A pilot/aircraft engineer who later assessed the aircraft for recovery purposes reported that the grass was about 60 cm long. The pilot later advised that when he applied full power for take-off, the manifold pressure gauge was indicating 26 inches and tachometer was indicating 2,600 RPM.

FACTUAL INFORMATION

A Piper Chieftain registered as VH-HVA (HVA) had been flight planned to operate a flight from Maitland to Sydney at 6,000 ft. Another Chieftain registered VH-TXK from the same company was planned to conduct a flight from Gunnedah to Sydney at 7,000 ft. There was approximately 15 degrees between the inbound tracks of the two flights and their respective flight times and estimated time of departures indicated that they would arrive at Sydney at about the same time.

The two aircraft departed and were approaching Sydney when the pilot of HVA reported his position to the Departures North controller (DEPN). The pilot advised that the aircraft was 44 NM north of Sydney, and he was requesting an airways clearance. The secondary surveillance radar (SSR) transponder replies for HVA were not being received and that aircraft was not displayed on the DEPN radar display. DEPN misheard the transmission and assumed that the clearance request was from the pilot of TXK, which was displayed on the controller's radar display. The radar display indicated that this aircraft was 60 NM to the north-west of Sydney. This was a difference of 16 NM from the distance reported. DEPN issued a clearance for TXK to enter controlled airspace at 7,000 ft. The pilot of HVA believed this clearance was in response to his request and acknowledged the clearance but incorrectly read back the level as 6,000 ft. DEPN did not challenge the read back by the pilot of the incorrect level.

Approximately two minutes later, the pilot of TXK requested from DEPN a clearance to enter controlled airspace. DEPN re-issued the clearance at 7,000 ft. The pilot of that aircraft correctly read back the clearance.

The flow controller was concerned that HVA was not being displayed on the radar and requested the DEPN controller to attempt to contact that aircraft. DEPN transmitted to HVA and after receiving a reply from the pilot, requested the latter to change the aircraft's transponder code. This new code was observed on the display approximately 13 NM north of Sydney and 2.2 NM from the symbol for another aircraft at 6,000 ft. The required horizontal separation standard was 3 NM. There was a breakdown of separation.

The Sydney terminal radar consists of two radar systems; a primary radar with a range of 50 NM and an SSR which has a range of 250 NM. Consequently, aircraft with an inactive or unserviceable SSR transponder more than 50 NM from Sydney airport were not displayed. Pilots were required to check that an aircraft transponder was receiving and replying to an SSR. The pilot of HVA checked the transponder in flight and believed that the system was operating as he approached Sydney controlled airspace.

The callsigns of the two aircraft were distinctly different but some transmissions were truncated or clipped which made reception of the broadcasts difficult.

One of the methods available to a controller to identify an aircraft on radar was to correlate the observed and reported positions. When using this method a controller was required to ensure that the observed position was within the navigation tolerance of the reported position. The DEPN controller had other means available to him to identify an aircraft on radar. The investigation was unable to identify the radar identification method used by the controller.

ANALYSIS

The DEPN controller missed an opportunity to confirm the identification of the aircraft requesting a clearance when he did not correlate the observed radar position, of what he believed was TXK, with the actual position provided by the pilot of HVA. The difference between the positions was approximately 16 NM. This disparity in the positions could have alerted the controller to the possibility of a misidentification. However, the controller did not use this information to assist in the identification of the aircraft.

The pilot of HVA had an expectation of receiving a clearance from DEPN following his request. This expectation led him to believe that the clearance issued was for his aircraft, despite the clearance being prefixed with a different callsign and not at his planned level.

The pilot's subsequent read back of the incorrect level was not recognised by DEPN and the misidentification of the aircraft remained undetected.

The reason for DEPN not observing and querying the primary radar symbol from HVA was not ascertained. Similarly, the reason for the eventual operation of HVA's transponder was not ascertained.

SIGNIFICANT FACTORS

1. DEPN did not observe the primary radar symbol from HVA while the aircraft was within 50 NM of Sydney.

2. The SSR label for the HVA was not displayed on the controller's radar.

3. The controller did not correlate the pilot position report of HVA with the observed radar position on the display.

4. The pilot of HVA acknowledged and read back the clearance incorrectly.

5. DEPN did not challenge the incorrect level read back from the pilot of HVA.

The pilot reported a loud bang from the right engine, during the take-off roll. The take-off was rejected, and the engine was subsequently shut down.

