As the pilot taxied his aircraft towards his normal parking place on the G.A. apron he was aware of an aircraft to his right parked next to the refuelling installation, and a refuelling tanker parked on the apron to his left.

It is common to have tankers on the apron, although this tanker was parked further away than normal from the aircraft it was servicing. The pilot was concentrating on ensuring clearance from the parked aircraft to his right, and experienced sun glare when looking towards the tanker.

Although the aircraft was taxiing on the centreline of the taxiway, the pilot realised too late that the left wingtip would not clear the tanker and was unable to prevent a collision which damaged the wingtip and aileron.

Factual Information

Sequence of Events

The crew of VH-SSV planned for a flight from Bankstown to Coffs Harbour as VH-SSW. The plan nominated flight within controlled airspace (CTA). A change of aircraft occurred and, after taxiing to the holding point, it was established that air traffic control (ATC) would require a delay before issuing a departure clearance into CTA. The crew therefore decided to proceed outside controlled airspace (OCTA) and departed at 0642 ESuT, climbing below the CTA steps.

At 0646 the aircraft passed the Hawkesbury Bridge, and the crew transferred to the flight service (FS) area frequency of 125.7 MHz. They requested that the flight service officer (FSO) inquire of Sydney Sector 1 (Sec 1) if an airways clearance was available as they had planned about 70 minutes earlier. This request was not relayed to Sec 1 until 0654 due to the workload on FS 4. At the time of the co-ordination, the sector controller had not received the flight plan details at the console.

Also at this time, the FSO passed traffic information on two IFR aircraft which were in the area and in possible conflict. Consequently, the crew of one of these aircraft (VH-KZQ) and the crew of VH-SSV arranged mutual vertical separation. During this time, the crew of VH-SSV reported maintaining 6,000 ft to FS.

VH-TQL had planned a flight from Williamtown to Sydney at FL120 and at 0647 the crew reported taxiing at Williamtown on area frequency as Williamtown ATC had not yet commenced duty. RAAF ATC were due to commence services at 0700. This taxi call is required to be co-ordinated with Sec 1, and this was completed at 0651, delayed due to workload on FS 4.

At 0653 the crew of VH-TQL reported to FS its departure of 0652 and, as the airspace was uncontrolled, they were required to remain OCTA until Sec 1 could issue an airways clearance. As a result, VH-TQL was levelled at 8,000 ft to remain OCTA while awaiting airways clearance.

The FSO providing the FS 4 service had received from Sec 1 an expectancy  that VH-TQL would be given an airways clearance with little or no delay and therefore instructed the crew to contact control on 123.4 MHz on reaching 8,000 ft for a clearance and asked the crew to report approaching 8,000 ft before leaving his frequency. 123.4 MHz is Sydney Arrivals Control and the responsibility for informing that controller lies with Sec 1.

At 0654 FS 4 co-ordinated with Sec 1 regarding the request from VH-SSV for an airways clearance. This was the first time that Sec 1 had been passed information on this aircraft but agreed to take the aircraft on frequency for processing. FS 4 instructed the crew of VH-SSV to contact control on 126.9 MHz (Sec 1) for a clearance. It is the responsibility of Sydney Departures Procedural control to inform Sec 1 when an aircraft that has planned in CTA from Bankstown departs OCTA and requires a clearance en-route. This co-ordination was not carried out.

As the crew of VH-SSV were transferring frequencies, they observed that they had passed the next control area step and elected to climb to 8,000 ft OCTA while awaiting their airways clearance from Sec 1. Due to a delay in the issuing of the clearance, the aircraft was levelled at 8,000 ft in order to remain OCTA. As their track was 002 degrees, both 8,000 ft and their previous cruising level of 6,000 ft were contrary to the table of hemispherical cruising levels.

At 0655 FS 4 co-ordinated the departure time of VH-TQL with Sec 1. The Sec 1 controller found that he had four aircraft OCTA all wanting airways clearances. He decided to instruct all four to remain OCTA until he had identified them on radar so that he could guarantee adequate separation within CTA. This resulted in a short delay for both VH-TQL and VH-SSV while on separate control frequencies and both maintaining 8,000 ft on conflicting tracks.

