At about 1020 Eastern Summer Time on 15 December 2002, a Boeing 737-400 (737) aircraft, registered VH-TJF, departed runway 35 at Canberra Airport for Melbourne. As the aircraft was rotated, the handling pilot felt that the pitch control was unusually stiff. The crew informed air traffic control of the problem and climbed the aircraft to a safe altitude in order to conduct a controllability check. The crew declared an urgency emergency phase as a precaution. The aircraft subsequently landed at Canberra Airport, at about 1115, with airport emergency services in attendance.

The operator’s maintenance personnel could not reproduce the problem on the ground. After investigation and replacement of the system B flight control module an assessment flight was conducted the following day to Melbourne Airport. That flight determined that the defect was still present and the aircraft was relocated to the operator’s maintenance facility in Melbourne for further investigation.

After an extensive investigation by the operator, the elevator binding was reproduced and found to be due to an incorrectly located elevator control cable. The control cable was hooked over the lip of a J shaped floor support beam, beneath the aft galley. The angular deflection of the cable over the floor support beam was such that the cable would only bind intermittently. The cable was repositioned and re-rigged in accordance with the manufacturer’s aircraft maintenance manual. An assessment flight was conducted and it confirmed that the defect was no longer evident.

A scheduled maintenance inspection on the 737 was completed on 13 December 2002. A review of the aircraft’s technical log indicated that on three of the eleven sectors flown since that inspection, reports of heavy and binding flight controls were noted. During the scheduled maintenance inspection completed on 13 December 2002, several flight control cables had been disconnected to carry out a modification that required the removal of the flight control columns. One of those cables was found, during the operator’s subsequent investigation, to be hooked over the aft galley floor support beam. The scheduled maintenance inspection did not require the floor panels to be removed and therefore did not allow a complete inspection of the cables after the modification was completed. Although there was no reported work carried out on the control cable system in that area, several maintenance work cards detailed maintenance near that area.

The operator conducted tests to determine how the cable might have become hooked over the J section floor support beam. With normal operating tension on the cable, a force of approximately 30 kg was required to place the cable over the beam. With only slight tension on the cable and the cable clamped, it could be readily placed over the beam. The test also determined that with the aft galley installed, as was the case, access to the location where the cable was hooked over the floor support beam was very limited.

The manufacturer’s aircraft maintenance manual contained instructions for maintaining a light tension on control cables that were disconnected but not removed. The instructions detailed the installation of cable clamps on the affected cables, to ensure that the cables do not unwind on their cable drums or become displaced from their pulley guides. If the cables were between rig pin locations, then rig pins were to be installed through the applicable cable drum or quadrant.

The aircraft manufacturer indicated that during certification of the 737, tests were performed to determine if an untensioned cable during emergency operations of the flight controls would interfere or hang up on adjacent structure. The manufacturer determined that the J section of the floor support beam did not present a risk.

The operator conducted an inspection of other 737 aircraft and found that two other configurations existed. One installation was the same as the incident aircraft but the cable was located within a plastic tube. The other installation had the floor support beam facing in the opposite direction (J section tail of the beam facing away from the cable). The manufacturer determined that the configuration of the incident aircraft was in accordance with the design drawing for the aircraft and that the floor support beam location was limited to the operator’s fleet.

History of the flights

A de Havilland DHC-8-315 (Dash 8) was being operated on a scheduled service to Mackay from Townsville under the instrument flight rules (IFR). The crew had been authorised by Brisbane Centre air traffic control to descend their aircraft to 6,000 ft. The duty runway at Mackay was 14 and, at 1503:00 Eastern Standard Time, the crew reported that they were tracking on the 304 degree radial of the Mackay VHF omni-directional radio range (VOR) navigation aid and were 30 NM from Mackay. The Mackay aerodrome controller (ADC) instructed the crew to `Report approaching 6,000 ft with DME [distance measuring equipment] distance’.

An IFR category Boeing 717-200 (717) was being operated on a scheduled service to Mackay from Brisbane. Its crew reported at 1503:22 that they were tracking on the 130 degree radial of the Mackay VOR, also on descent to 6,000 ft. The Brisbane Centre controller had assigned both crews 6,000 ft prior to instructing them to transfer to the Mackay ADC radio frequency. The assignment of the same level was an authorised practice, because the Brisbane Centre controller would continue to radar monitor the separation of all arriving aircraft until the first aircraft was at or below 5,000 ft. The ADC subsequently instructed the 717 crew to descend to 4,000 ft. The crew asked whether they could expect a left base and the ADC responded saying that they could expect a left base to runway 14.

The Dash 8 was in cloud, and at 1506:17 the ADC instructed that crew to descend to 4,700 ft. There was no separation standard being applied between the Dash 8 and the 717 and separation was no longer assured. The infringement of separation was not recognised by the Mackay ADC. The ADC instructed the 717 crew to descend to 3,000 ft and to reduce speed. The crew was told that they were number two to a Dash 8 from the north and the ADC asked them to report when visual. The Dash 8 crew reported approaching 4,700 ft at 14 DME and was instructed to descend to 2,000 ft, not below the DME steps.

