When the aircraft arrived in Brisbane, ground engineers noticed that the left number 11 leading edge flap was missing, and that there was slight damage to the number two engine core cowl. No evidence was found to indicate the primary failure point. A new flap was fitted, and the aircraft was dispatched the next day.

The aircraft was engaged in aerial seeding and was being operated from a grass strip. The pilot reported the take-off direction was towards the north-west, to take advantage of a 12-15 kt wind blowing from slightly left of the take-off direction. The aircraft became airborne with about 100 m of the strip remaining but failed to accelerate and climb out of ground effect. Turbulence was encountered about 100 m beyond the end of the strip, which yawed the aircraft to the right, through about 60 degrees.

The pilot selected the hopper dump lever to the fully open position, in order to jettison the load, and attempted to manoeuvre the aircraft to avoid a line of trees. When it became apparent, he would not be able to fly over the trees, he tracked towards the clearest area within the tree line. At a height of about ten feet the wings collided with small trees. The aircraft continued for a short distance before striking the ground and sliding to a halt. The pilot escaped without injury. He was subsequently told, by a person who had been located nearby, there had been a major wind gust/shift in the area at the time of the accident.

After carrying out a damage inspection of the aircraft, the pilot reported that about 90% of the load had remained in the hopper during the accident sequence. Whilst he described the load of seed and superphosphate as dry and free flowing, he considered that the design of the hopper base was not satisfactory, as the gate-like opening inhibited the free flow of solids. Had he been able to jettison a greater portion of the hopper load in the time available, he believed the resulting improved climb performance of the aircraft would have allowed him to avoid the trees.

The hopper base was described as a gate box type, principally designed for use with liquids. The pilot indicated that operators may use this style of hopper base for both liquid and solid applications during those times when the aircraft may be required to frequently change from one medium to the other.

The Sector 15W controller became busy with a number of aircraft and subsequent co-ordination and did not pass the radar identification of a northbound B737, on climb to flight level (FL) 330, as the aircraft approached

Williamtown airspace. The Sector 15W controller was also briefing another controller with the intention of opening the planner position. The APPR controller contacted the Sector 15W controller and requested departure instructions for an aircraft at Williamtown about to depart via Sector 15W airspace. While the two controllers were discussing the availability of departure instructions for this aircraft, the APPR controller observed an unidentified aircraft overhead Williamtown and requested details from the Sector 15W controller. The Sector 15W controller advised that the aircraft was a B737 at flight level (FL) 330 tracking direct to a position near Coolangatta.

The APPR controller considered there had been a breakdown in procedures but did not discuss the perceived breakdown with the Sector 15W controller. The Sector 15W controller believed he was operating in accordance with the co-ordinated arrangements and continued at the position until the completion of the shift. There was no breakdown in separation.

ANALYSIS

The APPR controller could have used a number of specific terms to grant approval for the transit of Sector 15W's aircraft through military airspace. Any of these terms would have explicitly indicated the status of the approval. The Sector 15W controller could have been more vigilant when he accepted the offer of the use of the airspace. Possibly, in his haste to utilise the airspace he did not appreciate the ambiguity of the phraseology.

The use of imprecise and ambiguous co-ordination phraseology enabled a situation to develop which could have had more serious consequences.

SIGNIFICANT FACTORS

1. Neither controller considered the ambiguous aspects of the non-standard co-ordination phraseology.
2. The Sector 15W controller did not pass the radar identification of the B737 to the APPR controller in a timely manner.

The SAAB 340B aircraft was conducting a regular public transport flight from Wagga to Sydney via the Bindook VOR navigation aid. The crew had been told by ATC to expect an OAKDALE 2 arrival into Sydney. Approaching Bindook the SAAB was instructed by ATC to enter the holding pattern at FL170.

The captain removed his headset to advise the passengers on the public address (PA) system of the delay, whilst the first officer handled the aircraft. Shortly after, as the captain was addressing the passengers, ATC cancelled the holding and instructed the SAAB to turn onto a heading of 180 degrees, on descent to FL160. The first officer acknowledged the cancellation of the holding, and the descent clearance, but did not readback the assigned heading.

When the captain had completed the PA announcement the first officer advised him that they had been cleared to leave the holding pattern and track direct to the Bindook VOR for an OAKDALE 2 arrival. The captain was unaware that the aircraft had been assigned a heading.

