The pilot was returning from a local sheep mustering flight on his property. When the gyroplane failed to return to the airstrip, and the pilot could not be contacted by CB radio, a search was commenced. The wreckage of the gyroplane was found about 230 metres west of the airstrip, having struck the ground in a steep descent with little forward speed, fatally injuring the pilot. The weather conditions at the time of the accident were reported to have been affected by strong gusting north- westerly winds, associated with blowing dust and reduced visibility.

An inspection of the wreckage revealed no evidence of any pre-existing mechanical fault or defect. However, whilst the gyroplane was in flight, the rotors had struck the tailplane and fractured the tail boom to the rear of the engine mounting. This damage was consistent with excessive flapping of the rotor blades associated with air flow reversal through the rotor disc. Air flow through the rotor disc normally enters from beneath the plane of the disc and exits above. Other effects of reversal of airflow are the irreversible deceleration of the rotor blades, and a nose down pitch change. In this accident the gyroplane appeared to have tumbled end over end, as well as rotating about the vertical axis.

The reason for the onset of airflow reversal on this occasion could not be positively established. However, in conditions of strong gusty winds, large changes in the vertical wind component could lead to airflow reversal. The likelihood of such an occurrence would have been increased if the gyroplane was being flown at relatively high speed.

The pilot suffered from epilepsy and was taking prescribed medication at the time of the accident. It could not be determined if the pilot's medical condition was a factor in this accident.

Following the completion of 27 jumps over a 9-month period using a student rig, the parachutist commenced conversion training to his own rig. This training consisted of three dual training jumps and two solo jumps. After a further five jumps using his own rig, the student took a two and a half months holiday during which he made no jumps.  Two weeks prior to the accident he made three jumps using his own rig.

The accident jump was part of the student's training towards a "B" licence. The training consisted of a "B relative" jump requiring him to perform certain manoeuvres relative to a tutor during the free fall period of the jump. He used his own rig for this jump.  On completion of the free fall component of the jump the two parachutists separated for the deployment of the parachutes. When his main parachute had deployed the tutor looked down and noted that the student's main parachute had not deployed normally and was being discarded. The tutor did not see the reserve parachute deploy before the student hit the ground.

No defect was found in the equipment which could have caused either the main parachute problem or the non-deployment of the reserve parachute. Damage to the Spandex pocket in which the main pilot parachute is kept suggested that the main pilot parachute throw-away procedure was mishandled resulting in the need for the main parachute to be discarded.

The main parachute was released at sufficient altitude for the reserve parachute to deploy. If correctly followed, the procedure taught for the rig in use should have ensured that the reserve deployed immediately after the main parachute was discarded.

It is possible that under the stress of the abnormal event the parachutist reverted to an earlier training awareness by waiting for some time for the reserve to automatically deploy following the release of the main parachute, as it does on the student rigs. Student rigs have a reserve static line (RSL) or an automatic activation device which automatically deploys the reserve parachute should the main parachute be discarded.

On-scene evidence indicated that the parachutist remembered too late that he had to manually deploy the reserve. If an RSL or an automatic activation device had been attached the accident may not have occurred.

SAFETY ACTION

Paragraph 5.1.16 of the Safety Requirements section of the Australian Parachute Federation Operational Regulations has been amended to read:

'All descents made by parachutists who do not hold a Certificate "E" must be made with equipment fitted with a functional reserve static line or an automatic activation device. The DZSO may permit exemptions to this rule for specific descents.

Note:  This regulation became effective on 1 February 1994 where the descent is being made with a harness/container manufactured after 30 July 1993, or on 1 February 1995 where the descent is being made on a harness/container manufactured before 1 August 1993.'

The main purpose for investigating air safety occurrences is to prevent aircraft accidents by establishing what, how and why the occurrence took place, and determining what the occurrence reveals about the safety health of the aviation system.

Such information is used to make recommendations aimed at reducing or eliminating the probability of a repetition of the same type of occurrence, and where appropriate, to increase the safety of the overall system.

To produce effective recommendations, the information collected, and the conclusions reached must be analysed in a way that reveals the relationships between the individuals involved in the occurrence, and the design and characteristics of the systems within which those individuals operate.

