind the direction of travel of the wheels. In addition, the person on headset should stay on the inside of any turn.

2. Investigate the feasibility of a small hook on the inside of the Boeing 767 nose gear doors to stop the headset cord from draping over the nosewheels.

3. Evaluate cordless communication headsets for use by the despatch engineer.

4. Initiate a positive practical training program which incorporates a recording system to show the level of competence achieved by each employee.

5. Establish a reporting system with the Federal Airports Corporation which will enable personnel to report all damage to tarmacs that could constitute a tripping hazard.

6. Recommend to the Federal Airports Corporation that all tarmac earthing points be flush mounted to eliminate them as tripping hazards. In this investigation it was not determined what caused the engineer to trip but the consequences of tripping and falling were tragically demonstrated. Accordingly, part of the investigation effort focussed on potential tripping hazards which is the reason for some of the above recommendations. In addition, the company's Safety Department believed that procedures concerned with training engineers for receipt and despatch of aircraft should be more tightly controlled and better records kept. The Bureau of Air Safety Investigation supports the recommendations made by the company and further recommends that other companies with engineers involved in pushback of aircraft consider this report and recommendations in relation to their own operations.

The helicopter had operated normally during the first flight of the day. After DEPARTURE on the second flight the aircraft overflew Pyrmont before heading east along Sydney Harbour. As it approached the Sydney Heads, at 500 feet above sea level, the engine failed. The pilot gave a mayday call and successfully ditched the helicopter some 500 metres from two Army landing craft. After landing in the water the helicopter rolled inverted and floated for about 10 minutes. The crew escaped from the aircraft and after spending five minutes in the water were picked up by the landing craft. Prior to leaving the water the pilot attached a line from the landing craft to the helicopter. The helicopter subsequently sank but remained attached to the line and was towed to Balmoral Beach. An inspection of the wreckage revealed that a material failure of the acceleration bellows in the engine fuel control unit had caused the engine failure. The reason for the material failure was not established. The component has been forwarded to the manufacturer for further examination.

Circumstances:

At approximately 1809, (23 minutes before last light) during final approach to landing at Carnarvon, the pilot noticed that the landing gear had not extended correctly. The aircraft remained in the circuit area whilst the pilot attempted to lower the landing gear using both manual and emergency methods. He also sought assistance from the company's, Perth based, duty pilot and Carnarvon based engineers. After exhausting all possible methods of lowering the gear the pilot decided to land with the landing gear and flaps retracted. The pilot rejected a landing on the sealed runways because he was apprehensive that it would cause unnecessary damage to the aircraft and could result in a fire. He considered landing in a riverbed (rejected by the Senior Operational Controller), alongside one of the sealed runways (the surface was unsuitable) and on one of the dirt strips. The pilot was offered a flare path on dirt runway 27 however, he declined and indicated that he would try to land using the available light. At 1856 (last light was at 1832) the pilot attempted a landing on runway 27. On late final approach the aircraft collided with a one and a half metre high levy bank, 270 metres short and 115 metres to the right of the threshold. The pilot was trapped in the wreckage for some time after the aircraft came to a stop. The landing gear problem arose when the left main landing gear would not lower. Examination of the aircraft revealed that both hinges fitted to the inboard landing gear door had fractured. The forward hinge had fractured as a result of fatigue and the rear hinge as a result of overload. The fatigue crack initiation had occurred at a sharp edged, prominent forging flash on the inner radius of the hinge and had grown over approximately 4000 load cycles. A similar fatigue problem had been identified on an earlier version of the hinge (part number 46653-00), however, regular inspections for fatigue cracking were discontinued when hinges with part number 47529-32 (as fitted to VH-DEG) were introduced in 1980. Similar fatigue cracking was found in the forward door hinge of another PA31 during the investigation. The fractured hinges jammed the left main landing gear mechanism and neither the normal or emergency extension systems could extend the gear. The pilot was apprehensive about wheels up landings. Much of his decision making was aimed at reducing the risk of fire and minimising the damage the aircraft would sustain during the landing. e.g. Selection of a dirt runway instead of the sealed strip, landing with flaps retracted etc. During the pilot's attempts to rectify the landing gear problem, and up until the time of his touchdown, he was subjected to considerable radio transmission traffic involving questions, directions and suggestions which distracted him from his primary tasks. The pilot indicated on at least two occasions that he was ready to land, however, each time advice and questions from the ground personnel involved overrode his intentions. When the pilot was asked if he wanted a flare path on runway 27 there was still some natural light available and he was intending to land. However, by the time he was able to make his final approach it was dark and he was unable to see the ground. Studies have shown that aircrew subjected to high levels of stress can suffer skill fatigue and cognitive task saturation, which in turn can lead to a breakdown in the decision-making process. It was apparent from the pilot's radio transmissions and the quality of the decisions made in the latter part of the flight that his information processing and decision-making abilities had been degraded by the stress of continuous radio transmissions and continuous, and sometimes conflicting, instructions. As a result, what should have been a relatively simple wheels up landing in daylight was turned into an extremely difficult wheels up landing at night. With the landing gear retracted the aircraft's taxi and landing lights were not available to the pilot.

