Fuel starvation

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

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

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

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

Wreckage information

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

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

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

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

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

Testing of components

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

Meteorological information

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

Personnel information

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

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

Helicopter information

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

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

Fuel planning/loading

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

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

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

Operational information

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

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

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

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

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

Organisational information

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

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

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

Survival information

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

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

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

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

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

The pilot had planned to conduct a charter flight, with three passengers, from Essendon to Latrobe Valley, Vic. in a twin engine Beech Duchess aircraft. The pilot reported that he arrived at the Essendon airport about 90 minutes prior to the scheduled departure, carried out the daily inspection on the aircraft and submitted an instrument flight rules flight notification. He checked the aircraft maintenance release and the company fuel log that included the aircraft's last flight four days earlier. The pilot reported that he checked the two fuel quantity gauge readings which indicated a half-full tank and a slightly less than half full tank. He then visually checked the contents of the tanks relative to the '30 US gallon' metal tabs that are visible through the filler opening. He estimated that the fuel tanks contained a total of about 200 litres, but did not confirm this, as a fuel tank dipstick was not provided for that aircraft. The pilot's flight plan indicated that 128 litres of fuel, including reserves, would be required for the flight.

During the climb to the planned altitude of 7,000 ft, the right engine's power reduced. The pilot concluded that, from the engine tachometer reading of 1,500 revolutions per minute, and the manifold pressure indications, the right engine had partially failed. He carried out engine failure confirmation checks, but as the propeller pitch lever was very stiff, was unable to place it in the feather position. The pilot later reported that, during manipulation of the pitch lever, the aircraft had yawed significantly. Therefore, he decided to reset the right engine controls to a cruise setting because partial power was preferable to no power.

The aircraft was unable to maintain altitude so the pilot decided to return to Essendon. He requested an air traffic clearance from the Melbourne Approach air traffic controller (ATC) when the aircraft was about 50 NM east of Essendon. After receiving a clearance, and as he turned onto a westerly heading, the aircraft descended into cloud. At the pilot's request, ATC provided headings for the pilot to track further to the south to avoid the higher terrain on the direct track to Essendon. Lowest safe altitude (LSALT) is a published or pilot calculated minimum altitude that ensures terrain clearance during flight in instrument flight conditions. Flight below an LSALT altitude is only permissible during visual meteorological conditions or while conducting a published instrument approach. When the aircraft descended below the LSALT, ATC advised that a diversion to the closer Moorabbin airport, which was to the south east of Essendon and to the south of the aircraft, was available. That option would have allowed the aircraft to track over lower terrain and would have minimised the track distance over the Melbourne suburbs. However, the pilot decided to return to Essendon, where the operator's maintenance facilities were located and the passengers could be transferred to another company aircraft. After descending through the next LSALT step while in cloud, the aircraft descended into visual conditions about 21 NM east of Essendon at about 2,500 ft. The aircraft continued to descend until it stabilised in almost level flight at about 1,500 ft. The pilot then tracked direct to Essendon and carried out a visual approach and landing.

The pilot had bypassed two other suitable airfields, Lilydale and Coldstream, approximately 10-15 NM to the right of his track. The Civil Aviation Safety Authority (CASA) Civil Aviation Orders (CAO) 20.6 permitted the pilot of an aircraft with a failed engine to fly past a suitable aerodrome if another suitable aerodrome was available nearby and the pilot assessed that the aircraft could be flown safely to that aerodrome.

Company engineering inspection of the aircraft found that the right fuel tank, that was supplying the right engine when it lost power, contained no fuel. The right fuel quantity gauge transmitter unit was corroded and seized in a position that resulted in the gauge always indicating half-full. It was possible to feather the right propeller, although the pitch control was stiff.

The control cable and the fuel tank sender unit were subsequently replaced. The pilot commented that he had conducted a feather check as part of the pre-takeoff checks and although the right pitch lever was stiff to operate, he was satisfied that the propeller feathering mechanism was operating satisfactorily. The pilot later commented that the engine had failed due to fuel starvation and that he had not recognised the symptoms of a piston engine failure. He reported that he did not notice the reduced fuel pressure to the right engine until after the aircraft descended into visual conditions.

The aircraft's pilots operating handbook cautioned pilots against attempting to determine the inoperative engine by reference to the tachometers or the manifold pressure gauges and stated that those instruments often indicated near normal readings after an in-flight engine failure.

The pilot had recently resumed employment with the operator. He began his career with the operator and had flown as a first officer on F-27 turboprop aircraft for four years. He then obtained employment with a regional airline for two years as a first officer on turboprop aircraft, and had just completed line training as first officer on a jet aircraft when that airline suspended operations.

The day before the incident, the pilot had completed a 12-hour tour of duty, including 8.1 hours of flight time completing a co-pilot endorsement on a business jet. The two days prior to that had been spent on ground duties. He had 6-8 hours rest overnight at home and had risen early on the day of the occurrence. The pilot reported that he was tired on the day of the occurrence and that he had felt similarly for some time. He had been on duty for 16 consecutive days or a total of 159.4 hours duty time, primarily in a capacity unrelated to his employment as a pilot. Those additional duties were reflected in the pilot's recorded duty times.

The pilot had logged about 3,600 hours total flight time, including 600 hours in command on piston-engine aircraft. Those command hours consisted of about 200 hours twin-engine, of which 25 were in Duchess aircraft. All his other flying had been in turboprop and jet aircraft. During the three months preceding the incident, the pilot had flown approximately 70 hours, but had only flown the Duchess for three hours during that time.

The pilot's work/rest history for the four weeks prior to the incident was examined using a computerised fatigue algorithm developed by the Centre for Sleep Research, University of South Australia. The results indicated that the pilot was probably experiencing moderate levels of fatigue in the week leading up to, and on the day of the incident.

The pilot of a Cessna 210 Centurion was tasked to fly three passengers from Kalgoorlie WA to Rawlinna WA and return.

