A Brasilia VH-XFZ was on a visual approach to Cairns from the south-east and was tracking to left base runway 15. A Citation VH-PSU departed from runway 15 without a separation standard being applied by the approach controller between the two aircraft. The aircraft passed with approximately 500 ft difference in their altitudes when there was less than 3 NM laterally between them.

The controller could have either coordinated the use of a visual separation procedure with the aerodrome controller or the crew of either aircraft, or employed a 1,000 ft vertical separation standard or a 3 NM radar standard to ensure that the aircraft were separated.

The investigation revealed that the controller was aware that a separation standard was required. This was confirmed by the controller's request to the pilot of XFZ to report seeing PSU that was shortly to depart. However, subsequent actions limited the ability of the pilot of XFZ to comply with the request. If this sighting had been achieved, it would have allowed the transfer of separation responsibility from the controller to the pilot. This procedure did not provide separation assurance and was a "fail-unsafe" procedure as it relied solely on the pilot's ability to see the other aircraft and limited the controllers' options should the pilot be unable to comply.

When the crew of XFZ were unable to sight PSU the controller then monitored PSU's climb performance and assessed that the aircraft would not collide. However, vertical separation reduced to less than the standard when there was no radar standard being applied.

The use of a radar standard was constrained by the disposition and intended tracks of the aircraft. In this situation, the Manual of Air Traffic Services (MATS), 9-2-1, paragraph 19 states that a procedural separation standard shall be applied. Also, the controllers actions did not comply with MATS 4-1-1, paragraphs 4-6 which places greater emphasis on traffic planning and conflict avoidance by controllers instead of conflict resolution. The use of separation assurance techniques by the controller would have ensured the separation of the aircraft.

During the take-off roll, the crew of the Boeing 767 heard a loud bang sound so they immediately discontinued the take-off. A runway inspection by the airport safety officer and fire crews found fuel and engine components on the runway. The aircraft was towed to the company maintenance facility and the runway was reopened after approximately 30 minutes.

Maintenance inspection found metal particles in the tailpipe of the engine. An engine change was carried out and the aircraft was returned to service.

Disassembly of the removed engine found that a blade in the second stage high-pressure turbine (HPT) had failed. The liberated blade then caused catastrophic secondary damage to components downstream during its passage through the engine. The manufacturer's design features for failure containment prevented damage to the aircraft or other systems by trapping high-velocity debris within the engine. Some low-velocity debris was ejected from the tailpipe.

The remaining segment of the blade firtree root in the HPT disc was retrieved and examined. The examination revealed the presence of a casting defect in a cooling-air channel web of the firtree root. This led to initiation of fatigue crack growth and eventual fracture of the turbine blade. Fatigue crack initiation was associated with a discontinuity created during casting. It was evident that the fatigue crack did not intersect the outer surface of the blade prior to failure.

After completion of the examination, the blade was returned to the engine manufacturer who has been requested to furnish a report on the metallographic sectioning examination of this component.

The crew of the Dash 7, registered VH-UUM, were cleared to track visually via Kuranda. The crew of the Cessna 310, registered VH-XXT, were cleared to track visually via Stoney Creek. Both aircraft had flight planned IFR and were entitled to positive air traffic control separation. Such separation was not provided and the required radar separation standard of 3 NM between the two aircraft was infringed.

The investigation revealed that the strategy for separation employed by the approach controller did not provide a separation standard. Radar separation was an option, in accordance with the Manual of Air Traffic Services (MATS), 9-2-1, paragraph 19, if the departing aircraft had been issued a standard radar departure. Such a departure was not provided. Moreover, because vertical separation had not been employed, the controller had to rely on lateral separation to ensure the aircraft did not conflict. However, lateral separation would not exist if both aircraft were simultaneously east of a line Stoney Creek-Kuranda. There was no separation assurance. MATS 4-1-1, paragraphs 4-6 place significant emphasis on the need for controllers to apply separation assurance techniques.

Realising the potential confliction after take-off, the controller attempted to establish a visual sighting of the departing aircraft by the crew of the arriving aircraft. The visibility was reduced due to smoke haze, making a sighting unlikely. If a sighting had been achieved, it would have allowed the transfer of separation responsibility from the controller to the pilot. The crew of the arriving aircraft were unable to sight the departing aircraft. The controller then requested the crew of the arriving aircraft to make a right orbit but the crew were unable to comply due to high terrain. The crew suggested a left orbit, which was agreed to by the approach controller. The left orbit however, further reduced the distance between the two aircraft.

The crew of the departing aircraft then sighted the arriving aircraft, with the assistance of the aircraft's TCAS, and were able to visually maintain separation. Vertical separation was reduced to 100 ft when the aircraft were 1.5 NM apart. The required radar separation was 3 NM or 1,000 ft vertically.

1. The Adelaide flight progress strip in the tower was misplaced on the airways clearance delivery console during the handover/takeover of the surface movement control/airways clearance delivery positions.
2. The coordinator did not review the flight progress strip to ensure the crew had been cleared before coordinating the Sydney flight data record for VH-HYY.
3. The absence of ticks on the Sydney flight progress strip did not alert controllers to the fact that a clearance may not have been read back or issued.

Although the annotated Adelaide flight progress strip was accidentally placed on the airways clearance delivery console during handover/takeover, there were at least two chances of detecting the error (at the coordinator and aerodrome control positions, for instance) before the aircraft departed. The controllers were supposed to ensure that the flight progress strip annotations reflected the current status of the flight. They should have ticked the clearance to show that it had been issued and read back. Perhaps the controllers assumed the strips were correct because they had been forwarded from at least one other position. Alternatively, the controllers at the positions may have been distracted while managing other aircraft or tasks.

Because air traffic controllers need accurate flight information, they have to continuously assess and confirm data from different sources. Even if crews provide the destination when asking for taxi clearance, mistakes can still happen if controllers do not scrutinise the information.

The Australian Advanced Air Traffic Control System (TAAATS) held two flight data records for VH-HYY, one from Melbourne to Adelaide and the other from Melbourne to Sydney. The crew were cleared to Adelaide but the Sydney flight data record was coordinated in TAAATS. After the aircraft departed, the controller saw that its radar track did not "couple" with the flight data record. This was achieved when the air traffic system linked an aircraft's secondary surveillance radar track with the flight data record assigned to that code. Separation standards were not infringed.