While Sec 1 was co-ordinating the clearances for the two aircraft with arrivals control, the initial radar returns indicated that the aircraft were in close proximity and on converging headings. The sector controller issued VH-SSV with a radar vector OCTA for collision avoidance. Traffic information was passed to both crews, and a mutual sighting was achieved during the turn manoeuvre.

The aircraft passed approximately 600 m apart at the same altitude.

Flight Planning

It is common practice for pilots to plan IFR in CTA ex Bankstown and then elect to proceed OCTA when ATC issue a delay for an airways clearance. It is also common practice for crews to hold a second, OCTA, plan in the cockpit for such eventualities. However, they do not submit this OCTA plan as the pilots prefer to operate IFR in CTA and they believe that ATC will always send them OCTA if such a choice exists on the flight plan. This causes problems in the distribution of flight details to FS.

Co-ordination

When an aircraft departs OCTA from Bankstown having planned in CTA, Bankstown ATC are required to pass the details to Sydney FS and Departures Procedural. Departures Procedural then passes this information on to Sec 1 for processing.

Hemispherical Levels

IFR aircraft are required to be flown in accordance with the table of hemispherical cruising levels. On this occasion the crew of VH-SSV chose to fly at a non-hemispherical level. The correct altitudes for their track would have been 5,000 ft and 7,000 ft in lieu of 6,000 ft and 8,000 ft.

Change of Level OCTA

The crew of VH-SSV were maintaining 6,000 ft when transferred by FS to control frequency. Shortly after, they initiated climb to 8,000 ft to remain OCTA in the belief that a clearance would be given by the time they reached that level, however the delay in obtaining the clearance resulted in the aircraft maintaining 8,000 ft. Neither the crew nor ATC informed FS of this change in altitude, which is contrary to requirements.

The FSO did not pass traffic to either aircraft in the belief that they were separated by IFR cruising levels, but he was aware of the requirement for VH-SSV to pass through the level of VH-TQL once ATC issued approval for climb into CTA. He considered that ATC would separate the aircraft on climb as both were on control frequencies with an expectancy of an airways clearance almost immediately (as this was normal practice).

Control Frequencies/Airspace Configuration

The two aircraft were transferred to separate ATC frequencies by the FSO. This was common practice but was not in accordance with Local Instructions. It resulted in neither crew being able to hear transmissions involving the other at a time when they were on conflicting tracks. The correct procedure would be for both aircraft to contact Sec 1 whose airspace they were about to enter.

FS Workload

The FSO was rostered to perform the FS 4 duties on his own until 0800 when a relief officer commences duty. The workload builds up after 0630 each morning and becomes very busy from approximately 0645. It has become common practice for the FS 4 operator to request the assistance of the Team Leader to act as co-ordinator during this period.

One reason for this rise in workload is that Williamtown ATC commence duty at 0700 each weekday and this results in an added workload for the FS 4 operator in that an update of all traffic in the Williamtown area is required to be passed to ATC. The process for passing this information is very formal and convoluted.

Findings

1. No flight plan for VH-SSV to depart Bankstown OCTA was submitted.
2. Sydney Departures Procedural did not co-ordinate the departure of VH-SSV as required by Sydney District Local Operating Instructions.
3. The FSO was experiencing a period of heavy workload.
4. The two aircraft were transferred to different control frequencies.

Significant Factors

1. The crew of VH-SSV elected to fly at a non-hemispherical altitude.
2. Neither the crew of VH-SSV nor ATC informed FS4 that the aircraft had changed level while remaining OCTA.
3. The FSO did not pass traffic information on either aircraft to the crew of the other.

Safety Action

As a result of the investigation the following Safety Advisory Notices were issued:

SAN 940093: The Bureau of Air Safety Investigation suggest that the Civil Aviation Authority and the RAAF conduct a joint review of their procedures with respect to:

1. the coordination of traffic information concerning aircraft departing WLM CTR for possible climb or cruise OCTA;
2. notification of the opening of military airspace, with particular reference to RAAF/FIS coordination.

SAN940079: The Bureau of Air Safety Investigation suggests that the Civil Aviation Authority conducts a consultative meeting with local industry to discuss the practices and procedures used for IFR operations in Sydney airspace. This meeting should particularly address those operations departing Bankstown OCTA.