At 1507:53, the crew of the 717 reported visual at 7 NM and advised that they were able to track for left base. The ADC told them to maintain 3,000 ft and to track for left downwind. The crew was asked to sight a helicopter in front of them at 2,000 ft and 4 miles east of the aerodrome. The crew replied `for the base runway 14 and looking’.

The crew of the Dash 8 reported visual (clear of cloud) and was cleared to make a visual approach straight in to runway 14 at 1508:38. The crew of the 717 was cleared for a visual approach at 1508:51. The crew of the 717 responded by reading back the clearance. The controller then said `and maintain downwind heading, the Dash 8’s currently at 9 mile’. The 717 crew neither heard, nor responded to, this subsequent transmission. The ADC did not query the lack of acknowledgment of that requirement.

Approximately 90 seconds later, the ADC observed the 717 turning left base and converging with the Dash 8 on final approach. This was a second, and more critical, infringement of separation between the two aircraft.

The crew of the Dash 8, on final approach, observed the 717 turn onto base towards their aircraft. The ADC instructed the crew of the Dash 8 to turn right, away from the 717. The ADC issued traffic information to the 717 crew who, after sighting the Dash 8, elected to maintain 1,500 ft. The ADC confirmed with the Dash 8 crew that they could see the 717 and authorised them to continue the approach. The ADC subsequently instructed the crew of the 717 to climb to 2,000 ft and make a left circuit before returning for landing.

Weather

The weather, reported as Information Golf on the automatic terminal information service, was runway 14, wind 100 degrees M at 16 kts, crosswind 10 kts, visibility greater than 10 kms, cloud scattered at 2,000 ft, showers in the area, temperature 27 degrees C and the barometric pressure at 1012 hectopascals.

The investigation report prepared by Airservices Australia indicated that although the conditions included some haze, conditions were suitable for the application of visual separation.

Airspace

Air traffic controllers from Airport Services Group, Airservices Australia, staffed Mackay Tower, which was a non-radar Class D tower. The Manual of Air Traffic Services (MATS) 9.1.2 stated that Class D airspace encompassed control zones of defined dimensions, and associated control area steps generally below 4,500 ft above mean sea level around designated aerodromes. Some of the lower levels of the Class D airspace at Mackay were below radar coverage. Airspace in the vicinity of Mackay above 4,500 ft was Class C.

In Class C and Class D airspace, an air traffic control service was provided for all IFR aircraft. In Class C airspace, a separation standard was required to be provided between all IFR aircraft, and between IFR aircraft and Visual Flight Rules (VFR) aircraft. In Class D airspace, a separation standard was required to be provided between all IFR aircraft and a separation service was required to be provided between IFR aircraft and Visual Flight Rules (VFR) aircraft airspace.

Equipment For most of the 1990s, controllers sought the provision of a radar display in towers where radar coverage was suitable. This was based on evidence that similar procedures were used in the UK in Class D towers, and in the USA in VFR Towers. Prior to the Sydney Olympics, a Tower Situational Awareness Display (TSAD) was installed in Bankstown Tower and during December 2000 test units were installed in Mackay and Rockhampton towers.

At Mackay, radar data was received by a dedicated personal computer located in the Mackay Maintenance Services division building and, after the data was processed, was relayed for display in the tower cabin. The unit displayed secondary radar returns only. The Mackay TSAD, although operating in the tower, was not approved for operational use because a safety case had not been completed. The Temporary Local Instruction (TLI AS/02/076) stated: `Controllers are reminded that until formal commissioning takes place, TSAD shall not be used in any operational sense (notwithstanding aircraft emergencies).’

Procedural separation

There was no evidence that the incident aircraft were provided with any form of procedural separation. Moreover, there was no evidence to show that the Senior Controller at Mackay or the subsequent investigation conducted by Airservices Australia identified that the ADC had not applied procedural separation standards. This oversight is not unusual, as procedural separation is a highly conceptual, rule-based air traffic control skill that demands cognitive rigour.

All IFR category aircraft in Class D airspace were to be provided with an air traffic control service. MATS defined an air traffic control service as follows: `A service provided for preventing collisions between aircraft, between aircraft and obstructions, and to expedite and maintain an orderly flow of air traffic’.

Radar control is the provision of air traffic control services using radar-derived information. Where radar is not available, procedural control is used. Procedural control is the provision of air traffic control services using information derived from sources other than radar. Such information is usually derived from pilots accurately reporting their aircraft’s position in three dimensions.

MATS stated that in a non-radar environment `controllers shall ensure that position reports are received from all aircraft in Class C and Class D airspace and for IFR flights in Class E airspace, unless: a. otherwise instructed by Air Traffic Control, or b. radar identified, or c. if the flight is specifically exempted’.

The crews of the incident aircraft were never instructed to provide a position report, which would have facilitated the selection and establishment of an appropriate procedural separation standard.

Despite the controller’s oversight in not obtaining aircraft position reports from the crews involved, the controller did provide position information about aircraft to crews. Information such as `traffic for you to sight is a Kawasaki helicopter, he’ll be in your one o’clock low at 2,000, he is 4 miles east of the field at the moment’. Another example was `maintain downwind heading, the Dash 8’s currently at 9 mile’.