The aircraft departed Kalgoorlie at 0804 Western Standard Time for Rawlinna with the flight proceeding without incident. The trip fuel log showed that the pilot believed that the aircraft arrived in Rawlinna with approximately 106L remaining in the left tank and 130L remaining in the right tank. The aircraft was not refuelled at Rawlinna.

Two passengers watched the pilot prepare for the return journey from Rawlinna. They reported that the pilot appeared to do a walk around the aircraft and one passenger stated that although he saw the pilot `check things at the front, wingtips and tail', the pilot did not check the fuel tanks in the wings. At approximately 1250, the flight departed for Kalgoorlie. One of the passengers recalled that, shortly after reaching a cruise altitude of about 4,000ft, the pilot appeared to become agitated and was checking something on the floor between the seats. This concerned the passenger, but after a few minutes, the pilot settled down and the passenger assumed that whatever had been a concern, was resolved. The fuel selector is located on the floor between the two front seats.

One passenger with recollection of the remainder of the flight from Rawlinna, stated that it appeared routine up until the engine lost power while the aircraft was approaching Kalgoorlie. (Due to the serious nature of the head injuries sustained in the accident by all of the passengers, their recollections of the flight prior to the engine power loss were very fragmented.)

At approximately 1413, the pilot was heard to broadcast a distress call including the aircraft altitude of 2,000 ft above sea level and his intention to land on a road. During the landing attempt, the passenger in the right front seat observed a car appear in the landing path. The passenger reports of what occurred after the car appeared were consistent with the pilot attempting to climb the aircraft to avoid the car and subsequently losing control of the aircraft during the manoeuvre.

The driver of the car and his wife saw the aircraft pass silently overhead as it crossed the road in a southerly direction. When it impacted the ground, the car driver's wife said that it appeared to `really bury in' before it was obscured by a large cloud of dust.

The driver immediately called emergency services and then he and his wife attempted to render assistance to the occupants. The pilot was fatally injured while the passengers were seriously injured.

Wreckage information

The aircraft impacted the ground in a left wing low, nose-down attitude. Examination of the aircraft found the left and right fuel tanks intact, but the fuel system plumbing was disrupted by cabin distortion at the fuel tank selector valve under the floor. The fuel line to the firewall mounted filter strainer and engine was broken and the strainer was destroyed during the accident impact sequence. The forward door pillar had been severed on the right side of the aircraft by hydraulic cutters used during the rescue effort to free the trapped front seat passenger. The examination of the fuel tank selector revealed that the right fuel tank was selected at impact.

Fuel had poured on to the right front seat occupant during the rescue and had continued for a considerable amount of time after the accident. No fuel remained in the right tank when it was examined by the investigation team on site. The rescuers said that they had not observed fuel to leak from the left wing onto the ground at any time. The aircraft's left wing low attitude uncovered the engine fuel supply lines at the inboard end of the tank and, as a result prevented the remaining left tank contents escaping through the damaged connections to the fuel selector. Less than half a litre of clean fuel remained in the outboard section (lowest point) of the left tank compartment and was considered to approximate the unusable amount for the tank. A sample of the Avgas, which was normal green colour, was taken from the aircraft and inspected at the accident site. It was free of any water or particles in suspension and visible contaminants. The fuel uplift for the flight was from the Kalgoorlie aerodrome. This fuel supply was tested by the supplier and found to be within correct specification.

The left-wing vent line was also clear of the remaining contents and did not appear to have been capable of allowing the remaining contents to drain off through the left-wing tip vent due to the syphon effect. The fuel contractor's log showed that there were multiple deliveries from the same batch of fuel to other aircraft operating from Kalgoorlie airport coincident with the delivery to VH-LMX. The bureau found no reports of fuel related problems with any of these other aircraft.

The fuel system components were bench tested and found to be capable of normal operation within the manufacturer's parameters. The wreckage, engine and component examinations found no evidence of pre-existing mechanical defects with the aircraft or its systems, that would have prevented normal operation of the aircraft prior to the accident.

Fuel pump switch

The auxiliary fuel pump switch is a two-segment split rocker type mechanism. The right half was colour-coded yellow and the left half red. The yellow half was marked START, with the upper position as ON and was used for normal start and some minor vapour purging if required. It was usually selected OFF for normal flight. In the event of an engine driven fuel pump failure in cruise flight, the yellow switch selected to ON should have provided, through a micro-switch arrangement, sufficient fuel for normal engine operation. The red half of the switch was marked EMERG (emergency) with its upper position marked as HI. This red switch was used in the event of an engine driven fuel pump failure during take-off or high-power operation and also extreme vapour purging. When the auxiliary fuel pump switch was removed and examined the yellow segment was found in the ON position.

A fuel dipstick with graduated markings on it was found in the baggage compartment of the aircraft. It was marked C210M VH-WXC and had the following graduations: LEFT FULL, 140, 100, 60, 30 with identical graduations and the word RIGHT on the reverse side of the stick. A check of the type certificate data sheet revealed that the C210N (accident aircraft) was fitted with identical type and capacity fuel tanks to the C210M.

Emergency locator transmitter

The aircraft was fitted with an emergency locator transmitter that activated upon impact. The transmission was received and logged by the Australian search and rescue organisation (AUSSAR) for 2hrs 39 mins before local police disabled the transmitter.

Pilot information

The pilot held a valid Australian commercial pilot licence and command instrument rating. He held a valid Class 1 medical certificate and did not require vision correction while operating an aircraft. At the time of the accident the pilot had accrued a total of 1,087 hours flying experience with 317.5 hours on the Cessna 210. From interviews and postmortem results, no evidence was found that the pilot had any personal or medical problems that may have adversely impinged on his ability to conduct the flight.

Survival

The nose-down, left wing low attitude of the aircraft as it impacted the ground exposed the left front seat occupant (the pilot) to the full force of the impact.

