FACTUAL INFORMATION

At 0721 EST, while taxiing for take-off at Coolangatta, the pilot informed the aerodrome controller that he intended to fly along the coast at 500 ft. He had not submitted a flight plan and did not require search and rescue services.

The early part of the flight to Noosa was without apparent difficulty. The aircraft was last observed by radar at 0820, crossing the coast on a north-westerly track south of the Wide Bay Restricted Area. Radar returns indicated that the aircraft was at 2,500 ft at the time. The pilot did not communicate with the Brisbane Flight Service unit.

At about 0907 witnesses on the ground heard what they believed was aircraft engine noise, which was varying in intensity, followed by a loud bang. A short time later several large pieces of aircraft were seen to fall from the low cloud base, followed by a shower of lighter material.

The Area 40 weather forecast covering the period from 0300 to 1800 on 26 October 1995, indicated wide-spread rain from stratiform, layered cloud, with a base below 1,000 ft. A clearing change, gradually moving east, was expected at the coast about midday. Pilots who flew in the area at about the time of the accident reported that the cloud mass was quite thick, with a base at about 600 ft and tops to 14,000 ft in places. Witnesses on the ground said that the cloud base was unbroken at about 500 ft above ground level. No thunderstorms were reported in the area. An Area 40 forecast was available to the pilot before the flight commenced but it is not known whether he obtained one from the Brisbane Briefing Office.

Examination of the wreckage found that the left wing had failed in overload and had separated from the fuselage.

The remainder of the aircraft structure then rapidly disintegrated. There was no evidence of an in-flight explosion. The landing gear was found in the extended position.

The validity of the aircraft's Maintenance Release expired on 20 October 1995.

The pilot was the owner of the aircraft, and he used it almost exclusively for transport between the Gold Coast and Rockhampton where he had business commitments on a semi-regular basis. On the day of the accident, he had business scheduled in Rockhampton. He did not hold an instrument rating but did hold a night visual flight rules (NVFR) rating. His logbook showed that he had completed his endorsement training in the aircraft in October 1990. He had not undertaken a biennial flight review within the two years prior to the accident.

In 1990 the pilot underwent heart bypass surgery. Since the operation he had regained his Class 2 medical certificate and was allowed to exercise the privilege of his pilot's licence. The post-mortem examination revealed the presence of ischaemic heart disease, a deficiency of blood in part due to functional constriction or actual obstruction of a blood vessel.

ANALYSIS

Weather and Flight Planning

Both the Area 40 forecast and actual weather reports indicated that it was unlikely that the pilot could have completed his flight in visual meteorological conditions.

The Pilot

Examination of his logbook showed that the pilot first flew VH-YAB during training for a Constant Speed (Propeller) and Retractable Gear endorsement in October 1990. In September 1991 he obtained a NVFR rating. The last log-book entry was dated March 1995. However, a detailed, current notebook recorded his flying activities. He had noted 45 flight hours in VH-YAB since March 1995, mostly on flights to and from Rockhampton.

The NVFR rating is not regarded by the Civil Aviation Safety Authority (CASA) as an instrument rating; however, the pilot would have gained limited instrument flying experience during his training for the rating.  A passenger on an earlier flight said that on one occasion they were caught above cloud. The aircraft entered cloud and seemed to be out of control for a period of time.

The post-mortem examination report revealed the presence of ischaemic heart disease. The report found that there may have been a cardiac episode prior to the crash which affected the pilot. With the degree of ischaemic heart disease found, any relative hypoxia of the myocardium might have precipitated a rapid and/or irregular rhythm, bringing about left ventricular failure. The report noted that anxiety with a rapid heart rate might trigger such a sequence. A specialist report from the Directorate of Aviation Medicine, CASA, endorsed the findings of the post-mortem examination report, adding that unfavourable in-flight conditions may have brought on some degree of myocardial ischemia through anxiety.

Aircraft Operation and Crash Site Examination

The crash site is situated on the direct track between Maroochydore and Gladstone. Examination of the aircraft's gyro flight instruments confirmed that they were functioning up to the point of breakup. The Piper Auto control 111 automatic pilot was switched on.  A Magellan NAV 1000 PLUS (Marine) Global Positioning System (GPS) had been connected to the aircraft's electrical system. All GPS data was lost due to the loss of aircraft power supply and its battery pack backup. However, it is possible that the pilot had the relevant data entered in the GPS receiver and was flying along the route.

The altitude at which the aircraft broke up could not be determined. Examination of the recorded radar tapes did not show the aircraft. The Mt Alma radar near Rockhampton is a monopulse secondary surveillance radar which relies on an operating aircraft secondary surveillance radar transponder. The pilot may have switched his transponder off, or the aircraft may have been operating below the radar horizon. Interpolation of radar coverage maps indicated that the radar horizon is approximately 6,000 ft over the crash site.

Witnesses described the engine sound as varying before the aircraft broke up. The varying engine noise was probably due to the doppler effect as the aircraft, relative to the witnesses, continually turned away and towards them in a downward spiral.

The aircraft had an automatic gear extension system which lowers the landing gear when the speed drops below about 90 kts. That the landing gear was down and locked could indicate that the air speed dropped below normal cruise speed some time before the breakup, or that the gear was deliberately lowered.

CONCLUSIONS

Findings

1. The aircraft was overdue for maintenance but was otherwise serviceable for flight as far as could be determined.
2. The pilot was not trained or rated for flight under instrument flight rules.
3. On a previous flight, the pilot had flown into cloud and probably lost control of his aircraft.
4. The pilot had scheduled business in Rockhampton on the day of the accident.
5. The weather was unsuitable for visual flight.
6. The pilot continued the flight without visual reference to the ground or horizon.
7. The pilot was suffering from ischaemic heart disease and may have been incapacitated.
8. The pilot lost control of the aircraft.
9. The aircraft was overstressed and as a result broke up in flight.