Visual separation

Clearances for simultaneous visual approaches were authorised in MATS subject to certain criteria. These criteria were that the flight paths were to be greater than 90 degrees apart and that there was no significant cloud at or below the levels assigned to the aircraft. In addition, actual visibility was to be 30 km or more and both aircraft instructed to report at a distance outside the point at which lateral separation would be infringed and at which distance it was known that visual separation could be applied. The 717 and Dash 8 crews were not instructed to report outside of a lateral separation point.

After the controller had sighted both of the aircraft, the controller was authorised to separate them using visual separation as defined in MATS 4.5. Each crew was required to report when visual as a criterion to be met before they could be assigned a visual approach.

The crew of the Dash 8 was cleared for a straight in visual approach, while the crew of the 717 was tracking to join the circuit on left downwind, maintaining 3000 ft. The 717 crew was trying to sight a helicopter at 2000 ft, when they were also cleared to make a visual approach. The clearance for a visual approach authorised the crew to descend their aircraft below 3,000 ft.

MATS 4.5.2.3 stated: `When aircraft are operating visually as aerodrome traffic or in an Aerodrome Traffic Zone, ATC shall issue clearances designed to maintain separation and/or sequencing instructions, and provide traffic information’.

The controller only partially met the MATS requirement. Although the controller immediately followed up the visual approach clearance and issued a sequencing instruction: `and maintain downwind heading, the Dash 8’s currently at 9 mile’, a readback of the sequencing instruction was neither received nor requested. Traffic information on the Dash 8 was not issued to the crew of the 717.

Clearance readbacks

Air traffic controllers were required by MATS 6.1.13 to ensure that crews read all clearances, or amendment to clearances, back correctly. The accuracy of the readback was to be confirmed by the transmission of the aircraft’s callsign. Key elements of the clearances, instruction or information were to be read back. This included heading instructions.

Organisational aspects

In April 2003, Airservices Australia amended MATS to remove the requirement to pass traffic information to aircraft operating visually in the Aerodrome Traffic Zone (see Visual separation). The change was not reflected in the Manual of Standards Part 172 published by CASA and a safety case was determined to be not required. The amendment was considered by Airservices to be a more flexible requirement for traffic information when a tower controller was visually separating aircraft.

The MATS 4.5.2.3; `When aircraft are operating visually as aerodrome traffic or in an aerodrome traffic zone, ATC shall issue; (a) clearances designed to maintain separation; and/or (b) sequencing instructions; and/or (c) relevant traffic information.'

The previous version of MATS did not have the `and/or' for traffic information, it stated `and’, which indicated a mandatory rather than an optional requirement.

Shortly after commencing descent from flight level (FL) 310, the pilot of the Cessna Conquest noticed that the cabin altitude indication was rising. When passing through FL270, the cabin rate of climb rose to 3,000 ft/min with an accompanying decrease in cabin differential pressure and both master warning and "ALT" annunciators illuminating. When the annunciator lights illuminated, the pilot observed that the cabin oxygen masks had failed to auto-deploy as required. As the patients were already on oxygen and the flight nurse had donned a spare mask, he did not deploy them manually. The pilot donned his own oxygen mask and commenced a rapid descent to 10,000 ft.

The pilot reported that the cabin altitude indication increased to a peak of 17,000 ft before decreasing during the descent. A subsequent maintenance inspection found water contamination present in the cabin door seal pressurisation solenoid valve and it was suspected that this water froze, preventing the correct operation of the valve.

The failure of the oxygen mask auto-deployment system was also investigated and the wiring to the barometric activation switch was found to have a high resistance. This wiring was replaced. As a precaution, the wiring to the barometric switch that activated the cabin altitude annunciator warning light was also replaced. During these rectifications, the maintenance personnel discovered that there was no procedure published by the manufacturer to correctly adjust and test either barometric switch set-point after maintenance.

Manufacturers' maintenance manual procedures

A sampling of maintenance manual procedures for aircraft types, representative of the current Australian fleet and manufactured in countries such as the United States, United Kingdom and Switzerland was carried out. This sampling concluded that the maintenance deficiency for test and return to service of the oxygen deployment and cabin altitude alert barometric switches, found in the occurrence aircraft maintenance procedures, was also apparent in all but one of the other aircraft type manufacturer's maintenance procedures.

Regulatory requirements

The regulations currently in force in Australia state that: `CASA must issue a type acceptance certificate for an aircraft manufactured in a foreign country, without making the type certificate subject to any conditions, if a foreign type certificate or equivalent document issued by the NAA of a recognised country is in force for aircraft of that type'. CASR 21.183 deals with the issue of standard certificates of airworthiness and does not state any requirement specific to these altitude warning and oxygen deployment systems, other than that the general manufacture and modification status must conform to the production certificate or type certificate of an NAA or approved modifications to those standards.

