A Boeing 737-476 (737) was en route from Melbourne to Coolangatta tracking northeast at flight level (FL) 310. A Cessna Aircraft Company C500 (Citation) was tracking southwest from Coolangatta to Essendon at the same level. The aircraft were on reciprocal tracks and the air traffic controller did not provide any assurance of separation between the two aircraft. The rate of closure of the aircraft was later calculated to be in excess of 800 kts. When the distance between the two aircraft was approximately 22 NM, the controller instructed the crews of both aircraft to alter heading and flight level. The controller's intervention ensured that a separation standard was established and maintained. The radar system's short-term conflict alert (STCA) activated. While the horizontal radar separation standard of 5 NM was never infringed, vertical separation, which assured separation for aircraft on reciprocal tracks, was not established until 25 seconds prior to the aircraft passing.

The 737 was being operated as a regular public transport flight and was flight planned at FL350. That aircraft departed Melbourne at 09:37 Eastern Standard Time and tracked via air route H66. That air route passed through the Benalla sector controller's area of responsibility. The Benalla sector controller was located in the Melbourne Air Traffic Control Centre. The crew of the 737 had requested FL290 on first contact with the Benalla sector controller, which was approved. At 09:52:51, the crew requested climb to FL310. The controller assigned FL310 at 09:55:59 and the recorded radar data indicated the aircraft reached that level at 09:57:43.

The Citation was operating a private flight at FL310 and departed Coolangatta at 08:16. Flight level 310 was a non-standard level for the track flown. Cruising levels were published in the Manual of Air Traffic Services (MATS) and the Aeronautical Information Publication (AIP). MATS also stated that aircraft operating at other than a level conforming to the table of cruising levels for the particular direction of flight or notifying intention to cruise at such a level, shall be advised accordingly and the pilot's intention sought. Non-standard levels were regularly used by air traffic control for maximum utilisation of available airspace.

The Citation pilot had flight planned to track via Parkes and TAREX, which was a non-standard route. The AIP stated that prior air traffic control approval was required for RNAV [area navigation] tracking on routes other than those published in AIP. An aircraft tracking from Coolangatta to Essendon would normally have tracked via air route Q94 and would have remained clear of the Benalla sector airspace. The pilot of the Citation had not received prior air traffic control approval to plan and conduct the flight via a non-standard route.

At 09:41:22, the crew of the 737 established radio contact with the Benalla sector controller. The controller was managing the combined airspace sectors of Eildon Weir and Benalla. The 737 crew was on climb FL200 and was recleared to the requested level of FL290. The controller was expecting the crew of the 737 on frequency and had earlier anticipated that the aircraft may be a problem at the planned flight level. However, at FL290 it would be separated from other aircraft.

Due to confusion caused by an anomaly with another aircraft, the Benalla controller was required to complete a significant period of coordination with another sector controller. The Benalla controller was discussing that problem at the console with the team leader when the crew of the 737 again made radio contact at 09:52:51. They reported maintaining FL290 and requested climb to FL310. The controller acknowledged the request and annotated the flight track with that request. The controller continued his discussion with the team leader and did not immediately coordinate the higher level request with the adjacent Parkes Sector.

At 09:53:37, the controller designated and accepted jurisdiction on the radar display of the Citation's flight track. That was before the pilot of the Citation established radio contact at 09:54:18 and reported maintaining FL310. The controller acknowledged that transmission and then transferred jurisdiction of two other aircraft to the Parkes sector controller.

At 09:55:56, about three minutes after receiving the 737 crew's change of level request, the controller coordinated the 737 with a request for FL310 with the Parkes sector controller. The Parkes sector controller concurred with the higher level and the Benalla controller cleared the 737 crew to climb. The controller did not recognise the potential conflict between the 737 and the Citation and continued his discussion with the team leader.