The Bureau issues the following, additional, Safety Advisory Notice:

SAN940095: The Bureau of Air Safety Investigation suggests that the Civil Aviation Authority review the staffing procedures at Flight Service Units to ensure that they are adequately manned during known periods of high workload.

The pilot was conducting a charter flight involving four legs. He was familiar with the routes being flown and carried fuel sufficient to complete all legs without refuelling.

It was the pilot's normal fuel management practice to fly the first leg on the left tank and change to the right tank prior to landing. He would then fly the next leg on the right tank and change to the left tank for landing. This procedure was normally used for each of the remaining legs.

During the second leg the pilot forgot to change to the left tank for landing. He did not recognise his error until taxiing for departure for the final leg to Kununurra. At that point the pilot was uncertain as to the exact contents of each tank although it was evident that the left tank contained significantly more fuel than the right. He decided to fly the final leg using the contents of the right tank with the intention of changing to the left tank for the landing. The pilot was not in the practice of changing fuel tanks during transit due to the inhospitable terrain in the Kimberley region.

The engine stopped, due to fuel starvation, as the aircraft entered the circuit for a low-level approach. The pilot selected the left hand tank, which contained almost two hours of fuel, but the engine did not restart before the pilot was forced to manoeuvre for an abnormal approach and landing. The aircraft was landed across the runway, and the impact was sufficiently hard to cause the mainwheel legs to splay, the nosewheel leg to collapse and the bottom of the fuselage and the propeller to contact the ground. The aircraft stopped within the runway flight strip and the occupants evacuated uninjured.

The aircraft fuel gauges were serviceable, and the aircraft was fitted with a fuel calibration card.

The investigation determined that the pilot did not use a fuel logging system other than a very general mental tally of fuel used. The sequence of events indicates that the pilot failed to complete his pre-landing checks on at least two occasions as he did not change the fuel selector to the fullest tank for landing as was his normal practice. Other evidence indicated that although the fuel gauges were serviceable the pilot ignored their indications because he considered them unreliable. The company provided a fuel dip stick which the pilot did not use even when he became unsure of the actual fuel contents because he thought he had sufficient knowledge of the fuel state. Finally, the pilot was not concerned that the engine might stop as a result of fuel starvation because his experience led him to believe that it would restart quickly once a tank, with fuel in it, was selected.

The pilot was very familiar with the route flown and it is probable that he had become complacent about fuel management.

The pilot had developed a habit of completing a low-level circuit as he believed it assisted his control of aircraft speed. It is possible that the pilot's decision to conduct a low-level circuit contributed to the accident. Had the aircraft been at normal circuit height there may have been sufficient time for the engine to respond to the alternate fuel tank selection.

The operator's check and training system did not disclose the pilot's apparent complacency or unusual circuit procedures as he had performed more than adequately on check rides.

VH-EAN was en route from Sydney to Perth, cruising at flight level (FL)350. N99SC was en route from Essendon to Sydney cruising at FL410 and requiring descent. Both aircraft were under the control of the Melbourne Air Traffic Control Centre, Sector 7. It was apparent that the two aircraft would be in lateral conflict near Yass. The controller cleared N99SC to descend to FL360.

Above FL290, for aircraft that are not laterally separated, the minimum vertical separation is 2000 feet. In this instance the controller had only provided 1000 feet. The two aircraft passed with about three and one half miles lateral separation and 1000 feet vertical separation. For aircraft not vertically separated, the minimum lateral separation in this instance was five miles.

The controller realised his error but too late to rectify the situation. Investigation revealed that prior to the incident the controller had been busy with aircraft inbound to Sydney, entering the holding pattern at Bindook. All levels assigned to other aircraft had been in the range of FL210 to FL260 where only 1000 feet vertical separation is required. He believed it was this that had led him to inadvertently apply the same standard to VH-EAN and N99SC

On commencement of the take-off, power was increased normally and at approximately 60 kts a loud mechanical noise was heard from the right engine with the right torque meter showing large deviations.

The take-off was rejected. Smoke was then observed in the cockpit and the cabin rapidly filled with dense smoke. The aircraft was stopped on the taxiway and emergency checklist actions and evacuations procedures were carried out.  All crew and passengers successfully evacuated the aircraft in a timely manner.

Examination of the engine found that the primary reason for the engine failure was the failure of the number three bearing which had allowed the low-pressure impeller to move forward relative to its housing, causing secondary damage and the subsequent engine failure.