CASA advised that, although CAO 108.26 was still in force, it was not actively applied by CASA during the Australian airworthiness certification process. CASA had introduced new legislation under CAR 22A and CAR 24 in 1990, later superseded by CASR 21.29A and CASR 21.183 respectively, that facilitated the entry to Australia of new types and models without having to comply with Australian design standards. This legislation abandoned the practice of applying Australian design standards to aircraft manufactured outside Australia and certificated in any of five major aviation countries. The Federal Aviation Administration (FAA), being the National Aviation Authority (NAA) of the United States and one of these recognised countries, has also promulgated amendments to FAR Part 25 and FAR Part 23 at amendment 23-17 that require cabin altitude warnings to trigger at 10,000 ft. CASA stated that the latest Australian legislation, in combination with the FAA Regulations, makes the requirements of CAO 108.26 Para 3.1 redundant.

On 12 July 2002, in a further response to recommendation R20000289, CASA recognised that there was scope for confusion and advised that it was considering amending CAO 108.26 to delete all requirements except the operational requirements imposed by CAO 20.4 sub-section 3 and the specification for protective breathing equipment imposed by CAO 20.4 sub-section 10. The response also stated that if CAO 108.26 is amended, the background to the amendment will be explained in an article in `Flight Safety Australia'.

History of the flight

The pilot was conducting a charter flight in the Nomad N22C aircraft with 11 persons on board from Wanggoolba Aircraft Landing Area (ALA), Fraser Island to Coolangatta. During cruise flight at 1,000 ft, approximately 2 NM north of Porpoise Point, South Stradbroke Island, the pilot noticed a slight yaw to the left and felt the aircraft decelerate. He then saw that the left engine low oil pressure and generator warning lights had illuminated. While responding to the left engine failure, the pilot noted that both low fuel pressure warning lights had illuminated and that the right engine had failed. The pilot then conducted a successful forced landing straight ahead on the northern end of Main Beach, immediately south of the Gold Coast Seaway.

After arriving at the beach landing site, the owner/chief pilot and engineering personnel inspected the aircraft, during which it was noted that the left fuel gauges indicated 120 lbs and the right fuel gauges indicated 160 lbs fuel remaining. A small amount of fuel was visible in the left fuel tank from the left filler point and no fuel was visible in the right tank. The gradient of the beach resulted in the aircraft being slightly left-wing low. Operator personnel used jerry cans to add a total of 178 L of avtur to the aircraft and bled air from both the left and right fuel lines. The owner/chief pilot then flew the aircraft from the beach to Coolangatta.

After the aircraft arrived back at Coolangatta, engineers disconnected the fuel lines from the engine-driven fuel pumps and ran the electric fuel pumps until the low fuel pressure lights illuminated, indicating that fuel was no longer being pumped. The fuel debi-meter indicated that 192 lbs, or approximately 107 L of fuel had been recovered. The estimated fuel consumption for the flight from the beach to Coolangatta was approximately 40 L, leaving approximately 30 L of the 178 L added on the beach unaccounted for. The aircraft flight manual stated that total unusable fuel was 19 L. No evidence of a fuel leak was identified. Although Operator personnel conducted a comprehensive engineering inspection of the aircraft's fuel system, the missing fuel could not be accounted for.

The incident flight was the aircraft's first commercial flight following a period of maintenance work during which engineers had ground run the aircraft several times and the owner/chief pilot had conducted two test flights.

Fuel

Before departing Coolangatta on the first leg of the days flying, the pilot had noted the fuel gauge indications and calculated that he required 200 L to attain full tanks. He then asked the refueller to add 120 L to the left tank and 80 L to the right tank. The pilot did not mention to the refueller that he intended to depart with full fuel tanks. After the refuelling was completed, the pilot noted that the fuel gauges indicated full, however he did not visually check the contents of the fuel tanks. The refueller later stated that neither fuel tank was full after he had added the requested amount of fuel to each tank.

The aircraft fuel system included four usable fuel tanks, two in each wing. The two tanks in each wing were filled from a single filler point. There were four fuel gauges, one for each of the four usable fuel tanks. During refuelling, it took a little time for fuel to flow from the outboard tank to the inboard tank. When asked to fill the tanks, the refueller normally had to fill one side, then fill the other side before returning to each side in turn to top them up. The refueller later commented that on the morning of the occurrence flight, he was able to add the requested amount of fuel without having to return to each tank to top it up, confirming that the aircraft fuel tanks were not full after the requested amount of fuel had been added.

During the day, the pilot landed the aircraft on three occasions at aerodromes where additional fuel was available. Based on the assumption that the aircraft was full on departure from Coolangatta, the pilot believed that the aircraft carried sufficient fuel, including reserve fuel, to complete the flight from Wanggoolba ALA to Coolangatta.

Operator pilots usually recorded fuel added, fuel on board, flight times and fuel consumed (from debi-meter indications) on a daily flight sheet. About six months prior to the incident, the Operator began using flight sheets with a carbon copy page so that the previous day's flight details were available to the pilot. Normally, the fuel details on the previous day's flight sheet could have been compared with the fuel gauge indications to provide additional information to the subsequent pilot regarding the fuel on board the aircraft. However, the details of fuel consumption during the maintenance-related ground runs and test flights had not been recorded on a flight sheet. Therefore, that information was not available to the incident pilot during his pre-flight preparations.