At 09:59:55, the controller activated the "individual quick look" function for the flight plan tracks of both aircraft. Almost simultaneously, the controller commenced action to ensure a separation standard was maintained between the two aircraft. The controller instructed the crew of the 737 to expedite descent to FL290 and instructed the pilot of the Citation to turn right 30 degrees. At 10:00:15, he further instructed the crew of the 737 to turn right 20 degrees. He also broadcast essential traffic information to the 737 crew about the position of the Citation. During that transmission, the short term conflict alert on the controller's radar display activated at 10:00:28 highlighting the close proximity of both aircraft. The traffic alerting and collision avoidance system (TCAS) of the 737 also activated, providing a traffic advisory warning to its crew. At 10:00:34, the controller told the pilot of the Citation to climb to FL320. At 10:00:57, a 2,000 ft vertical separation standard was established between the two aircraft when they were approximately 9 NM apart.

The controller had held a full performance rating within the group for a period just less than four years. He was completing the third day of a 5-day roster cycle. Although the controller was working a combined sector, the workload was considered light to moderate.

The British Aerospace BAe 146-200A (BAe 146) was being operated on a regular public transport service from Brisbane, Qld to Canberra, ACT. Approximately 5 minutes after take-off the flight crew detected that smoke was present on the flight deck. They donned their oxygen masks in accordance with the emergency checklists that dealt with smoke, fumes or fire and made a PAN transmission to air traffic control, requesting a return to the airport. The approach controller issued radar vectors to facilitate the prompt return of the aircraft to Brisbane and placed the airport's emergency services on standby. During the descent, the pilot in command briefed the cabin crew, alerting them to the possibility of a cabin evacuation.

At the time of the incident, the BAe 146 Quick Reference Handbook (QRH) contained an emergency checklist procedure titled Smoke, Fumes or Fire on Flight Deck or in Cabin - Any Source. That checklist inferred that if the source of the smoke was identified, the crew should then conduct an appropriate procedure from a choice of further checklists contained within the QRH. The crew's selection of an appropriate checklist was dependent on whether the source of smoke was either from the electrical system, from the air conditioning system, or from the cabin equipment/furnishings.

Initially believing that the electrical system was the source of the smoke, the crew commenced the emergency checklist for Electrical Smoke, Fumes or Fire of Unknown Origin. That checklist had the potential to take in excess of 8 minutes to complete because it involved the troubleshooting of the aircraft's electrical system to determine the source of the smoke. As the aircraft was close to landing and the crew's priority was to land as soon as possible, that checklist was not completed. Since the incident, the aircraft manufacturer issued a revision to the QRH that simplified and combined the checklists described above. The new checklist was not generated in response to this particular incident.

The aircraft landed 20 minutes after take-off without further incident. Rescue and fire fighting services (RFFS) were in attendance as the crew stopped the aircraft on the taxiway. The RFFS personnel inspected the aircraft's electronics bay in an attempt to trace the source of the smoke, but nothing abnormal was observed. The aircraft was then taxied to the airport terminal and the passengers were disembarked. The co-pilot suffered eye irritation as a result of the smoke, but the passengers and the other members of the crew reported no symptoms.

Maintenance personnel inspected the aircraft and established that the smoke and fumes in the cockpit were due to contaminated bleed air from the number 1 engine. During normal operation, bleed air from that engine, along with bleed air from the number 2 engine, was fed to air conditioning pack one. Pack one supplied conditioned air to the flight deck and augmented the passenger cabin supply. Bleed air from the number 3 and number 4 engines was fed to pack two, which in normal operation supplied air to the cabin only.

The engineers addressed the defect in accordance with the Civil Aviation Safety Authority (CASA) airworthiness directive AD/BAe146/86 and the British Aerospace Systems Information Service Bulletin (ISB) 21-150. That ISB required certain actions to be performed whenever a cabin air quality problem was identified, which was suspected of being associated with oil contamination of the air supply from the air conditioning packs. The bleed air supply from the number 1 engine was isolated, and the defect was deferred in accordance with the aircraft's approved Minimum Equipment List. The aircraft resumed service, and no further smoke or fumes were evident during subsequent flights.

