FACTUAL INFORMATION

The crew of an instrument flight rules (IFR) Boeing 737 (B737) had been cleared to descend to flight level (FL) 120 while tracking inbound to Darwin. The aircraft was tracking via the 163 radial of the very high frequency omni-directional radio range (VOR) navigation aid. The crew had transferred from Brisbane En Route Control to Darwin Approach Radar Control at approximately 60 NM from Darwin. An IFR Airbus Industrie A320 had departed Darwin for Alice Springs and was tracking via the 163 VOR radial on climb to FL370. The approach radar controller was busy with aircraft operating predominantly within 20 NM of Darwin aerodrome and did not recognise the potential for conflict between the aircraft.

When the B737 was approximately 45 NM from Darwin, the approach radar controller was alerted to the conflict with the A320 by another controller. The approach radar controller instructed the crews of both aircraft, in separate transmissions, to turn right 30 degrees. In the first transmission, the B737 crew did not understand the instruction and the approach radar controller had to repeat the instruction. Subsequently, the aircraft passed with less than 1,000 ft vertical separation and 2.4 NM lateral separation. The required minimum separation standard was either 3 NM laterally or 1,000 ft vertically. There was a breakdown of separation. B737 crew The B737 was fitted with a traffic alert and collision avoidance system (TCAS) and consequently, the crew was aware of the approaching A320. They were prepared to comply with any avoiding instructions expected from the approach radar controller. However, the initial instruction was given very quickly and was difficult to understand, and the crew had to ask the controller to repeat the transmission. Radar display The approach radar controller was responsible for managing the airspace encompassed by a circle with a radius of 50 NM, centred on Darwin. The approach controller used a main radar display with the range set to 50 NM and a smaller secondary display window with the range set to 100 NM.

The main display was primarily used to separate and manage aircraft close to Darwin while the smaller window was used for the management of aircraft that were further than 50 NM from Darwin. To avoid clutter on the display, the radar display labels on the secondary window were suppressed for all aircraft within 30 NM of Darwin. Just prior to the occurrence, the A320 would have been displayed on the main display with a full label and on the secondary window without a label. The B737 would have been displayed on the secondary window with a full label. Approach radar controller The approach controller was busy with aircraft conducting practice instrument approaches at Darwin and other arriving and departing aircraft. The controller was using flight progress strips and radar to manage aircraft in the area of responsibility. The Brisbane sector 11 controller advised the approach radar controller of the radar identification of the B737 and the assigned level of FL120 when the aircraft was 68 NM from Darwin. The approach controller reported the departure of the A320 to the sector 11 controller during the same coordination exchange. Neither controller remarked on a need to coordinate a separation procedure for the aircraft. Coordination The approach coordinator advised the sector 11 controller when the A320 taxied for departure.

The approach coordination controller and the sector 11 controller did not recognise the potential for conflict between the B737 and the A320. There were no specific procedures to ensure that Brisbane and Darwin controllers coordinated separation procedures for aircraft that were likely to pass near the boundary of the respective areas of responsibility. Generally, the approach coordinator would have alerted the approach radar controller to the potential for conflict before a taxiing aircraft departed. The investigation did not ascertain why the approach coordination controller did not advise the approach radar controller of the situation.

ANALYSIS

It is probable that due to the busy nature of the traffic environment at the time, both the approach coordinator controller and the approach radar controller became so fixated on the coordination and separation of aircraft close to Darwin that they were unable to comprehend the developing conflict. This aspect is further supported by the fact that the approach radar controller did not appreciate the potential conflict when the B737 was handed off from Brisbane and the departure time for the A320 was advised to Brisbane, in the same coordination exchange. The display of the radar tracks and labels for the aircraft on separate windows would have constrained the approach radar controller's ability to develop an appreciation of the potential conflict. However, flight progress strips were available and if they were scanned regularly by the approach radar controller, they should have provided a prompt for that controller. The aircraft passed at a position approximately 35 NM south-south-east of Darwin, which was well within Darwin's area of responsibility. Consequently, while the coordination of a procedure for the separation of the aircraft between Brisbane and Darwin Air Traffic Control would have assisted in the occurrence, it was not considered to be a significant factor.

SIGNIFICANT FACTORS

1. The approach coordination controller did not warn the approach radar controller of the potential conflict between the aircraft.

2. The approach radar controller's attention was diverted from scanning the flight progress strips for potential conflicts.

SAFETY ACTION

Local action

Darwin and Brisbane Air Traffic Control have developed a Manual of Air Traffic Services Supplementary Procedure which requires controllers to coordinate a separation procedure for aircraft that may conflict in the area between 40 NM and 80 NM from Darwin.