The student hang glider pilot was performing his first soaring flight. His glider and another were observed to be flying about 200 feet above the same hill. The gliders collided, and the glider flown by the student spiralled into the ground. The student received fatal injuries, and the other pilot was uninjured and able land his glider.

The surviving pilot advised that he did not see the other glider, possibly because he was flying into the setting sun at the time of impact, but felt something strike the left wing of his glider.

Information concerning this accident was provided to the Bureau by the Safety Director for the Victorian Hang Gliding Association.

History of the flight

The helicopter carrying one pilot and three passengers departed Gladstone aerodrome at 1035 hours EST on a charter flight to Heron Island.  It was equipped with emergency flotation and overwater survival equipment consisting of life vests and a raft.

En route three miles out to sea near Facing Island and when cruising at an estimated 1500 ft, the pilot transmitted a mayday call on the mandatory traffic advisory frequency. He advised that he was returning to Gladstone because the helicopter had experienced a severe jolt in flight.  Soon after the mayday call, the pilot advised that he was ditching.

The only survivor, a passenger with no aviation qualifications, was seated in the right rear seat.  She recalled that the helicopter airframe gave a kick in flight immediately before the pilot transmitted a mayday.  During the descent, she heard the engine making an unusual shuddering noise and saw the nose of the helicopter twitching left to right several times.

The emergency popout floats comprising six float bags were deployed before the helicopter impacted the water at 1043 EST.  The severity of the structural deformation and the break-up was consistent with the helicopter impacting the water with high vertical deceleration forces and some forward speed.  Only two float bags remained inflated after impact and the helicopter sank in 24 metres of water with the pilot and the front passenger still strapped in their seats. The passengers in the left and right rear seats were thrown from the cabin on impact.

The helicopters buoyant emergency locator beacon was lost at sea and the non-buoyant beacon, which was attached to the airframe, sank with the helicopter.  No signal was heard from either beacon.  The life raft was found afloat but still packed in its valise.  The pilot and the passengers were wearing serviceable life vests which were not inflated. Pathological examination of the three fatalities revealed that the cause of death was drowning.

The helicopter was recovered at latitude 230 16 S longitude 1510 24 E at a position 20 kms NE of Gladstone and about 5 kms from Facing Island, the nearest landmass.

Wreckage Examination

An examination of the wreckage revealed no evidence of airframe or system malfunction which may have contributed to the accident.  The gross weight and centre of gravity were within prescribed limits.

A detailed examination of the engine and its accessories revealed that most of the stator vanes of stages three and four of the compressor were missing.  Five of the fourth stage stator vanes and all but one of the third stage vanes were fractured in the upper case-half and the majority of the third stage vanes were fractured in the lower case-half. All fracture surfaces were destroyed by secondary damage.  Available evidence indicated that the reason for the vane failures was a fracture of one or more of the third stage stator vanes probably resulting from erosion in the upper case-half.

Erosion to the lining of the compressor halves was found to be present around a number of adjacent vanes in the first, second, fifth and sixth stages.  The engine operations and maintenance manual requires the removal of the vane assemblies in these conditions.  Measurement of the first stage vane showed that it did not meet the chordal and thickness erosion limits specified in the manual and a second stage vane did not meet thickness requirements. Particles embedded in the eroded region of the first stage vanes were high in silicon content.  None of the compressor rotor blades were fractured.

The case-halves of the engine compressor were last inspected by a licensed aircraft maintenance engineer at

Gladstone on 18 March 1993.  The engineer advised that the inspection was performed in accordance with the Allison engine maintenance manual and the compressor was deemed to be serviceable. Between 18 March 1993 and the accident, the compressor had operated for 135 hours.

The engine manufacturer requires compressor inspections at intervals not exceeding 300 hours time in service with more frequent inspections required when operating in harsh conditions such as salt water and sandy or dusty environments, where abrasive particles may enter the compressor.   No other defect was found with the engine which could have contributed to the engine malfunction.

