Circumstances:

VH-HYF departed Adelaide Airport on an 'Adelaide East 2 Mildura' Standard Instrument Departure (SID), with an unrestricted climb to its cruising level of Flight Level (FL) 370, then via the 'Tango 77' route to Brisbane. Because a Boeing 747 from Melbourne would be overflying Mildura at FL 310, Melbourne had co-ordinated with Adelaide a requirement for VH-HYF to reach FL 330 by 37 km south-west of Mildura. VH-EAK was flying from Sydney to Adelaide via Mildura, cruising at FL 310. It was on the reciprocal heading to VH-HYF and appeared on the Adelaide Control radar display at 235 km from Adelaide. When VH-HYF was transferred to Adelaide Control, the controller requested that the aircraft maintain its best rate of climb to FL 330. His objective was to climb VH-HYF above VH-EAK, using radar to maintain separation instead of procedural control. This would allow VH-EAK to follow its preferred descent profile to Adelaide, and for VH-HYF not to be held at a lower level until procedurally separated with the overflying Boeing 747. Approaching FL 310, VH-HYF experienced an increase in ground speed due to a strong westerly windshear increasing the closing speed between the aircraft. While maintaining maximum rate of climb, the air speed of VH-HYF fell below the minimum manoeuvring speed. With the airspeed trend indicator fluctuating due to turbulence, the Captain reduced the climb angle to accelerate the aircraft without advising the controller of the reduction in climb performance. VH-HYF passed VH-EAK 200 km north-east of Adelaide, with 800 ft vertical and 0.4 nm horizontal separation with less than the required standard of 2000 ft vertical or 7 nm horizontal separation. VH-HYF had regained its normal rate of climb as the aircraft passed. The controller had been operating two sectors on combine, with a subsequent increase in co-ordination workload. He had monitored VH-HYF during its climb to FL 310, at which time it was 76 km to the west of VH-EAK. At its initial climb rate he expected VH-HYF should have passed FL 340 by the estimated time of passing. The controller continued his scan of the radar display. When his gaze returned to these aircraft, the noticed that the radar returns were merged, which would be normal as they passed. When the radar returns separated, the controller noted that the altitude indication for VH-HYF was showing the aircraft to be at FL 330. He therefore had no reason to believe that a breakdown in separation had occurred. A discussion had also been in progress during this period with other controllers regarding industrial matters. This situation was causing the controller considerable amount of anxiety and may have been a factor in this occurrence.

Significant Factors:

The following factors were considered relevant to the development of the incident

1. The controller applied inadequate separation standards so as not to cause inconvenience to the aircraft.

2. The controller expected that VH-HYF would maintain the same rate of climb to FL 330.

3. The controller was operating two positions on combine.

4. VH-HYF experienced windshear increasing the tailwind component and closing speed with VH-EAK.

5. In turbulent conditions the air speed of VH-HYF fell below its minimum manoeuvring speed. The Captain accelerated the aircraft, reducing its rate of climb without advising the Controller.

6. The controller's attention may have been affected by anxiety concerning industrial matters. This incident was not the subject of an on-scene investigation.

Circumstances:

1.1 VH-TAH

Significant Factors:

1. Incorrect flight data preparation.

2. Probable distraction from primary control function.

3. Information transfer failure relative to airway tracking data.

4. Inappropriate airway route reporting waypoints for transfer of jurisdiction purposes.

Recommendations:

The Civil Aviation Authority should give consideration to

1. reviewing all airway route structures to identify similar airways which do not have a published waypoint at airspace boundaries;

2. allocating waypoint names to all such airways; and

3. in the interim providing airway identification and a readback of that airway during co-ordination exchanges.

Circumstances:

Three aircraft, VH-TBN, VH-HYB and VH-ANF were tracking towards Eildon Weir (ELW) en route to Melbourne from the north-east. VH-TBN was a few miles ahead of the other two aircraft. VH-HYB was cruising at Flight Level 240 (FL 240). The other two aircraft were at higher levels, but VH-TBN was on descent to FL 160. VH-ANF and VH-HYB were required to enter the holding pattern at ELW to facilitate sequencing to Melbourne. VH-TBN was cleared to continue but instructed to reduce speed to 230 kts on descent. VH-TBN was paralleling track about 6 NM to the left to stay clear of the ELW holding pattern traffic. VH-ANF was scheduled to leave ELW before VH HYB and in preparation for this, the sector controller decided to descend VH-ANF below VH-HYB. Because there was only about 2 NM between these two aircraft on track, the sector controller instructed VH-HYB to turn 30` left onto 200`, which was towards the position of VH-TBN. The sector controller passed advice on the track and airspeed details for VH-TBN to the arrivals controller and then transferred control of VH-TBN to that controller. VH-ANF was initially cleared to commence descent to FL 250. Details on the track of VH-HYB and the reason for turning VH-HYB left were also passed to the arrivals controller. Control of VH-HYB was also handed off to the arrivals controller at that time. The crew of VH-HYB were then told to call arrivals control. In response, they acknowledged the instruction and asked the controller to advise the height of the aircraft in front of them. Realising that a loss of separation had developed between VH-HYB and VH-TBN, which had been placed under a speed restriction, the sector controller instructed VH-HYB to turn left onto 030`. He also told the crew that the other aircraft was about 200 ft below. The arrivals control position was being operated by a trainee under the supervision of an instructor. The relative positions of VH-HYB and VH-TBN were checked by the instructor when control of VH-HYB was transferred to them. At the time they were transferred, they were separated by about 5.7 NM. At that time, the minimum allowable separation was 5 NM horizontally or 1,000 ft vertically. The instructor and trainee then became involved in other aspects of the training management task. It was then noticed that the radar returns from VH-TBN and VH-HYB were in close proximity. VH-TBN, which was on descent to FL 160, was instructed to expedite descent. VH-HYB was instructed to make a turn, but the aircraft was still on sector frequency. Separation reduced to a minimum of about 200 ft vertically and one NM horizontally. In giving VH-HYB the initial instruction to turn left onto 200` the sector controller had inadvertently overlooked the potential conflict situation with VH TBN ahead but at a significantly reducing speed. The recorded radar data showed that as the incident developed, the closing speed between the two aircraft increased to about 180 kts. The radar screen labels for each aircraft included a read out of groundspeed. The arrival controllers did not detect the large closing speed. The traffic workload at the time was moderate. The sector controller had a low level of label brightness selected. The high rate of closure between the two aircraft was partly due to the fact that VH-TBN was operating at a reduced airspeed and partly because of the direction of the strong wind, which gave VH-HYB a reduced headwind component while being vectored left of track.

Significant Factors:

The following factors were considered relevant to the development of the incident

1. Significant oversight by the sector controller in vectoring VH-HYB towards VH-TBN, which was ahead and restricted to a slower speed.

2. Strong upper wind situation which increased the ground speed of VH-HYB when it was given a turn onto a heading of 200`.

3. The attention of the two arrivals controllers was diverted at a critical stage and they did not detect the situation of a high closing speed between the two aircraft. This incident is one of eight similar airmiss incidents which are being considered as a part of a special investigation aimed at identifying any ATS systemic deficiencies which may be contributing to airmisses. Any recommendations arising from this and the other reports will be addressed as part of the special investigation.

Shortly after 1000 hours, VH-ANE taxiied for departure from runway 03. Prior to the aircraft being given a takeoff clearance another aircraft departed from the same runway. As a result it was necessary to turn that aircraft, to provide the required separation, prior to VH-ANE being cleared for takeoff. When the tower controller had established separation, VH-ANE was given a clearance to commence an immediate takeoff. By this time VH-RME was established on final approach for runway 03. The pilot of VH-RME then became concerned that the runway might not be available for him to carry out a landing and he commenced a go-around. The tower controller was advised immediately and he instructed VH-ANE to abandon the takeoff. VH-RME subsequently completed a circuit and landed, and VH-ANE then departed for Melbourne. The investigation revealed that at the time VH-RME commenced to go around the aircraft was about 400 feet above ground level. The tower controller responsible for the separation of landing and departing aircraft was of the opinion that the required runway separation would have been achieved had VH-RME continued with the landing.

Circumstances:

Brisbane Sector 4 is the military (RAAF) sector in the Brisbane Area Approach Control Centre. It is normally manned by two RAAF controllers who rotate between the radar and procedural positions. At the time of the occurrence, however, the sector was manned by one RAAF controller. At 0039 hours UTC, VH-CZD reported to Brisbane Sector 5 its position Longreach, Flight Level (FL) 370, estimating Taroom (165 miles from Brisbane) at 0120 hours. This position was coordinated to the Sector 4 controller as Restricted Area R614, which includes the airspace above and to the east of Taroom, was active and under the control of Sector 4. The Sector 4 controller read back the level correctly but annotated FL 270 on the flight progress strip for VH-CZD. At 0109 hours, VH-TJA departed Brisbane tracking via Taroom on climb to FL 350. At 0120 hours, VH-CZD reported to Sector 4 its position Taroom, FL 370, estimating Brisbane at 0049 hours. The Sector 4 controller did not detect that the flight progress strip had been incorrectly annotated. At 0121 hours, and at about 60 m from Brisbane, VH-TJA transferred to Sector 4 frequency and reported maintaining FL 350 estimating Taroom at 0140 hours. On the controller's request, VH-TJA confirmed cruising at FL 350. At 0127 hours, VH-CZD requested descent and was cleared to descend to FL 210. At 0129 hours, VH-CZD reported left FL 370. The crew of VH-CZD recalled seeing VH-TJA pass below and with a lateral separation of a few hundred metres as descent was initiated. The Sector 4 controller reported that the radar returns of the aircraft merged shortly after VH-CZD reported commencing descent. Investigation of the occurrence revealed that the controller's workload during the period leading up to the occurrence was low, with only two aircraft on frequency. The controller also had engaged in extensive non operational communications during this period. It was further established that the controller was facing a number of significant personal issues which could have had a distracting influence and had experienced disturbed sleep on the night before the occurrence. Low workload is a common predisposing factor in many air traffic control occurrences involving individual controllers. Low workload tends to lead to under-arousal or complacency, causing work performance to suffer. Low workload can also provide the opportunity for personal concerns to intrude and divert attention from the primary task. A fatigued person can generally cope with a short burst of mental effort but can have difficulty in conducting protracted monitoring tasks. The controller's failure to detect the discrepancy between the actual flight level of VH-CZD and that annotated on the flight strip was probably due to the controller having a false mental picture of the traffic situation. Fatigue and personal concerns could have reduced the controller's ability to detect information which contradicted the mental picture. The notion that VH-CZD was at FL 270 had begun as a minor slip, but had grown into a strong idea that was resistant to challenge. Even when VH-CZD reported Taroom at FL 370, the controller heard what was expected rather than the actual words spoken.

Significant Factors:

The following factors were considered relevant to the development of the occurrence

1. Personal concerns, non-operational communications and fatigue probably distracted the controller from the primary task.

2. The controller annotated the incorrect altitude on the flight strip for VH-CZD.

3. The controller failed to detect the flight strip error when VH-CZD reported Taroom.

4. VH-CZD was given descent clearance without adequate separation from the conflicting traffic VH-TJA.

While being towed to the planned launch height, the glider under tow and another glider in the circuit area, collided. The collision caused the tow rope to break and the pilot of the glider, although injured, was able to land his aircraft. The tailplane of the other glider separated in the collision and the aircraft descended uncontrolled into the ground. The tug aircraft was undamaged and landed safely. The glider rejoining the circuit approached the tug and glider under tow from the right rear quarter. Immediately prior to the collision, witnesses reported that the glider attempted avoiding action. The reason the pilot did not see the two other aircraft until it was too late to successfully take avoiding action, could not be determined. However, the combination of a broken cloud cover and a mottled background would have made the pilot's task more difficult.

Circumstances:

VH-CAG had taken off from runway 27, turned left, and was climbing through about 1700 ft on the downwind leg when it collided with glider VH-GXO, which was turning right in thermalling flight. The Bonanza lost its right 'Vee' tail on impact and entered an inverted spin, which continued until ground impact. The glider, although sustaining substantial damage to the right wing and lower fuselage, was able to be flown to a safe landing. Tocumwal Aerodrome is provided with sealed runways in the 18/36 and 09/27 directions. Powered aircraft normally use the sealed runways. Gliding operations are conducted during daylight hours from grass strip 18/36 situated west of runway 18/36, or grass strip 09/27 situated north of runway 09/27, dependent on wind conditions at the time. During daylight hours, for traffic separation purposes, contra-rotating circuits are in operation. Right hand circuits apply to runways 09 and 36, and to gliding strips 18 and 27. All other circuits are in a left hand direction. The aerodrome is uncontrolled, and operational information is provided by Melbourne Flight Information Centre on a radio frequency of 118.6 MHz. In addition, gliders operating at Tocumwal monitor a frequency of 122.9 MHz. Radio communications on 118.6 MHz are automatically recorded. The recorded radio communications of VH-CAG were consistent with normal operational procedures. Radio communications on the local glider frequency were not recorded. No evidence was found to indicate that VH-CAG made any transmissions on that frequency in the period leading to the accident. Details of special procedures in use at Tocumwal at the time of the accident were provided in Enroute Supplement Australia (ERSA), a document issued by the Civil Aviation Authority. Although the glider frequency was published in ERSA, there was no requirement for powered aircraft to listen out or broadcast on the glider frequency. On the day of the accident, weather conditions were bright and sunny with no obstructions to visibility. Witnesses reported that the surface wind was light, mostly from the south but occasionally backing to the west. Gliding operations had been conducted throughout the day from strip 18, utilising a right hand circuit direction. The pilot of VH-GXO had been authorised to undertake thermalling flight to the south-west of the aerodrome. At the time of the collision, the glider was being operated in accordance with that authorisation.