Significant factors

1. The pilot was unable to continue visual flight rules flight along the coast as planned and entered cloud, probably relying on his autopilot and GPS to aid him in control and guidance of his aircraft.
2. Control of the aircraft was lost by the pilot either through disorientation, incapacity, or a combination of both.

1. FACTUAL INFORMATION

1.1 History of the flight

The pilot had commenced mustering at Kilclooney Station at about 0700 EST. A refuelling stop was made at about 0930 when the mustering operation had been completed. After refuelling, the pilot took off and returned to the homestead, which was about 5 minutes flying time away, intending to collect his swag and the helicopter canopy cover and then return to his home base at Greenvale, 76 km west of Kilclooney. The pilot phoned his wife at about 1045 to say he was departing Kilclooney. At about 1050 the power supply to the homestead failed. The homestead was unattended at the time. At 1330 the company chief pilot reported to Brisbane Search and Rescue (SAR) the aircraft had not arrived at Greenvale. At 1348 the Brisbane Area Approach Control Centre (AACC) co-ordinator advised SAR that an emergency locator transmitter (ELT) signal had been heard by an overflying aircraft. The Queensland Emergency Services helicopter was then tasked to conduct a search in the area where the beacon was heard. At 1506 the wreckage of the helicopter was located at Kilclooney Station.

The helicopter had collided with a single 19-kilovolt powerline located near where the helicopter had been parked overnight. He had apparently landed near the homestead, to collect the swag which was known to be on the back of a vehicle, and then repositioned the helicopter to the parking area to pick up the canopy cover.  Two parallel wires

15 metres apart were strung from poles near the homestead and passed alongside the parking area in a southeast-northwest direction.

1.2 Impact information

It is probable that as the helicopter was approaching the parking area from the south, the left skid passed under the second wire which had a span of approximately 150 metres. The helicopter travelled a short distance before impacting the ground in a steep nose-down attitude and caught fire. The three-strand 12-gauge steel wire did not break and was trapped under tension by the wreckage for some time. The left skid was thrown clear of the fire when it became detached by heat and the wire separated from the wreckage. The wire was substantially stretched and was within 4 metres above ground level after becoming detached from the wreckage.

1.3 Pilot in command

The pilot was correctly licensed and endorsed and appeared to be in good health immediately prior the accident.

1.4 Meteorological information

Station personnel reported that the weather was fine with a moderate northerly wind at the time of the accident.

1.5 Wreckage examination

The cabin area forward of the firewall was completely destroyed by fire. The engine suffered substantial fire damage, and all engine accessories were damaged beyond the point where the serviceability of these items could be assessed. The ELT was a fixed installation in the engine bay and was destroyed by fire, it was of the type that complied with TSO C91. No mechanical failures or defects were discovered with the engine which would have prevented it from operating normally. The tail boom was separated from the main wreckage and remained clear of the fire. The tail rotor and tail rotor gearbox appeared undamaged, indicating that a steep nose-down impact had occurred.

2. ANALYSIS

The wind direction would have required an into-wind approach to be made over two wires which were about 15 metres apart. The approach over the second wire would have to be steep to achieve a touchdown near the fuel drum where the canopy cover was located and would therefore have taken the helicopter close to the second wire. During the accident sequence the helicopter actually struck the drum. Why the helicopter struck the wire could not be determined, but it is probable that the helicopter was capable of normal operation up to the time of the accident. The canopy cover was on the ground beneath an upright 200-litre fuel drum, located about 10 metres from the powerline. The helicopter was probably previously parked in this particular position as the pilot did not want to frighten horses in an adjacent paddock.

3. CONCLUSIONS

3.1 Findings

1. The pilot was correctly licensed and fit to perform the flight.
2. There were no mechanical defects discovered which may have contributed to the accident.
3. The helicopter had been previously parked in close proximity to a single strand powerline and was being manoeuvred to land at this position to allow the pilot to collect the helicopter canopy cover.
4. The wind direction required an approach from south to north over the top of the powerline.
5. The helicopter struck the powerline.

3.2 Significant factors

1. The aircraft was being manoeuvred in close proximity to a single-wire powerline.
2. The pilot failed to see and avoid the powerline.

The pilot hired the aircraft with the stated intention of conducting practice circuits at Archerfield. When he taxied, he told the Surface Movement Controller that he was proceeding to the (Archerfield) Southern Training Area. The aircraft departed the circuit area at 0927 EST.

At about 0955, a witness near Mt Warning heard an aircraft engine operating at high rpm followed by the sound of impact. Later an aerial search found the fragmented and burnt wreckage of an aircraft at the base of a near vertical cliff on the north face of Mt Warning. The aircraft had impacted head on, near the geometric centre of a large triangular shaped cliff face. The weather at the time was fine with a clear blue sky and light winds.

On the basis of information received concerning the circumstances of this occurrence, the Bureau has discontinued its investigation.

1. FACTUAL INFORMATION

1.1 Sequence of events

The aircraft was on a powerline inspection flight. It was crewed by a pilot employed by the operator of the aircraft and by an observer from the power supply company. The purpose of the flight was to enable the observer to identify obstructions in the form of trees and branches potentially too close to the powerlines and constituting a fire hazard, and to assess the condition of the conductor and associated items.

To enable the observer to inspect a powerline such aircraft are flown 150 feet above ground level, at 70 knots, with flaps extended 10 degrees. The aircraft is tracked down the left side of the powerline to give the observer in the right seat a good view of the line.