The operator's company policy required pilots based at Gladstone to record relevant engine power trend parameters on each day a helicopter flew.   From 18 June 1993 until 26 July 1993, pilots recorded thirty-one sets of engine power trend figures for VH-PCR and this trend monitoring showed no degradation of power in the engine and gave no warning of an imminent compressor failure.

Pilot Information

The pilot held a Commercial Pilot Licence (Helicopters) with a valid class 1 medical certificate.  He had been rostered off duty for the three days immediately prior to the accident and he had adequately rested prior to the flight which was conducted within his normal duty period.  He had no known medical problems at the time of the accident.

The pilot received endorsement training on Bell 206 helicopters during February and March 1993. This training involved five hours of dual instruction, followed by 4.6 hours of operations in-command-under-supervision, flying a Bell 206 between Gladstone and Heron Island.  His most recent dual check was on 31 May 1993 at Gladstone in a Bell 206. Since 1989 he had accrued over 1000 hours as co-pilot of twin engine helicopters engaged in offshore operations.  His total experience as pilot-in-command was 254 hours of which 95.4 hours had been flown in Bell 206 helicopters.

The pilot did not hold a helicopter utility float endorsement nor was there a legal requirement in Australia for the pilot to hold such an endorsement for over-water operations in a helicopter equipped with emergency popout floats. Popout floats are designed for emergency use only and do not inflate until activated by the pilot.  Practice autorotative descents in helicopters equipped with emergency popout floats are not normally carried through to termination onto the water and popout floats are not normally inflated during such practice descents.  In contrast, utility floats are expected to be permanently inflated when fitted to a helicopter.  They are more robust and are designed for regular landings onto water, including termination onto water following a practise autorotative descent.

No evidence was found to indicate that the pilot had flown a helicopter with inflated floats or that he had received any training in simulated engine-off touchdowns onto water. He had successfully undergone helicopter underwater escape training on 31 July 1991.

Weather

Forecast weather was for south-south-easterly winds at 10 to 15 kts turning more easterly in the afternoon with a sea swell up to one metre.

The crew of a company helicopter which arrived overhead the survivor and the floating wreckage about 20 minutes after the accident reported that the sea surface at the accident site had about half a metre swell with occasional white cap waves. Visibility was in excess of 40 km and the wind was blowing from the east-south-east at about 10 kts. The crew considered the sea surface conditions to be suitable for a safe ditching.

Rotor RPM

The low rotor RPM warning system fitted to a Bell 206B helicopter consists of a warning light on the instrument panel and an audible tone from a cockpit speaker. It is activated when the rotor RPM is less than 90% and the collective pitch lever is raised above the fully down position.

Seven radio transmissions made by the pilot were recorded on the AVDATA logging recorder at Gladstone.  The recorded information was examined, and the results were compared with the helicopter manufacturers data and with inflight recordings obtained during subsequent flight tests in a Bell 206B.

During the first three transmissions, when operations appeared normal for taxiing and departure from Gladstone, rotor RPM remained constant at approximately 99.5% (98-100% being normal).  Throughout the remaining transmissions including the mayday and declaration of ditching, the main rotor RPM appeared to range from

81.6 % to a maximum of 96.6% and then decrease to 75.9% over a period of approximately 28.4 seconds.  The last transmission occurred 19.6 seconds later and was approximately one second in duration and it was not possible to determine the rotor RPM during this transmission.  An audible tone, which may have indicated the low rotor RPM aural alert, was also heard during periods of the fourth and fifth transmissions and continuously during the sixth and seventh transmissions.

Inflight yaw

Difficulties associated with maintaining balanced flight would be increased by fluctuations in torque.  It is also more difficult to maintain balanced flight with inflated floats than with standard high or low skid landing gear, or with emergency floats stowed. The survivor's description of the nose of the helicopter moving left to right during the descent was consistent with torque fluctuations.

Descent over water

The helicopter was equipped with a radar altimeter and after the accident, the warning light on the radar altimeter was found set to activate at 200 feet above terrain or water. The check captain who gave the pilot the Bell 206B endorsement advised that he had verbally explained the operation of the radar altimeter to the pilot.  However, during the endorsement and subsequent training, they did not practice power terminations over water or land by reference to the radar altimeter.  The engine malfunction occurred when the helicopter was over water with no other visual cues (such as land mass or trees) to assist the pilot with depth perception for flight termination onto the water. It could not be determined if the pilot used the radar altimeter to assist with judgement of ditching on the day of the accident.