After removing the engine from the aircraft, the operator sent it to the approved overhaul organisation in England for examination. The examination report concluded that the engine failure was caused by failure of the Stage 2 forward cooling plate. The failed plate then caused extensive damage to the hot section and power turbine components.

About three months after the incident, in April 1997, the United States Federal Aviation Administration (FAA) issued Airworthiness Directive (AD) 97-05-12 addressing the cooling plate failure. The AD calls for regular plate inspection at set intervals. The AD recommendation was adopted by the Australian Civil Aviation Safety Authority (CASA) who issued AD/CT7/7 effective from 17 July 1997.

The operator indicated that they have initiated a program requiring all engines to be inspected in accordance with AD/CT7/7.

FACTUAL INFORMATION

On departure from Bathurst Island for Darwin the pilot of the Cessna 402 (C402) transmitted a broadcast on the local common traffic advisory frequency (CTAF). He then contacted Darwin Approach and requested and was given an airways clearance to track direct to Darwin at 3,000 ft.

Shortly after levelling off at the assigned cruising altitude the C402 was passed by opposite-direction traffic identified as a Cessna 310 (C310). The pilot of the C402 estimated that there was approximately 200 ft lateral and no vertical separation between the aircraft.

At the time of passing, the aircraft were approximately 1.5 NM from the control zone boundary and still within the Bathurst Island CTAF area. Shortly after the aircraft passed, the pilot of the C402 was informed by Air Traffic Control (ATC) of opposite-direction traffic. The information provided by ATC indicated that the C310 was at 4,000 ft and had left controlled airspace and that the aircraft's transponder had been switched off. The pilot of the C402 had not heard any radio broadcasts from the pilot of the C310.

In discussions with the pilot of the C402, the Bureau learned that there had been several similar unreported occurrences at Bathurst Island. The pilot's comments were consistent with information derived from the Bureau's database relating to the operation of aircraft including high-capacity air transport aircraft in the MTAF and CTAF environments throughout Australia.

The Bathurst Island CTAF is unique in that the southern boundary adjoins and lies beneath the Darwin Control Zone. Traffic departing from Darwin have little time in which to change frequencies and make the required calls when notified by ATC of leaving controlled airspace. This difficulty in notification adds to the problem of traffic separation as these aircraft are not notified to traffic that may be inbound to Darwin. Although there may be vertical separation between the aircraft, this is not always the case, as was evidenced in this occurrence.

SAFETY ACTION

The investigation of this occurrence identified two aspects of the operation of aircraft outside controlled airspace, which are currently the subject of safety deficiency analysis by the Bureau. The lack of guidance material for air traffic services personnel to provide timely traffic information had been raised during previous investigations. Similarly, the use of inappropriate self-separation procedures by pilots operating in Class G airspace, such as CTAFs, had also been identified as a deficiency.

The results of this investigation will be used in a broader analysis of these safety deficiencies.

Darwin ATC now request that aircraft departing the Control Zone leave their transponders on so that they may provide a better radar return in an area that has a poor radar coverage, and adequate traffic information can then be passed to other traffic.

As a local safety action, the operator involved implemented visual tracking procedures for use when operating within the Bathurst Island CTAF. These visual tracking procedures should ensure that this operator's aircraft, arriving and departing from the island have sufficient lateral separation.

FACTUAL INFORMATION

An instrument flight rules (IFR) Piper Chieftain (PA-31-350) departed Wynyard for Moorabbin on climb to 8,000 ft. Five minutes later an IFR Beechcraft Baron (D55) departed Smithton for Bankstown, tracking via East Sale, on climb to 9,000 ft. The intended tracks of the aircraft crossed at a position approximately 50 NM north of Wynyard. The PA-31-350 was operating a regular transport flight while the D55 was on a charter flight. The visibility was in excess of 20 km and there was no cloud below 10,000 ft.