The operator's operations manual, section 3.5, titled "Fuel Documentation" stated that before commencing each flight or flight segment, the pilot in command shall be personally responsible for...verifying, by means of fuel gauges and visually, the total fuel on board is sufficient for the flight...". The pilot stated that he had never visually checked fuel tank contents in the Nomad, or in the Cessna Caravan, the other aircraft type he flew for the operator. The chief pilot and other operator pilots said they did not always visually check the contents of aircraft fuel tanks during pre-flight inspections.

Pilot experience and training

The pilot had accumulated a total of about 2,750 hours flying experience, of which 70 hours was in the Nomad. The majority of his recent flying was in Cessna Caravan aircraft, in which he had accumulated about 1,500 hours. The operator considered that the Caravan was equipped with a fuel quantity indicating system that was more accurate than that installed in the Nomad.

The pilot had completed his Nomad endorsement training and ICUS (in command under supervision) training with the operator. In a general sense, endorsement training was designed to provide training in the systems and characteristics of the new aircraft type, while ICUS training was designed to train the pilot in the normal operations of the aircraft type, including pre-flight inspection procedures. The pilot did not recall any discussion during his Nomad endorsement training regarding the accuracy of the Nomad fuel quantity indicating system in comparison with the Caravan. The pilot indicated that he had always calculated the amount of fuel required to be added based on fuel gauge indications. He had used this procedure when flying both the Caravan and the Nomad, and while undergoing ICUS training on the Nomad.

Microbiological contamination

Inspections of the fuel tanks identified contamination with microbiological material. There was one fuel quantity transmitter unit in each of the four useable fuel tanks. All four transmitter units were contaminated by microbiological material. The transmitter units consisted of a float inside an aluminium tube. Fuel entered the tube through small holes in the bottom of the tube, and the level of the float was electrically sensed and transmitted to the fuel gauges in the cockpit. The amount of microbiological material in the fuel quantity transmitter units was sufficient to interfere with the flow of fuel into the tube and to affect the electrical circuits at the bottom of the tube.

Various species of bacteria and fungi can grow in aircraft fuel systems given suitable temperature conditions and the availability of water and essential nutrients. In particular, cladosporium resinae fungus can grow into a "mat" at water collection points, and corrode tank lining and structural components.

The aircraft manufacturer recommended that fuel tanks and fuel quantity transmitter units be cleaned every 1,800 hours time in service. The transmitter units in VH-MSF had been cleaned less than 1,000 hours prior to the occurrence. The operator's fuel supplier at Coolangatta added fuel system icing inhibitor (FSII) to the bulk fuel supply. FSII is an effective biocide in avtur if used continuously. The operator also added a biocide to the aircraft fuel tanks each month.

The Beechcraft Queen Air and Rockwell Aero Commander were being used by a company to conduct private category passenger-carrying flights to transport its workers from Leonora to Laverton in Western Australia. The Aero Commander had departed and was established in the Leonora circuit area when the Queen Air took off. The pilot and one of the passengers of the Queen Air reported the take-off roll appeared normal until the aircraft crossed the runway intersection, when they felt a bump in the aircraft. The pilot reported hearing a loud bang and noticed that the inboard cowl of the right engine had opened. He also reported that he believed he had insufficient runway remaining to stop safely, so he continued the take-off. The cowl separated from the aircraft at the time, or just after the pilot rotated the aircraft to the take-off attitude. He reported that although the aircraft had left the ground after the rotation, it then would not climb. The aircraft remained at almost treetop level until the pilot and front-seat passenger noticed the side of a tailings dump immediately in front of the aircraft. The pilot said that he pulled the control column fully back. The aircraft hit the hillside parallel to the slope of the embankment, with little forward speed. The impact destroyed the aircraft. Although the occupants sustained serious injuries, they evacuated the aircraft without external assistance. There was no post-impact fire. The aircraft-mounted emergency locator transmitter (ELT) did not activate.

The Aero Commander pilot reported the accident to Perth Flight Service at 1746. Flight Service advised the local police of the accident at about 1750, however, the police were unable to locate the occupants until about 1848 because the details of the aircraft's whereabouts provided by the Aero-commander pilot were inaccurate.

Sequence of events

Three days before the accident flight, the Queen Air was privately hired from its owner and used to transport ten workers from Manjimup to Leonora. During the return flight to Manjimup, the pilot discovered that the left engine had developed a fuel leak and the right engine's oil pressure indication was low. The pilot returned the aircraft to Leonora and landed without further incident. He then returned to Manjimup using a commercial air service.

On the day of the accident, the original Queen Air pilot (pilot A) returned to Leonora in the Aero Commander. He was accompanied by a Licensed Aircraft Maintenance Engineer (LAME), another passenger and another pilot (pilot B). Pilot B was to fly the Queen Air to Manjimup.

By about 1330, the LAME had repaired the left engine. Pilot A then conducted a test flight and after landing, the aircraft was shutdown and checked. He then conducted a .6 hour refamiliarisation flight with pilot B. Both pilots reported that the flight included upper air work and three circuits. The aircraft landed at about 1600.