Warning and caution lights

The filaments of the globes in the warning and caution panel were inspected.  The engine out warning filaments showed some signs of stretching including a broken filament.  The low rotor RPM filaments showed definite evidence of stretching including a broken filament.

This indicates that electrical power may have been present in the filaments during the impact sequence.  It is probable that the engine-out and low-rotor RPM warning systems activated during the descent.

ANALYSIS

Introduction

The two main factors considered relevant to the development of the accident were the failure of the engine compressor in flight and the ensuing termination of the autorotative descent.  The pilots report of a severe jolt, as well as the kick and engine shuddering described by the survivor, were consistent with symptoms of an engine compressor failure.

Low rotor RPM during the descent

The analysis of the AVDATA tape recording revealed a rotor RPM lower than prescribed operating limits.  During the sixth transmission, rotor RPM reached 75.9% and at such a low RPM level the helicopters rate of descent would have been considerable.  It is possible that the pilot was trying to ascertain the extent of available power and any attempt to increase power by raising the collective pitch lever, would probably have increased the likelihood of compressor surging or stalling.  This would cause corresponding torque fluctuations, and the damaged engine would not have been able to produce sufficient power to maintain rotor RPM within limits.

Sustained low rotor RPM

At the operating weight at the time of the occurrence, the normal rate of descent during an autorotative descent would be approximately 1,500 ft/min.  If the pilot had maintained the collective lever in a slightly raised position for several seconds, including the period of the descent through the last 100 ft, the main rotor RPM would have decreased to  a less than desirable level with a descent rate considerably greater than 1,500 ft/min.  With main rotor RPM reaching a low of 75.9%, the inertia retained in the rotor would be considerably reduced.  If the pilot then attempted to reduce the rate of descent near the sea surface by increasing collective pitch, the rotor would not have been capable of producing sufficient lift to arrest the abnormal rate of descent.  Left unchecked the remaining rate of descent would have ensured a hard landing on the water.

High collective pitch pull increase

The pilot may have achieved a stable autorotative descent, but before he had descended to the height where autorotation would normally be terminated, he may have experienced problems with depth perception.  If collective pitch was increased with the helicopter too high above the water, the rate of descent would reduce initially, but then increase considerably as rotor RPM decreased. This would result in a hard impact with the water.

CONCLUSIONS

Findings

1. The pilot was suitably licensed and qualified to undertake the flight, and there was no evidence that he was suffering from any illness or incapacity during the flight.
2. Prior to the accident, the pilot had been briefed on the operation of the emergency popout floats of the Bell 206B. There is no evidence that he had flown any helicopter with inflated floats before the accident flight.
3. There was no requirement for pilots operating emergency flotation equipped helicopters to satisfy the water endorsement criteria of the flying training syllabus.
4. The helicopter was equipped for overwater operations and the pilot and passengers wore approved life vests. The life raft and vests were found to be not inflated after the accident.
5. The helicopter was fitted with emergency flotation equipment which was inflated by the pilot before the helicopter impacted the water.
6. The fuselage was severely broken up and deformed in a manner consistent with high vertical deceleration forces.
7. The weather and sea conditions should not have precluded a safe ditching.
8. The helicopter's gross weight and centre of gravity were within prescribed limits.
9. The engine compressor failed, and the engine then lost power in flight to a degree that the pilot was forced to ditch the helicopter.
10. The main rotor RPM decreased to 75.9% during the descent.
11. The cause of the compressor vane failures was a fracture of one or more of the third stage stator vanes resulting from erosion in the upper case-half.
12. Regular engine power trend monitoring records revealed no degradation of engine power and gave no warning of an imminent compressor failure.
13. The compressor had operated for 135 hours time in service since the last compressor case-half inspection.
14. No airframe defect was found which may have contributed to the accident.

Significant factors

1. The engine compressor failed due to the fracture of one or more of the third stage stator vanes. Erosion in the upper case-half of the compressor may have contributed to the failure.
2. For reasons which could not be determined a safe autorotative landing onto the water was not made.