Additionally, Darwin Air Traffic Control has established an arrival position to reduce approach radar controller workload.

FACTUAL INFORMATION

The Australian-registered Boeing 767 (B767) had departed Brisbane on a flight to Christchurch, New Zealand and had passed the reporting point STUDA (30.18S 155.17E) at 1006 EST. The crew were maintaining the aircraft at flight level (FL) 370 on air route L503.

The foreign-registered B767 had departed Nadi, Fiji on a flight to Sydney and had passed Lord Howe Island at 1009 EST. The crew were maintaining the aircraft at FL390 on air route B450, which crossed the track of the Australian B767 approximately 90 NM south-west of Lord Howe Island.

Both aircraft were under the jurisdiction of Brisbane Air Traffic Control Sector 8. After receiving the foreign registered B767's position report at Lord Howe Island, the controller was required to forward the time estimate for the aircraft's next position report to Sydney approach control. This communication was to be carried out via a link that requires the receiving controller to depress a switch, indicated by a flashing light on the control console, in order for conversation to commence. On this occasion the Sydney controller was busy and it took almost seven minutes for the link to be opened.

There were five aircraft en-route from Australian airports to New Zealand that were under the control of the Brisbane controller. The flight times and disposition of these flights were such that several traffic separation conflictions would arise in Auckland's sector of responsibility unless corrective action was taken. At 1015, the Brisbane controller coordinated various matters with the Auckland controller and proposed some solutions which he could initiate to assist the Auckland controller in preventing the traffic conflicts. In particular, he suggested that the Australian B767 should climb to the non-standard FL390 and another aircraft climb to the non-standard FL350. The Auckland controller stated that he would consider these, and other, options before further coordination with the Brisbane controller.

At 1017, the crew of the Australian B767 requested a climb to FL390 due to turbulence. Although this was a non-standard level for eastbound flights, it did offer an immediate solution to four of the five prospective traffic conflictions. The Brisbane controller decided to approve the climb after discussing the issue briefly with the Auckland controller during a second coordination exchange, but without carrying out appropriate checks for lateral separation between the aircraft where air routes B450 and L503 intersect.

Just prior to approving the Australian B767's climb, the Sydney approach controller responded to the Brisbane controller's earlier attempt to coordinate details of the foreign B767. By this time the Brisbane controller could not recall the reason for initiating the call and the two controllers terminated the conversation without completing the intended task. The climb was approved at 1018.

At 1021, the Brisbane controller realised that he had not carried out all the required checks to ensure separation before approving the change in flight level. Although he did not make a specific scan of his flight progress strips, he was uneasy about the decision and elected to cancel the climb approval. He issued instructions for the crew of the Australian B767 to descend back to FL370.

The crew were passing FL385 on climb when they saw the other B767 some 25NM ahead and passing from left to right. They did not receive a warning from the traffic alert and collision avoidance system (TCAS).

The analysis of the radar recording was unable to establish the separation distance as both aircraft were outside radar coverage at the crossing point. Extrapolation of the last observed radar data for the Australian aircraft and the first observed radar data for the foreign aircraft, indicates that they passed with at least 25NM horizontal separation. However, as no procedural standard had been achieved, there was a breakdown of separation standards.

The Brisbane controller was working Sector 8 Radar and Sector 8 Ocean at the time of the occurrence. Together these two sectors form the Oceanic group. Workload was light to moderate during the period surrounding this occurrence. A team leader was rostered on duty but was conducting tasks outside the immediate work area at the time of the occurrence. Another controller was also rostered for duty on the Ocean group but was taking a rest break.

ANALYSIS

The Brisbane Sector 8 controller approved a change in flight level for the Australian B767 without carrying out the required checks for possible conflicts. This action may have been a result of the controller focussing his attention on resolving potential conflicts for the Auckland controller.

More specifically, the controller's omission occurred at a highly automised, skill-based level of performance. Following the Australian B767 crew's request to go to the non-standard FL390, a controller should normally undertake the following actions:

1. Check the flight strips and ensure there was no potential conflictions.

2. Communicate with relevant controllers to obtain approval for a non-standard flight level.

3. Approve or disapprove the change in flight level.

In this particular case, the controller had already discussed the possibility of a higher level for the B767 with the Auckland controller shortly before the flight crew requested the level change. When the Brisbane controller received the request, there would have been a strong, natural tendency to immediately provide this information to Auckland and therefore continue the previous conversation. Indeed, by continuing the conversation in a subsequent coordination call to Auckland just 2 minutes after the first contact, the controller had commenced his response to the B767 flight crew's request for a change in flight level. However, he had started the task at the second step in the sequence and omitted checking the other flight strips for potential conflictions.