After the refamiliarisation flight, the aircraft was again shutdown and further maintenance was conducted on the left engine. The LAME reported that while he conducted maintenance on the left engine, both pilots were standing next to the right engine with the inboard cowl of the engine open. He reported that the pilots had found a set of pliers in the engine bay. Once he had ascertained that the pliers were not his, the LAME said that he went back to work on the left engine. He reported that he did not do any subsequent maintenance on the right engine and therefore did not check the security of the cowl of the right engine before the aircraft flew again. Pilot B said that he was assisting the LAME at the left engine and that pilot A had found the pliers in the right engine bay. A witness reported that pilot A had opened the right engine cowl and retrieved the pliers however, pilot A reported that pilot B had unfastened the cowls on the right engine to check for a small oil leak.

The pilots' original intentions were that once the Queen Air was repaired, the two aircraft would return the passengers to Manjimup. However, after the test and refamiliarisation flying had been completed, and during the planning for the flight to Manjimup, the pilots decided that the weather at Manjimup was unsuitable for VFR flight. They decided to conduct the flight the following day. Consequently, the pilots, LAME and passengers went to Leonora Township to find accommodation for the night and at about 1700 they met in a local hotel. Because there was insufficient accommodation available in Leonora, the group decided to fly to Kalgoorlie that afternoon. The pilots then became concerned about the wet weather approaching Kalgoorlie and Leonora, so they decided to fly both aircraft and all the passengers to Laverton for the night. Laverton was located about 15 to 20 minutes flying time north of Leonora.

Pilot A, who was flying the Aero Commander, reported that he had conducted the take-off in daylight conditions at about 1710. Pilot B, flying the Queen Air, reported that he had started the engines at the same time as pilot A had started the Aero Commander's engines but the time was about 1720. He reported that he had conducted the take-off in daylight conditions soon after. Documentary evidence indicated that the Aero Commander had been refuelled at about 1726. A witness reported that when he was leaving the airfield, he saw the passengers about a kilometre from the airfield and walking towards it at about 1710. Another witness reported seeing the passengers still walking towards the airfield at 1720 and that the aircraft were both on the tarmac without the engines running. One of the passengers of the Queen Air recalled seeing the Aero Commander depart at about 1730.

One of the passengers in the Aero Commander reported that it was getting dark with the sun just above the horizon when he embarked in the aircraft while pilot A conducted post- refuel checks. He also reported that the Aero Commander taxied about 10 minutes after refuelling and that the Queen Air had not started at the time they taxied. One of the witnesses also reported hearing the aircraft start at about 1735 and seeing one of the aircraft take-off soon after and circle the airfield. He also reported hearing the police sirens at about 1755. The police running sheet shows the police responded to the accident at 1755.

Pilot B reported that he had conducted the run-up checks on the apron before taxying to the runway and backtracking to the threshold of Runway 30. He reported that during the take-off roll he felt a "substantial impact" when the aircraft crossed the runway intersection. The passenger occupying the front passenger seat reported feeling a "fair bump" as the aircraft crossed the intersection. Pilot B said that it was after the bump that he heard a, "loud metallic bang". He reported that the noise caused him to look across the cockpit and out the right side window. He noticed the inboard cowl of the right engine opening in the propeller slipstream. The front seat passenger recalled seeing the cowl open when the aircraft experienced the bump. He said that the cowl fully opened as the aircraft left the ground and soon after, fell away. Another passenger recalled seeing the cowl open and come off before the aircraft took off.

Pilot B recalled having set a power of 45 inches of manifold air pressure (maximum continuous power) on the engines. He also recalled rotating the aircraft to lift off at 85 kts when he saw the engine cowl fall away. He said that he maintained the power setting because he, "was being very careful to avoid an overboost (engine) condition" and that the aircraft would not climb, remaining just above treetop level. He then saw the tailings dump embankment. He said that at about that time, the front seat passenger was telling him to pull up. He pulled back on the control column and the aircraft pancaked onto the embankment.

A passenger located in the Aero Commander, reported seeing the Queen Air "wallowing at low speed" just after it took off. He said that he saw the aircraft's landing lights illuminate the tailing dump before the aircraft pitched-up and bank to the right before hitting the hill. Pilot A reported the accident to Perth Flight Service but the details initially passed indicated that the aircraft had hit the ground on the airfield. The tailings dump was about 1 km beyond the airfield boundary.

Weather information

Last light for Leonora on the day of the accident was at 1732. There was mid- to high-level cloud with the lowest base being about 16,000 ft over the Leonora area. The wind was a light north-westerly.

Airfield information

Runway 12/30 was the only useable runway at Leonora airfield at the time of the accident because extensive works were being conducted on the main runway. Runway 12/30 was not lit and was therefore, unsuitable for use at night.

Pilot Information

Pilot B had extensive experience flying single engine aircraft but had last flown a twin-engine aircraft at night 3 years prior to the refamiliarisation flight. He had not flown a Queen Air for 7 years. He had advised the owner of the Queen Air that he had 300 hours flying experience in the Queen Air aircraft type. However, his pilot's logbook revealed that he had accumulated a total of just 30 hours flying experience in the type of which about 6 hours were as pilot in command. He subsequently reported that he had gained many more, "unofficial", hours in the Queen Air.