SAFETY ACTIONS

Safety action implemented by helicopter operator

Since the accident, the operator has trained its Gladstone based helicopter pilots in operations with utility floats fitted, including complete touchdown autorotations onto water.

Recommendation

As a result of the investigation into this occurrence, the Bureau has made the following recommendation R940236:

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority review the requirements for pilots operating helicopters fitted with emergency flotation equipment.  The review should consider the applicability of a requirement to satisfy the water endorsement criteria of the flying training syllabus.

The pilot who had assembled the aircraft was also distributing the aircraft in Queensland. He had planned to fly the aircraft from Caboolture to an airshow at Hervey Bay.

The flight from Caboolture to Gympie took about two hours because of headwinds encountered en route. At Gympie the pilot refilled the left fuel tank of the aircraft from a 20-litre container he carried in the aircraft. He was then given a ride to a nearby service station where the container was refilled. Upon returning to the aircraft the refilled container was strapped to the seat beside the pilot. The pilot boarded the aircraft and after starting the engine the aircraft was taxied for take-off. Witnesses reported that after the aircraft became airborne it climbed overhead the airfield before setting course to the north. The witnesses also stated that the aircraft appeared to be operating normally and that engine operation was also normal.

About five minutes later the aircraft was observed to the east of Gympie flying in a northerly direction. The engine was then reported to have misfired and stopped. The aircraft was turned to the west and overflew a golf course. The western side of the course was bounded by pine trees about 10 metres in height and the Bruce Highway. The aircraft cleared the pine trees but impacted the highway directly in front of a vehicle. The vehicle struck the fuselage of the aircraft which was dragged underneath the vehicle for a short distance.

The fuselage and inboard section of the wing were severely damaged by ground and vehicle impact. However, an inspection of the wreckage did not reveal any faults that may have contributed to the accident. The engine was removed from the aircraft and inspected. Apart from some minor accident damage it appeared in good condition. The engine was internally inspected and the only fault found was some minor scoring on the forward face of the number 1 piston which would indicate that the piston may have partially seized previously. The effect of this scoring on the operation of the engine prior to the accident could not be determined.

The pilot was experienced in the operation of ultralight aircraft and a senior ultralight flying instructor. He had operated this particular aircraft for all of the 25 hours it had flown since assembly. Following the reported engine problems, the aircraft was flown over the golf course which contained several fairways that would have been suitable for landing the aircraft in an emergency.

SIGNIFICANT FACTORS

1. The reason for the reported loss of engine power could not be positively determined.

2. The pilot overflew suitable landing areas without attempting a landing.

3. The pilot lost control of the aircraft at an altitude that was too low to effect recovery.

The aircraft, with only the pilot on board, was being flown from Archerfield to Caboolture via the light aircraft lane to the west of Brisbane in company with another aircraft. About five minutes after departing Archerfield, the pilot radioed that he was experiencing problems with both engines and that he was in an emergency situation. The pilot of the other aircraft advised him that there were suitable forced landing areas in and around a nearby golf course. However, the aircraft continued and slowly lost altitude before rolling inverted and diving steeply into the ground.

Ground witnesses reported hearing loud backfiring and fluctuating engine RPM from the aircraft. These sounds were accompanied by erratic rolling and yawing of the aircraft before it rolled to the left and inverted. The right wing was severed outboard of the engine as the aircraft impacted a large tree before crashing onto a road.

Wreckage examination revealed that the fuel selectors for both engines were set at the auxiliary tank positions, causing fuel for each engine to be drawn from the corresponding auxiliary tank in each wing. It was established that the aircraft had been refuelled to full main tanks prior to the flight. Further, the pilot had advised in a telephone conversation with an engineer before the flight that the contents of both auxiliary tanks was 60 litres or less. All fuel tanks except the left auxiliary tank were ruptured during the impact sequence. About one litre of fuel was recovered from this tank.

Examination of the aircraft engines indicated that the right engine was under power at impact while the left engine was not. The mechanical condition of the engines indicated that they were capable of normal operation.