Airservices Australia found that, in anticipation of a busy departure period, the controller operating the combined surface movement control and airways clearance delivery positions noted clearance details on all pending flight progress strips. The controller cleared the crew of HYY for Adelaide and ticked the clearance and altitude annotations on the strip after receiving a correct read-back. This was required to confirm that the clearance had been issued and read back correctly. After the surface movement control and airways clearance delivery positions were individually activated, and during handover/takeover, the Adelaide strip for HYY was accidentally placed on the airways clearance delivery console and the Sydney strip placed on the surface movement control console. When the crew sought a taxi clearance, the surface movement controller did not notice that the clearance annotated on the Sydney strip was unticked but still activated the strip. The strip was then passed to the coordinator position and the controller there changed the state of the HYY flight data record in preparation for the aircraft's departure. The coordinator processed the first observed record for that aircraft and did not notice that the clearance had not been ticked. The departure controller then received a system "preactive" electronic strip showing that HYY was taxiing for a departure to Sydney. The strip in the tower was then passed to the aerodrome control position. Neither of the two controllers staffing that position noticed that the clearance on the HYY strip had not been ticked. Controllers at each operating position were required to maintain and arrange their strips.

Because TAAATS gave a separate secondary surveillance radar code to each flight data record in the system, the Adelaide and Sydney flight data records for HYY had different codes. The HYY crew were later cleared for take-off and after departure, the Sydney flight data record did not link to the aircraft's radar track. After confirming that the aircraft track displayed on the radar was that of HYY, the departure controller told the crew to select the aircraft's transponder on the secondary surveillance radar code assigned to the Sydney flight data record. The track then linked to the flight data record and the electronic strip on the departure controller's display changed to active. Shortly after, the departure controller gave an amended clearance to the crew of HYY for direct tracking to Sydney. The crew replied that the flight was to Adelaide.

The Aeronautical Information Publication AIP GEN 3.4-36-38 gives the radiotelephony phraseology required around an aerodrome. When pilots seek a clearance and clearance delivery is in operation, they must provide the aircraft's flight number and the aerodrome where they first plan to land. When they seek a clearance to taxi, they may include this aerodrome if they wish. The automatic voice recording confirmed that the HYY crew had supplied their destination when seeking a clearance but that they did not include it when asking for a taxi clearance. In other words, they had complied with the AIP radiotelephony phraseology procedures.

1. Weather conditions deteriorated more rapidly and more severely than was initially forecast in the weather reports obtained by the pilot.
2. The pilot was unaware of amended weather information that accurately forecast the deterioration in weather conditions.
3. The pilot continued flight into non-visual meteorological conditions

The pilot obtained the correct weather forecasts for the flight. The investigation found no record of the pilot having updated his weather information during the flight. Consequently, although he expected a gradual deterioration of the weather he would not have had any warning of the more rapid deterioration, and greater severity of conditions.

It is likely the pilot only realised that the weather was significantly different from the forecast when he was tracking across the higher terrain south-east of Oberon. Due to his lack of exposure to similar weather, it is possible he delayed making a decision to divert until too late. Having flown into those conditions the pilot then found himself trapped between the ridges and the cloud base, unable to continue or turn back. His instrument flight skills would have been inadequate to attempt flight in cloud under those conditions. When the aircraft entered cloud the pilot was no longer able to rely on external visual references and probably became spatially disorientated. The aircraft subsequently entered a left turn, descended rapidly and collided with the ground. The accident was consistent with loss of control following flight in instrument meteorological conditions by a non-instrument rated pilot.

The pilot with two passengers was conducting a private flight in a Piper Archer from Merimbula to Bathurst, to be carried out in accordance with the visual flight rules (VFR). The intended route was coastal to Wollongong and then direct to Bathurst. The latter part of the route passed over the Oberon area where the elevation of terrain was between 3,300 and 5,000 ft.

At about 0900 EST the pilot telephoned a relative near Katoomba to obtain an appreciation of the weather in the area. He was told the conditions were overcast but clear. About 20 minutes later the relative tried unsuccessfully to contact him to advise that light rain had begun falling.

The pilot and his passengers arrived at Merimbula airport at approximately 0930. He asked the locally based flying instructor for weather details and was shown a facsimile copy of the current Area 21 forecast, obtained at 0911 from the AVFAX briefing facility. At the pilot's request the instructor obtained terminal area forecasts (TAFs) for Wollongong, Bankstown and Bathurst from the AVFAX briefing facility at 0957. The Area 21 forecast, which was valid for the period 0900 to 2100, indicated that visual meteorological conditions could be expected along the planned route, with areas of rain and showers extending east across the forecast area. Isolated thunderstorms were also expected to develop over the ranges along the planned track, and to slowly extend east after 1300. Conditions at Mt Victoria, south-east of Bathurst, would be suitable for visual flight until 1400. The Bathurst TAF, issued at 0410 and valid from 0600 to 1800, forecast visual meteorological conditions to exist throughout that period.

The pilot did not seek any further weather information from the instructor and did not submit flight details. He was later seen refuelling and preparing the aircraft for flight. At 1028 the pilot advised flight service of his departure from Merimbula. That was the only recorded communication between the pilot and flight service.

At approximately 1230 witnesses south of Oberon reported seeing an aircraft flying very low and at times circling. They reported that it occasionally entered patches of low cloud and disappeared from view behind higher terrain. Some of the witnesses reported the engine sounded as if it was revving and cutting. Witnesses in the area to the south and west of Oberon subsequently reported several similar sightings of the aircraft at about that time. At 1256 witnesses on a property 9 Km west-north-west of Oberon reported hearing an aircraft overhead. They could not see the aircraft because of fog and mist but heard it circle their house twice. The engine noise increased followed by the distinct sound of an impact. They subsequently found the wreckage of an aircraft approximately 250 metres west of the house. The occupants of the aircraft were fatally injured.

The aircraft had collided with grass-covered sloping terrain at an elevation of 3,300 ft. Examination of the accident site and wreckage determined the aircraft had been descending in a left wing low attitude under high power and at high speed. No defect that may have contributed to the accident was found in either the aircraft or its systems.