Shortly before the aircraft crashed, it was observed flying along a spurline. It was at this time flying essentially downwind. Some minutes later, the wife of a nearby farmer who had been listening to the approaching aircraft realised that she could no longer hear the engine. Her husband located the wrecked aircraft in a paddock and initiated an emergency response. There were no witnesses to the accident. Neither the pilot nor the observer survived the impact.

1.2 Wreckage and impact information

The aircraft had impacted the ground in a nose-down attitude of approximately 45 degrees. The right wing was down approximately 30 degrees relative to the horizon. The wreckage trail was short, indicative of low forward speed at impact. The disposition of the wreckage indicated that the aircraft had been rotating to the right before impact.

Wreckage analysis disclosed no pre-impact faults. The aircraft had sufficient fuel for the flight and had been properly maintained. There were no pre-existing defects recorded on the maintenance release. The pilot had updated personal, company and aircraft records at the completion of the previous day's flying.

1.3 Pilot details

The pilot commenced flying training in 1987. He obtained his commercial pilot licence in December 1991, an instructor rating in May 1992, and a command instrument rating in July 1993. His logbook recorded that while flying as an instructor he had instructed student pilots on the causes of stalling and on stall recovery techniques. He had flown a total of 1,276 hours.

He commenced his training in powerline inspection flying techniques on 19 July 1994. After eight hours instruction over five flights, he was assessed as having met the required standard. Accordingly, he was approved to conduct powerline inspection flying for a period of 12 months. At the time of the accident, he had conducted 209 powerline inspection flights totalling 462 hours. The latest check for revalidation of his powerline inspection flying approval, carried out on 13 July 1995, was valid for one year and was therefore valid at the time of the accident.

The pilot had ferried the aircraft from Moorabbin to Hamilton three days prior to the accident. Including the ferry time, he had flown for four hours, two hours and three hours respectively, on the three days prior to the accident. On the day of the accident, he flew for just under three hours. The aircraft was one of two that were conducting powerline inspections out of Hamilton aerodrome. The pilot of the second aircraft advised that the crews had a quiet night and were well rested before commencing the day's operation.

The pilot held a valid medical certificate. The post-mortem examination did not disclose any medical factors that may have contributed to the accident.

1.4 Meteorological information

The property owner advised that the weather at the time of the accident was fine with a light breeze from the northwest. This was consistent with the forecast issued by the Bureau of Meteorology which had predicted a 15-knot breeze for the area. Weather was not considered to have been a factor in the accident.

1.5 Roll and cut manoeuvre

If an observer does not get a clear view of an obstruction, then the aircraft is required to fly a specific manoeuvre to give the observer a better view. The manoeuvre is called a 'roll and cut'. When the aircraft is flying on the left of the line and the observer calls 'roll' the pilot rolls the aircraft to the right to cross the powerline at 45 degrees. This enables the observer to look back down the line at the obstruction. If after crossing the line, the observer requires a further look at the obstruction, he calls 'cut'. The pilot then continues the right turn until the aircraft has turned through 270 degrees from the original heading. The aircraft is then rolled wings-level to cross the line at right angles, giving the observer a clear view of the obstruction to the right as the aircraft passes over the line. After crossing the line, a 270-degree left turn is made to re-position the aircraft to continue the inspection.

The wreckage was located in a paddock with the wreckage trail aligned nearly at right angles to and under the powerline that was being inspected. In the paddock there was one line of scrub before the accident site and one tree after the accident site that might have been subject to a cut and roll inspection manoeuvre. Due to the lack of witnesses to the accident the investigation was unable to determine what manoeuvre was being carried out prior to the loss of control which preceded the accident.

The power supply company advised that in the year before the accident, some 56,000 km of line was patrolled, finding 27,514 trees that needed attention. This would mean that to verify the hazard, at the very least one cut and roll is required for approximately every two kilometres flown.

1.6 Powerline inspection: flight parameters

The aircraft operator and the power supply company determined the optimum height for inspection of powerlines to be 150 feet above ground level and the optimum speed to be 70 knots. It is the pilot’s responsibility to maintain these parameters. The height of the power poles varies between 25 feet and 40 feet. There was evidence that, on occasions, powerline inspection aircraft had been observed to fly lower than 150 feet. Some pilots had commented that occasionally the observers asked for the aircraft to be flown at a lower height. The pilots considered that this might have been due to difficulty observing powerlines in certain conditions of sun and light and to the difference in visual acuity between individual observers. The power supply company did not have standards for, and did not require a check of, the observer's visual acuity. When the observer completed his training two years before the accident his visual acuity was obviously acceptable. However, there was no ongoing program to check and detect any deterioration that may have occurred since that time.

1.7 In-flight incapacitation

Post-mortem examination disclosed that the observer suffered from asthma and had advanced heart degeneration.

Microscopic examination of his lungs showed changes in keeping with asthma. However, no macroscopic findings were seen that would have indicated he had suffered a severe asthma attack.

The post-mortem examination showed significant coronary artery disease with a 75 per cent stenosis of the left anterior descending coronary artery. Expert pathological opinion was that an individual with significant coronary artery disease may have an episode of myocardial ischemia leading to severe pain or change in conscious state. However, the physical reaction could be expected to be benign, resulting in slumping of the body. The observers sit with the seat at the limit of its aft travel to enable them to use their maps clear of interference with the control column and to give the best view through the right window. It is unlikely that control interference would occur due to a body slumping while the seat was in the aft position. It could not be determined if the observer suffered any form of incapacitation in the period immediately before the accident.

Neither the observer's family nor his employer was aware of his medical condition. The employer did not require the observers to meet a minimum medical standard.