Both aircraft were operating in uncontrolled, class G, airspace. The crews of IFR aircraft operating in class G airspace are required to be provided with information on other IFR traffic by the responsible air traffic services (ATS) operator. The area in which the flights were operating was the responsibility of the Melbourne Sector 3 Low controller.

The Sector 3 Low controller had been rated in the position for approximately five months. Traffic levels were high and there was a considerable number of radio transmissions that required her attention. The controller advised traffic information, with the exception of the PA-31-350, to the pilot in command (PIC) of the D55 when that aircraft was taxiing at Smithton. She had previously advised traffic information on four other IFR aircraft to the PIC of the PA-31-350. Flight details of all aircraft were available to the controller on flight progress strips.

The controller endeavoured to plot the tracks of the two aircraft on a chart to assess whether they would conflict. However, she was distracted by radio transmissions and by the need to conduct co-ordination with other ATS positions and was unable to complete the plot.

There was provision for a planner controller, adjacent to the Sector 3 Low controller's position, but it was not occupied. The normal practice was to staff the Sector 3 Low position with a single operator. The team leader was available to assist the controller, but the controller was satisfied with the situation and did not think assistance was required.

The PIC of the PA-31-350 had maintained his aircraft at 5,000 ft to avoid two other aircraft inbound to Wynyard on the route. As he recommenced climb to his planned level of 8,000 ft he sighted an aircraft to his left. This aircraft appeared to be on climb and was at a distance of approximately 2 NM. The PIC of the PA-31-350 was aware that the converging aircraft was the D55, as he had previously heard the PIC of that aircraft arranging separation with the crews of other aircraft. The PIC of the PA-31-350 established communications with the PIC of the D55 who advised that he had the PA-31-350 in sight and would restrict his climb to pass below that aircraft. The two aircraft passed with approximately 300 ft vertical separation.

ANALYSIS

The controller was not sure whether the tracks and levels of the two aircraft would cause them to conflict and had endeavoured to plot the tracks to clarify the situation. A more experienced controller, faced with the same concern in a high workload period, may have passed traffic information to the two crews in lieu of increasing the complexity of the task by plotting the tracks. This action would have required little effort in comparison to drawing and assessing a plot of the intended tracks. In addition, the immediate provision of traffic information would have been more expeditious and would have ensured that the pilots received the information in sufficient time to co-ordinate their mutual separation.

The operation of the position by a single controller was adequate for the majority of traffic situations. However, the supervisor should have recognised the increasing complexity of the situation and offered the inexperienced controller some assistance during the high workload period when she was probably becoming task saturated. The limited experience level of the controller probably prevented her from recognising her own level of task saturation.

The situational awareness and visual scan of the pilot in command of the PA-31-350 assisted him in sighting and co-ordinating separation with the other aircraft.

SIGNIFICANT FACTORS

1. The Sector 3 Low controller's limited level of experience.

2. The complexity of the traffic situation due to the high number of radio transmissions.

3. Inadequate monitoring of the controller's workload by the supervisor.

When the landing gear was selected down on arrival at Karratha, the green down and locked light did not illuminate. The light tested serviceable on the press to test function. The landing gear motor kept running until the landing gear circuit breaker tripped. The pilot ascertained that the main landing gear was down and locked but not the nose landing gear.

The pilot then climbed the aircraft to 1,500 ft and held north of the aerodrome. He checked the hydraulic fluid level, which was satisfactory, and then cycled the landing gear approximately 15 times but still with the same result. He then made a touch and go landing in an attempt to jar the nose gear down, but this also was unsuccessful. The pilot also attempted to pump the nose gear down by the emergency lowering system, again with no success.

After briefing his passengers, the pilot landed the aircraft with the nose gear retracted. Subsequent investigation revealed a fault with one of the nose gear doors which resulted in the door jamming the nose gear in the up position.

The pilot reported that on entering the aircraft during the preflight inspection he noticed a strong chemical odour. Discussion with the duty tarmac engineer confirmed the aircraft had been sprayed for pest control the previous night. During the flight to Emerald the pilot began feeling ill. During the turnaround at Emerald, he contacted company operations and said that he was feeling ill but was of the opinion that he was well enough to return to Brisbane. During the later stage of the flight from Blackwater to Brisbane, the copilot also started to feel ill and described the same symptoms that were affecting the pilot. Both pilots then used the crew oxygen system and began to feel better after about 10 minutes. On arrival Brisbane both pilots were unable to continue duty. Both pilots visited their medical examiners who were of the opinion that the pilots had been exposed to a poisonous substance.