An amended Bathurst TAF issued at 1018 forecast significantly deteriorating conditions after 1100. Unlike the earlier forecast, it indicated that from 1100 visual meteorological conditions in the Bathurst area would have been marginal and at times non-existent. Similar conditions were confirmed by witness accounts of weather in the Oberon area at the time of the accident, and by a later analysis of data by the Bureau of Meteorology. Conditions depicted by the Sydney weather radar at 1300 included an area of high intensity rainfall south of Oberon.

The pilot held a Private Pilot Licence and a valid Class 2 medical certificate. He had undertaken navigation training between February and June 1998. His instructor reported that the navigation training had been undertaken in mostly ideal weather and he had not been able to demonstrate flight in marginal weather. The pilot had, as part of his training, received 3.3 hours instrument flight instruction but was not qualified to fly in instrument meteorological conditions. He had not recorded any further instrument flight training since his licence test in June 1998.

Subsequently, the pilot undertook training in the Piper Archer. He had been shown the operation of the aircraft equipment including the use of the global positioning system (GPS) to assist navigation. Since gaining his private licence qualification the pilot had made three extensive interstate flights. The instructor reported the pilot was cautious about the weather and if the forecast was doubtful he would contact an instructor for advice. Apparently, on at least one occasion, when the weather was unfavourable, he had terminated the flight short of his destination. The pilot hired the aircraft for three days and was not expected to return from Merimbula until the day after the accident.

Sequence of events

The Cessna Silver Eagle aircraft, a turbine-powered, pressurised Cessna 210, was conducting a private flight from Maroochydore to Bankstown under the Instrument Flight Rules (IFR), cruising at flight level (FL) 160. Meteorological conditions conducive to icing had been forecast for the route.

While enroute, the pilot faced adverse weather and requested a diversion around the weather. Air traffic control (ATC) cleared the aircraft to divert then, when clear, to track direct to Mount Sandon. The pilot requested, and was approved to, climb to FL 180. Twenty four minutes later, the pilot told ATC that he required a descent to FL 140 due to icing. Six minutes after that, the pilot stated that he required a further descent to FL120 due to icing, and four minutes later, requested descent to 10,000 ft due to icing.

Two minutes later, the pilot reported an engine failure. One minute and 43 seconds later he reported that he had lost generator power and that the aircraft was descending through 8,500 ft. ATC then asked the pilot to activate the emergency locator transmitter (ELT). A Distress Phase was declared and, after further attempts to communicate with the pilot were unsuccessful, search and rescue (SAR) action was started.

Several hours later, search aircraft found the wreckage on steep mountainous terrain, 380 m south-east of its last position showed by radar. The accident was not survivable.

Wreckage examination

Onsite investigation revealed that the right wing had failed before impact, both at midspan and at the fuselage attachment point, because of aerodynamic forces that exceeded the wing structural load limits. The empennage had also separated from the fuselage before impact. The right horizontal stabiliser and elevator were not present at the accident site. Objects thought to be parts of the missing empennage were sighted from the air. Their location was 330 m from the main wreckage site, and on the northern slope of a ridge. The main wreckage was on the southern slope. The wreckage trail was consistent with the direction of flight as recorded on radar.

The fuselage, with the engine and left-wing still attached, had impacted the ground in a steep nose-down, inverted attitude. The cabin section of the fuselage comprising the pressure hull, had remained intact until impact with the terrain. The landing gear and wing flaps were found to be in the retracted position.

The evidence showed that the propeller was still attached to, and was being driven by, the engine at impact. The engine and cockpit firewall, with most of the instrument panel attached, had separated from the fuselage during the impact sequence and had been destroyed by post-impact fire. Most of the left-wing was also destroyed by post-impact fire. The intensity of the fire suggested the aircraft was carrying a significant fuel load at impact. There was no evidence of any pre-impact fire.

The aircraft had been fitted with a fixed and two portable ELTs, all of which had been destroyed by impact forces.

The engine was subsequently stripped and inspected. The inspection revealed that the engine was producing significant power at impact. The wreckage examination did not reveal any pre-existing technical fault that would have contributed to the accident.

Aircraft

The aircraft was registered in the USA and was maintained to US Federal Aviation Administration requirements. It was fitted with an Allison 250-B17F/2 turbo-propeller engine. Section 2 page 5 of the approved flight manual supplement for the aircraft stated:
"For flight at ambient temperatures of 4 degrees Celsius and below, the fuel used in this aircraft MUST have an anti-icing additive in compliance with MIL-I-27686D or E or Phillips PF A55MB, incorporated or added into the fuel during refuelling in accordance with the additive manufacturer's instructions."

Section 2 page 9 of the approved flight manual supplement for the aircraft stated:
"Flight into known icing conditions is prohibited."

The engine-driven generator installed in this aircraft was designed to automatically shed all electrical load when engine compressor revolutions per minute (RPM) fall to 70%.

Inspection of the aircraft technical logbooks revealed compliance with all applicable Airworthiness Directives and Service Bulletins.

Fuel

The aircraft was refuelled before departure from Maroochydore. No evidence was found to suggest that anti-icing additive had been added to the fuel at that time.

On the day of the accident, several other aircraft, including one high-capacity regular public transport aircraft, had been refuelled from the same fuel supply as N62J. None of the pilots of these aircraft reported any problems with fuel.

Pilot

The pilot held a US commercial pilot certificate with a valid Class 2 medical certificate, a command instrument rating, and was endorsed for the aircraft type. His total experience was 3,229 hours with 629 hours on the aircraft type. He was reported as being a cautious pilot who planned his flights carefully and correctly applied inflight procedures. He was aware of the aircraft limitations about flight in icing conditions.

Pathological and toxicological examination did not reveal any evidence of any medical condition affecting the pilot that could have prevented him from safely operating the aircraft.

Weather

The amended area forecast showed rain and thunderstorms with a freezing level of 10,000 ft; moderate icing in the tops of large cumulus, altocumulus and altostratus cloud, temperatures of 2 degrees C at 10,000 ft and minus 6 degrees C at FL 140.

The actual freezing level was approximately 11,500 ft with severe icing and turbulence in thunderstorms. Conditions in the area at the time the pilot reported the engine failure were conducive to airframe and engine intake icing. Interpretation of the enroute weather reports suggested that the aircraft might have passed through a line of showers and thunderstorms.