The passengers sustained numerous serious injuries in the form of fractures to legs, upper bodies and heads as well as injuries to internal organs. The leg injuries probably occurred when the floor was forced in an upward direction during the impact sequence. The floor movement also released the anchor points for the front seats. The middle row right seat remained fixed to its mounts. The middle left seat remained fixed by its rear mounts and forward left mount but with the front right mount partially released. There were no upper body restraint systems fitted to the passenger seat row positions in the aircraft, nor were any required to be. The upper body and head injuries sustained by all occupants were probably due to upper torso flailing contact with interior structure and objects. The front seat positions were fitted with upper body restraints. The effectiveness of the front seat restraint systems was compromised by the loss of integrity of the seat to floor attachments. The rearward movement of the engine firewall during the impact sequence may also have reduced the front seat survival space between front seat occupants and control panel structures; which would have increased exposure to injury.

Weather

The weather forecast for the day was for fine conditions, but with thunderstorm activity expected in the Kalgoorlie area during the afternoon after the flight. Other pilots reported experiencing some heavy turbulence in the area during the day and the operator's Chief Pilot remarked it was, `the first really rough day of the season'. The passengers recalled that, for the portions of the flight that they could remember, there was some turbulence but remarked that it was not unusually rough.

Aircraft fuelling

The afternoon before the charter flight, the aircraft operator requested the fuel contractor to fill the aircraft tanks (capacity 160L in each of two tanks) `to the tabs', which equated to a fuel quantity of approximately 120L in each fuel tank. The fuel request form was normally faxed to the fuel depot during the afternoon, but as no request had been received by the time he was due to commence fuelling tasks, the fuel contractor obtained the request sheet by walking to the aircraft operator's office and retrieving the original. The contractor noted that the sheet had been amended by the use of white-out correction fluid and that the original request entered had been for full tanks. It could not be positively determined if the pilot had sighted this fuel quantity request sheet.

Company pre-flight briefing

Some months after the accident, a director of the company stated that he spoke to the pilot in the afternoon prior to the accident flight. This conversation covered the task briefing for the following day and included the fuel load as being `to the tabs'. If this was so, the weight and balance calculations made by the pilot for the flight, in which a `full fuel' quantity was used and showed that the aircraft was close to maximum take-off weight, did not reflect any knowledge that he had received the `fill to tabs' fuel information. The director could not confirm whether the pilot assimilated this information at the time he talked to him.

Aircraft service history

The aircraft had been maintained in accordance with the relevant Civil Aviation Regulations and Orders. The aircraft had a valid maintenance release at the time of the accident with no maintenance overdue. Because a fuel quantity system calibration was required by the Civil Aviation Safety Authority (CASA) every three years as part of an airworthiness directive (AD), a calibration had been carried out six months prior to the accident in accordance with the AD. The gauge calibration results recorded in the aircraft logbook were as follows:

Left 10/46, 20/83, 30/117, 40/167, F/169 (Gallons/Litres)
Right 10/38, 20/65, 30/100, 40/145, F/164 (Gallons/Litres)

The aircraft fuel gauges, calibrated in US Gallons, were within the required parameters but the quantities differed between the left and right tanks for a given scale marking. This was compensated for by having a calibration correction card fitted to the aircraft. The calibration recordings in the logbook did not include a value for E (empty). However, the calibration card fitted to the aircraft stated that for E indication on the gauge, the tanks were to be read as empty.

A review of the aircraft's history revealed that, when being operated by its previous owner on the east coast, it had been involved in a similar accident in 1995 when it was force landed due to engine power loss. The aircraft had also taken off with the fuel tanks filled `to the tabs', and on that occasion it was estimated that the pilot had operated the aircraft for approximately 1 hour and 40 minutes when the engine lost power. The left fuel tank was used for the entire flight and when examined at the accident site, it was found to be empty.

Flight trip log

A company trip fuel log for the flight was found at the accident site. This log was being used by the pilot to record flight times and fuel usage from each tank for the flight. It had the following annotations:

The trip fuel log noted that the fuel tanks contained 160L in each tank on departure from Kalgoorlie.

The take-off from Kalgoorlie had been conducted using fuel from the left tank. The trip fuel log indicated that the aircraft had consumed 54 litres from the left tank and 30 litres from the right tank during the flight to Rawlina. Additionally, the log indicated that the pilot elected to remain on the left tank for the taxi, pre-take-off checks, take-off and departure from Rawlinna thereby carrying out both take-offs using fuel from the left tank. The pilot recorded an initial use of 15L from the left tank on departure from Rawlinna, followed by 40L from the right. At 13:45 WST he changed the selection to the left tank. About 28 minutes later, the engine lost power.

Pilots Operating Handbook (POH)

The aircraft was fitted with a placard that provided information in the form of a checklist in the event of major fuel flow fluctuations and/or engine power surges. Additionally, the POH provided expanded procedures for inflight engine restarts and excessive fuel vapour in the fuel system. The POH also noted that if the propeller is windmilling, the engine will start automatically within a few seconds. If the propeller has stopped (possible at lower speeds), turn the ignition switch to START, advance the throttle slowly from idle, and (at higher altitudes) lean mixture from full rich.

The POH went on to indicate that with fuel quantities of less than a quarter tank, prolonged uncoordinated turns or slips should be avoided as it might uncover the fuel tank supply outlets and starve the engine of fuel.

Engine out glide distance

The MAYDAY transmission made by the pilot placed the aircraft at a height of 800 ft above ground level. This height, according to the Maximum Glide graph in the POH, equated to approximately 1.2 NM, or approximately one minute of glide time from the time at which the engine lost power to the impact point.

The Bell Jetranger 206B (III) helicopter was engaged in aerial firefighting operations utilising an external water bucket and staging out of a nearby national park campground. The pilot reported that he started flying at approximately 0750 EST after completing a pre-flight check of the helicopter which included draining the fuel sump, inspecting the fuel and confirming 106 L or 27.9 United States Gallons (USG) of total indicated fuel. At approximately 0825, while engaged in water bucket operations, he discussed his fuel status with other company pilots on a common radio frequency and noted 38 L (10 USG) of indicated fuel remaining. He finished a swath run of the fire area, dropping water and then decided to complete one more swath run before returning to refuel.

