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 Rawlina 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.
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 takeoff 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.
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 post mortem 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.
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.
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.
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
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 takeoff 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-takeoff checks, takeoff and departure from Rawlinna thereby carrying out both takeoffs 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.
Fuel quantity calibration and indication
Although the aircraft fuel gauges differed between left and right tanks for a given scale marking, this was compensated for by having a calibration correction card fitted to the aircraft. It is not uncommon to have such discrepancies between multiple gauges in the same aircraft and should not have been a factor in this accident.
As a back up measure the aircraft also carried a dipstick, which was usually locally manufactured by the maintenance organisation. It could be used by the pilot to verify the actual fuel quantity on board before or between flights. The dipstick found at the crash site, although not calibrated specifically for the accident aircraft, should have given a reliable enough reading to alert the pilot to the 80L discrepancy in the fuel quantity on board; if it had been used. Passengers did not see the pilot verify the fuel quantities at Rawlinna, either visually or by using the dipstick. It could not be determined if the pilot verified the actual fuel quantity on board, visually or by dipstick prior to departing Kalgoorlie but, considering the incorrect trip log annotation of 160L in each tank, it is unlikely that he did.
The fuel that rescuers observed leaking onto the front seat occupant and which had pooled under the aircraft, probably came from the disrupted fuel lines around the fuel tank selector in the first instance and later augmented by the right door pillar supply line from the right tank that was severed during the rescue. As the residual fuel in the left tank was not able to feed to the fuel selector supply lines, the fuel remaining in the left tank only approximated to the unusable amount, as published in the POH, for that tank.
The selected position of the yellow segment of the auxiliary fuel pump switch as observed at the accident site, was consistent with emergency checklist action following an inflight engine power loss or vapour purge.
The fuel selector was found selected to the right tank. The fuel pump switch and fuel selector position observations were considered in conjunction with the pilot's trip log notes showing that the flight immediately prior to the power loss was conducted on the left tank. If the pilot had conducted the emergency checklist actions, as seems likely based on the auxiliary fuel pump switch selection, then he had selected the fuel selector to the opposite tank. The evidence was consistent with a power loss while operating from the left fuel tank and a probable attempted engine re-start after changing fuel tank selection to the right tank.
In flight engine restart
The radio call made by the pilot gave the aircraft height of about 800ft above ground level (AGL) at the time the engine lost power. This would have provided gliding time of approximately one minute in the flaps up configuration recommended by the POH; and used by the pilot. This short interval after the engine power loss may have been insufficient for the pilot to successfully complete an in flight engine re-start drill.
Fuel tank exhaustion - fuel supply starvation
The aircraft fuel usage annotations recorded in the trip fuel log by the pilot showed that he had started his fuel calculations with 80L more fuel than was on-board. The annotations also showed that the left tank had been used for taxi and take off on both flight sectors that day. Take-offs were the periods of highest fuel demand by the engine and in accordance with the POH, should have been conducted from the fullest tank. The trip fuel log showed that, on departure from Rawlinna, the right tank contained the most fuel and, therefore, should have been used for that take off.
Whether prolonged taxi or extended use of climb power using the left tank took place could not be verified and the possibility of additional fuel usage from the left tank during these periods could not be ruled out.
The pilot's fuel usage annotations showed that he calculated the aircraft had used approximately 69L from the left tank and 70L from the right tank in total for both sectors that day, up to the last hand written entry for the fuel tank selection change at 1345. Using the operator's average fuel consumption figure for this aircraft, a further 28L needed to be used from the left tank by the time that the engine lost power; approximately 1413. If the tank selections were correctly carried out as annotated by the pilot, the total fuel burn from the left tank would have been around 97L, which should have left approximately 23L remaining in that tank. The tank was observed, at the accident site, to contain approximately half a litre of (unusable) fuel. It could not be positively determined why only unusable fuel remained in the left fuel tank.
The previous accident in 1995 demonstrated, that on at least one other occasion, this aircraft's left fuel tank contents could be exhausted after one hour and 40 minutes of operation from a `tabs level' fuel quantity. Flight time of the Kalgoorlie accident flight, while operating on fuel supplied only from the left tank, was estimated to have totalled approximately one hour and 37 minutes. It was therefore possible that the contents of the left tank may have also been exhausted on the Kalgoorlie, Rawlinna, Kalgoorlie flight in this period of time.
Operations with low-fuel quantity
The trip fuel log revealed that the pilot would have expected to have 40L more fuel remaining in each tank at the time the engine lost power. Consequently, he may not have considered a low fuel state as a possible cause for the engine power loss.
Flying in turbulence with a low fuel state can also lead to uncovering of the fuel outlets in the fuel tanks. If the pilot had correctly carried out the tank changes noted in the trip log, the left tank should have had approximately 23L of fuel remaining when the engine lost power; which equated to about an eighth of a tank. If such a quantity was present in the reported turbulent conditions, then the possibility of unporting the fuel outlets could not be ruled out.
The low fuel-state of the left tank alone, or in combination with the forecast turbulence, probably caused the engine to lose power.
In the absence of evidence of a mechanical failure leading to engine loss of power, the most likely cause of the engine loss of power was associated with fuel supply starvation or exhaustion.
The presence of a vehicle on the road appeared to have caused the pilot to initiate a sudden pull back on the flight controls that led to a loss of control and subsequent impact with the ground.
Verification of the actual fuel quantity during pre-flight inspection would have alerted the pilot to the amended state of fuel quantity on board the accident aircraft. CASA produced an Advisory Circular in September 2001 on fuel planning as guidance for operators and pilots to help ensure correct pre-flight planning procedures and that aircraft carry sufficient fuel to safely complete each flight.
The fitment of upper body restraints to the passenger seat belt systems may have reduced the exposure to some of the serious injuries incurred in this accident. Recommendation R19980281 arising from occurrence 199802830, dated 26 July 1998, was previously made to CASA to address this perceived deficiency with regard to upper body restraints. In response to this recommendation, CASA issued a Discussion Paper `Proposed Airworthiness Directive, General Series - Upper Torso Restraints for Occupants in Small Aircraft' explaining the intention to introduce such a requirement and inviting comment by the industry. The public comment period closed 01 March 2002 and CASA is now considering these comments prior to promulgation of the AD.
The Bureau's response to that action was RESPONSE STATUS: MONITOR. The ATSB will continue to monitor the CASA action and any further correspondence will be published on the ATSB website www.atsb.gov.au.
|Date:||14 November 2001||Investigation status:||Completed|
|Time:||1415 hours WST|
|Location:||10.7 km ESE Kalgoorlie/Boulder, Aero.|
|State:||Western Australia||Occurrence type:||Fuel starvation|
|Release date:||16 September 2002||Occurrence category:||Accident|
|Report status:||Final||Highest injury level:||Fatal|
|Aircraft manufacturer||Cessna Aircraft Company|
|Type of operation||Charter|
|Damage to aircraft||Destroyed|
|Departure point||Rawlinna, WA|
|Departure time||1250 hours WST|
|Role||Class of licence||Hours on type||Hours total|