The pilot reported that soon after take-off the engine oil temperature increased. He also reported that he considered the indication was likely to be an electrical malfunction based on previous occurrences of a similar fault although such occurrences had not been recorded in the helicopter's maintenance documentation. Despite the lack of secondary indications to confirm the existence of a major problem, the indication was apparently sufficient to raise a doubt in his mind as to whether or not he had properly secured the engine oil filler cap. There was no reference in the helicopter's flight manual that indicated any immediate action was required. Although there was no information to indicate that an immediate landing was required, the pilot conducted a continuous turning descent to an immediate landing rather than performing the recommended reconnaissance procedure.

The recommended reconnaissance procedure in which the pilot had been trained for conducting landings in confined or unfamiliar areas, noted that a high reconnaissance should be made at about 400 ft above ground level before making an approach. The procedure included recommendations on how to assess the likelihood of a wire hazard. In this case, the terrain was flat and the spur line led to farm buildings that were 3 km from the junction with the main power line. There were few, if any, impediments to recognising the existence of the spur line. Consequently, it is likely that if the pilot had conducted the prescribed reconnaissance procedure, he would have had a higher probability of seeing the spur line. The pilot's perception that an immediate landing was required appeared to have diverted him from conducting the recommended reconnaissance procedure prior to making the final approach. These actions may have been a reflection of his low level of aviation and helicopter flying experience.

The stowage of the glass bottles in the baggage compartment under the passenger's seat would have significantly reduced the impact absorption qualities of the seat. It could not be determined, however, whether the stowage of the glass bottles was a factor in the passenger not surviving the accident.

The inconsistencies between the pilot's recollection of events immediately prior to the accident, and the wreckage evidence which indicated that the helicopter was in a nose-low attitude and possibly travelling at relatively high speed, could not be resolved.

History of flight

The owner-pilot had used the Robinson R22 helicopter during the previous 14 days to transport himself and his assistant to several towns in the north-west of Western Australia in the conduct of his business. During the return journey to Geraldton, the pilot landed the helicopter the afternoon before the accident, at a relative's farm located near Binnu. At about 0850 WST on the morning of the accident, the helicopter departed from the farm to fly to Geraldton approximately 45 NM to the south. The pilot reported that about 10 mins after take-off and when he had climbed to about 500 ft, the helicopter's engine oil temperature indication rose. There was no other cockpit indication of a potential malfunction. He suspected an electrical problem associated with the indicator due to previous occurrences, but the indication also caused doubts in his mind as to whether he had properly secured the engine oil filler cap during the pre-flight inspection. Consequently, he decided to land to check. He reported that during the approach he saw the main power line and thought he was positioned such that he was clear of all power lines. The pilot reported that he did a reconnaissance of the proposed landing site by conducting a descending right turn from 500 ft. During the final approach, the helicopter struck a power line. The helicopter fell to the ground and was destroyed by the impact. There was no fire. The pilot sustained serious injuries and the passenger was fatally injured. The pilot reported that he never saw the wire and the last thing he recalled was feeling as though the helicopter had been "grabbed." He thought that the helicopter's airspeed was about 35 to 40 knots when it hit the wire.

Accident site

The accident occurred approximately 5 km south of where the helicopter departed. The helicopter struck the upper conductor of a dual-conductor spur line running at approximate right angles to a main transmission power line located about 500 m to the south-west. The helicopter struck the spur line two bays from the main line about mid span at a height of about 8.4 m. The span distance was 205 m. Seven bays, approximately 1100 m, of conductor was pulled from the insulators and poles by the impact and the wire was dragged about 42 m during the accident. As well as itself breaking, the conductor broke several steel ties as it was pulled from the poles during the accident sequence. The steel ties secured the conductor to the insulators.

Weather

Observations at Geraldton and information provided by witnesses who were in the area at the time, indicated that the wind was a light southerly. There was some low-level cloud and the temperature was about 20 degrees C. There were no reported restrictions to inflight visibility.

The helicopter

The helicopter was a Robinson R22 Alpha, which is a two-place, single main rotor, single engine helicopter constructed primarily of metal and equipped with skid landing gear. The maximum gross weight of the helicopter is 1370 lbs. The approved grade of fuel for the helicopter was 100/130-grade aviation fuel. 100/130-grade aviation fuel is dye-coloured green. Automotive petrol (MOGAS) is coloured red.

The pilot reported that he suspected the high engine oil temperature indication was an electrical problem based on previous occurrences although the occurrences were not recorded in the aircraft's maintenance release or logbook. He also reported that there were no secondary indications, such as a fall in engine oil pressure or the illumination of a warning light. The Robinson R22 flight manual noted, "When a red warning light comes on, select the nearest safe landing area and make a normal landing as soon as practical." If an engine oil light illuminates, the flight manual noted that it, "indicates possible loss of engine power or oil pressure. Check the engine tach and oil pressure gauge. Continued operation without oil pressure may cause serious damage to the engine and engine failure could occur." The flight manual emergency procedures did not include any actions in response to an increasing engine oil temperature indication. The helicopter's manufacturer reported that it was considered unlikely that a missing engine oil filler cap would result in sufficient oil being lost to result in either low engine oil pressure or high engine oil temperature. Several maintenance organisations reported that a missing engine oil filler cap might lead to an indication of low oil pressure.

Baggage space is located under each of the seats. Each seat is equipped with a combined seat belt and inertia reel shoulder strap. The Robinson Helicopter flight manual requires the fitment of a placard in each baggage compartment, part of which states, "Avoid placing objects in compartment which could injure occupant if seat collapses during hard landing."

The daily inspection certification and aircraft time-in-service section of the helicopter's maintenance release had not been completed by the pilot during the 14 days prior to the accident although the helicopter had flown at least 20.9 hrs on 5 separate days. The pilot reported that he had conducted the required daily inspections but he intended entering the data on arrival at Geraldton. The maintenance release also revealed that a required 25 hourly servicing, oil change and set of inspections were due about 4 hours prior to the accident. The pilot reported that he had conducted the required inspections although they had not been certified in the maintenance release. He also reported that he had not completed the required oil change because he considered that it was not necessary. The engine manufacturer however required the oil to be changed every 25 hours and this periodicity was reflected in the maintenance release requirements. Several maintenance organisations confirmed that the oil change was required. Because the daily inspections had not been annotated as having been completed and required maintenance had not been completed, the helicopter was not being operated with a valid maintenance release. The helicopter had not been modified to use MOGAS and neither the helicopter's manufacturer nor the Civil Aviation Safety Authority (CASA) had approved the use of the fuel type in the accident helicopter. The pilot had also stowed a container of fuel in the cockpit, which was not in accordance with the Civil Aviation Regulations (CARs) pertaining to the carriage of dangerous goods.