Significant Factors:

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

1. Manufacturing defect. A forging flash created a stress concentration which led to fatigue cracking.

2. Inadequate inspection procedures. Previous inspection procedures introduced to disclose similar cracking were withdrawn on the introduction of later part numbered hinges.

3. Apprehension of the pilot. The pilot was apprehensive about apparently significant dangers of landing an aircraft, wheels up, on a sealed runway.

4. Inordinate interference in aircraft operations by ground-based advisors. The ground advisors input overrode the pilot's decision on a number of occasions with the result that a simple exercise became very complicated.

5. Cognitive task saturation and skill fatigue. The amount of information, advice and suggestions being passed via the radio communications system overloaded the pilot decision making abilities.

6. Improper in-flight decisions. As a result of task saturation, the final decision made by the pilot to attempt a night landing on an unlighted strip was incorrect.

7. The pilot did not see and therefore was unable to avoid the levy bank.

Recommendations:

That the Civil Aviation Authority give consideration to amending AD/PA-31/93, to include the later part number hinges (P/N 47529-32 and 46653-00 (steel) which were introduced by SB 682) for a repetitive inspection in addition to the inspection called up for Pre SB 682 hinges.

Earlier on the day of the accident the pilot had experienced a loss of engine power during an attempted takeoff. The problem did not reoccur during a static engine run-up, and the pilot assessed the possible cause as being the hot air temperature. Flight was again attempted later in the afternoon, however, shortly after takeoff at approximately 60 feet above ground level the engine ran roughly, lost all power and produced black smoke. The pilot closed the throttle and attempted to land straight ahead. The aircraft touched down at the end of the strip, entered an overrun area of soft sand and overturned. Examination of the engine revealed that it had been operating on an excessively rich mixture. It was found that an incorrect model carburettor had been fitted, which would have provided too rich a mixture. The engine was being operated using a mixture of mogas and avgas, and the synthetic float in the carburettor was found to be significantly heavier than that specified due to absorption of mogas products. Tests indicated that the resulting high level of fuel within the carburettor float chamber, when combined with pitch changes associated with takeoff and initial climb, caused significant power loss and rough running due to spillage of fuel into the carburettor throat. Simulating the effects of turbulence and vibration exacerbated the power loss, and it is probable that the engine had lost all power due to a rich cut.

During the preflight inspection, the pilot dipped the fuel tanks and noted that the left tank contained 25 litres and the right tank approximately 30 litres. The aircraft was taxied out to the run-up area using fuel from the left tank. Before the run-up, the pilot switched the fuel selector lever to the right tank and left it there for the takeoff and remainder of the flight. The pilot decided to finish the flight with a touch-and-go landing followed by a final circuit. Following the normal application of full power for takeoff, the aircraft climbed to 100 - 250 feet above the ground when the engine surged and lost all power. The pilot chose a football field straight ahead and made a successful touchdown. However, he became so engrossed with missing objects and steering the aircraft that he forgot to use the brakes effectively. The aircraft ran on and struck two goal posts and a tree before coming to rest against a security fence. The two occupants exited without injury. The engine had failed due to fuel starvation when all the usable fuel from the right fuel tank had been consumed.