The Bonanza had commenced to taxi from the western end of the aerodrome at about the time the glider was aerotowed from strip 18. A few minutes later, the aircraft was observed to backtrack on runway 27 before commencing a take-off roll from the beginning of the runway. Witnesses later reported that, at the time, the wind was from the west at up to 12 kts. The pilot-in-command of the Bonanza was aware that gliding operations using strip 18 had been conducted earlier in the day. After take-off the Bonanza turned left onto an easterly heading, directly into the glider circuit. Why the crew of the Bonanza did not sight the glider can only be surmised; however, a number of factors may have been relevant, including a lack of contrast between the glider and the sky background; the size of the glider as a target; the low rate of movement relative to the Bonanza; the absence of any traffic alert concerning the presence of the glider; and possible distraction from a known inbound aircraft to the north-east of the aerodrome. The pilot of the glider was unaware of the presence of the departing Bonanza, having heard no radio calls concerning VH-CAG on the glider frequency. He also did not see the Bonanza as the glider was turning right, although this could have been difficult as the Bonanza presented a head-on view and would have blended into the ground background as it climbed.

Significant Factors:

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

1. The crew of VH-CAG were unaware of the presence of the glider.

2. No communications from VH-CAG were heard on the gliding frequency.

3. The pilot of VH-GXO was unaware of the presence of VH-CAG.

4. Fluctuating wind conditions.

5. Conflicting circuit directions.

6. The crew of VH-CAG was possibly distracted by known inbound traffic.

7. Poor conditions for target discrimination, (both aircraft).

8. The pilot-in-command of VH-GXO failed to see the approaching Bonanza.

9. The crew of VH-CAG failed to see and avoid the glider.

The student glider pilot had carried out three previous flights during the day. Her instructor had informed her that she was at a suitable stage of training to be introduced to practice emergency procedures. After sighting her training log book, the instructor for the final flight left the glider to speak to the pilot of the tug aircraft. The instructor returned to the glider and preparations for take-off were then continued. Witnesses observed that the tug and glider became airborne and subsequently carried out normal turns to position the aircraft on a downwind leg at about 500 feet above ground level. The tug aircraft was then seen to waggle its wings sharply three times. Almost immediately this aircraft assumed a steep nose-down attitude, its tail apparently being pulled into a vertical position by the tow rope which was still attached to the glider. The glider then also assumed a steep nose-down attitude and both aircraft spun or spiralled towards the ground. The tow rope was released from both aircraft, but neither pilot regained control before impact with the ground. The subsequent investigation did not disclose any defect or malfunction with either aircraft that might have contributed to the development of the accident. During glider towing operations when the pilot of the tug waggles the aircraft wings it is a signal to the glider to immediately release from the tow. This "wave-off" signal would normally be given when the tug pilot detects some malfunction or when the glider is sufficiently far out of position behind the tug to affect the tug pilot's control of his aircraft. On this occasion it was considered possible that the instructor in the glider had arranged for the tug pilot to simulate an emergency by giving a wave-off signal. The wave-off signal was observed to be given in the normal position relative to the strip for such training manoeuvres to be performed. The reason for the subsequent loss of control of both aircraft could not be determined, however it was evident that when the aircraft released the tow rope there was insufficient height remaining to permit recovery to normal flight.

During the launch by a tug aircraft for the pilot's first flight of the day, turbulence was encountered at about 40 feet agl. The pilot released from the tow and attempted to land straight ahead, however the right wing struck a post of the aerodrome boundary fence and the aircraft ground looped before coming to rest. The pilot had earlier experienced difficulty in fitting the all-moving tailplane to the glider during the pre-flight assembly. Shortly after becoming airborne the turbulence led the pilot to believe he had elevator control problems and he released from the tow. He then planned to land straight ahead, controlling the rate of descent with the air brake and making virtually no elevator movements. The use of air brake shortened the gliding distance to the point where the aircraft could not clear the boundary fence. Subsequent investigation revealed no defect with the elevator controls or the tailplane.

Upon arrival at Mitta Mitta the pilot performed a touch and go on the 1000 metre long gravel strip, before approaching for the full-stop landing. After touchdown, the aircraft veered to the right but was repositioned on the centreline within a short distance. However, it again veered to the right and departed the hard packed gravel surface of the strip and entered an area of long, damp grass. The pilot was unable to control the direction of travel and the aircraft encountered a drainage ditch, an earth mound and a fence before coming to rest with its noseleg collapsed. No fault was found with the aircraft systems that may have contributed to the accident. The pilot had not flown the aircraft for 18 months and it is probable that the veer was caused by differential braking in combination with the damp, slippery grass on the sides of the strip. Weather conditions were fine and calm and were not considered a factor.