1.8 Flight path simulation

A flight was undertaken to simulate the inspection of the spur line that was being inspected immediately prior to the accident. The flight was conducted by the operator's manager of powerline flying and conformed to the required parameters of height, speed, and configuration. The flight was watched by some persons who saw the accident flight, shortly before the accident, and by some who had watched other powerline inspection flights. They said that they had seen many flights, including the accident flight, operated either more slowly and/or at a lower height and/or with greater bank angles, than those demonstrated during the simulation flight.

2. ANALYSIS

The accident probably occurred when control of the aircraft was lost while it was flying at a height too low for the pilot to apply effective stall/spin recovery techniques. The sequence of events that led to the loss of control could not be established because there were no witnesses to the maneouvres that preceded the accident. However, there was evidence that some powerline inspection flights had not complied with the operator's height, speed, and angle of bank requirements. This may indicate that some of the pilots had become complacent and had a lowered awareness of the dangers of flying low and slow and lacked appreciation of the importance of strictly adhering to the operator's flight parameters.

Although the observer was suffering from a medical condition which may have led to his becoming disabled, there was no evidence that this had occurred. Had an episode occurred it could have resulted in severe pain or collapse. Either could well have been distracting to the pilot. It is unlikely that the onset would have been of such severity as to cause involuntary limb and body movements that may have interfered with the flight controls, leading to loss of control of the aircraft.

3. CONCLUSIONS

3.1 Findings

1. The aircraft was properly certificated and maintained, held sufficient fuel for the flight, and was serviceable at the start of the flight.
2. The pilot was properly licensed and had been properly trained and checked for conducting low-level powerline flights.
3. Some powerline inspection flights had been observed to deviate from the required flight parameters.
4. The power supply company did not have minimum medical standards for its observers.
5. The observer had a medical condition that may have incapacitated him.

3.2 Significant factor

1. Control of the aircraft was lost at a height from which the pilot was unable to recover.

4. SAFETY ACTION

4.1 Immediately after the accident the power supply company suspended flying and, with the operator, assisted in the conduct of the investigation. When it became apparent that the operator's flight parameters were not always being observed, the operator instituted a campaign to improve pilot awareness and discipline. When flying recommenced, the observers advised that there was a marked difference in the way the pilots manoeuvred the aircraft.

4.2 Both the powerline company and the aircraft operator conducted a major reassessment of the operation. They have decided to:

(a) fit four-piece crew restraint harnesses to all aircraft;

(b) supply crash helmets for both the pilots and observers, and require that they be worn;

(c) require observers to meet a minimum medical standard; and

(d) initiate crew resource management training for pilots and observers, with emphasis on safety awareness.

4.3 Before the accident the operator and power supply company commenced experimenting with the use of differential video imaging and infra-red detectors to aid in the identification of hazardous trees. When implemented, this system is expected to reduce the need for continuous roll and cut manoeuvres. The optimum height above ground level for this system has been determined to be approximately 250 feet which should improve the margin of safety.

1. FACTUAL INFORMATION

1.1 History of the flight

The pilot planned a private business flight under visual flight rules (VFR).  He took off from Moorabbin shortly after 0800 EST and collected two passengers from Melbourne Airport prior to flying to Warrnambool.   After working in the Warrnambool area during the day, he took off from runway 31 at about 1948 EST.  Conditions in the circuit area were very dark with limited ground lighting, high overcast cloud, some low cloud, and patches of drizzle.

The complete flight path after take-off is unknown.  However, witnesses heard and saw the aircraft flying low to the north-west and west not far from the aerodrome.  The last sighting was of the aircraft climbing to the east-south-east towards the centre of runway 31, followed by a left turn and a steep left spiral dive from an estimated height of about 500 feet.  At 1950 the aircraft crashed 255 metres to the right of runway 31 centreline. Runway 31/13 lights were illuminated at the time.

At impact the fuel cells burst.  There was a flash fire along the wreckage trail.  However, most of the fire damage was confined to the detached wings.

1.2 Damage to aircraft

The aircraft was destroyed by the ground impact and by post-impact fire.

1.3 Weight and balance

The aircraft weight and balance were within approved limits for the flight.

1.4 Personnel information

The 54 year old pilot was correctly qualified and endorsed to perform the flight.  He held a private pilot licence (aeroplanes) and a single-engine night rating valid for automatic direction-finding equipment and very high frequency omni-directional radio range.  The night rating was issued on 11 October 1994.  His total night flying experience was 22.3 hours.  This comprised 13.3 hours dual flight instruction in a Piper PA28, a 3.3 hours flight test in a PA28 with an approved testing officer, and 5.7 hours as pilot in command, of which 2.5 hours were in a PA28 and 3.2 were in the Cessna 182.  His most recent previous night flight occurred on 6 October 1995.  His Civil Aviation Safety Authority medical certificate was valid until 14 August 1997.  He was required to wear spectacles for close vision.

1.5 Meteorological information

A weather observation taken by a trained observer at Warrnambool at 1800 indicated: QNH 1011.6 hectopascals, surface wind 320 degrees 18 knots, visibility 20 kilometres, light rain, cloud 8 octas of altocumulus base at 8,500 feet, temperature 15 degrees Celsius, dew point 15 degrees Celsius.

An observation taken at Warrnambool at 2100 indicated: QNH 1015.5, surface wind 230/10 knots, visibility 50 kilometres, weather nil, cloud 8 octas of altocumulus, base 8,500 feet, temperature 13 degrees Celsius, dew point 15 degrees Celsius.

Charts provided by the Bureau of Meteorology indicate that the accident occurred as the tail end of a cold front was passing through Warrnambool.

Witness evidence of weather at the time of the accident varies.  However, the consensus was that it was very dark because cloud had obscured the moonlight, and that there was intermittent drizzle in the area. Because it was so dark, witness estimates of cloud amount and height varied but indicated that there were patches of cloud below 1,000 feet in the area.