The defective engine was removed from the aircraft 5 days later and was returned to the engine manufacturer for overhaul. The overhaul procedure revealed that the engine's number 2 forward and aft carbon seals had heavy carbon build-up and were leaking oil. The manufacturer's report stated that the engine's number 4 carbon seal also showed evidence of oil leakage. Previous incidents of air system contamination on this type of aircraft had indicated that the fumes were a consequence of failures of the engine oil seals.

It has been noted in previous incidents, both in Australia and overseas, that there was a reluctance of the crews to use oxygen masks when air contamination was detected on the flight deck. Those incidents indicated that operating crews were not aware of their potential impairment and the consequent effect on their decision-making ability. The safety implications of that impairment was reflected in the decision by CASA to adopt a United Kingdom Air Accidents Investigation Branch (AAIB) recommendation requiring flight crew to use oxygen masks selected to 100 percent when there was a suspicion of flight deck or cabin air contamination.

An Airbus Industries A330 (A330) aircraft was en-route from Melbourne, Vic. to Denpasar, Indonesia. The Yarowee sector air traffic controller had issued the crew of the A330 with a clearance to climb to flight level (FL) 340. The A330 was on a crossing flight path with a Boeing 737 (737) that was en-route from Adelaide, SA to Melbourne, Vic. at FL310. The 737 was under the control of the adjacent Canty sector controller. Both the Yarowee and Canty sector controllers had recognised that there was a potential confliction between the two aircraft. The controllers discussed the potential confliction at 1119 EST and estimated that the aircraft would pass close to the boundary between the two sectors. The Yarowee controller accepted the responsibility for separation. That controller reported a reasonably low traffic level, which allowed him the opportunity to monitor the separation between the two aircraft. To ensure that the minimum horizontal separation standard distance of 5 NM was maintained, the Yarowee controller advised the Canty controller that the A330 would travel to the left of the proposed track and pass to the west of the 737.

Subsequent to that decision, the Canty controller reassessed the separation between the two aircraft and concluded that the potential confliction would occur inside the Canty sector. At 1121 the Canty controller instructed the Yarowee sector controller to assign the A330 crew FL300 on climb. Maintaining that altitude would ensure that the vertical separation minimum of 1,000 ft would not be infringed. The Yarowee controller entered FL300 into The Australian Advanced Air Traffic System (TAAATS) as the amended cleared flight level (CFL) for the A330. That entry changed the colour of the CFL in the label of the A330 that was displayed to the Yarowee controller on his air situation display. According to TAAATS procedures, the different colour provided a memory prompt to the Yarowee controller indicating that he had not received a correct amended CFL read back by the crew of the A330. Normally, once a controller had assigned a CFL to a crew and received a correct read back of that CFL, the controller would cancel the prompt and the CFL in the aircraft label would return to its regular colour.

There was a distraction at a neighbouring console just after the Yarowee controller had entered FL300 into TAAATS but before he had assigned the crew of the A330 the amended CFL. When the attention of the Yarowee controller returned to the Yarowee air situation display, the cleared flight level for the A330 was highlighted to prompt him to confirm that FL300 had been issued to the A330 crew. The controller believed he had already issued the crew of the A330 the amended CFL and that he had received a correct read back of the amended CFL from the crew prior to the distraction. The Yarowee controller cancelled the prompt. Analysis of the voice recording confirmed that the crew of the A330 had not been issued FL300.

The Yarowee controller incorrectly believed the A330 crew had been assigned FL300 and consequently that a vertical separation standard of 1,000 ft had been established between the A330 and the 737. At 1127, the controller approved the A330 crew to track direct to Woomera. That action placed the two aircraft on crossing flight paths with no prescribed lateral separation.

At 1131, as the A330 approached the Yarowee sector boundary, the Yarowee controller transferred jurisdiction of the A330 to the Canty controller. The Canty controller accepted jurisdiction of the A330 at FL295 and waited for the A330 to call on the Canty frequency.