As the request for the level change was due to turbulence, the controller may have felt some urgency to respond to the request. In addition, the Brisbane controller's awareness of the foreign B767 may have been reduced in the period prior to the occurrence. Firstly, the Sydney controller did not initially respond to the Brisbane controller's attempt to pass coordination for that aircraft. Secondly, the controller's attention was focussed on the other aircraft under his control during his discussions with the Auckland controller.

Skill-based errors, such as the one involved in this occurrence occur when a person performs a familiar task in an environment which is slightly different to that which is normal. In this case the difference was that the Brisbane and Auckland controllers were discussing a level change shortly before it was requested by the Australian B767 crew.

Skill based tasks are usually performed semi-automatically, with a low awareness of the actions taken by the individual. Reducing the incidence of such errors can be difficult due to this low level of awareness at which skill-based behaviour is performed. Airservices Australia will soon be introducing The Advanced Australian Air Traffic System (TAAATS). This new system will involve significant changes to the way many air traffic control tasks are performed. For procedural enroute controllers, a notable change will be the introduction of a display which gives a plan position indication for aircraft in their area of responsibility. This change will probably make the detection of potential traffic conflicts easier.

The likelihood of detecting and correcting such skill based errors before their consequences are significant could be improved through the introduction of an automatic conflict alert. Such an alert is currently being considered for radar tracks in TAAATS but not for other tracks. An alternative defence is the presence of other controllers to supervise or support a controller. Although there was provision for other controllers to be on duty, this defence was not present at the time of this occurrence.

SIGNIFICANT FACTORS

1. The Brisbane Sector 8 controller approved a change in flight level without carrying out the required separation calculations.

2. The Brisbane Sector 8 controller was attempting to solve future separation conflicts and may have been distracted from the immediate task.

SAFETY ACTION

As a result of this and several other occurrences, the Bureau of Air Safety Investigation (BASI) examined issues associated with Airservices Australia's operation of teams in air traffic services. This examination resulted in BASI issuing the following Safety Advisory Notice to Airservices Australia on 27 January 1998:

Safety Advisory Notice SAN 970137

Airservices Australia should take note of the safety deficiencies detailed by this document and take appropriate action.

The safety deficiencies referred to in the document were:

1. an undesirably low level of operational support provided by experienced controllers, including team leaders and other full performance controllers, to controllers working in operational positions.

2. an inappropriately low level of emphasis on team development activities, such as the provision of team leader training and support, and the regular provision of team days with structured learning content for team members.

3. performance evaluation systems for team leaders that do not ensure relevant team leader performance areas are measured, and also do not ensure that any degradation in a team leader's proficiency on operational positions will be detected.

4. an inappropriately low level of training and development for many controllers on human factors issues, particularly those associated with inter-controller coordination and communication.

The pilot reported that he was in the Coolangatta training area practising forced landing procedures with a student pilot. An autorotation was entered by lowering collective initially, then the throttle was wound off. Carburettor heat was selected fully on, carburettor air temperature was indicating approximately 12 degrees Celsius, and the engine was idling. The pilot said he turned towards the forced landing area and was briefing the student on the wind direction. The rotor RPM was in the green range and indicated airspeed was 55 knots, the correct autorotation airspeed. The pilot said that at this stage he was downwind (5-10 knots approx) and was ready to turn into wind at approximately 300 ft AGL. The collective was raised and the throttle was opened fully, but the manifold pressure increased only to 14-15 inches, there was a definite lack of power and the rotor RPM decayed. He maintained heading and airspeed and re-entered autorotation heading for the forced landing area when he noticed the engine had stopped. He said he attempted a restart but at this stage he was too low to risk a turn and accepted his present direction. The landing was made onto a tree lined track. The main rotor contacted trees and the aircraft rolled over to the right on the sandy surface. The pilot suspected that carburettor icing may have been the problem.

The weather conditions at the time were light drizzle or rain with a temperature of 18 -20 deg C. These conditions were conducive to carburettor icing. The pilot said that he had experienced power loss with this type of helicopter in similar situations, but usually on the initial entry into the autorotation. The aircraft manufacturer carried a technical investigation and found no evidence of any failure or malfunction that may have led to the accident. The manufacturer stated that the carburettor heat fully applied in autorotation produces an indication on the carb air temp gauge of full scale deflection. However, this has not been the operators experience. The operator advised that with full carb heat the temperature remains in the mid (caution) range and pilots have been advised to terminate autorotations and apply power if the carb air temp falls below this value. The operator now requires pilots to practice autorotations over a clear landing site, so that a landing may be terminated should the situation recurr.