At 1900, before leaving Warrnambool city, the pilot telephoned the Civil Aviation Authority briefing office, and a briefing officer gave him a detailed update on the forecast weather for the proposed flight.  The pilot had already submitted a night visual flight rules flight plan for the return flight to Moorabbin via Avalon.  During the five-minute discussion, the briefing officer advised of the area forecast 30/32, Melbourne aerodrome forecast, and Moorabbin aerodrome forecast.  From the discussion it was apparent that the pilot was fully aware of a weather front passing through Warrnambool at about the time of the telephone call.  He advised the briefing officer that there were some fairly low cloud layers at Warrnambool at the time.  The forecast weather ahead of the front and well behind it was suitable for night visual flying, whereas weather associated with the front included scattered cloud from 1,000 feet to 2,000 feet and visibility reduced to 3,000 metres in drizzle.  He advised the briefing officer that if he could depart Warrnambool quickly, he would be ahead of the trough and that he would telephone the briefing office again to lodge a search-and-rescue time when he was about to depart Warrnambool aerodrome.

The taxi driver who drove the pilot and the two passengers to the aerodrome, arriving at about 1930, advised that as they neared the aerodrome it was a moonlight night, but the clouds were rolling in from the west and starting to obscure the moonlight.

At 1933 the pilot telephoned the briefing office from the aerodrome and lodged a search-and-rescue time of 2130 for arrival at Moorabbin.  The briefing officer advised that Warrnambool was probably still east of the trough/cold front.

1.6 Aids to navigation

Warrnambool has a pilot-monitored non-directional beacon which was transmitting on 395 kilohertz at the time of the accident.

1.7 Communications

Warrnambool has a common traffic advisory frequency of 126.0 megahertz which is not recorded. The common traffic advisory frequency applies for a radius of five nautical miles and up to 3,000 feet above the aerodrome reference point.  Had the pilot flown beyond five nautical miles or above 3,000 feet, he probably would have made a departure call to Melbourne flight service and this call would have been recorded.  The flight service communications tape has since been monitored.  No departure call was recorded.

1.8 Aerodrome information

Warrnambool Airport is 11 kilometres north-west of Warrnambool city.  It has two runways.  Runway 31/13 is the only one with runway lighting installed.  The runway lighting is a pilot-activated system. Because the runway lights were on, it is probable that the pilot of VH-XTK had activated them prior to take-off. Runway 31/13 is 1,372 metres long, 30 metres wide, and the surface is asphalt.  The aerodrome is 242 feet above sea level.  The surrounding terrain varied from relatively flat to gently undulating.

1.9 Wreckage and impact information

The impact site was abeam a position approximately 925 metres along runway 31 and 255 metres to the right of centreline.  At impact the aircraft was an estimated 70 degrees nose down, facing 278 degrees magnetic and left wing low.  Wreckage was spread over 107 metres in the direction of 008 degrees.  The engine was torn out of the airframe and was found four metres from the point of initial impact.  Most of the fuselage came to rest within 58 metres of the initial impact point.  Both of the wings were torn off.

The control system was inspected and the damage sustained was consistent with impact damage. The flaps were up at impact.

The propeller was torn from the engine. A subsequent inspection showed evidence of its being within one degree of full fine pitch at impact.

The engine and its accessories were inspected.  A metallurgist examined the exhaust pipe and confirmed that the engine was producing hot exhaust gases at impact.

The engine-driven vacuum pump was subsequently determined to have been serviceable at impact.  The artificial horizon showed impact evidence of a steep nose-down attitude.  The turn co-ordinator showed evidence of hard left bank at impact.  The altimeter subscale setting was 1013 hectopascals.

Fuel filters were found clean.  The fuel on board was of the correct type and of sufficient quantity for the flight.

No fault was found with the aircraft or its systems that may have contributed to the accident.

The accident was not survivable.

1.10 Medical information

The specialist forensic pathologist who performed the autopsy on the pilot documented the cause of death as multiple injuries.  However, he advised that the presence of ischaemic heart disease in the pilot may have contributed to the accident.

1.11 Emergency locator beacon

The emergency locator beacon did not function correctly after the accident.  The antenna cable was severed at impact. When tested, a low-level signal was received at very close proximity.  The battery was one month past its replacement date, but the voltage was within tolerance.  The negative terminal was corroded, causing a high resistance joint which resulted in low signal strength.

1.12 Spiral dive

Some basic spiral dive trials were subsequently conducted in another Cessna 182R.  With his aircraft at 6,000 feet and trimmed to 100 knots indicated airspeed, 20 inches manifold air pressure and 2,400 revolutions per minute, the pilot closed the throttle and gently banked the aircraft 45 degrees left without applying back pressure on the control yoke to maintain height.  The nose began to drop.  By 100 feet height loss, the vertical speed indicator had reached 500 feet per minute rate of descent.  With 280 feet total height loss, the vertical rate of descent was 1,400 feet per minute. With 450 feet total height loss, the vertical speed indicator needle was on the 2,000 feet per minute descent stop and the indicated airspeed was 125 knots.

A similar exercise was conducted leaving the power at 20 inches manifold air pressure.  In about 200 feet height loss, the vertical rate of descent reached 2,000 feet per minute and the airspeed was about 135 knots and increasing rapidly.

1.13 Pilot training

The pilot's night VFR training was conducted from Moorabbin by a Grade Two instructor.  The training included navigational exercises to Essendon, Latrobe Valley, Bendigo, Ballarat and Mangalore.  In excess of three hours dual night circuit training was conducted at Moorabbin and Latrobe Valley.  The pilot also performed night landings and take-offs at Bendigo, Ballarat and Mangalore.  The Mangalore circuit area was known to contain minimal ground lighting.