At 1132, the Canty controller received a TAAATS Cleared Level Adherence Monitor (CLAM) alarm when the A330 passed FL303 on climb to FL340. A short time later, when the A330 and the 737 were 12.5 NM apart, both the Canty and the Yarowee controllers received a Short-Term Conflict Alert (STCA) alarm from TAAATS. This alarm indicated to the controllers that the two aircraft were in potential conflict. Vertical separation reduced to 900 ft while horizontal separation reduced to 7.5 NM. That horizontal distance exceeded the minimum separation standard. There was no infringement of separation standards.

At the time of the CLAM and STCA alarms, the crew of the A330 was still on the Yarowee sector frequency. The Yarowee controller reported observing the A330 pass FL303 and resumed jurisdiction over the A330. That controller then queried the A330 crew about their assigned flight level. He did not pass traffic information to the crew of the A330 about the 737 because he did not believe there would be an infringement of separation standards. Nonetheless, he subsequently issued a turn instruction to the A330 crew to ensure that separation was maintained. The A330 crew acknowledged traffic following that controller's query regarding their CFL.

The Canty controller was unable to contact the crew of the A330. The controller was aware that the A330 had climbed through what the controller believed was the assigned level of FL300 and issued turn instructions to the 737 crew to ensure that separation was not infringed. The Canty controller did not inform the 737 crew of the reason the vector was issued, however, the 737 crew subsequently acknowledged sighting the A330.

The Canty sector was combined with a low-level sector at the time of the incident and the controller reported that there was a medium traffic level at the time of the occurrence.

The Yarowee controller had recently returned from leave. He had completed the three required familiarisation shifts, had a two-day break, and completed one unsupervised shift during the day prior to the incident shift.

On 25 May 2002, at 1157 hours Eastern Standard Time, a Cessna 172 (Cessna) came within approximately 600 m of a departing Boeing 747-300 (B747) while the B747 was climbing through the altitude of the Cessna. The pilot of the Cessna was tracking in accordance with what he believed to be the visual clearance issued by Cairns air traffic control at 1,000 ft AMSL. The B747 crew was tracking via a standard instrument departure (SID) which specified a left turn after take-off.

The aerodrome controller issued the pilot of the Cessna with a clearance to track via the 'southern shores'. The term 'southern shores' was referred to in the Cairns local air traffic control instructions as the 'southern shores of Trinity Inlet'. The aerodrome controller understood that the clearance referred to the shoreline between the Cairns inlet and False Cape along the southern shore of the Cairns harbour. The pilot of the Cessna was not familiar with the term 'southern shores' and thought the controller meant the shoreline on the southern side of Cairns airport (which was the northern shore of the Cairns harbour). The term 'southern shores' was not specified in any document available to the pilot.

The pilot correctly read back the clearance to the aerodrome controller. That correct readback indicated to the aerodrome controller that the pilot could comply with the clearance.

The Cairns local air traffic control instructions stated that a clearance to aircraft to track via the 'southern shores' was meant to provide wake turbulence separation between an aircraft departing Cairns via a runway 15 SID and an aircraft over the southern shore of the Cairns inlet.

The aerodrome controller reported that he had kept both the B747 and the Cessna in sight and that visual separation was maintained between the two aircraft throughout the occurrence. The ADC provided the Cessna pilot with turn instructions, to enable him to avoid the B747, and traffic information about the B747 and a wake turbulence advisory. The B747 crew received a resolution advisory from their traffic alert and collision avoidance system about the Cessna.

The controller issued a clearance to the pilot of the Cessna that was, to the aerodrome controller, a specified route but one that was not known to the pilot. The aerodrome controller was not aware that the pilot's understanding of the 'southern shores' differed from his own. The meaning of the term 'southern shores' was not available to the pilot of the Cessna and therefore the potential existed for the misunderstanding between the pilot and the aerodrome controller that resulted in this occurrence.

The Hughes 369E helicopter, with the pilot the sole occupant, departed Strahan aerodrome at 0815 hours Eastern Standard Time (EST) for charter operations in the Western Tiers area of north-western Tasmania. Multiple flights were required from a base at Lake Mackenzie to a number of dispersed mountain hut locations. The flights involved transport of varying amounts of external loads and personnel, and included extensive periods on the ground with the helicopter engine running.