FACTUAL INFORMATION

A Piper Chieftain departed Sydney for Maitland via Kamba, a position located 30 NM north-east of Sydney, on climb to 5,000 ft. The Chieftain was on an Instrument Flight Rules (IFR) flight and the pilot-in-command's (PIC) estimate for Kamba was 1756 EST. Kamba was the position where the Chieftain would leave controlled airspace (CTA) and the PIC would transfer from the air traffic control (ATC) frequency to the flight service (FS) frequency.

At 1753 a DeHavilland Twin Otter taxied at Aeropelican for a IFR flight to Sydney via the Calga Non-Directional Beacon (NDB) navigation aid at a planned altitude of 6,000 ft. Calga NDB was located approximately 32 NM north of Sydney and 12 NM to the west of Kamba. The Twin Otter's intended track crossed the Chieftain's planned track north of Kamba. The Twin Otter departed at 1756 and was transferred to ATC at 45 NM from Sydney. While the aircraft was in non-controlled airspace the PIC continued to monitor the FS frequency on a second radio.

The weather in the area north of Sydney was such that conditions were Instrument Meteorological Conditions (IMC). The Chieftain was approximately three minutes ahead of the PIC's estimate for Kamba due to a strong tailwind. The PIC transferred to the FS frequency at 30 NM from Sydney and reported that the aircraft was maintaining 5,000 ft. The FS operator did not acknowledge the report and the PIC of the Chieftain did not confirm that FS had received this report.

At 1759 the PIC of the Chieftain reported to the FS operator that the aircraft was leaving 5,000 ft on descent into Maitland. The FS operator acknowledged the report. Shortly after, the FS operator gave the crews of both aircraft the relevant traffic information on their flights. The PIC of the Twin Otter called the PIC of the Chieftain and reported passing 5,300 ft on climb. The PIC of the Chieftain sighted the Twin Otter off to his right and about 400 ft above the level of his aircraft but was unable to assess the distance between the aircraft. The crew of the Twin Otter did not sight the Chieftain. The investigation did not ascertain the actual vertical and lateral distance between the aircraft.

The FS operator was required to give traffic information to the crews of IFR flights about other IFR flights. The Manual of Air Traffic Services detailed criteria to be used in assessing whether traffic information was required to be advised. The FS operator had correctly assessed that traffic information would need to be issued to the crews of both aircraft because of their respective tracks. A local instruction required FS operators to give traffic information to the appropriate ATC sector for relay to crews of aircraft before leaving CTA. In this instance the FS operator believed he would have sufficient time to give the traffic information to both crews once they were on his frequency. He also thought that the PIC of the Chieftain may request a climb to 7,000 ft or an amended track direct to the destination, which would amend the traffic information.

ANALYSIS

The FS operator advised the crew of the Twin Otter to contact ATC at 45 NM Sydney which was prior to the crossing point of the tracks of the two aircraft. Traffic information on the Chieftain should have been given to the crew prior to their being instructed to change to the ATC frequency.

The FS operator believed that the level or route of the Chieftain might change and this aspect probably caused him to delay giving the traffic information to the crew of the Twin Otter. Subsequently, the FS operator either forgot or became distracted with other actions such that the information was not advised until the aircraft were in close proximity.

The reason for the FS operator not hearing the initial report from the PIC of the Chieftain could not be ascertained. The PIC of the Chieftain should have continued to report to the FS operator until an acknowledgement was obtained. A lack of acknowledgement may mean that either the aircraft's or the ground operator's radio was unserviceable. The PIC may have been distracted by the weather or some aspect of the aircraft's operation and consequently did not appreciate that his report had not been acknowledged.

SIGNIFICANT FACTORS

1. The FS operator did not request ATC to give traffic information to the PIC of the Chieftain prior to the aircraft leaving CTA.

2. The FS operator did not give traffic information to the Twin Otter crew prior to the aircraft entering an area of conflict. 

3. The FS operator did not hear the initial report by the PIC of the Chieftain.

4. The PIC of the Chieftain did not ensure that his report was acknowledged by the FS operator.

HISTORY OF THE FLIGHT

The pilot and the passenger, who was also the owner of the aircraft, performed a pre-flight check of the aircraft. Seated at the right control position, the pilot then taxied the aircraft for departure with the intention of conducting cross wind circuits. The airstrip was aligned approximately 020 degrees magnetic.

Shortly after take-off, when the aircraft was about tree top height, the passenger became aware that the aircraft did not appear to be performing normally. At about the same time the pilot assessed that the nose attitude was too steep. He lowered the nose and felt the aircraft descend. He confirmed that the throttle was set at full power and, assuming that the aircraft was stalling, lowered the nose further. When the aircraft continued to descend, the pilot attempted to land in an area about 100 m beyond the end of the airstrip.