His licence was not endorsed with a night visual flight rules (NVFR) rating and his single engine instrument rating had expired 10 months prior to the day of the accident. His multi-engine command instrument rating had expired 6 years previously. The pilot's interpretation of the regulations and orders was such that he claimed that he did not require a NVFR rating because he previously held an instrument rating. The Civil Aviation Safety Authority reported that the pilot's interpretation of the requirements was incorrect.

The pilot who conducted the refamiliarisation flying reported that the accident pilot handled the aircraft well during the short refamiliarisation flight.

Wreckage Examination

The aircraft hit halfway up the embankment of a tailing dump about 1.7 kms from the runway and slightly left of the extended centreline. The embankment was about 30 ft high, with a 38-degree slope. The trees between the runway and the embankment were about 3 to 5 m tall. The fuselage had failed at the rear window line and twisted to the left. The cabin door was torn off and the right cabin windows were broken. The rear left seat had separated from the seat rails and the forward cabin ceiling lining had collapsed onto the seats. A small aluminium ladder was on the rear right seat. Several small hand tools and three protective helmets were in the rear of the cabin. All the cargo was unrestrained although a cargo tie-down net lay loosely in the rear of the cabin. The remote ELT control switch was in the armed position but the ELT had not activated. The ELT was undamaged and mounted correctly behind the rear cabin bulkhead. A subsequent inspection of the ELT found no fault with the unit.

The inboard cowling of the right engine was missing from the wreckage. It was found resting to the right side of the runway, about 850 m from the threshold of runway 30. An engineering inspection of the engine bay and cowl found that all its latches and locking mechanisms were serviceable. The two top hinges had failed in overload. The cowl was otherwise in good condition.

The left propeller and reduction gearbox, both main gears and the lower nose gear had all separated during the accident. Damage to the blades of both propellers was consistent with both engines delivering power at impact. A considerable quantity of Avgas was drained from both wing tanks during the recovery operation. Evidence indicated that both engines were capable of normal operation at the time of the accident.

The aircraft was not fitted, nor was it required to be, with a flight data or voice recorder.

The aircraft's maintenance release had not been completed during the 8 days prior to the accident including the maintenance conducted on the day.

Circumstances:

The aircraft was operating on a pleasure flight in a mountainous area. The aircraft had been flown to the area at 6000 ft and was planned to operate below 5000 ft for 20 min before returning to Canberra. The aircraft was observed flying at low level following the floor of a valley. After completing a pass in a northerly direction, the aircraft continued tracking north-west to climb over a range. While over rising terrain, the aircraft struck a tree, the impact tearing the right wing from the airframe. The right wing remained lodged in the tree approximately 27 m above the ground while the aircraft descended through the trees and impacted the ground, on its right side, approximately 35 m beyond the first tree impact. The aircraft was destroyed by fire and the occupants received fatal injuries. Examination of the wreckage at the accident site and a subsequent strip examination of the engine did not reveal any technical defects that would have caused the accident. Examination of the propeller indicated that it was rotating as the aircraft descended through the trees but was stationary at the time of impact with the forest floor. Onsite examination of the engine revealed the throttle in the closed position and the mixture selected to 'Idle Cutoff'.

However, damage to the right wing was consistent with a high-speed impact, indicating that the aircraft possessed the necessary kinetic energy to maintain terrain clearance. The flap lever was found in the fully retracted position, a further indication that the initial impact with the tree was unexpected and did not result from the pilot attempting a forced landing in the treetops. The pilot was medically fit and endorsed on the aircraft type. The aircraft was serviceable at the time of the occurrence, but its gross weight was estimated to have been approximately 37 kg above the permissible maximum. The weather was clear and mild, but the combination of high terrain and temperature produced density altitudes between 3900 and 5500 ft which would have adversely affected aircraft performance. Reduction of available engine power, coupled with high aircraft gross weight, would have degraded climb performance and aircraft manoeuvrability, both critical factors for low level operations in mountainous terrain. The pilot had not been formally trained in low level operations, his training having been limited to low level.

Significant Factors:

The following factors were considered relevant to the development of this accident:

1. The aircraft was flown at low level in mountainous terrain.

2. The pilot lacked the necessary experience for safe low-level operations.

3. The aircraft gross weight was above the permissible maximum.

4. Density altitude degraded aircraft engine performance.

5. The combination of density altitude and high aircraft gross weight degraded aircraft manoeuvrability.

6. The pilot either misjudged clearance from treetops or under-estimated the effect of aircraft inertia on aircraft manoeuvrability.

On 20 January 2011, a Piper Aircraft Corporation PA‑28-140 aircraft, registered VH-TXW (TXW), was approaching the Moorabbin, Victoria inbound visual flight rules (VFR) approach point of Brighton. At the same time, a Cessna Aircraft Company 172 aircraft, registered VH-TSP (TSP), had departed Moorabbin, tracking   for Williamstown via Brighton. TSP was at an altitude of about 1,500 ft at Brighton.