The aircraft was on the first flight since the completion of a 100 hourly maintenance inspection. The pilot reported that the engine oil pressure decreased to an unsafe level, 16 minutes into the flight, so he carried out a precautionary landing on a short disused strip. Towards the end of the landing roll, the pilot attempted to groundloop the aircraft to avoid rolling off the end of the strip. During the groundloop, the right main gear collapsed and the rear fuselage was distorted. The investigation revealed that one of the nuts securing the vacuum pump was loose and the gasket had failed. The loose nut had allowed engine oil under pressure, from an adjacent oil gallery, to force past the gasket and pump overboard. The vacuum pump had been fitted during the last maintenance inspection and a gasket of incorrect material had been fitted. The current Visual Terminal Chart for the area shows an aerodrome landmark at the location of the incident. This strip did not meet the Authorised Landing Area standards and the identifier on the chart clearly indicated that the status and serviceability of the strip were unknown. The surface condition and length of the strip were unsuitable for a safe precautionary landing, but the pilot had no means of ascertaining this prior to touchdown. The presence of the symbol on the map may have suggested to the pilot that there was no need to look for a more suitable landing area.

The pilot was attempting to bring the helicopter to a hover in the lee of a hill, but found that there was insufficient power to arrest the rate of descent. The aircraft struck the ground and rolled over. The pilot reported that the conditions were very windy. The helicopter was reported to have been operating normally prior to the accident. The pilot stated that in attempting to arrest the rate of descent he had inadvertently overpitched the rotors at an altitude from which recovery was not possible. This accident was not the subject of an on-site investigation.

The helicopter was being used to spot cattle. During what was apparently the first sweep of the area, the helicopter passed over the crest of a ridge and collided with a single power line. The angle between the fore-and-aft axis of the helicopter and the wire was approximately 40 degrees. The helicopter slid along the wire before the tail boom and then the tail rotor contacted the wire. The helicopter came to rest in a nearby gully. No fault was found in the aircraft powerplant or systems which might have contributed to the accident. Neither the pilot nor the passenger had conducted spotting operations in the area previously, and there was no evidence that either was aware of the position of the wire. It is likely that the helicopter crossed the ridge at a very low level and approximately 40 metres from a power pole carrying the wire. Background vegetation and overcast conditions may have made it difficult to distinguish the wire and power pole.

The driver of a Rescue and Fire Fighting Service (RFFS) vehicle intended to carry out a routine road test, using the runway at Devonport. He received approval to enter the runway from the duty Flight Service Unit (FSU) officer. While the road test was in progress, the pilot of the aircraft reported that he was taxying for departure. The FSU officer apparently overlooked the fact that the RFFS vehicle was on the runway, and advised the pilot that there was no traffic in the area. The driver of the vehicle did not hear this exchange. Prior to entering the runway, the pilot checked for other aircraft, but did not sight the RFFS vehicle. As the pilot commenced his take-off run, the vehicle was heading towards the taxyway intersection from the opposite end of the runway. The pilot saw the vehicle in time to become airborne and pass over the top of it. The driver of the vehicle sighted the aircraft as it became airborne, and also took evasive action. It was likely that the pilot did not sight the vehicle earlier because of sun glare, and visibility from the cab of the vehicle was temporarily impaired because foam from the monitor had sprayed onto the windscreen during the test procedure. In order to prevent similar occurrences in the future, RFFS vehicles conducting test runs are now required to have a minimum of two crew members on board, and new procedures have been implemented at the FSU to alert the duty officers when vehicles are using the runways.

The pilot was engaged in a muster of cattle for a brucellosis test. He was chasing a calf that had broken away from the main herd. When the animal turned towards the helicopter, the pilot attempted to take evasive action. He felt the aircraft rock, and believing that it had been struck by the animal, pulled it up to about 40 feet above the ground. The aircraft began to yaw. During the subsequent landing, while still yawing, the landing skids collapsed. The investigation revealed that the animal had not contacted the aircraft. During the evasive action taken by the pilot the tail rotor had contacted the ground which resulted in the loss of directional control. This accident was not the subject of an on-site investigation.