The aircraft collided with a stack of several large posts and concrete pipes and came to rest inverted 120 m from the northern end of the airstrip but displaced about 50 m to the west of the airstrip alignment.

Both the pilot and the passenger sustained serious injuries.

At the time of the take-off the pilot had estimated that there was an easterly crosswind of about five knots, with a headwind component of about three knots. The windsock was located to the north-west of, and close to the hangar and farm buildings. A worker employed on Tartrus reported that the wind had been a light south-easterly.

The pilot normally flew and instructed in Cessna C172 or Piper PA28 type aircraft. He held an Australian Ultralight Federation pilot's certificate, but had limited experience flying ultralight aircraft. He had previously flown the aircraft at Tartrus Station four or five times.

Both the pilot and the passenger indicated that although the engine seemed to operate normally the aircraft had lacked performance. The passenger noticed that when the nose of the aircraft was aligned approximately with the horizon, the aircraft was descending. She was aware that there was a large performance degradation with two people on board and would normally fly the aircraft alone. When flying with a passenger she preferred the cooler hours of the day and would make as much use of ground effect as possible after lift-off.

AIRCRAFT EXAMINATION

The Hughes Lightwing GA-55 was manufactured in Ballina, NSW, and was powered by an Aeropower (modified Volkswagen) four cylinder, four stroke, air cooled engine driving a two bladed wooden propeller. The airframe was of high wing monoplane design. An Artex E03 emergency locator beacon was mounted behind the pilot's seat and was activated by the impact.

The aircraft forward fuselage area below and in front of the rudder pedals had sustained substantial damage.

No pre-existing defect which may have affected the controllability of the aircraft was found.

Examination of the fuel tanks found that the tanks were empty but the soil beneath the right fuel tank filler cap was found to be soaked with fuel to a depth of about eight centimetres.

The engine was fitted with a standard aircraft magneto and dual electronic modules. The electronic modules were found to be impact damaged and could not be tested. Specialist examination of the engine indicated that the magneto external timing was advanced 10 degrees beyond the recommended setting but was serviceable. No evidence was found that the magneto timing adjustment was altered during the impact sequence. No other pre-existing defect was found.

ANALYSIS

It is likely that the position of the windsock resulted in a shielding effect when the wind was south-easterly. This may have caused the pilot to incorrectly assess both the wind direction and the strength. Consequently, it is possible that the marginal performance of the aircraft was further degraded when, shortly after take-off, the aircraft encountered a crosswind with a tailwind component.

The pilot's limited experience flying this aircraft type, and ultralight aircraft generally, may have led him to apply an inappropriate handling technique in response to the low performance.

SIGNIFICANT FACTORS

1. The aircraft had marginal performance characteristics when carrying a passenger.

2. The pilot was inexperienced on the aircraft type.

3. The pilot did not maintain adequate flying speed after take-off.

The pilot of the helicopter was conducting a familiarisation flight for the wife of the station owner who had contracted the helicopter. It was late afternoon, with the sun low on the horizon and the fine weather with no cloud or wind. End of daylight was approximately 1745. The homestead, from which the helicopter departed, was located to the west of a swamp. The swamp's water depth was approximately 1 m and the surface was reported as being mirror-flat at the time of the accident. There were two islands located in the swamp and their foliage had a maximum height of approximately 3 m.

The helicopter departed at approximately 1700 and tracked north, climbing to approximately 800 ft AGL before completing a counterclockwise circuit towards the swamp. The pilot decided to make a shallow, northerly approach to the southern island. The island's southern shore was approximately 500 m from the mainland approaching from the south. As the helicopter crossed the mainland-shore on the final approach, the pilot assessed his height as being 20 to 30 ft. 

Late in the approach the pilot decided that a landing on the island was impractical and he commenced a go-around. He stated that he placed the helicopter in an accelerative-attitude and commenced a slight right turn to avoid a bird. The passenger, sitting in the right seat, stated that she thought that the helicopter was at about 10 ft from the surface of the water as the turn commenced. She recalled a spray of water from the front right side just before the helicopter impacted the water. 

The occupants remained secured to their seats and the helicopter remained substantially intact although the canopy bubble imploded, the tail rotor gearbox was flung clear and the main rotor system and fuselage were substantially deformed. The wreckage spread and passenger report indicate that it is likely that the main rotor struck the surface of the water causing the helicopter to cartwheel before coming to rest upright.

After the impact, the occupants released themselves from the wreckage and waded ashore. They reached the shore at approximately 1725.