The pilot's instructor taught him to take off and fly solely on instruments from the moment the runway lights disappeared from view on take-off until 500 feet above ground level.  From about 500 feet on the crosswind climb, he was taught to fly 75 per cent on instruments and 25 per cent by visual reference; on downwind, 50 per cent on instruments and 50 per cent visual, on base, 25 per cent instruments and 75 per cent visual.  The pilot was given two hours night dual flight instruction practising navigation by reference to navigational aids.  He was also trained in recovery from unusual attitudes at night.  His instructor advised that the pilot displayed good airmanship and a responsible attitude while under training.

During an interview after the accident, the instructor was asked what he thought the pilot would do if at 500 feet after take-off he looked out and found himself in cloud. The instructor replied that he thought the pilot would immediately descend to regain visual flight.

2. ANALYSIS

With pre-flight planning/preparation, early departure from Moorabbin, business meetings through the day and the 1948 EST estimated take-off time from Warrnambool, it is possible that the pilot was suffering from fatigue at the time of the accident.  However, the degree of fatigue and the degree to which it contributed to the accident remains unknown.

It also remains unknown how the onset of darkness and the degree of darkness hampered the pilot's ability to assess the amount and base of the cloud and/or the existence of drizzle in the circuit area immediately before take-off.

It is possible that the pilot first looked out at 500 feet after climbing on instruments and found himself in drizzle or in cloud, with limited or no external visibility. If this happened, it is likely that the pilot immediately descended to become visual and then attempted to return for a landing on runway 31.  This is consistent with witnesses seeing the aircraft flying at low level.

Why the pilot flew towards the centre of runway 31 immediately prior to entering a steep left spiral dive, could not be determined.  Perhaps low cloud or drizzle prevented the pilot from flying further downwind to position for a landing on runway 31, or perhaps he could have been positioning the aircraft for a departure.

As witnesses clearly saw the aircraft climb and then enter the spiral dive, it seems that the aircraft was not in cloud or drizzle for the spiral entry and subsequent descent.

The impact site was only 255 metres to the right of a row of the illuminated runway lights which should have given the pilot a visual reference to avoid the ground. There was no evidence of an attempted recovery from the left spiral dive.

Pilot disorientation is a possible reason for the spiral dive because conditions were dark and there was probably no visible horizon.  However, the aircraft was not in cloud or drizzle for the spiral and the accident occurred close to the illuminated runway, which should have given the pilot a reasonable visual reference to level the wings and attempt to recover from the dive.

It is also possible that the pilot suffered incapacitation during the flight.

3. CONCLUSIONS

3.1 Findings

1. The pilot was correctly qualified and endorsed to perform a night flight under visual flight rules, but his night flying experience level was low.
2. The pilot did not hold an instrument rating.
3. Weather forecasts, assessed by the pilot prior to take-off, indicated that the weather may have been suitable for night visual flight ahead of the cold front trough and behind it.
4. The accident occurred as a cold front was passing through Warrnambool.
5. There was a low cloud cover with associated drizzle in the area.
6. The aircraft was within its approved centre of gravity and gross weight limits at the time of the accident.
7. The fuel on board was of the correct type and of sufficient quantity for the flight.
8. No pre-existing fault was found with the aircraft which may have contributed to the accident.
9. The impact occurred close to and abeam runway 31 while the runway lights were illuminated.
10. The post-mortem carried out on the pilot indicated the presence of ischaemic heart disease may have contributed to the accident.

3.2 Significant factors

The factors which led to this accident could not be positively determined.  However, the three most likely factors are:

1. The pilot was suffering from fatigue at the time of the accident.
2. The pilot suffered some form of in-flight incapacitation.
3. The pilot lost control of the aircraft as a result of losing visual reference in adverse weather.

SAFETY ACTION

The Bureau of Air Safety Investigation is continuing to investigate a number of possible safety deficiencies in the operations area that have arisen from this accident. Any safety outputs arising from this investigation will be published in the Quarterly Safety Deficiency Report.

The flight was the second Metro III type-conversion training flight for the co-pilot. Earlier that night, he had completed a 48-minute flight.

During the briefing prior to the second flight, the check-and-training pilot indicated that he would give the co-pilot a V1 cut during the take-off. The co-pilot questioned the legality of conducting the procedure at night. The check-and-training pilot indicated that it was not illegal because the company operations manual had been amended to permit the procedure. The crew then proceeded to brief the instrument approach which was to be flown following the V1 cut. There was no detailed discussion concerning the technique for flying a V1 cut.

The co-pilot conducted the take-off. Four seconds after the aircraft became airborne, the check-and-training pilot retarded the left engine power lever to flight-idle. The landing gear was selected up 11 seconds later. After a further 20 seconds, the aircraft struck the crown of a tree and then the ground about 350 m beyond the upwind end of the runway and 210 m left of the extended centreline. It caught fire and was destroyed. The co-pilot and another trainee on board the aircraft were killed while the check-and-training pilot received serious injuries.

The investigation found that the performance of the aircraft was adversely affected by:

• the control inputs of the co-pilot; and
• the period the landing gear remained extended after the simulated engine failure.

The check-and-training pilot had flown night V1 cut procedures in a Metro III flight simulator, but had not flown the procedure in the aircraft at night. He did not terminate the exercise, despite indications that the aircraft was not maintaining V2 and that it was descending. There were few external visual cues available to the crew in the prevailing dark-night conditions. This affected their ability to maintain awareness of the aircraft's position and performance as the flight progressed.

A number of organisational factors were identified which influenced the aviation environment in which the flight operated. These included, on the part of the operating company:

• an inadequate Metro III endorsement training syllabus in the company operations manual;
• inadequate assessment of the risks involved in night V1 cuts; and
• assigning the check-and-training pilot a task for which he did not possess adequate experience, knowledge, or skills.