Investigation revealed that the chemicals used to treat the aircraft were "Permakill" and "Permethrin". There are two separate treatments. One treatment is for disinsection, and the other treatment is a surface treatment for cockroaches. The treatments are not normally carried out simultaneously, however, on this occasion they were. There were no instructions that required the treatments to be conducted separately. The chemical constituents of both agents are Dichlorvos and Chlorpyrifos. Both these chemicals are potentially dangerous, and the company has been advised to discontinue the use of such treatments. The recommended procedure for aircraft disinsection is spraying with synthetic pyrethroids which are quite safe for human exposure. The company has opted for this procedure to prevent a recurrence.

Amberley airspace was de-activated during the previous night and was to become active for military operations at 0800 local time. At 0747 a controller at Amberley co-ordinated the activation with the Brisbane Approach Planner. The planner informed the radar operators and set the planner console to show pending status. The co-ordination was conducted by Amberley with the Sector 4 controller shortly afterwards. Between 0755 and 0815 the person filling the planner position changed on two occasions. The Brisbane Terminal Airspace Co-ordinator (TAC) had been expecting the Amberley airspace activation but had been in a conference during this time.

At 0815, the current planner received co-ordination on the departure of VH-NJW. The planner conducted the appropriate co-ordination with the Sector 4 controller. None of the radar maps were showing the Amberley airspace as active at this time. NJW subsequently departed and was transferred to the Sector 4 frequency. The Sector 4 controller had not queried the transfer as Amberley radar had been unserviceable, and the controller assumed that the alternative had been to direct the aircraft to Sector 4. Amberley Approach later enquired as to whether the Sector 4 controller had a radar return in the area about 50 NM west of Brisbane. The approach controller was informed that the aircraft was VH-NJW. There was no breakdown in aircraft separation.

An investigation by Airservices Australia found that the TAC position was not occupied at the time of the airspace activation. In addition, the quick changes of staff in the planner position resulted in the loss of the information to the later staff. The activation times were routinely co-ordinated between Amberley Approach and the Brisbane planner position. This was considered the most appropriate method. The investigation found that the planner had not ensured that the radar maps were set correctly at 0800.

Procedures were changed to log the Amberley airspace activation and de-activation times in the Airways Operations Journal. Annotations confirming that the radar consoles had been set correctly were also to be entered.

During a normal circuit at the destination aerodrome, the pilot selected the landing gear down. Following the selection, there was no indication that the gear was extending. The pilot recycled the gear selection several times but the gear position indications remained unchanged.

The pilot then operated the emergency gear extension system. The main landing gears indicated down but the nose gear light was out and the gear unsafe light was on. He repeated operation of the emergency extension system a number of times with the same result. A flyby inspection near people at the airfield confirmed that the nose gear was trailing aft of the locked-down position. The pilot alerted the local emergency services before making a landing approach.

During the landing roll, the pilot shut both engines down and lowered the nose of the aircraft. The nose gear did not support the nose of the aircraft which then scraped along the runway until the aircraft came to a stop. All three occupants left the aircraft safely. A maintenance investigation carried out by the company found a defect in the normal landing gear system. A defective O-ring at the right hydraulic oil filter had been displaced by hydraulic pressure allowing oil to escape.

The emergency gear extension system was used to extend the nose gear after the aircraft was lifted off the runway. The system operated normally and no fault could be found. It is possible that in-flight air loads prevented the pilot from extending the nose gear fully.

The student pilot had been briefed and authorised to conduct solo circuit training. The runway in use was 36 and the wind was from 020 degrees at 10 to 15 kts. During the landing roll the aircraft encountered a gust of wind from the east. This caused the right wing to lift abruptly. Although the pilot applied full right aileron control, he was unable to arrest the aircraft's roll to the left. The aircraft then departed the runway before coming to rest inverted, on the western side of the runway.

The pilot exited the aircraft safely. The aircraft was not fitted with an emergency locator transmitter.