The pilot later reported that he was unaware of the difficulties associated with visually judging height over calm water. Lacking a radio altimeter, the final approach starting altitude and shallow angle was inappropriate in the prevailing conditions. It is likely that, when the pilot selected the accelerative-attitude and commenced the right turn, the helicopter descended slightly causing the main rotor to strike the surface of the water. The smooth water surface, failing light and low foliage height probably caused the pilot to underestimate the helicopter's height above the water and not perceive a slight descent during the go-around.

A Piper Chieftain (PA31) departed Bankstown on a flight to Moorabbin in accordance with the Instrument Flight Rules. The Sydney Departures controller issued the pilot with radar vectors to intercept the Sydney-Cordo track, together with an instruction to climb to and maintain 5,000 ft. At about that time a Boeing 747 (B747) was approaching Sydney from the west, in instrument meteorological conditions, following a RIVET Standard Terminal Arrival Route. The crew had been issued with a clearance to descend to and maintain 6,000 ft. The flight paths of the two aircraft were to cross each other at approximately right angles, some 8 NM to the south-west of Sydney.

The crew of the B747 subsequently advised the Sydney Approach controller that they had received a Traffic Collision and Avoidance System Resolution Advisory (TCAS RA). The RA instruction to climb the aircraft had been followed by the crew and the aircraft reached a maximum altitude of 6,300 ft before returning to the assigned level. At that time the controller observed the radar return of the PA31 descending through 5,300 ft and queried the pilot as to his present level. The pilot replied that he was returning to 5,000 ft. Neither crew sighted the other aircraft.

Analysis of recorded radar data revealed there had been a breakdown in separation between the two aircraft. The minimum vertical separation between the B747 and the PA31 was 600 ft whilst the lateral separation was 1.7 NM. The required separation standards were 1,000 ft vertically or 3 NM laterally. The PA31 reached a maximum altitude of about 5,400 ft. The pilot of the PA31 later reported he had been distracted at the time his aircraft was approaching 5,000 ft and had subsequently climbed through his assigned level.

FACTUAL INFORMATION

The pilot in command of a scheduled passenger service from Sydney to Cootamundra, via Cowra, discontinued the flight with the assigned aircraft due to a mechanical problem experienced during engine start at Cowra. The chief pilot had also been on board the aircraft, observing the flight procedures of the pilot in command. The scheduled service was subsequently completed by the pilot in command using a substitute aircraft, VH-XLA, which had been dispatched from Cootamundra.

After landing at Cootamundra the aircraft was taxied to the fuel bowser and shut down. In anticipation that he would be refuelling the aircraft, the pilot in command left a written note for the next rostered pilot which stated that the main fuel tanks were full. At about this time the chief pilot chose to carry out a debrief of the flight with the pilot in command. The two men sat down in the rear of the aircraft to discuss the flight. Whilst the debrief was in progress, a company engineer boarded the aircraft and taxied it to the hangar for routine maintenance. The pilot in command reported that he was distracted by the debriefing and did not subsequently return the aircraft to the fuel bowser to complete the refuelling process. In addition, the maintenance release (MR) did not show that the aircraft had been flown from Cootamundra to Cowra and return, nor were details of the flight, and fuel remaining on board at the completion of the flight, documented in other company records. The operator had planned to use the same aircraft for the scheduled afternoon service to Sydney via Young and Cowra.

The pilot rostered for the afternoon service arrived at 1300 EST to carry out a pre-flight inspection. Company fuel policy for that service required a minimum of full main tanks. Fuel records indicated that the main fuel tanks of VH-XLA had been refilled on the previous evening, information which was supported by the note left by the previous pilot. One of the company engineers, who was queried by the pilot, was not aware that the aircraft had been flown that morning but added that the engines had been run at considerable power for about 10 minutes. The pilot later reported that his observation of the fuel gauges confirmed the tanks were close to full. However, he did not carry out a visual inspection of the fuel levels in the tanks prior to departure. The aircraft subsequently departed Cootamundra at approximately 1525.

During climb after departing Cowra, the pilot observed the fuel gauges indicating less than he would normally have expected at that stage of the flight. He elected to cruise at 7,000 ft, and reduced power in order to decrease fuel flows. The pilot also contacted the company head office about possible fuel gauge anomalies. As the aircraft approached Bindook, the pilot carried out a further check of the fuel gauges and chose to land at Camden as a precautionary measure. A PAN call was transmitted to Flight Service, and the passengers were advised that the aircraft would be landing at Camden due to a low fuel indication. The pilot executed a normal landing following a straight-in approach.

Two hundred litres of fuel were added to the main fuel tanks in order to complete the flight, but the pilot was unable to start the left engine. Ground transport was subsequently used to take the passengers to Sydney. A further 182 L were added to fill the main fuel tanks, bringing the total amount of fuel added at Camden to 382 L. The combined usable fuel capacity of the main tanks is 402 L.