Wreckage

The main wreckage came to rest about 69 m beyond where the helicopter impacted the power line. The damage to the aircraft was consistent with ground impact in a nose low, left bank attitude. The left seat squab supporting structure was found deformed from compression type loads generated in the accident sequence. Empty glass bottles were found under the passenger's seat. The nose low, left bank attitude of the aircraft resulted in the greater part of the impact forces being transferred through the fuselage to the left seat supporting structure and its occupant. An examination of wreckage did not revealed any pre-existing mechanical problem that may have contributed to the accident. Wreckage evidence and the pilot's report indicated that the engine was operating normally before the accident.

The left seat-belt anchor point, in the centre of the cabin seating structure, had failed. This failure liberated the inner belt anchor point from the aircraft structure and rendered the left occupant restraint system ineffective.

The fuel tanks had ruptured during the accident and consequently, no fuel remained in the fuel tanks. A plastic container, almost full of fuel, was found amongst the main wreckage. The fuel was red in colour and smelled of automotive fuel. The pilot confirmed that the container was filled with MOGAS and that he had it available for emergency purposes. He also advised that he had, on occasion, used MOGAS in the helicopter. Before the wreckage was removed from the site, a very small amount of fuel was found in the helicopter's fuel line. The fuel appeared to be automotive fuel. The pilot declined to comment to the investigation about whether or not he had fuelled the helicopter with MOGAS prior to the accident.

Evidence, including wire scrape marks on the landing skids and damage to the power line, appeared consistent with the helicopter hitting the wire in a nose low attitude and possibly at a relatively high speed.

The pilot

The pilot had accumulated a total of about 290 hours flying experience, all in the Robinson R22. He gained his private helicopter pilot's licence 17 months prior to the accident and had flown about 26 hours in the 30 days prior to the accident.

The pilot had not received formal low flying training and was not authorised by CASA to operate the helicopter below the minimum altitudes prescribed in the CARs.

Flying procedures

The flight-training documentation provided by the training school that conducted the pilot's helicopter licence training, highlighted the need for vigilance against wires when landing in unfamiliar areas. The prescribed procedure for landing in unfamiliar areas recommended that a high reconnaissance involving a series of checks (including checking for hazards such as power lines) be made at about 400 ft above ground level before making an approach. The procedure included, "Do not descend until you are sure that there are no powerlines that are going to interfere with your operations. Look for anything that uses electricity e.g. houses, sheds, pumps, lights etc. If necessary follow along a nearby powerline to ensure it does not go anywhere near your landing area. Look for stay wires, crossbeams, junction boxes etc. to indicate change of direction or spur lines".

Regulations

The CARs also detailed the requirements pertaining to maintenance releases. A maintenance release ceases to be in force if a requirement or condition imposed in respect of the maintenance of the aircraft has not been complied with. Additionally, the regulations required the recording of total time-in-service of the aircraft on the completion of flying operations each day on the day.

The container of fuel was not packaged in accordance with dangerous goods requirements. The carriage of the fuel container in the helicopter cockpit was not, according to advice provided by the Civil Aviation Safety Authority, permitted by the CARs pertaining to dangerous goods.

The disparity between the TAAATS training and management of sector 6, the differences in coordination and management between TAAATS and sector 6 and the limited opportunities to use radar vectoring, all contributed to limit the controller's ability to successfully resolve the conflict.

The ready provision of direct tracking to Mudgee for aircraft that had planned via H29 increased the controller workload. While this factor was minor in comparison to the others previously mentioned, it nevertheless resulted in some additional action by the controller. Had aircraft been required to intercept and rejoin air route H29 prior to the majority of the intersections with other routes it is likely that the complexity of the controller's task would have been reduced.

Prior to the crew requesting the availability of alternative separation methods the controller had formulated a traffic management plan that would ensure separation was maintained between the aircraft. After the crew's query, the controller adjusted his plan to compensate for the changed circumstances but was inadequately prepared to ensure maintenance of separation using the radar.

VH-CZU a Boeing 737 (B737), was en route from Adelaide to Sydney at flight level (FL) 370 on air route H31. VH-CZS a B737 was tracking north on H29 en route from Melbourne to Brisbane at FL370. Their respective air routes intersected at a position approximately 25 NM north-east of Wagga and their relative positions and groundspeeds indicated that the radar separation standard of 5 NM would not be maintained.

The Melbourne Sector 6 controller coordinated with the Canty Sector controller for the crew of CZU to be issued with a requirement to descend to FL350 by 110 NM from Culin, a position approximately 34 NM north of Canberra. The intent of the instruction was to ensure that the vertical separation standard of 2,000 ft was established between the aircraft prior to the lateral distance between them reducing to less than the standard. Following the acknowledgment and read back of the requirement, the crew of CZU queried whether radar vectors would be available, as they preferred to maintain FL370 due to cloud and possible turbulence below that level. The Canty controller advised the crew to stand by and after conferring with the sector 6 controller instructed them to transfer to the sector 6 frequency. Once established on the sector 6 radio frequency the crew was instructed by the controller to turn right heading 130 degrees. The controller issued further instructions to the crew of CZU to turn onto 140 degrees and 150 degrees.

The controller then instructed the crew of CZS to turn right onto 060.

CZU passed 4 miles behind CZS while they were at the same level. There was an infringement of separation standards. The incident occurred during the period when Melbourne air traffic controllers were transitioning from the old centre that used the Australian Computer Air Traffic Control System radar and procedural flight strip bay facilities to new facilities using the Advanced Australian Air Traffic Control System (TAAATS). Sector 6 was in the old centre while Canty sector was a TAAATS position. TAAATS has a number of alarms to alert controllers of potential separation infringements. During the occurrence the short-term conflict alert operated at the Canty position. The sector 6 controller was busy at the time with a moderate level of traffic. The complexity of the management of sector 6 was compounded by weather that was causing flight crews to request advice of weather on various routes and also for diversions to avoid developing weather cells. Sector 6 had two control positions, radar and procedural and was normally operated in the combined configuration. The controller was managing both positions at the time. Another controller was available to assist at the position. This controller was not utilised until after the occurrence.