Approaching the fire line, the helicopter entered a left turn at approximately 200 ft above ground level (AGL). The pilot reported that the helicopter was buffeted by strong turbulence, which caused the helicopter to yaw left and go out of trim. He reported that the engine power then began surging and, subsequently, an engine flameout occurred. He continued the left turn, jettisoned the water and initiated a power-off autorotation to a heavily wooded area.

During the autorotation, the helicopter's main rotor blades contacted nearby trees, damaging the blades and displacing the main rotor transmission. The helicopter then came to rest on its right side, on a 45 degree slope. The pilot exited the helicopter and was picked up by another company helicopter and transported to hospital for observation. The pilot suffered minor injuries and the helicopter was substantially damaged. There was no evidence of any in-flight or post-accident fire.

The pilot reported that he had no recollection of any illuminated caution advisory lights during or prior to the event, or of the position of the switches and circuit breakers of the fuel boost pumps. He stated that he followed flight manual checklists when starting the helicopter and preparing for takeoff.

Wreckage examination

The helicopter sustained damage to the main rotor blades and controls, main rotor transmission, transmission to engine driveshaft, tail rotor driveshaft, pilot's perspex and right side forward fuselage. Examination of the engine revealed no external damage or damage to the compressor.

Fuel system examination and background

After the helicopter was repositioned upright, the fuel gauge indicated approximately 19 L (5 USG). The fuel in the fuel tank was examined and appeared to slightly cover the base of the fuel boost pumps. Examination of the airframe fuel filter revealed full fuel in the filter bowl and no contamination. Examination of the engine fuel filter revealed a small amount of fuel and no contamination. The forward fuel boost pump circuit breaker was noted as disengaged.

Unusable fuel was defined as, `Fuel that cannot be used in flight with wings level and at cruise angle of attack (or nose 3 degrees up)'. Of the total fuel on board, 4 L (1 USG) were unusable. Upon removal from the accident site, the helicopter's fuel system was drained and 23.5 L (6.2 USG) of fuel were removed. The fuel correction card annotated, `gauge indicates 38 L (10 USG) for an actual of 45.6 L (12 USG)'. The fuel correction card values were verified by adding measured amounts of fuel.

An option on that model helicopter was a FUEL LOW caution advisory light that illuminated with approximately 76 L (20 USG) of total fuel remaining. The helicopter was not equipped with that advisory light. It was equipped with two electrically operated submerged fuel boost pumps located in the fuel cell and connected in parallel to the engine's fuel supply line. Those pumps were located on the helicopter's centre-line. Both boost pumps were examined following the accident and they were determined to be serviceable.

Fuel consumption

According to the operator's operations manual, the fuel consumption rate of the Bell 206B (III) helicopter was 110 L (28.9 USG) per hour. In the 35 minutes of operating time that the pilot reported prior to the accident, approximately 64 L (16.8 USG) of fuel should have been consumed, leaving approximately 30.8 L (8.1 USG) of useable fuel remaining. That amount should have been sufficient for approximately 17 minutes of engine operating time.

Engine auto-reignition

The helicopter was not fitted with an optional engine auto-reignition system. Because of the low height AGL at the time of the engine surging and flameout, the pilot did not have an opportunity to attempt a manual restart of the engine.

Engine testing

The Rolls-Royce Allison model 250-C20B engine, serial number CAE 840551, was removed from the helicopter and transported to an engine test cell for testing. Following motoring and priming, the engine started on the first attempt with Turbine Operating Temperatures, N1 (gas generator speed) and N2 (power turbine speed) values within normal operating parameters. Engine deceleration and acceleration tests were conducted in order to simulate power changes experienced during flight. The results of the testing indicated that the engine was serviceable at the time of the accident.

Helicopter manoeuvring in turns and flight manual requirements

During coordinated turns, centrifugal force acting on the helicopter and fuel tank causes the fuel to collect evenly in the bottom of the fuel tank. It is then available for pick up by the fuel boost pumps at the boost pump inlets and through to the inlet of the main fuel supply line and to the engine. During uncoordinated turns, centrifugal force may not displace the fuel to the bottom of the tank evenly and instead fuel sloshing may take place.

The helicopter's flight manual contained a warning regarding flight with one fuel boost pump inoperative. It stated, `Due to possible fuel sloshing in unusual attitudes or out of trim conditions and one or both fuel boost pumps inoperative, the unusable fuel is ten [US] gallons'.

Component testing

The forward fuel boost pump circuit breaker was removed and tested. Aircraft system 28 DC voltage was applied and varying amperes were introduced to the circuit breaker in an attempt to determine its serviceability. The circuit breaker operated normally up to its rated 10 ampere rating with no anomalies noted.

Pilot's shoulder harness

The pilot's left shoulder harness had broken and separated at a point just forward of and below the pilot's shoulder. The manufacturer's date stamped on the harness belt was March 1973. The pilot's seat belt had an inspection tag attached with the inspection date 11/99 annotated. Details of the inspection were not annotated in the helicopter's documentation.

Pilot shoulder harness testing

The pilot's left shoulder harness was sent to an independent belt and harness testing and repair organisation for testing. The webbing was identified as MIL-T-50368 Type IV, 2 inch Nylon Webbing, rated at 2,000 pounds strength. The rated assembly strength of the harness assembly was 1,500 pounds. Testing revealed that the webbing failed at a value of 391 pounds, or less than 20 percent of the original strength of the material. Factors contributing to the loss of original strength were ageing related to ultraviolet light exposure, abrasion damage and contamination by turbine oil.

Seat belt and shoulder harness standards

Australian Civil Aviation Order (CAO) Part 108, Section 108.42, contained specifications for aircraft safety belts (seat belts), harnesses (shoulder harnesses) and inertia reels manufactured in Australia. Contained within CAO Part 108, Section 108.42 was a reference to Technical Standard Order (TSO)-C22g, which specified minimum performance standards of aircraft seat belts when new.

CAO Part 108, Section 108.42, also contained a reference to British Air Registration Board (ARB)/Civil Aviation Authority (CAA) Specification Number four (issue two). That document specified minimum performance standards for British manufactured aircraft shoulder harnesses when new and was not applicable to equipment manufactured in the United States of America (USA) such as the separated harness in this occurrence.