An engineering examination of the aircraft did not reveal any anomalies with the fuel system or fuel quantity gauges which may have contributed to the incident. It was determined that the pilot had used an incorrect start procedure at Camden, causing problems in starting the left engine. Fuel calculations, based on the company fuel policy, indicated that the aircraft had departed Cootamundra with approximately 250 L on board, equivalent to about two-thirds of the combined fuel capacity of the main tanks. The actual fuel required for the flight, including 113 L of standard reserves, was calculated to be 358 L.

The pilot held a valid licence and ratings for the operation being undertaken. He had commenced full-time employment with the company on 24 January 1996 after working part-time with the same company since early 1995. He had accumulated 1,275 hours in Piper Chieftain (PA31) aircraft, all of which had been flown in company aircraft.

The pilot believed that fuel would not be visible in the main tanks, as viewed through the filler caps, if any more than a few minutes of fuel had been burned. This did not appear to be a view held by other company personnel. Moreover, the pilot indicated that had he visually inspected the tanks prior to departure from Cootamundra, and not been able to see fuel, he would still have concluded he had sufficient fuel based on all other available information and the knowledge that the engines had been run for approximately 10 minutes during maintenance checks. A number of operators of Chieftain aircraft were consulted, all of whom said that a total of some 300 L remained in the main fuel tanks when fuel was just visible on the sloping bottom surface of each tank.

The company aircraft checklist required that, as a minimum, the fuel gauges/contents are to be checked prior to start-up and during the pre-take-off procedure. However, the pilot confirmed that following his first observation of the gauges during the pre-flight inspection, he did not check the gauges again until he had departed Cowra. He reported that he had experienced a high workload on this flight, due to a full complement of passengers and a significant amount of baggage to deal with and had overlooked this check. Since he also assumed the main fuel tanks had been full when the aircraft departed Cootamundra, he did not expect the fuel gauges/contents to be a checklist item requiring close and frequent attention.

ANALYSIS

The responsibility of ensuring that there was sufficient fuel to complete the flight rested with the pilot of the afternoon service. However, the incident resulted from a chain of errors and omissions involving a number of company personnel, which ultimately led to insufficient fuel being on board the aircraft to complete the scheduled flight from Cootamundra to Sydney.

In the first instance, the MR had not been certified by the pilot who ferried the substitute aircraft to Cowra. In the second instance, the pilot in command who had completed the scheduled flight in the substitute aircraft, did not complete the flight details nor certify the MR. In addition, the pilot in command was normally in the habit of completing the note, which indicated that the main tanks were full, before leaving his control seat immediately prior to refuelling. However, his normal routine had been interrupted when the chief pilot chose to debrief him before he had time to complete all required administrative and refuelling tasks. His pre-occupation with the chief pilot's critique of his flight subsequently led to these tasks being forgotten.

As a result of the oversights which occurred during the morning, the supporting documentation available to the pilot rostered for the afternoon service did not indicate that a flight had taken place in the aircraft earlier that day. The note left by the pilot of the earlier flight indicated that the main fuel tanks were full. In addition, the pilot's understanding of the fuel system was incorrect. This is considered to be the most significant factor in the chain of events. It was ultimately his responsibility to determine that there was sufficient fuel for the flight. He did not carry out a visual check of the main fuel tanks. However, even if fuel had not been visible, his assessment of the fuel quantity would not have altered. Because of his inadequate knowledge of the fuel system, such an observation would not have alerted him to the discrepancy between the fuel documentation and the actual fuel contents.

The pilot's understanding of the aircraft's fuel system differed with that of his peers within the company, and with other operators of the aircraft type. In addition, this understanding was inconsistent with the general view held by other company personnel that he displayed competence and professionalism in his flying duties. The investigation was unable to resolve this inconsistency.

It was determined that the fuel gauges should have indicated a maximum of three-quarters full at the time of the pre-flight inspection. It is considered probable that the pilot's observation of the fuel gauges reading close to full prior to departing Cootamundra was strongly influenced by the other fuel-related information available to him prior to departure. This expectation was then carried throughout the rest of the flight until he finally became aware of the apparently low-reading fuel gauges after leaving Cowra. Even at that stage he thought the readings were incorrect but wisely decided to land at Camden as a precaution.

SIGNIFICANT FACTORS

1. The maintenance release had not been certified, and details of the morning flight in the substitute aircraft, including flight times and fuel remaining, had not been documented.

2. The pilot in command of the morning flight had written a note stating that the main fuel tanks were full but was distracted from his duties and did not complete the refuelling process.