At approximately 1500 hours the pilot conducted a flight with an external load from Lake Mackenzie to Lake Nameless Hut. He then landed to embark three passengers for transfer to another hut. Two of the passengers occupied the remaining two front seats and the third passenger occupied the cabin right rear seat. The pilot reported that, while on the ground, the fuel low level advisory light had momentarily illuminated, but that he attributed that illumination to the distribution of fuel in the tank due to the slope of the ground. At that time, he reported also noting 100 lbs (86.9 lbs useable) of fuel indicated on the fuel quantity indicator. At 1515 hours, the helicopter departed Lake Nameless Hut for Tom Whitely's Hut, which was located approximately 5 km to the north-east. A passenger reported that, during that flight, a caution advisory light had illuminated. The investigation could not confirm the identity of that light. Having overflown the hut landing area, the pilot initiated a left descending turn to the south prior to commencing an approach to land.

The pilot reported that at 1524 hours, as the helicopter descended through about 200 ft above ground level (AGL), and at a speed of 70 kts, the main rotor speed decreased and the engine auto reignition advisory light illuminated. Assessing that the engine had lost power, the pilot reported that he initiated an autorotation to land. He stated that "...the aircraft landed normally, although heavily". He reported that, after the initial ground contact, the aircraft was "...suddenly rotated through 180 degrees". That rotation was reported by the pilot to be as a result of entanglement with an unseen "...little wire or whatever hooked the aircraft".

The helicopter was destroyed by impact forces. There was no fire. The pilot and three passengers sustained serious injuries.

Wreckage information

The helicopter impacted the ground heavily on the rear of the right landing skid, collapsing it and separating the left landing skid. The fuselage impact ground scar measured about 2 m in length. The main rotor blades struck the ground and severed the tail boom. The helicopter came to rest about 7 m and bearing 200 degrees magnetic from the initial impact point, facing the direction from which it had approached, and lying on a fence line. There were no ground impact scars between the fuselage impact ground scar and the helicopter's final position. The right side rear fuselage floor area sustained severe impact damage and the right fuel cell bladder was ruptured.

The forward section of the cockpit was destroyed during the impact sequence. The two front seat passengers were ejected from the helicopter, in the direction of flight. On-site inspection found the pilot's and passengers' seat belts and attachment points intact and that the pilot's shoulder harness was separated at the harness-to-inertia reel strap buckle. There was no evidence that the passengers' seat belt buckles had received damage due to impact forces. The pilot and front seat passengers' seat structure was deformed and wrinkled. Information from the helicopter manufacturer indicated that a vertical impact force loading of the airframe in excess of 10 g would have been required to deform the seat structure in that manner.

The investigation determined that there was minimal rotation of the tail rotor driveshaft at ground impact. That was confirmed by the lack of any impact or rotary damage to the tail rotor blades. The engine output driveshaft was separated at the driveshaft lobes and displayed little or no rotation at the time of separation.

The external load long-line was found attached to the cargo hook. There was no evidence that the long-line had snagged on the ground, other obstacles or the helicopter prior to impact.

An old wire and timber post fence was located in the vicinity of the accident site. The fence was about 1 m high and aligned about 050/230 degrees magnetic. The fence was laterally displaced about 3.5 m from the initial impact point. The fence posts and wire exhibited no evidence of having been contacted prior to, or during the helicopter's initial ground impact.

Testing of components

Analysis of the helicopter fuel system determined that a common fuel-sending unit activated the fuel quantity indicator and fuel low level advisory light. The fuel-sending unit, fuel quantity indicator and fuel low level warning system were removed from the helicopter and tested. Testing indicated that those components were serviceable in accordance with the manufacturer's maintenance manual. The fuel low level advisory light illuminated at 35 lbs fuel indicated on the fuel quantity indicator, in accordance with the manufacturer's maintenance manual. Testing, disassembly and inspection of the engine fuel pump, fuel control unit, fuel nozzle, bleed valve and power turbine governor, revealed no anomalies.