When CZS entered sector 6 airspace it was approximately 7 NM west of air route H29. This was normal practice as departure controllers were approved to instruct crews to track from their present position, within the terminal area (within 45 NM of Melbourne), direct to Mudgee. This required the sector 6 controller to calculate a specific solution for each potential crossing conflict with aircraft nominally tracking on H29 and aircraft on all intersecting routes. Sector controllers can use lateral separation diagrams to assist in the application of separation. However, the use of such diagrams was dependent upon aircraft operating within the navigational tracking tolerance of the air route being flown. Sector 6 did not have or use lateral separation diagrams.

Sector 6 was a joint radar/procedural sector with a majority of radar coverage. However, the size of the sector and the disposition of air routes within the sector meant that generally conflicts were resolved using procedural control methods. Radar vectoring was used to sequence aircraft for arrival into Sydney but was not generally used to establish separation between aircraft. Consequently, controllers had limited opportunities to practice vectoring techniques.

The controller had returned to the sector 6 staff roster approximately two weeks prior to the occurrence after being rostered for familiarisation training on 30 September and 1 October 1999. The controller had agreed to return to sector 6, following his TAAATS transition training, to enable other controllers to be released for transition training. The sector 6 area of responsibility within TAAATS had been divided into two sectors, Parkes and Bourke. The management of traffic and coordination requirements for these sectors differed considerably from those required for sector 6. The controller had undergone radar vectoring exercises during the transition training but these had focused primarily on developing human-machine interface skills and not traffic management skills. Also, some exercises used nil-wind conditions and thus were not reflective of conditions likely to be experienced on the job. The controller was rostered for two familiarisation shifts on the return to sector 6. However, after five hours during the first period of familiarisation, the controller felt comfortable and believed he was capable of operating at a satisfactory level and was subsequently endorsed to operate the sector.

The crew reported that they believed that the requirement, to descend to FL350 by 110 NM Culin, had been cancelled when the Canty controller advised them to stand by. The sector 6 controller did not instruct the crew to maintain FL370 once he had decided to vector the aircraft. Neither the crew of CZS nor the controller queried or clarified the status of the level requirement until after the occurrence.

Entries in the pilot's logbook indicated that in the past, the pilot had been prepared to abandon flights due to poor weather. This provided some support for the contention by those who knew the pilot that he was cautious with respect to weather. The weather forecasts obtained by the pilot did not indicate that conditions were unsuitable for the flight, and the decision to proceed at that stage was probably appropriate. However, the pilot had reported that the weather conditions while overhead Goondiwindi, approximately one hour before the accident, were not good. It should have become apparent to him as he continued towards the coast that the weather conditions were deteriorating to the point where they were unsuitable to continue the flight.

The investigation was not able to determine why the pilot made a decision to continue with the flight when confronted with weather conditions that were obviously worse than those forecast, and that appeared to be unsuitable for VFR flight.

The pilot's initial handling of the aircraft when in IMC appeared reasonable under the circumstances. The left turn to intercept the track from Toowoomba to Caloundra was performed with a degree of accuracy and was indicative that the pilot was probably using the GPS for navigation. The steady heading and slow but constant rate of descent which were evident after the aircraft was established on track to Caloundra suggested that the aircraft was probably being flown on autopilot.

The subsequent failure of the pilot to fly the assigned heading, the increased ground speed and rate of descent, and the consequent loss of control are consistent with the pilot becoming spatially disoriented during the right turn onto 130 degrees and having disconnected the autopilot. The aircraft impacted the ground in close proximity to the last radar-observed position, less than 90 seconds after the pilot's last radio transmission was received by ATS. Based on witness reports and evidence at the accident site, the aircraft was in a left spiral dive before impacting the ground.

The pilot of a VFR aircraft is solely responsible for ensuring that the flight is operated with due regard for changing weather conditions. In this particular instance, for reasons that were not established, the pilot placed himself in a situation where weather conditions were unsuitable for VFR flight; a situation for which he was not trained or qualified. Having placed himself in that situation, the ATS response became a matter of primary importance. ATS staff play a vital role in assisting pilots in an in-flight emergency situation. The timeliness and effectiveness of that assistance is particularly important when dealing with VFR pilots as they are subject to unique emergency situations and often have limited skills and experience. In addition, as VFR pilots generally operate as a single crew, they rely heavily on external assistance when faced with emergency situations such as inadvertent flight into IMC.

The ATS response to this in-flight emergency would have been enhanced through a greater understanding and application of the strategies and techniques suggested in the Manual of Air Traffic Services, the IFER training manual and the IFER checklist. Controller actions suggested that they did not have the background knowledge to effectively manage the in-flight emergency situation. In particular, the controllers did not appear to be aware of the potential consequences and therefore the priority that needed to be afforded to the pilot.

The strategy adopted by the controller in responding to the in-flight emergency situation was not consistent with the guidance provided in chapter 17 of the Manual of Air Traffic Services, the IFER training manual or the IFER checklist in use. In particular, the pilot was placed in a situation where he was turning and descending the aircraft at the same time. In addition, the pilot was also required to respond to questions from ATS while performing these manoeuvres. It was unlikely that the pilot had the skills or experience that were required to enable him to cope with these demands. Although the controller's communication style was in accordance with standard phraseology, the authoritative and interrogative style was inappropriate in the circumstances and was unlikely to have instilled confidence in or reassured the pilot.

Although the Manual of Air Traffic Services provided basic guidance on the strategy needed to deal with a VFR pilot operating in IMC and although the IFER checklist served as an aide-memoire, neither provided the level of detail contained in the IFER training manual. It is significant that this, or an ADF equivalent, manual was not available to ADF ATS units.

The circumstances of this accident are consistent with an uncontrolled collision with terrain following the pilot's loss of adequate external visual reference. It is likely that he became spatially disoriented and lost control of the aircraft soon after descending through 3,200 ft. The aircraft subsequently entered a left spiral dive before impacting the ground. As a result of concerns regarding military air traffic control officers' awareness of in-flight emergency response practices and procedures for civil aircraft, the Australian Transport Safety Bureau issued interim recommendation IR19990190 to the ADF on 16 December 1999.