Organisational factors involving the regulator included:

• a lack of enabling legislation prohibiting low-level night asymmetric operations;
• deficient requirements for co-pilot conversion training;
• inadequate advice given to the operator concerning night asymmetric operations and the carriage of additional trainees on training flights;
• deficient training and approval process for check-and-training pilots; and
• insufficient quality control of the company operations manual.

The investigation also determined that there was incomplete understanding within the company, the regulating authority, and some sections of the aviation industry of the possible effects of engine flight-idle torque on aircraft performance. Inadequate information on the matter in the aircraft flight manual contributed to this.

Witnesses reported seeing the aircraft depart runway 28 and complete a full circuit without landing. At a height of approximately 400 to 500 ft above ground level as the aircraft was turning onto final approach during its second circuit, it entered a steep nose down spiral to the right. The spiral descent continued to the ground and the pilot received fatal injuries during the impact. The wind at the time of the accident was reported to have been from the north-north-west gusting to 45 km/h.

Four ladies had reservations for a helicopter scenic flight and were met in the airport terminal by the ground hostess for transportation to the helipad in the company bus.

The ground hostess stated that while proceeding to the helipad she briefed the ladies about the helicopter, and the safety requirements when in its vicinity.

She parked the bus on the road adjacent to the helipad, approximately 12 metres to the right and well forward of the helicopter. The ladies were then told to remain at the bus until instructed to approach the helicopter.

Following normal practice to save engine cycles, and turnaround times, the pilot left the helicopter engine running after landing, then locked the controls and got out to assist the ground hostess disembark the passengers, who were then directed to the bus. The ground hostess accompanied them as far as the edge of the main rotor disc, then signalled the ladies to follow her back to the helicopter.

One lady had expressed an interest to occupy the front left seat during the flight. This was agreed to by the other ladies.

The ground hostess watched the ladies follow her towards the helicopter, but when she turned her head to check its proximity, the lady, who had requested the front seat, left the group to pass behind the helicopter, and walked into the tail rotor, receiving fatal injuries.

The ground hostess stated that after the occurrence she spoke to the ladies, who confirmed that they had understood her briefings, and had no idea why the other lady had not followed her instructions.

Statements taken by the police did not address whether the ladies had received a safety, familiarisation briefing, but covered the last instructions given by the ground hostess concerning waiting at the bus and approaching the helicopter. Only two of the ladies could now remembered these instructions.

Reports indicated that three of the ladies were partially deaf, and the other had assisted them. Because of this it is possible they may have missed some parts of the briefing.

The company requires all staff to be aware of, and act in accordance with the requirements of the Civil Aviation Regulations and Orders, and the companies' Operations Manual, including all safety aspects. There was no evidence to indicate that the staff had not acted accordingly.

The reason why the lady departed from the group, and attempted to pass behind the helicopter was not established.

1. FACTUAL INFORMATION

Summary

The helicopter did not arrive at its destination following a ferry flight. The wreckage of the helicopter was found by chance, late at night. It had crashed during a dark night. The engine had stopped before impact. The helicopter fell several thousand feet out of control.

The investigation did not find any mechanical defects which could have contributed to the accident.

History of the flight

During the day, the pilot flew on mustering tasks and an hour's ferry flight from Avon Downs to Headingly station. There he refuelled the helicopter with 50 litres of aviation gasoline. None of the Headingly station staff had the opportunity to speak with the pilot during his short stopover, but they saw the helicopter depart to the south-east at 1700 EST.

At 1950, the manager of Brighton Downs station heard a message from the pilot on the station's citizen band radio. The pilot said that he was 4 NM from Pot Jostler outstation and that he could see the lights of the house. The manager replied that a kangaroo shooter and his family occupied the house and that he could get a meal from them. The last radio message from the pilot wished the manager good night.

At about 2100, the kangaroo shooter and his family were returning from a paddock about 20 km north of the outstation.  They saw a piece of Perspex lying on the access track about 5 km short of the house and recognised it as a part of a helicopter. A short search by truck headlights revealed a tail boom sticking out of the ground. They found the main fuselage of the helicopter some 300 m south of the tail boom.

The family said that they had not left any lights on at the outstation in their absence. The only lighting available was gas powered.

Weather conditions

Last light is regarded as the time when the ambient light value falls below that required for aircraft operating under day visual flight rules and is defined as the time when the setting sun is six degrees below the western horizon. Ambient light may be varied by a cloud cover which has the effect of bringing on an earlier last light. Last light at Pot Jostler outstation was calculated as 1832, 1 hour and 18 minutes before the pilot radioed Brighton Downs.

The Bureau of Meteorology analysis of the weather conditions agreed with reports from local observers. There was a cloud cover of five octas strato-cumulus, base of about 2,000 ft.  Above the lower layer of cloud was a higher-level alto-cumulus cover of five to six octas. Cloud obscured any starlight. The moon was in its last quarter and did not rise over the accident site until 2305. A ground observer stated that it was a very dark night without a visible horizon.

The wind at ground level was relatively strong and gusting at 10-20 knots from the south-south-east.

Whether the pilot obtained a weather forecast is not known.

The helicopter

The helicopter had undergone a periodic inspection on 14 July 1995 at the company's maintenance facility at Mt Isa. A new maintenance release was issued and was valid until 14 July 1996 or 595.2 hours total time in service. It was valid for day visual flight rules operations in the categories of private, aerial work, and charter. The helicopter's hour meter recorded 12.7 hours since the maintenance release was issued.

The helicopter was not fitted with attitude instruments essential for night operation. Along with other company helicopters, it was fitted with a global positioning system. The fitment allowed pilots to save flight time by being able to track direct to a destination over featureless terrain.