Meteorological information

The Bureau of Meteorology Area Forecast, valid at the time of the accident, indicated Visual Meteorological Conditions with moderate southerly winds. The pilot and passengers reported bright, sunny conditions and a light and variable southerly wind.

Personnel information

The pilot in command held an Air Transport Pilot (Helicopter) Licence, a Command Multi-Engine Instrument Rating and was endorsed on the Hughes 369E helicopter type. At the time of the occurrence, the pilot had accumulated a total of 3,565 flying hours, including 74.0 hours on type. He had flown 34 hours in the previous 90 days, of which 5 hours was on type. He was reported to be fit and well rested prior to the flight.

On the afternoon prior to the occurrence, the pilot completed a 0.5 hour proficiency check flight with the company Chief Pilot, in accordance with the company Operations Manual and CAO 20.11 appendix 4. It was reported that the check flight did not include external load or autorotation sequences. The pilot reported that he had significant prior external load experience, conducted in several helicopter types. He was unsure when he last practised an autorotation in the Hughes 369E. He reported, however, that he had completed autorotation and other emergency training in an Augusta 119 Koala helicopter about one week prior to the occurrence, and in a Bell 205 helicopter about one month prior to the occurrence.

Helicopter information

The maintenance release was current and there were no outstanding maintenance requirements. A routine 100-hourly engine inspection was carried out on 25 May 2002. Post-accident technical examination of the engine and wreckage indicated that the helicopter was capable of normal operation prior to the occurrence.

The gross weight of the helicopter at the time of impact was estimated to be within the authorised maximum operating and Height Velocity Diagram weight limits. The longitudinal and lateral centres of gravity were estimated to be within published flight manual limits. Helicopter performance was estimated to be sufficient for both in and out-of-ground effect flight.

Fuel planning/loading

The company Operations Manual stated a flight planning fuel consumption rate of 100 L (176 lbs) per hour for the Hughes 369 type. Charter helicopter fuel planning was required to include the provision of 20 minutes fixed and 15 per cent variable reserve. However, a reduction to a 10-minute fixed reserve was authorised for helicopter external load operations. That amounted to 42.4 lbs (29.3 lbs useable) indicated on the fuel quantity indicator at the company planning fuel consumption rate.

The pilot reported that the company Chief Pilot suggested a planning fuel consumption rate of 200 lbs per hour and that 100 lbs (86.9 lbs useable) indicated on the helicopter fuel quantity indicator equated to about 15 to 20 minutes flying time. He stated that, throughout the day's operations, he maintained a fuel log indicating an average fuel consumption of approximately 200 lbs per hour. The ground search and rescue party reported that, on arrival at the accident site, they collected paper and other loose items in the immediate vicinity of the wreckage. Those papers and items were secured in a large bag left at the accident site. The pilot's log was not recovered from that bag of items.

The pilot reported that a total of 280 L of fuel was added to the helicopter during the day using the operator's drum fuel stock and hand rotary fuel pump located at Lake Mackenzie. That amount of fuel was based on the pilot's understanding that approximately 280 turns of the rotary pump were made during the day's refuels and that pump output was 1 L per turn. He reported that he visually checked the fuel quality after each refuel. Post-accident examination of the remaining company drum fuel stock confirmed that it was JetA1 and did not reveal any contamination. Post-accident testing of the hand rotary pump used to refuel the helicopter determined an actual pump output of 0.7 L per turn.

Operational information

The helicopter flight manual stated that the fuel low level advisory light illuminated when approximately 35 lbs of fuel (21.9 lbs useable) remained in the fuel tank. The manual further stated that illumination of the fuel low level advisory light required the pilot to 'land as soon as possible', which was defined as:

Execute a power-on approach and landing to the nearest safe landing area that does not further jeopardise the aircraft or occupants.