3. Other documentation indicated that the main fuel tanks were full.

4. The pilot rostered for the afternoon flight did not visually inspect the fuel tanks, nor would he have changed his assessment of the fuel quantity if he had, given the information he had available to him and his incorrect understanding of the fuel system of the aircraft.

5. Due to a high workload, the pilot did not check the fuel quantity gauges in accordance with company procedures prior to departure from both Young and Cowra.

SAFETY ACTION

As a result of this occurrence, and in consultation with the Civil Aviation Safety Authority, the company has reviewed its policies and procedures in relation to the checking and documentation of fuel quantities in PA31 aircraft. The company Maintenance Control Manual was amended to ensure that a visual inspection of the fuel tanks was included in the pre-flight inspection.

FACTUAL INFORMATION

The crew of a Fokker Fellowship (F28) aircraft had flight planned to conduct navigation aid calibration of the Sydney runway 16L instrument landing system (ILS). Runways 16L and 16R were nominated for arrivals and departures. The crew received a clearance for a radar departure from runway 16R. The departures controller's intention was to radar vector the F28 to the east and north of the aerodrome for an intercept of the 16L ILS from the north. The F28 departed from runway 16R, heading 170 degrees, on climb to 3,000 ft. When the F28 was 8 NM south of the aerodrome the departures controller instructed the crew to turn left onto a heading of 120 degrees, to parallel the RWY 16L departure track. The controller had six aircraft on frequency, with a number of pending departures for both runways. He planned to vector the F28 across the RWY 16L departure track between two B737s departing from runway 16L. The first B737 took off with an instruction to turn left onto a heading of 060 degrees. The F28 was also instructed to turn left heading 060 degrees. The controller assessed that the F28 could cross the RWY 16L departure track ahead of the second B737, which had also taken off, and instructed the F28 to turn onto a heading of 020 degrees.

The crew of the second B737 had earlier been issued with a West Maitland 7 SID, on climb to 5,000 ft. The SID required the aircraft to track 155 degrees until reaching 600 ft, and then to turn left to intercept the 126 degrees radial of the Sydney VHF omni-directional radio range (VOR) navigation aid. The B737 crew were subsequently re-cleared to climb to their planned level of FL210 immediately after departure. The controller observed the reducing distance between the F28 and the second B737, but believed the B737 would climb above the F28, and that the vertical separation standard of 1,000 ft would be achieved prior to the distance reducing to less than the required lateral standard of 3 NM. However, when the B737 reached 3,000 ft the crew levelled the aircraft to accelerate to 250 kts. As the nose of the B737 was lowered the pilot in command observed the F28 at the 11 o'clock position, at a distance of 1 to 2 NM and slightly below their level. Just prior to the distance between the aircraft reducing to less than 3 NM, when the vertical separation was 300 ft, the controller instructed the crew of the F28 to turn right onto a heading of 040 degrees. He then instructed the crew of the B737 to turn right onto a heading of 180 degrees. The aircraft passed with less than the minimum vertical and lateral separation standards. Aircraft departing to the north and east were normally instructed to to depart from runway 16L, if that was operationally acceptable. The F28 had been parked overnight at Sydney aerodrome on the tarmac adjacent to the threshold of runway 16R. There was no operational reason for the aircraft not to have used RWY 16L for departure.

ANALYSIS

The controller relied on his understanding of B737 performance to establish vertical separation between that aircraft and the F28. The lack of application of separation assurance techniques provided no alternative means to maintain separation when the B737 was unable to attain the expected altitude. The controller had a number of aircraft under his control and this aspect should have been a prompt for him to ensure separation was assured between aircraft. Had a clearance been issued for the F28 to depart from runway 16L it is unlikely that the incident would have occurred.

SIGNIFICANT FACTORS

1. The controller's expectation that the B737 would climb 1,000 ft above the level of the F28 before lateral separation reduced to less than 3 NM.

2. The controller's lack of application of separation assurance techniques.

3. The departure of the F28 from runway 16R when runway 16L was available meant that the F28 would have to cross the departure track of runway 16L in order to carry out its intended operation.

The pilot reported that during cruise at 2,300 ft the engine gradually lost power until he was committed to a forced landing. During the forced landing the aircraft flew through the tops of 40 ft trees and then under a powerline. The aircraft then hit and killed two sheep, ran through a depression, became airborne again and finally hit the ground heavily before coming to a stop. The engine is a sealed rotary liquid cooled unit which can only be dismantled at the manufacturer's facility in England. A post-accident inspection revealed a coolant hose had detached from the water pump but it could not be determined if this initiated the engine failure or was a result of the accident. Traces of internal seal material were found in the exhaust system so it is possible that a seal failure initiated the engine failure. The owner does not intend to return the engine to the manufacturer for dismantling.