The bearing which had been fitted to the engine since manufacture had been removed, checked and reinstalled during the engine turbine modification upgrade about 530 hours before the incident.  Subsequently during the post-incident inspection one of the bearing balls was found to be approximately 1 mm smaller than the remaining balls.  The presence of the smaller ball resulted in alternating tensile stress in the bearing cage, resulting in fatigue fracture propagation through the cage ligaments at the smallest ball.

The quantitative fractography of the cage fracture surface concluded that the fatigue crack appeared to have initiated near or shortly after the time of the engine turbine modification upgrade.

Significant factors

The following factors are considered relevant to the development of this incident.

1. One ball in the number three bearing cage was 1 mm smaller than the remaining balls.
2. The presence of the smaller ball resulted in alternating tensile stress in the bearing cage, causing fatigue fracture propagation through the cage ligaments at the smallest ball.
3. The failure of the number three bearing allowed the low-pressure impeller to move forward relative to its housing causing secondary damage.

The joy-flight was proceeding northwards over the beach of Surfers Paradise and had been cruising at 500 feet for just over a minute when the engine power reduced to idle. After conducting his trouble checks and finding no way to restore power the pilot selected an area for a landing on the beach. The aircraft came to rest in shallow water after manoeuvring to avoid people on the beach.

On inspecting the engine area, the pilot found that a ball joint in a push-pull rod to the carburettor throttle valve had failed, allowing the throttle to close. Further examination by the maintenance organisation revealed that a plate to which the rod was attached was shaped incorrectly. This caused the spring-loaded ball joint to wear abnormally until it fell off. The engine had been overhauled 200 hours earlier.

The pilot was conducting his first solo navigation exercise and had arrived overhead the destination aerodrome. He attempted to identify the wind direction and speed by observation of the windsock. The indications from the windsock were confusing and the pilot continued to observe it as he entered downwind and extended the leg. The resulting landing approach was long and flat, requiring significant power to reach runway 04. As he flared to land and reduced power the landing gear warning horn sounded. He applied power but the aircraft settled onto the runway with the landing gear retracted.

It was later found that the windsock was wrapped around its pole.

While cruising at 3000 ft, the engine suddenly lost power to the extent that level flight was no longer possible. The pilot conducted a forced landing on to a rough field, causing damage to the landing gear, fuselage, and propeller. Investigation revealed a failure in the rocker gear of the number four exhaust valve.

While enroute from Batchelor to Tindal, the pilot encountered deteriorating weather conditions and landed the aircraft in a suitable paddock, on Bonrook Station. The following day he inspected the landing area and judged the length to be 500 metres and that the area was suitable for take-off. However, the weather conditions were still unsuitable for departure.

The next day, after obtaining a weather forecast and being satisfied that the weather was suitable, the pilot decided to continue the flight. He and his passenger boarded the aircraft, and the pilot configured the aircraft for a short-field take-off. During the subsequent take-off the pilot rotated the aircraft at 55 kts. It became airborne and commenced to climb clear of the 10-metre-high trees at the end of the strip. However, the pilot became concerned about a tall tree directly ahead and commenced a left turn to avoid the tree. The stall warning sounded, one wing dropped, and the aircraft impacted the trees. The pilot suffered minor lacerations to his head, probably as a result of being struck by sections of the broken windscreen, and the passenger received minor bruising.

Checks of the fuel did not reveal any contamination, and the pilot believes that the engine was operating normally during the take-off.

An inspection of the take-off area revealed that the surface was firm and that the grass had recently been slashed.

The performance charts contained in the flight manual show that the strip distance available was adequate for a take-off from a dry grass runway. However, on this occasion, it is likely that the surface was wet and covered in recently slashed grass and that take-off performance was degraded. The pilot was not familiar with operation from such strips.

The student pilot, returning from a solo training session, carried out a normal circuit and approach for landing, but the aircraft bounced slightly on touchdown. The pilot applied some forward elevator control, but the aircraft veered about 90 degrees to the left and ran off the runway.

The pilot unsuccessfully attempted to control the swing with right rudder, then applied full power to go-around. She then observed another aircraft taxiing and turned the aircraft left to avoid that aircraft. The left wing struck the ground and the aircraft cartwheeled.