Flight fuel

Direct track distance between Headingly station and the crash site was 186 NM. Given a flight time of 170 minutes, the average groundspeed was calculated at 65 kts. Normal cruise speed is 80-85 kts true airspeed. The loss of 15-20 kts in ground speed confirmed the earlier weather assessment.  The helicopter's fuel endurance was approximately 3.5 hours from full tanks. Whether the pilot filled the tanks to capacity at Headingly station is not known.

Wreckage examination

The wreckage was scattered along a 1,000-metre trail, aligned with the prevailing wind, 165/345 degrees magnetic. The investigation team found small pieces of Perspex at the northern extremity of the trail and the tail boom was 300 m north of the main fuselage, which was the southernmost piece of wreckage. The fuselage gave the appearance of having been involved in a very heavy landing. It was upright but squashed to half its normal height. One complete main rotor blade and one half of the other were still attached to the mast. A remnant of the second blade had come to rest a short distance away. Both blades were bent. One blade was bent up, the other was S-shaped. The mast had been subjected to one severe mast bump. The base of one blade had crimped the mast. The main rotor blades had severed the tail boom and penetrated the cabin.

Those first at the scene said that there had not been any fuel smell. The main fuel tank was holed on impact, but the auxiliary tank was intact. The latter contained 1.5 litres, the equivalent of unusable fuel. Stretched light globe filaments revealed that the following warning lights were illuminated at impact: Clutch, Low Fuel, Low Rotor RPM, and Rotor Brake.  A later specialist metallurgical examination of crimped sections of exhaust manifold found that the manifold was cold at impact. The engine was stripped later in an engineering workshop, but nothing was found which could have prevented normal operation.

The flight manual warned that when the Fuel Low warning light illuminates, the pilot has five minutes to land the helicopter before fuel exhaustion.

Trajectory analysis of the wreckage trail found that the helicopter broke up between 2,400-2,800 ft above ground level.

Pilot experience

The pilot was first issued with a commercial helicopter pilot licence on 11 May 1993.  The company had employed him since 2 May 1995. He had previously been employed by a Western Australian pastoral company where pilots worked as ringers in a private operation. Another pilot from this Western Australian company reported that pilots were required to fly excessive hours per week, often beyond daylight hours.

When the present company's chief pilot gave him a check on company flying operations, the pilot indicated that he had previously flown a Robinson R22 helicopter at night. The chief pilot warned him not to continue the practice with this company. Extracts from his detailed notebook recovered from the wreckage indicated that the pilot had flown at night on two subsequent occasions. One entry, dated 23 June 1995, read: 'Left Serpentine at 5 pm for Pot Jossler (Jostler). Arrived at Pot Jossler in pitch dark at 7:10 pm. Flew last 20 min. at 4,500 ft so as not to run into anything'.

An inspection of his logbook revealed that the pilot had not received any formal training in night flying, nor had he logged any solo night flying.

The manager of Brighton Downs station said that the pilot had worked the property several times and was becoming familiar with it. The pilot had flown 11 hours on the day of the accident, a large proportion of it in mustering, which is a high workload task.

2. ANALYSIS

Conduct of the flight

The pilot's diary indicated that he had on occasions continued to fly the helicopter at night after joining his present employer. Company supervision had not been sufficient to discover these practices. The helicopter was not equipped with the necessary flight instruments to safely conduct flights after last light. It was fitted with a global position system navigational aid.

The terrain along track is relatively featureless and the area is poorly serviced by radio navigation aids. A global positioning system is a useful aid, but in this case, it would have enabled the pilot to continue flight after last light when navigation by other means was impossible.

Fuel

Those first at the scene could not smell any fuel. Subsequent specialist examination confirmed that the Fuel Low warning light was on at impact and the engine was cold, an indication that it had stopped. All evidence pointed to fuel exhaustion as the reason for engine stoppage. Disorientation

When the pilot radioed the manager of Brighton Downs station, he said that he could see the lights of the house. Since there were, in fact, no lights on at the house, the pilot must have seen some other light, perhaps a star visible through a small break in the cloud cover. Such a mistaken belief would have caused immediate disorientation by giving him a false horizon reference.

The sudden illumination of the bright Fuel Low warning light may also have contributed to the pilot becoming disorientated. This light, which is a bright red colour, is designed for daytime operation and cannot be dimmed. The pilot would have lost any outside visual reference in the low ambient light conditions following illumination of the warning light.

Either or both of the two events could have led to a loss of control. Such loss of control must have been sudden because the pilot did not transmit on the radio link established earlier.

Fatigue

Having flown for 11 hours, the pilot had exceeded the daily duty time limitations of Civil Aviation Order 48 by 2 hours. These limits were formulated to prevent pilots flying when fatigued. Such a long working day culminating in a stressful night flight could only have left the pilot fatigued. One of the most dangerous aspects of performance degradation with fatigue is that a person is unlikely to be aware of the manner and extent of this deteriorating performance (see F.H.Hawkins, Human Factors in Flight, Ashgate, Aldershot, 1987). Fatigue can result in a number of significant performance decrements such as poor self-monitoring, increased susceptibility to distraction, lowered arousal and increased reaction time.

3. CONCLUSIONS

3.1 Findings

1. The helicopter was certified for day, visual flight rules operations only.
2. The pilot had operated the helicopter at night.
3. The pilot was not qualified for night flying.
4. The night was very dark without a visual horizon.
5. The pilot was probably 'fatigued', having flown excessive hours that day.
6. The engine probably stopped due to fuel exhaustion.
7. The pilot probably became disorientated and lost control of the helicopter.
8. The rotor RPM decayed significantly.

3.2 Significant factors

1. The pilot continued the flight after dark when neither he nor the helicopter was equipped to do so.
2. The pilot probably lost control following fuel exhaustion.