The Australian Civil Aviation Safety Authority (CASA) Airworthiness Directive, AD/RES/29 amendment 1, mandated identification of aircraft seat belts to indicate that the part was an item approved by the manufacturer. Part of that directive mandated appropriate identification to demonstrate compliance with CAO Part 108, Section 108.42.

The helicopter was manufactured in 1979 in the US under the requirements of the US Federal Aviation Administration (FAA), Federal Aviation Regulations. FAA Technical Standard Order (TSO)-C22g (amended 1993) outlined minimum performance standards for aircraft seat belts when new. TSO-C114 (initial issue 1987) outlined minimum performance standards for aircraft torso restraints (shoulder harnesses) when new. Prior to 1987, there were no requirements for shoulder harnesses. Only TSO-C22 was in effect when the occurrence helicopter was manufactured.

At the time of the occurrence, there were no requirements to confirm compliance to applicable design standards of shoulder or seat belt harnesses while in service, or to specifically identify shoulder harnesses.

A Boeing 717 aircraft was in a left turn holding pattern, descending through flight level 230, when the right engine shut down. The flight crew actioned the emergency procedures and attempted, unsuccessfully, to restart the engine. They notified air traffic control of the problem, then requested and received a vectored straight-in approach and landing.

Following the event, the operator's maintenance personnel conducted troubleshooting of the right engine. Several fault codes were noted in the computer memory, which related to Channel A of the electronic engine controller (EEC). A maintenance records check found that the right engine fuel metering unit (FMU) had been replaced approximately 50 flight hours prior to the event. At the time of the event, there were no maintenance manual requirements for an EEC stored faults check following an engine run after replacement of the FMU. Maintenance personnel noted, then cleared, the fault codes from the computer memory and the engine was successfully test run. They then chose to remove both the right engine FMU and the EEC for further testing. The EEC unit was sent to the engine manufacturer for bench testing and operating on a test bed engine.

Component testing

The FMU manufacturer's testing found no faults in the unit. Initial testing of the EEC by the engine manufacturer could not duplicate, on the test bed engine, the dual channel failure and subsequent shutdown. Analysis of the fault codes recorded by the operator's technicians following the event confirmed that several FMU electrical related fault codes were pre-existing on Channel A of the EEC at the time of the occurrence. When the engine manufacturer repeated the testing with the recorded fault codes entered into Channel A of the EEC, and simulated loss of Channel B, they successfully repeated the dual channel failure and resulting engine shutdown.

Electronic engine controller

The electronic engine controller was a two-channel (Channels A and B) electronic unit with system redundancy. It controlled, among other items, engine start sequencing, power requirements, operating temperature, turbine speeds, fuel flow, engine monitoring, and automatic relight. It contained fault detection, storage, and readout capabilities, all stored on an electrically erasable/programmable read-only memory (EEPROM) located on a computer board assembly. The EEPROM provided a history for troubleshooting purposes of any fault event within the EEC or associated control systems by logging a fault code of the event. Those fault codes were then stored until intentionally cleared during maintenance action. The distinct two-channels in the unit ensured that should one channel fail, the other would assume control and monitoring of the engine. Testing by the engine manufacturer revealed that repeated random access memory (RAM) parity errors in Channel B of the EEC resulted in repeated multiple resets of the channel. Those repeated resets had proven to result in a loss of Channel B functionality.

Engine rotation during restart attempts

Following the event, the flight crew stated that they could not obtain a windmilling engine N2 (gas generator RPM) value of 14% as required in the emergency procedures for restart of the engine. They stated that the maximum engine N2 witnessed was 8%.

The engine manufacturer recommended a 14% N2 value (approximately 2,380-RPM) at fuel introduction during engine starting procedures. That allowed a cooler start and prevented engine deterioration. The value of 8% N2 for the ALL ENGINE FLAMEOUT emergency windmilling procedure was based on the minimum engine-driven fuel pump pressure to open the engine pressurising valve. The airframe manufacturer reported that windmilling flight tests were successfully demonstrated at airspeeds as low as 240 knots with N2 windmilling rotor speeds as low as 8%.

The airframe manufacturer estimated that at a stable condition of 10,000 ft altitude, and 250 knots indicated airspeed, the occurrence engine should have exceeded 10% N2 before engine start switch engagement. Their review of the digital flight data recorder (DFDR) revealed no evidence of N2 increase as would be seen with engine starter engagement. The airframe manufacturer reported that their understanding was that the anomalies experienced during the event would have prevented the starter air valve opening during the restart attempts.

Flight data recorder

Examination of the recording indicated that the aircraft arrived at the destination and then departed on another flight to the north. The reported ground runs had not been recorded, as required by Civil Aviation Order (CAO) 20.18 Section 6 paragraph 6.6.

Australian CAO 20.18 Section 6 paragraph 6.6 stated, "The operator of an aircraft which is required by this section to be equipped with recorders shall take action to ensure that during ground maintenance periods the recorders are not activated unless the maintenance is associated with the flight data recording equipment or with the aircraft engines."

Australian CAO 20.18 Section 6 paragraph 6.3 stated, "Where an aircraft is required to be so equipped by this section, the flight data recorder system shall be operated continuously from the moment when the aircraft commences to taxi under its own power for the purpose of flight until the conclusion of taxiing after landing."

The intent of the Australian legislation was that when an aircraft commenced taxiing under its own power for the purpose of flight, the flight data recorder (FDR) would record until the aircraft was parked at the conclusion of the flight. That action ensured a continuous record of aircraft operation was maintained for the duration of the flight.

Subsequent Enquiries made to Boeing Long Beach Division, the aircraft manufacturer, revealed that when the aircraft park brake was set, the FDR would cease recording. Boeing Long Beach Division stated that the FDR would begin recording by two methods. The first "normal" recording mode activated when either fuel shutoff switch was set to run and the park brake was released. The second "maintenance" recording mode was activated by accessing a FDR RUN command via the Multifunction Control Display Unit.