A warning was included in the flight manual that, with the fuel low level advisory light illuminated:

Sideslips may cause fuel starvation and result in unexpected power loss or engine failure.

The flight manual also contained a Height Velocity Diagram that represented combinations of altitude and airspeed from which "a successful autorotation landing would be difficult to perform". Those figures were calculated at mean sea level, over a smooth hard surface and on a standard day (15 degrees C temperature, 1013.2 mb atmospheric pressure). The manual mandated adjustment to the helicopter gross weight limits, as a function of density altitude, in order for the Height Velocity Diagram to remain applicable. The pilot reported that he entered autorotation from a descending left turn at approximately 200 ft AGL. While the speed of the helicopter as the pilot rolled out of the turn could not be accurately determined, the pilot reported that he established 65 kts in the autorotation descent.

Organisational information

The Civil Aviation Safety Authority (CASA) had conducted regular surveillance audits of the company since issuing the company with an Air Operator's Certificate. The last on-site audit was conducted on 6 July 2001 and a remote audit was conducted on 30 January 2002. Those audits did not indicate any safety deficiencies.

The Civil Aviation Safety Authority approved company Operations Manual directed that "...all operating personnel associated directly with..." the company were to observe the "...instructions, procedures and information contained in..." the manual. The Manual also directed that "...all company personnel associated with piloting and flight line management..." must sign the signature sheet in the master copy of the Operations Manual "...as evidence of having read, understood and agreed to apply the procedures and data contained in it". The occurrence pilot was employed by the operator on a "standard day" contract, and was therefore required to comply with the provisions of the Operations Manual, but was not required to sign the master copy of the Manual.

The coordinator for the Western Tiers operation reported that there was no formal contract in place with the operator for the day's operations and no formal audit of prospective helicopter support organisations by the charter client. It was reported that the operator was contracted for the day based on extensive previous experience operating with the charter client and the statewide experience of its pilots. The occurrence pilot had not previously flown in the Western Tiers area of Tasmania.

Survival information

The pilot reported that a flight operations brief was conducted with personnel present at Lake Mackenzie prior to commencement of the day's operations. That brief included operating around the Hughes 369E helicopter and the operation of the aircraft doors and safety belts. The pilot also reported that, prior to takeoff for the occurrence flight, he had asked the passengers to confirm their seat belts were secure. Passengers reported that they were not wearing headsets during that flight.

Flight notification details for the flight were not submitted to Airservices Australia, nor was there any requirement to do so. There was no formal flight-following process undertaken by the operation. The pilot reported that radio communications with Air Traffic Services (ATS) had not been possible. The pilot reported making a Mayday broadcast on the forestry service channel following the reported engine power loss. That broadcast was not reported as having been received by any station.

Prior to being noted overdue, the pilot had departed Lake Mackenzie for Lake Nameless with an external load and was to return to Lake Mackenzie. At about 1600 hours, the helicopter was reported overdue to the operator by the coordinator of the Western Tiers operation. The operator then alerted Melbourne ATS of the overdue helicopter. At 1652 hours, ATS alerted Australian Search and Rescue (AusSAR). The pilot reported manually activating the Emergency Locator Transmitter (ELT) shortly after 1700 hours. AusSAR directed an aircraft to the area to conduct a beacon search at 1715 hours. That aircraft flight crew made the initial detection of the ELT signal on 121.5 MHz at 1720 hours. The ELT signal was first detected by the COSPAS/SARSAT satellite constellation at 1756 hours.

At about 1900 hours, a rescue helicopter from Hobart located the wreckage and survivors. A number of attempts were made to land at the accident site. Low cloud and fog prevented the landing and the rescue helicopter departed for Launceston airport to refuel. The survivors reported that departure of the helicopter resulted in a marked decrease in their morale.

The ground search and rescue party arrived at the accident site at 2338 hours. The four survivors required treatment for varying degrees of hypothermia and spinal and other injuries. They were transported from the site by rescue helicopter and arrived at Launceston General Hospital by 0516 hours on 29 May 2002.