The PA-31 pilot's operating handbook states that the main fuel tanks must be selected for take-off. However, the behaviour of the aircraft, the position of the fuel selectors, and the information concerning the contents of the auxiliary tanks suggest that the pilot probably commenced the flight with the auxiliary tanks selected. As the flight progressed and fuel was used, intermittent un-porting of the fuel outlet lines occurred. This caused temporary fuel starvation, resulting in engine surging. These interruptions to engine power would have caused the aircraft to lose altitude, as described by witnesses, and airspeed. The event in which the aircraft rolled to the left and inverted is consistent with the right engine suddenly surging to high power when the aircraft was flying at a low airspeed while the left engine was delivering little or no power.

The pilot gained a PA-31 type endorsement in July 1992. At the time of the accident, he had logged a total of 37.8 hours flying multi-engine aircraft, including 35 hours on this aircraft type.

It was established that the pilot did not use a written checklist. Had such a checklist been used, the incorrect fuel tank selection may have been detected. Notwithstanding this, fuel system management is a basic and essential aspect of aircraft operation. In particular, fuel tank selection is a standard check item in the event of engine malfunction during flight. The pilot's apparent failure to select the main fuel tanks may be explained, at least in part, by his relatively low level of aeronautical experience, both overall and on type. Additionally, the pilot's information processing capacity may have been affected by the stressful situation in which he found himself. There were indications from the radio transmissions made by the pilot that he was in a highly anxious state when he reported that he was experiencing difficulties.

There were areas beneath the aircraft's flight path upon which a forced landing could have been conducted, albeit with probable aircraft damage. The pilot's failure to conduct a forced landing is considered a factor in the severity of the accident.

Evidence obtained during the investigation and the circumstances surrounding this occurrence suggest that the pilot did not have an adequate understanding of the aircraft systems.

Significant Factors

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

1. The pilot did not use a written checklist.

2. The pilot operated the aircraft with the auxiliary tanks selected when the fuel contents of these tanks was low.

3. The pilot failed to conduct a forced landing

The operator briefed the pilot to fly the helicopter along the powerline from one construction camp to the next and pick up passengers for transportation to another location. The operator left the construction camp in a vehicle at about the same time as the helicopter departed and drove to the camp expecting to see the helicopter on the ground. He became concerned when the helicopter had not arrived at the camp. A short time later, a construction linesman came across the wreckage of the helicopter some 74 m west of the powerline and about 18 km south of its destination.

Examination of the wreckage indicated low power and low rotor RPM at ground impact. The final descent was vertical amongst small trees with the helicopter's attitude 20 - 30 degrees nose high and approximately 40 degrees of left bank.

There had been only minimal damage to the engine, and it was later run prior to a specialist strip inspection.  Neither the test run, nor the inspection revealed any abnormalities that would have affected the operation of the engine. Examination of the remainder of the wreckage did not reveal any faults that may have contributed to the occurrence.

The weather in the range area consisted of low cloud and rain over the ridges. It is possible that the pilot encountered problems with lack of visibility as he proceeded along the ridgeline following the route of the new powerline. However, the dynamics of the crash would indicate that there was no loss of control due to inadvertent flight into cloud or rain.  The throttle was found in the closed position and the helicopter had impacted the ground with a high rate of vertical descent with no appreciable forward speed.

The post-mortem examination report indicated that the pilot was suffering a degree of myocardial fibrosis and coronary atherosclerosis. The report concluded that these conditions could have contributed to the accident by way of pilot incapacitation.

The factors contributing to the accident could not be determined.

On Friday 11 June 1993, at about 1918 EST, Piper PA31-350 Navajo Chieftain aircraft, VH-NDU, while on a right base leg for a landing approach to runway 01 in conditions of low cloud and darkness, struck trees at a height of 275 feet above the elevation of the aerodrome at Young, New South Wales, and crashed. The aircraft, which was being operated as Monarch Airlines flight OB301 on a regular public transport service from Sydney to Young, was destroyed by impact forces and post-crash fire. All seven occupants, including the two pilots, suffered fatal injuries.