Aircraft Australian certification

The Boeing 717-200 was issued a Type Acceptance Certificate in accordance with Civil Aviation Regulation, (CAR) 21.29A which allowed Type Certificate acceptance for imported aircraft certified by the National Airworthiness Authority (NAA) of a recognised country, in this case the United States of America. The Boeing 717-200 aircraft may not comply with the appropriate Australian Civil Aviation Regulations and associated Orders.

History of the flight

The pilot of a Cessna 402C aircraft, VH-NMQ, was conducting a scheduled passenger service from Tindal to Darwin, with 4 passengers.

During the climb to the planned cruise altitude of 8,000 ft, the fuel quantity gauges indicated that fuel was being consumed from the left tank only. At the top of climb, the fuel gauges indicated 100 lb in the left tank and 200 lb in the right tank. Once established in the cruise the pilot tried to balance the fuel load by positioning the left fuel selector to allow the left engine to be supplied with fuel from the right tank.

Approaching the midway point between Tindal and Darwin, the fuel gauges confirmed that the imbalance remained. The pilot assessed that sufficient fuel was available to continue to Darwin. As the flight approached the last suitable alternate aerodrome, the pilot calculated that 13 lb of fuel was needed to reach Darwin from that point, based on the current consumption rate. The left fuel tank gauge showed 40-lb remaining.

The pilot requested and was given a direct approach to runway 29. During the landing roll the left engine stopped, and the right engine stopped soon after the aircraft cleared the runway. The fuel quantity gauges showed 20 lb for the left tank and 200 lb for the right tank.

The operator's ground support staff then towed the aircraft to the terminal area where the passengers disembarked normally.

The aircraft had flown from Darwin for Tindal the previous day with 650 lb of fuel on board. The pilot's navigation log showed that 365 lb was required for the flight from Tindal to Darwin. This comprised 230 lb flight fuel (59 minutes), 100 lb fixed reserve (30 minutes), 25 lb variable reserve fuel, and 10 lb taxi fuel. The navigation log also showed the total fuel on-board at Tindal before departure for Darwin was 385 lb. The pilot reported that before departure from Tindal, the aircraft fuel quantity gauges showed 185 lb in the left tank and 200 lb in the right. The pre-flight check of the fuel cross-feed was normal.

A landing at an alternate aerodrome was not considered necessary, as the pilot had calculated sufficient fuel was available to continue to Darwin, and was conscious of the operating schedule for the aircraft. However, company management stated that there was no instruction or pressure on pilots in this regard.

The pilot held a current commercial pilot licence, a command multi-engine instrument rating a valid medical certificate, and had logged 2,454 hours aeronautical experience. This included 150 hours on Cessna 402C aircraft. The pilot's last proficiency check was on 8 March 2000.

On the day of the occurrence, 5 May 2000, the pilot did submit an incident report to the operator. However, due to a breakdown in the operator's reporting procedures following staff changes, the ATSB was not notified of the occurrence until 15 May. As a result, it was unable to conduct an examination of the fuel selector system fitted to NMQ before the aircraft was returned to service.

Background

The then Civil Aviation Authority of Australia issued Civil Aviation Advisory Publication No: 234-1 (0) in March 1991. It provided advice about the quantity of fixed reserve fuel to be carried, and noted the use of fixed reserve fuel was limited to unplanned manoeuvring in the vicinity of the destination aerodrome. It further noted that fixed reserve fuel would normally be retained in the aircraft until the final landing.

The operator's fuel policy stated that in all foreseeable circumstances an aircraft should complete a flight with at least the fixed reserve fuel intact. The standard fixed reserve for the operator's Cessna 402C fleet was 100 lb of fuel for 30 minutes of flight.

Cessna 402C Fuel Selector System

The two fuel selector controls are attached to the cabin floor between the pilot and co-pilot seats. The selectors enable the fuel selector valves, located behind the engine firewalls, to be positioned to the corresponding tank, crossfeed, or off. The arrow-shaped ends of the selector control handle points to the position on the selector placard that corresponds to the control valve position. Each handle connects directly to a gearbox located under the floor. Cables connect each gearbox to their respective fuel selector valve.

An inspection by the maintenance provider in Darwin confirmed that the pilot had positioned the right fuel selector handle to the right tank. However, the cable connecting the gearbox to the fuel selector valve did not position the valve to the right tank.

The right fuel selector gearbox was removed, the selector gearing adjusted and the selector cable re-rigged. The aircraft was returned to service after the fuel selector system was ground tested.

The Pilot's Operating Handbook for the aircraft contained a description of the fuel system and it's operation. In the Normal Procedures section of the handbook, pilots were cautioned that they should "Feel for (the) detent" when placing the fuel selector at the desired position.

Maintenance action

The operator's maintenance controller was located at Alice Springs. A sub-contract maintenance provider conducted maintenance at Darwin. The operator's maintenance controller was not advised of the occurrence until 23 May, and was therefore unable to specify extra inspection procedures for the operator's Cessna 402C fleet until that time. The maintenance controller issued maintenance alert MA/C400/2 on 25 May. It was applicable to all Cessna 402C aircraft used by the operator and its associate company, and required a detailed inspection of the fuel selector system. These checks were to be conducted at each scheduled inspection until the requirements were included in the operator's System of Maintenance.

During one such check of the fuel selector system on another of the company aircraft, VH-TZH, the screws securing the selector cable lever arm/travel stop to the sector gear were found to be loose. This allowed the travel stop to slide under the base-plate and the sector gear to move beyond the end of its travel, resulting in loss of synchronisation between the selector handle and the selector valve.

The operator immediately issued an amendment to maintenance alert MA/C400/2 that included photographs of the defective fuel selector on TZH. The alert specified that the selector gearbox was to be checked if the fuel selector valve was found not synchronised with the selector indicator. During the investigation the fuel selectors of two other of the operator's Cessna 402C aircraft were found to lack an effective detent.