ATC noticed the SAAB turning left through its assigned heading and queried the crew, reiterating the required heading of 180. As the SAAB turned right to 180 degrees, the separation between the SAAB and a British Aerospace 146 (BAe 146) was reduced to 3.5 NM laterally and 500 ft vertically. The SAAB passed behind the BAe 146 as ATC issued instructions to the aircraft to increase their vertical separation. The minimum required separation standard was 5 NM horizontal, or 1,000 ft vertical.

The expectation of an OAKDALE 2 arrival may have caused the SAAB's first officer to anticipate a standard intercept from the Bindook aid. This error could have been averted if ATC had queried the lack of the assigned heading readback by the first officer, and if the captain's attention had not been diverted by making a PA announcement. The captain reported that PA announcements are usually made at the commencement of holding, to minimise any conflict with normal ATC communications. However, he had not anticipated that the holding would be cancelled so quickly, and consequently had not heard the ATC instructions.

1. Reversal of the flight levels of the two eastbound aircraft.  That is, giving the actual flight level of the first aircraft as that of the second aircraft.  If this was the case, the aircraft in the B747 crew's 1 o'clock would have been at FL 250 as reported by them.
2. Reversal of the clock code position.  Where the 1 o'clock position was transposed with the 11 o'clock position. This may have been related to the mental inversion of the radar screen image required to be performed by the controller to give relevant information to the crew of the B747.  The view of the radar screen is north facing, whereas the B747 was heading south and separation had already been achieved between it and the aircraft below. The controller had ensured separation with the aircraft above by requiring the B747 to level out at FL 280.  Giving traffic on this aircraft was a safety measure to assist the B747 crew's situational awareness.

There also appeared to be a misunderstanding of the request from the B747 crew as to clearance to the next waypoint. The controller cleared the B747 to TAPOP when the request was direct to TAXON. This misunderstanding was not considered relevant to this occurrence.

The TCAS display reported by the captain of the B747 was due to the type of TCAS on the aircraft. TCAS II with a 604 software update will display a proximity target if the target is currently within 6 NM and 1,200 ft of the TCAS aircraft.  There was no traffic advisory given by TCAS, but the aircraft was displayed on the screen due to this sensitivity.

SIGNIFICANT FACTOR

Incorrect traffic information was passed to the crew of the B747.

The Inner North sector controller became distracted with a number of tasks at the position and with other aircraft in the sector and forgot to pass the radar identification of the B737 to the next control position; Departures South. The transfer of aircraft radar identification between the two positions is normally conducted between 35 NM and 40 NM from the aerodrome. This ensures that the next controller is aware of the position of inbound aircraft and can plan the separation with traffic in his sector prior to the aircraft entering the area.

At the time, the Flow controller had not annotated the flight progress strip (FPS) for the inbound B737 with a landing time. The FPS was located adjacent to the Departures South position to enable controllers to appreciate the sequence of arriving aircraft. The Flow controller handed over responsibility to another controller. The new Flow controller observed the inbound B737 on the radar display but did not annotate the FPS with a landing time.

The inbound B737 was maintaining 8,000 ft and was 20 NM from the aerodrome. The Inner North controller noticed that he had not transferred the inbound B737 and instructed the crew to call Departures South. The Inner North controller then electronically transferred the identification of the aircraft to the Departures South position. This was contrary to air traffic control procedures. The controller transferring responsibility for an aircraft must receive notification of acceptance of the aircraft, either by voice or electronically, from the controller receiving the aircraft prior to instructing the aircraft to call. The Inner North controller did not advise the Departures South controller of the late transfer of the radar identification and transfer of the inbound B737.

The Departures South controller was busy with other aircraft in the sector and monitoring the departure of a B737 on a Cowes standard instrument departure (SID) from runway 27. This aircraft had been initially assigned climb to 5,000 ft. The Departures South controller did not observe the inbound B737 within his area of responsibility and approved the outbound B737 to climb to flight level (FL) 200. When the crew of the inbound B737 contacted Departures South, the controller recognised the potential conflict and instructed the outbound B737 to maintain 7,000 ft. The crew of the outbound B737 were unable to arrest the rate of ascent until the aircraft had reached 7,600 ft. The Departures South controller issued traffic information to the crew of the inbound B737 about the other aircraft. The crew were able to observe the outbound B737 and maintain visual separation until radar separation was regained.

The two aircraft passed with vertical separation of 400 ft and horizontal separation of 2 NM. The separation required was 1,000 ft vertically or 3 NM horizontally. There was a breakdown in separation.