When about 1.5 NM (3 km) north-west of the Brighton visual flight rules (VFR) approach point, descending through 1,600 ft, the pilot of TXW observed TSP on a reciprocal track, about 200 ft below and a horizontal distance of 2 km. In response, the pilot of TXW took evasive action and observed TSP pass about 100 ft below the left wing of his aircraft. The pilot of TSP did not see TXW.

When flying in the vicinity of busy airports, pilots should be aware of the potential traffic conflicts, particularly around VFR approach points. The Civil Aviation Safety Authority's VFR Flight Guide recommends that aircraft departing Moorabbin should avoid the inbound approach points. For aircraft flying inbound via these approach points, it is important for pilots to maintain a vigilant lookout for conflicting traffic and be aware that aircraft may be in unexpected locations.

On 26 January 2011, at about 1315 Eastern Standard Time, a Robinson Company R44 Clipper II helicopter, registered VH-HFG, departed the Knuckle Reef Helipad, Queensland, for a 20-minute charter flight. On board the helicopter, were the pilot and three passengers. While returning to the Helipad 15 minutes later, at about 950 ft above mean sea level, the helicopter experienced mechanical problems, including a sudden loss of cylinder head temperature indication and variations in the engine manifold pressure.

The helicopter was unable to maintain altitude and began to descend at 200 ft a minute. The pilot elected to conduct a precautionary water landing, about 3.5 NM (6.5 km) south of Knuckle Reef and 0.5 NM (0.9 km) east of Line Reef. The pilot inflated the emergency floats, commenced an auto rotation at 500 ft and landed on the sea in a 1.5 m swell. The pilot secured the helicopter and radioed his GPS coordinates to another helicopter, who relayed these to Hamilton Island air traffic control. The other helicopter then liaised with the passenger transfer boat from Knuckle Reef, which picked up the pilot and passengers from HFG.

The helicopter was unable to be recovered before rapidly drifting into the path of an oncoming cyclone. A subsequent search failed to locate the helicopter which is presumed to have sunk.

The pilot's training underpinned the successful precautionary autorotation water landing onto a 1.5 m swell, thereby preventing significant injuries to the occupants.

On 20 January 2011, a Pacific Aerospace Corporation Cresco 08-600 aircraft, registered VH-KPY, was conducting a low level survey flight in the vicinity of Bingara, New South Wales.

The survey flight was conducted at 130 ft above ground level. During the fourth survey line the aircraft struck a powerline. The powerline was strung between two hilltops about 1,000 m apart at a height of 130 ft.

Following the collision with the powerline, the pilot noticed the wing skin was torn and he experienced some difficulties in controlling the aircraft.

The pilot elected to conduct a forced landing. During the landing the right wing collided with a hay bale. The pilot was not injured.

As a result of this accident, the aircraft operator intends to contact the power authority in each state to request the location of powerlines which they will overlay onto their Google Earth and topographic plans. It is proposed that this will occur on all surveying flights that present a risk.

The operator is also considering increasing the minimum height at which a survey can be conducted. If lower survey heights are required, and assessed to be suitable, they will be conducted by more experienced flight crew.

Safety summary

What happened

On 16 January 2011, while the products tanker Qian Chi was at anchor in Moreton Bay, Queensland, the ship’s number two oil-fired thermal oil heater exploded. The explosion seriously injured three crew members and severely damaged the thermal oil heater and surrounding equipment and fittings. The injured crew members received only rudimentary first aid on board. Shore-based emergency paramedics attended the ship and the injured crew members were evacuated by helicopter for treatment and recuperation.

What the ATSB found

The ATSB found that, during maintenance, the thermal oil heater burner nozzle had been assembled incorrectly. This was because the crew lacked experience with the equipment and the manufacturer supplied instructions were not clear and detailed. As a result, the nozzle leaked fuel into the furnace throughout the pre-ignition start sequence. The furnace exploded when the burner igniter started.

The ATSB also found that the ship’s crew were not aware of the importance of providing immediate and accepted first aid treatment for burn injuries. It was also found that deficiencies in the Brisbane port vessel traffic service procedures and preparedness contributed to delays in providing emergency assistance.

What has been done as a result

The ship’s operators have renewed the burner equipment installed in the ship for both oil-fired thermal oil heaters and altered the control system to better suit the fuel being used and the load demands placed on the heaters.

The heater’s supplier, Garioni Naval, advised they were updating documentation supplied with their machinery. They had also been in contact with the burner equipment manufacturer and others regarding this incident and equipment design.

Maritime Safety Queensland has undertaken a review of its procedures and practices to take into account the risks associated with ships within port limits but not at a berth and the emergency response required in such situations.

Safety message

Ship’s crew should remain vigilant to safety even when conducting repeated or seemingly simple tasks. Personnel need to consult equipment documentation and pay increased care and attention when undertaking unfamiliar tasks. To support that process, equipment documentation needs to be comprehensive and accurate.

Ship’s crew should also understand the importance of providing immediate and appropriate first aid to injured persons, especially burn victims. Burn injuries should always be immediately cooled, under clean, cold running water, for at least 10 minutes.