At the time of the occurrence, the maintenance release for NMQ contained an annotation arising from a previous report of uneven fuel consumption from the left tank. Examination of the fuel system related maintenance documentation for the aircraft revealed 17 events since December 1999. Seven involved reports of the aircraft using more fuel from the left tank than the right when the fuel selectors were correctly positioned. There was one report of greater fuel usage from the right tank. The rectification section for four of the entries stated that the fuel selector system was re-rigged. The reported defect for three of the entries was annotated "not major defect" and transferred to the deferred defects list. The fuel related defect entry for the 18 April 2000 stated "fuel not feeding correctly. Fuel noted to be crossfeeding some fuel in level flight - report further".

The last reference to fuel transfer problems, prior to the incident, was on 20 April. The endorsement on the trip record stated "both engines draw fuel from the left tank only". The rectification section of the record noted the fuel selector valve was removed, lubricated, refitted and pressure tested. The selector cable was re-rigged, and the system operated satisfactorily during ground testing.

Fuel system pre-flight checks

The fuel system pre-flight checks specified in the operator's Cessna 402C Operations Manual differed from the procedures specified in the manufacturer's Pilot's Operating Handbook.

The operator's standard operating procedures required pilots to operate the fuel supply cross feed for 60 seconds to verify normal operation. Also, pilots were to ensure normal operation of the fuel valves by positioning the fuel selectors to the off position to observe a decrease in fuel flow. Following these checks, pilots were to position the fuel selectors to the main tanks.

The manufacturer's Pilot's Operating Handbook did not specify checks for crossfeed operation or positioning the fuel selectors to the off position to observe a decrease in fuel flow.

The pilot did not move the fuel selectors to the off position as part of the pre-flight checks. This was because the Fleet Manager had advised his intention to amend the pre-flight check to delete the requirement. The pilot reported awareness of the need to feel for the detent when moving the fuel selectors, and was confident the detent was achieved during the pre-flight check.

On 16 May the operator issued a memo on the occurrence to its Cessna 402 pilots, and included new instructions for pre-flight operation of the fuel selector. The memo cancelled the previous requirement for pilots to position the fuel selectors to the off position to confirm a decrease in fuel flow.

History of the flight

The pilot hired a Beechcraft D55 Baron aircraft for travel associated with business commitments and submitted an instrument flight rules (IFR) flight plan from Bankstown to Warren and return. The flight to Warren proceeded normally. The pilot obtained an amended forecast before the return flight. The forecast indicated instrument meteorological conditions (IMC) for his arrival. Accordingly, he replanned via Bathurst in anticipation of an instrument arrival procedure to Bankstown.

The pilot departed Warren at 1628 ESuT and at 1705 reported 20 NM north west of Bathurst at 9,000 ft. That placed the aircraft inside controlled airspace without a clearance. The pilot was subsequently issued a clearance along the planned track. Approaching Bankstown the pilot encountered IMC and requested a Bankstown Radar Two arrival, anticipating a cloud break procedure from a radar vector. However, due to the missed approach flight path of that procedure conflicting with Sydney airspace requirements, the Sydney departures (west) controller, after determining that the pilot did not want the GPS approach, advised the pilot to expect a clearance for the Runway 11C Radar/Bankstown NDB/Sydney DME instrument approach. The pilot acknowledged the instruction. The approach controller subsequently observed the aircraft on radar to the right of the assigned approach track. He advised the pilot that he was right of track and cleared him to leave controlled airspace tracking to Bankstown along that procedure.

The pilot contacted Bankstown tower and advised that he was flying the Bankstown Runway 11C Global Positioning System (GPS) approach. The tower controller, who had been expecting the aircraft to be on a Runway 11C Radar/Bankstown NDB/Sydney DME approach, queried the pilot as to which approach he was using. The pilot confirmed that he was flying the GPS approach.

Recorded radar data showed that the aircraft had closely tracked the Runway 11C GPS approach path to a point 17 NM from Sydney, heading about 120 degrees at 2,500 ft. The aircraft then turned left to a heading of about 065 degrees and descended to 600 ft. The descent rate during that period was between 2,200 and 3,400 ft per minute. The aircraft then turned right to about 240 degrees and climbed to 1,100 ft. The minimum altitude for that segment of the approach profile was 1,400 ft. The Sydney departures (west) controller observed the aircraft on radar and advised the Bankstown tower controller. A short time later, the tower controller heard the transmission 'India Lima Mike emergency emergency'. Subsequent transmissions from the tower controller to the pilot went unanswered.

A witness, located approximately 2.5 km east of the accident site, reported seeing an aircraft pass overhead on a westerly heading with its engines surging before stopping. Other witnesses saw an aircraft apparently attempting to land in a nearby field. They described its approach as steep and slow. The aircraft descended into a grass-covered gully and impacted the ground. The impact collapsed the extended landing gear and the aircraft, although otherwise intact, was substantially damaged. The pilot, who was the sole occupant, received severe head and facial injuries.

Witnesses described weather conditions at the time of the accident as overcast with light rain falling and visibility estimated to have been between 3 and 5 km.

The pilot later stated that he had not previously flown a Runway 11C Radar/Bankstown NDB/Sydney DME instrument approach. Although he had acknowledged the controller's instructions for the approach to Bankstown, his intention had been to descend to the lowest safe altitude (LSALT) on that track and, if not in visual contact with the ground, to climb and divert to Bathurst. He reported that when he was not visual at 600 ft he commenced a climbing right turn onto a reciprocal track with the intention of diverting.

The pilot reported that after initiating the climbing turn onto a westerly heading, the left engine failed. He carried out the initial actions for engine failure but did not check the fuel selection at that time. He reported that checking the fuel selection was an item of his memorised trouble checks that in a multi-engine aircraft are performed after the initial actions and prior to feathering and securing the failed engine. However, before commencing the trouble checks the right engine failed and the pilot discontinued any further checks. He broadcast an emergency radio transmission and concentrated on controlling the aircraft. When clear of cloud, he manoeuvred the aircraft to avoid some towers and positioned the aircraft for a landing ahead, clear of houses and power lines.