ANALYSIS

The Inner North controller became distracted with other aircraft in his sector and did not transfer the identification of the inbound B737 to the Departures South controller as required by local instructions. Consequently, the Departures South controller was not aware of the inbound B737 as the aircraft entered his sector.

The lack of a landing time on the flight progress strip was a missing cue that may have alerted the Departures South controller to the inbound B737. The reason for the landing time not being annotated on the flight progress strip could not be ascertained.

The Departures South controller did not observe the inbound B737 enter his airspace prior to instructing the outbound B737 to climb to FL200. Had he maintained a more regular scan of the display it is possible that he would have observed the inbound B737 entering his sector.

When the Inner North controller became aware that the inbound B737 had entered the Departures South sector without a transfer of the aircraft's identification, he should have contacted the controller on the intercom. This would have alerted the Departures South controller to the presence of the inbound B737 and may have enabled separation to be maintained between the two B737s

SIGNIFICANT FACTORS

1. The Inner North controller did not pass the radar identification to the Departures South controller prior to the inbound B737 entering the latter's airspace.
2. There was no landing time annotated on the flight progress strip for the inbound B737 for the Departures South controller.
3. The Departures South controller did not observe the inbound B737 entering his sector.
4. The Inner North controller transferred the inbound B737 to the Departures South controller prior to conducting radar co-ordination.

VH-ANP, inbound from the north was being processed for a runway 26 ILS approach to Essendon. VH-EAJ, also inbound from the north, was being processed for a runway 27 ILS approach to Melbourne. While tracking in an easterly direction, on a right downwind leg for the ILS approach, the pilot of ANP reported he had Essendon in sight. He then requested priority as a Med 1 flight for clearance direct to Essendon.

To facilitate separation with, and priority for, ANP, EAJ was instructed to climb to and maintain 4,000 ft. Shortly afterwards, when in the Epping area, and maintaining 4,000 ft, EAJ was instructed to turn right heading 310 deg for a vectored right orbit. At this time, ANP was to the east of EAJ, on a southerly heading, on descent to 2,500 ft, on a wide right base for runway 26 and with the mode C level indicating 3200 ft. There was a strong westerly wind blowing above 2,000 ft and this resulted EAJ making good a track of approximately 335 deg from a heading of 310 deg.

The two aircraft passed with less than three miles horizontal separation when vertical separation was 800 ft. The pilot of ANP had EAJ in sight.

After departure, the pilot reported that the landing gear did not retract normally and requested a low-level flypast for a visual inspection. Inspection from the ground revealed that the right main wheel was turned through 90 degrees. Emergency services were requested and when they were in position the pilot elected to land on the grass strip with the landing gear retracted. The aircraft sustained substantial damage during the subsequent landing but neither of the occupants were injured.

A subsequent inspection of the aircraft revealed that the right main landing gear torque link bolt had failed, and the torque links had separated. This allowed the main wheel assembly to rotate away from its normal position. The aircraft's maintenance records indicated that maintenance had recently been carried out on the right landing gear. The accident flight was the second flight following completion of that maintenance.

He initiated a practice forced landing and conducted the required checks. At about 2,800 ft he attempted to warm the engine but obtained no response. The throttle was retried, still without response. The emergency checks were carried out again and a Mayday call was transmitted. The pilot attempted to restart the engine using the starter.

With no engine response, the pilot continued with the forced landing. Two fields were selected, with the secondary field being beyond an earth bank at the far end of the desired field, as the pilot had been experiencing a tendency to overshoot during the earlier flights. Since no response was obtained from the engine, the engine shut down checks were completed prior to landing.

Witnesses reported that the engine note had not varied during the approach to land. There was no surging or back firing. The aircraft touched down at the end of the primary paddock and rolled some 18 m before colliding with the earth bank which was about 1.8 m high. The fire wall and rudder pedal areas were distorted by the impact.

Subsequent investigation involved analysis of a fuel sample from the aircraft and examination of a section of exhaust pipe from the engine. The fuel was within specifications, and the exhaust pipe temperature was below the detectable limit. Since an idling engine could also have exhibited temperatures below that limit, no conclusion concerning engine operation could be reached. An examination of the engine and its systems did not find any abnormalities which could have caused the problem. The Bureau of Meteorology reported that the air was very dry and there was no possibility of carburettor icing. No reason for the engine's failure to respond has been established.

The aircraft was not equipped with an emergency locator transmitter.

SIGNIFICANT FACTORS

1. The engine failed for reasons not determined.
2. The pilot had low total flying experience.
3. The pilot misjudged the approach to land.