The investigation found that the circumstances of the accident were consistent with controlled flight into terrain. Descent below the minimum circling altitude without adequate visual reference was the culminating factor in a combination of local contributing factors and organisational failures. The local contributing factors included poor weather conditions, equipment deficiencies, inadequate procedures, inaccurate visual perception, and possible skill fatigue. Organisational failures were identified relating to the management of the airline by the company, and the regulation and licensing of its operations by the Civil Aviation Authority.

During the investigation a number of interim safety recommendations were issued by the Bureau. The recommendations and responses are summarised in Section 4 of this report.

The aircraft had been stored in a hangar/shed, in a partially dismantled state for about 4 months. The pilot assembled and rigged the aircraft with the help of a person not familiar with aviation, and without reference to any qualified person or documentation. The pilot then boarded the aircraft, started it, and taxied for take-off. The take-off appeared normal, and the aircraft turned 90 degrees to the right at the upwind end of the runway. During the climb, at about 300 feet above ground level, the aircraft was seen to adopt a steep right wing low attitude and enter a spiral descent to ground impact.

The pilot was rescued from the wreckage and taken to the hospital, where he later died. He was not wearing a helmet during the flight.

Inspection of the wreckage revealed a broken wooden plug in the wing warping rod, where it attaches to the forward part of the right wing. The remains of the plug were found partially withdrawn from the rod end and an inspection of the left wing warping rod revealed the wooden plug partially withdrawn from its rod end by an amount similar to that found in the right wing. Microscopic analysis of the broken plug showed that the plug had been broken prior to the ground impact and that its material, which did not meet the manufacturer's specifications, had also degraded after lengthy exposure to the environment.

The plug failure, alone, should not have resulted in the loss of control of the aircraft. The aircraft is controllable with an adjustment of the position of the controls to compensate for the loss of the warping rod.

No other defects were found in the aircraft which could have contributed to the loss of control and subsequent crash.

The pilot's logbook contained no reference to prior experience in flying the Scout aircraft and indicated that he was inexperienced in operating ultralight aircraft. Anecdotal evidence suggested that he had more total hours than recorded in the logbook and also had some flying experience in the Scout, about two years prior to the crash.

The pilot had been solo-checked eight months prior to the crash and his logbook indicated that he had flown, unsupervised, on many occasions since that flight check, in contravention of the Australian Ultralight Federation Operation Manual requirements.

The wind on the ground at the time of the take-off was westerly at about 5 knots and was likely to have been stronger above tree top level. As the pilot turned away from the take-off strip, he probably would have had a tailwind component.

It is probable that the wooden plug broke after take-off. The pilot lost control following the failure, either because of inexperience, or he was distracted by the failure and allowed the speed to decrease to the stall speed as the aircraft climbed. The rudder is normally used for primary roll control of the Scout and if the pilot had not been aware of this, he may have aggravated the situation by using other recovery techniques.

Safety Actions

The Bureau of Air Safety Investigation has made the following recommendations:

1.  That the Civil Aviation Authority, in consultation with the Australian Ultralight Federation;

i) Advise owners of Wheeler "Scout" Mk3 ultralight aircraft to examine the wing warping control attachments and replace any suspect parts, and ii) As a matter of urgency complete and distribute the AUF Technical Manual.

2. That the Civil Aviation Authority research the wearing of helmets in ultralight operations with the view to determining if regulation in this area is warranted.

3. That the Civil Aviation Authority;

i) Examine its procedures for surveillance of sport aviation groups to ensure that the standards required by the regulations are being met;

ii) Actively pursue breaches of regulations or operating procedures, and, in conjunction with the Australian Ultralight Federation,

iii) Maintain an ongoing education programme of all ultralight operators with regard to their privileges and responsibilities under the Civil Aviation Orders and the AUF Operations Manual.

The following Safety Advisory Notices have been sent to the Australian Ultralight Federation:

1. The Australian Ultralight Federation should consider reminding all ultralight operators of;

i) The dangers associated with substituting substandard parts in their aircraft, and, 

ii) The dangers associated with not maintaining their aircraft to manufacturers' specifications.

2. The Australian Ultralight Federation should emphasise the potential safety benefits in wearing helmets during ultralight operations.