The pilot of a Cessna 182J was conducting a private visual flight rules (VFR) flight, with one passenger, from Lightning Ridge to Caloundra. The passenger was also a qualified private pilot.

Prior to departure at about 0845 EST, the pilot obtained an Airservices Australia location briefing containing weather and notice to airmen (NOTAM) information relevant to the flight. At about 1000, the pilot used a mobile phone to contact an associate in Lightning Ridge. The pilot indicated that he was over Goondiwindi, tracking via Toowoomba for Caloundra, and that the weather was not good.

At approximately 1100, the Australian Defence Force (ADF) Amberley approach controller observed an unidentified code 1200 secondary surveillance radar (SSR) return in close proximity to the boundary of military airspace, about 10-12 NM north-east of Toowoomba. Code 1200 is allocated to VFR flights operating outside controlled airspace and not participating in a radar information service. The SSR return provided unverified mode "C" altitude information that indicated the aircraft was at 5,700 ft above mean sea level. The controller soon became concerned that the aircraft was going to enter controlled airspace, and that it might conflict with a General Dynamics F111 that was inbound to Amberley from the north with an in-flight emergency.

The controller attempted to contact the pilot of the unidentified aircraft by making a number of general broadcasts on the Amberley approach frequency. The controller also requested that the Airservices Australia Downs radar advisory service controller make a general broadcast for the pilot to contact Amberley approach, which he did at 1106:37. The Amberley approach controller informed the pilot at 1107:57 that his aircraft was identified on radar. At that time the aircraft was inside Amberley controlled airspace bearing 310 degrees M and 30 NM from Amberley. The pilot was immediately instructed to conduct a left orbit to provide separation with the F111.

During the orbit, the pilot advised the controller that the aircraft was "caught in cloud" and that he was "in trouble". A number of broadcasts between the controller and the pilot subsequently took place as the controller attempted to clarify the situation. During that time, the pilot asked whether he could use the automatic pilot. The quality of the radio transmissions from the aircraft was poor and the controller had difficulty in comprehending the full extent of the problem and the pilot's request to use the autopilot. The controller reported that these difficulties were exacerbated by the pilot's accent.

By the time the controller established that the pilot wanted to track to Caloundra and was rated only for VFR flight, but was in instrument meteorological conditions (IMC), the pilot had commenced a second left orbit. The aircraft was approximately half-way through the second orbit, passing a heading of approximately 240 degrees when the controller instructed the pilot to turn right and take up a northerly heading for Caloundra. While the aircraft was in the right turn, the controller asked the pilot if he wanted descent, to which the pilot replied in the affirmative. The controller then cleared the pilot to leave control area on descent.

Changes in the aircraft's altitude during the right turn were erratic. Radar recordings indicate that the aircraft descended to 4,400 ft in less than a minute, then climbed back to 4,800 ft. The pilot maintained the right turn onto a heading of about 130 degrees before making a left turn to intercept the track from Toowoomba to Caloundra. During that time, the controller advised the pilot that he could descend to 3,000 ft safely in the aircraft's current location. Once established on track to Caloundra, the aircraft maintained a steady heading, with a rate of descent of about 300 ft/min.

After the aircraft was established on track for Caloundra and was still in IMC, the controller became concerned that the aircraft was heading for an area of higher terrain, where the radar lowest safe altitude, as specified on the radar terrain clearance chart, was 3,800 ft. As a result, the controller instructed the pilot to turn right heading 130 degrees (a turn of about 90 degrees). The aircraft was passing 3,700 ft when the pilot commenced the right turn. Recorded radar data indicated that the aircraft continued the right turn through the assigned heading and that the aircraft ground speed and rate of descent increased during the turn.

The aircraft SSR return disappeared from the radar display at approximately 1116 as the aircraft was passing 3,200 ft on a heading of about 210 degrees. Controllers at Amberley reported that that was consistent with known radar coverage in the area. The pilot responded to a question from the controller regarding the aircraft's in-flight conditions at approximately 1116:00. Radio contact with the pilot was lost after that time. The Amberley approach supervisor subsequently contacted the emergency services number to find out if there had been any reports of accidents. The supervisor was switched through to Ipswich police, who advised that they had received a report of an accident in the Esk area.

The wreckage of the aircraft was located approximately 6.5 km north of Esk on flat pastoral land. A nearby resident caught a glimpse of the aircraft just before impact and then observed a plume of fuel and debris. He immediately notified emergency services, who recorded the call at 1117:30. Impact evidence indicated that the aircraft was in a left turn in a nose-low attitude and that the aircraft was not in a stalled condition. This is consistent with witness reports that indicate the aircraft was descending in a left turn. The impact destroyed the aircraft and both occupants were fatally injured.

Pilot in command

The pilot held a private licence, together with a valid class two medical certificate, and was appropriately endorsed. However, he did not hold a rating for flight in IMC, nor was the aircraft approved for flight in IMC. The pilot had logged a total flight time of 220 hours, comprising 90 hours dual and 130 hours as pilot in command by day. No evidence was found that the pilot was suffering from any medical condition that could have contributed to the accident.

The pilot was reported as being cautious and conscientious in his approach to flight preparation and in-flight procedures. In particular, flying instructors who had flown with the pilot reported that he was wary of flying in poor weather. The pilot's logbook indicated that on at least three previous unrelated occasions, the pilot had abandoned flights and returned to Lightning Ridge due to adverse weather. An associate of the pilot reported that he spoke to him prior to his departure on the day of the accident and that the pilot had expressed reservations about making the flight to Caloundra. He had stated that he intended assessing the weather at Goondiwindi before proceeding further.

Aircraft information

A periodic maintenance inspection was due approximately 10 hours after the commencement of the accident flight and there were no known outstanding maintenance defects. Evidence indicated that the engine was operating at impact and examination of the wreckage did not reveal any deficiencies that were likely to have contributed to the accident. The aircraft was fitted with an emergency locator transmitter (ELT), which was destroyed on impact. A global positioning system (GPS) unit was fitted to the aircraft and the pilot was also carrying a hand-held unit.

Meteorological information

On the morning of the flight, the pilot obtained area forecasts (ARFORs) 22, 40 and 41, which covered his route. He also received terminal area forecasts (TAFs) for relevant en-route airfields and for Maroochydore and Archerfield, but there was no evidence that he received a TAF for Caloundra. ARFOR 40 covers a large part of south-east Queensland, including the eastern Darling Downs and the Amberley area.