The pilot later stated that he had intended to change from the auxiliary fuel tanks to the main tanks before commencing the approach. However, anxiety at having to fly an unfamiliar approach in IMC had distracted him and he had forgotten to change tanks. The pilot had not referred to either the approach or landing checklists that each included a check of the fuel tank selection.

Pilot experience, qualifications and recency

The pilot held a Commercial Pilot Licence and a valid Class 2 Medical Certificate. His Command Instrument Rating was endorsed for ILS, LLZ, VOR and NDB approaches. A log book entry on 24 May 1996 certified him as competent to use the GPS for en route navigation only. His total instrument flight time was 129 hours. No instrument flight time was recorded in the 90 days prior to the accident. His instrument rating renewal on 13 April 1999 had included an NDB approach. He had subsequently recorded an NDB approach, in flight, on 13 August 1999 and had made two practice NDB approaches in a ground procedure trainer on 20 September 1999. Recent experience requirements in Civil Aviation Orders Part 40.2.1 specified that the holder of a command instrument rating must not carry out an NDB approach in IMC unless in the preceding 90 days the holder has flown that type of approach either in flight or in a synthetic flight trainer.

At the time of the occurrence the pilot was operating under the privileges of a Command Instrument Rating (Multi-engine). On 10 March 2000 the Civil Aviation Safety Authority promulgated Civil Aviation Order 40.2.3 "Private IFR Rating" that allowed private pilots who had received appropriate training to fly in IMC under conditions less strict than those required for an instrument rating. The Private IFR Rating specified a flight review at intervals of two years. Civil Aviation Advisory Publication 5.13-1(0) Private IFR Rating recommended that recent experience requirements of the command instrument rating be used for guidance as to instrument flight time and instrument approaches.

The pilot had recorded 45.7 hours on the Beechcraft Baron type. His initial Baron endorsement training was undertaken in the B58 model but all his recent time on type was in the D55 model.

Fuel system and management

The D55 Baron fuel system consisted of a separate main and auxiliary tank in each wing. A selector for each fuel system was located on the floor between the front seats. The selector had four positions marked OFF, AUX, MAIN and CROSSFEED. A placard on the fuel selector directed pilots to use the auxiliary tanks in level flight only. The Pilot's Operating Handbook advised pilots to preplan fuel and fuel tank management before the actual flight and to utilize the auxiliary tanks only in level cruise flight. The last item of the descent checklist was "Fuel Selector Valves - MAIN".

Single fuel quantity indicators for both the left and right fuel systems were mounted on the pilot's lower panel. A toggle switch on the electrical sub-panel enabled selection of the quantity indication for either the main or auxiliary tanks.

The later model Beechcraft B58 Baron has a single tank in each wing, simplifying fuel selection and fuel quantity indication.

Wreckage examination

Examination of the wreckage did not reveal any pre existing defect that may have contributed to the accident sequence. There was no fuel in the auxiliary tanks. Approximately 170 litres of Avgas was recovered from the main tanks. The fuel selectors and the fuel quantity gauge switch were selected to the auxiliary tank positions. The wing flaps were not extended.

The aircraft was certified for IFR flight and was equipped with a GPS receiver that met the requirements for conducting GPS non-precision approaches. Documentation found in the wreckage included a set of current approach charts but the investigation was unable to determine which approach chart the pilot had used for the approach.

Shoulder harness attachment

The upper attachment of the pilot's shoulder harness failed during the accident sequence. The harness had no inertia reel and required manual adjustment. The pilot reported that he had been unable to adjust the shoulder harness as firmly as he desired. Examination of the upper attachment found that the installation was not in accordance with the approved modification and the bolt had pulled through the window pillar (see photos Fig. 1 and 2 below). The attachment for the right seat shoulder harness conformed to the approved modification.

Figure 1: Photograph of the failed shoulder harness attachment showing (above) where the bolt had pulled through the pillar.

Figure 2: Photograph of the bolt and harness end fitting.

Attachments for the shoulder harnesses had been installed in January 1973. This was carried out to comply with Airworthiness Directive AD /GENERAL/28 "Safety Belt and Harness Installations" that was issued in May 1972. The AD required an additional, single, shoulder strap to be fitted to the front cockpit seats of all Australian registered aircraft. The aircraft's logbook indicated compliance with the AD in accordance with an approved design drawing.

Figure 3: Cross-section through pilot's window pillar as appeared on the approved modification drawing.

Figure 4: Cross-section through pilot's window depicting the installation as found on VH-ILM.

The investigation was unable to determine how and when this attachment was altered. Maintenance records showed that since modification the aircraft had been resprayed and the pilot's side window panel had been replaced. Either procedure may have required removal and reinstallation of the attachment. The attachment in the aircraft, as depicted in the diagram at Fig. 4, was significantly weaker than the approved method of attachment shown in the diagram at Fig. 3, thereby reducing the protection provided by the design. The fact that it was an incorrect installation may not have been apparent to maintenance personnel. The approved installation drawings were held by the organisation that originally performed the modification and were not readily available for reference by subsequent maintenance personnel.

Maintenance personnel normally referred to the illustrated parts catalogue for identifying correct components and assemblies. That catalogue, produced by the aircraft manufacturer, did not incorporate modifications by other than the aircraft manufacturer. As such, the modification of the shoulder harness installation did not appear in the catalogue. Approved maintenance data, as required under Civil Aviation Regulation CAR 2A, provided guidance as to the information and documentation required to assist licenced aircraft maintenance engineers (LAMEs) to carry out aircraft maintenance, including modifications.

Civil Aviation Regulation 50A entitled "Aircraft Log Book" stated in part;

"…the holder of the Certificate of Registration for an Australian aircraft must:

(a) keep a log book for the aircraft, and
(b) make the log book available, and other documents referred to in the log book, available to CASA and to persons engaged in maintenance on the aircraft…."

Investigation into a fatal floatplane accident at Calabash Bay, NSW on 26 July 1998 (Occurrence 199802830) also found incorrectly fitted seat belt attachments. The report noted that failure of these attachments might have contributed to the severity of injury to the occupants. In both the Calabash Bay accident and this occurrence, aircraft had been found to have been operated with incorrectly attached restraint systems.