The Area 40 forecast was valid from 0717 to 2100 EST. The forecast overview indicated cloudy conditions with rain areas and isolated thunderstorms, clearing from the west after 1800. Forecast cloud consisted of isolated cumulo-nimbus with a base of 6,000 ft and scattered stratus between 1,200 ft and 6,000 ft in rain, broken near thunderstorms. Also forecast was scattered cumulus and strato-cumulus with a base of 3,000 ft between the coast and the ranges and 4,500 ft inland, with broken alto-cumulus and alto-stratus layers above 16,000 ft. The predicted visibility was 5,000 m in rain and smoke and 2,000 m in the vicinity of thunderstorms.

The TAFs for Archerfield and Maroochydore were current from 0600 to 1800 EST. They predicted visibility in excess of 10 km, light rain and scattered cloud at 2,500 ft, and also forecast intermittent periods of reduced visibility down to 4,000 m, rain and broken cloud at 1,000 ft.

The pilot of the F111 reported that the area was dominated by large cumulus cloud with associated stratus. He reported that there were occasional gaps between the cumulus and stratus cloud levels, which resulted in small pockets of airspace where visual flight was possible. However, these pockets were only present above 5,000ft and were totally surrounded by cumulus and stratus cloud. The crew of the F111 reported that the cloud during their approach to Amberley, approximately 30 NM to the south-east of the accident site, was consistent broken low cumulus and stratus with a base of 650 ft above mean sea level.

A Bureau of Meteorology observer at Amberley stated that on the day of the accident, the weather was influenced by an easterly moving trough lying north-south through central Queensland and a north-easterly breeze off the ocean. The observer stated that these two influences were known to produce a build-up of low cloud against the ranges. Witnesses on the ground in the vicinity of the accident site described the weather as showery, with cloud covering the tops of the hills.

Air traffic services inflight emergency response

Air traffic services (ATS) emergency procedures were outlined in chapter 17 of the Manual of Air Traffic Services, a joint military/civil document. Section 3 of chapter 17 provided guidance on emergency phase declaration. Paragraph 1 stated that "[t]he appropriate emergency phase shall be declared to show the degree of apprehension felt for the safety of an aircraft and an indication of the scope of the SAR [search and rescue] action to be provided." Paragraph 6 stated that "[a]n Alert Phase exists when there is apprehension as to the safety of an aircraft and its occupants", and specifically noted that an Alert Phase existed when a flight restricted to visual meteorological conditions (VMC) was operating in IMC.

Section 4 of chapter 17 referred specifically to procedures for the handling of in-flight emergencies by ATS staff. Paragraph 1 of section 4 stated:

"While it is impracticable to set out a detailed response to every emergency situation, it is possible to identify broad groups of incident types and to generalise appropriate courses of action".

Paragraph 2 stated:

"In resolving inflight emergencies, units should use the Inflight Emergency Response Checklists as a basis for the provision of assistance to pilots".

Information and guidance specific to "Flight confined to VMC but operating in IMC" was contained in paragraphs 48 to 53 of section 4. Paragraph 48 highlighted the fact that "[t]his type of inflight emergency is potentially a very serious situation which has often led to fatal consequences".

The section also provided general guidance to ATS staff on issues about which they needed to be aware, and strategies to be employed in responding to this type of in-flight emergency. In particular, it stated that ATS staff should be aware that a pilot in this situation would have difficulty with the following:

1. maintaining headings;
2. maintaining altitude; and
3. perceiving aircraft attitude.

Furthermore, the section stated that ATS should endeavour to provide reassurance to the pilot in the initial communications and limit communication so as not to divert the pilot's attention from flying the aircraft.

More detailed guidance on handling in-flight emergency response situations was provided in Airservices Australia's Inflight Emergency Response (IFER) Training Manual. The IFER training manual expands on specific issues listed in the Inflight Emergency Response Checklists.

The ATS strategy for an aircraft in a "VFR in IMC" situation was detailed in the IFER training manual and stated that it "should reflect the absolute pilot priority to control the aircraft ahead of navigation or communications". The following advice to assist pilots in such a situation was provided in the training manual:

"

1. Provide the pilot with some reminders on aircraft handling. While [the controller] is not expected to "fly" the aircraft for the pilot, the following handling actions are universally recognised as appropriate basic advice to an inexperienced pilot in distress:

   1. concentrate on aircraft attitude ie.:

      - maintain steady heading;
      - keep wings level;
      - keep speed constant

   2. trust instrumentation;

   3. when manoeuvring commences:

      - no abrupt manoeuvres;
      - shallow/climbs/descents/turns;
      - turns first, establish straight and level then climb/descend,

2. Provide navigation information to the pilot that will allow the aircraft to be re-established in VMC.
3. Communicate with the pilot using the following techniques:
   1. keep instructions simple and distractions to a minimum;
   2. keep regular radio contact without overloading;
   3. instil confidence and reassure the pilot; and
   4. pass only one item at a time

The IFER training manual also provided guidance on the communications style which should be adopted by controllers when dealing with this type of emergency. Specifically, the manual noted that a VFR pilot in an IMC situation is under considerable stress and there was a need for ATS staff to convey empathy, patience and confidence. This required ATS staff to adopt a markedly different technique to the customary delivery of ATS information, where precision and economy of words are appropriate to communications between confident professionals. Furthermore, in establishing the necessary background information, it was vital that questions not be put in an interrogative manner.

The IFER checklists, a document separate from the IFER training manual, contained items that should be considered when responding to specific situations. However, checklists serve primarily as an aide-memoire. A high level of background knowledge and situational awareness by the controller is required to expeditiously provide assistance to the pilot. In this regard, while the checklists are a useful tool, they need to be considered in conjunction with more detailed guidance, such as that contained in the IFER training manual.

A review of the audio voice recording revealed that the controller's manner while communicating with the pilot was authoritative, with questions being posed in an interrogative style. The controller used the IFER checklist during communications with the pilot. However, the unit was unaware of the existence of the IFER training manual.

The register of copy holders in the front of the IFER training manual indicated that ADF was a registered holder of three copies. However, the ADF was unable to locate these copies and the manual was not held by any ADF ATS unit. Airservices Australia records did not provide any receipt confirmation advice relating to the document copy numbers listed against the ADF.