Following an outlanding the pilot arranged an aerotow. The take-off was commenced into wind and up a rise. The glider became airborne but on breasting the rise, the tug pilot aborted the take-off as trees and a fence appeared closer than expected. The tug aircraft which had just become airborne turned left and the left wing tip struck the ground before the aircraft came to rest. The glider pilot released the tow but the glider's right wing tip contacted the ground then the fence before the glider impacted the ground beyond the fence. Before commencing the aerotow the pilot of the tug aircraft had estimated that sufficient distance was available for the take-off to be completed. He did not measure the distance available nor consult the aircraft performance chart. The chart indicated that with the prevailing conditions, insufficient distance was available to successfully complete the take-off.

Circumstances:

Both aircraft were parked side by side. Because the battery was low in HGW, it had to be started by hand swinging the propeller. The pilot of HGW swung the propeller while the pilot of FEU occupied the cockpit. After the engine was started, the pilot of FEU returned to his aircraft and started its engine. The pilot of HGW returned to his cockpit to reset the engine speed for warmup but he did not actually enter the cockpit. He then left the aircraft with the engine running to get a weather report. Shortly afterwards, the pilot of FEU noticed that HGW was starting to move forward and turn towards FEU. The pilot of FEU left his cockpit and tried to manoeuvre the tail of HGW to direct it away from FEU, but was not successful and the two aircraft collided, with engines running. The pilot of HGW believed that the pilot of FEU had set the park brake for the engine start. He did not check it himself before leaving the aircraft with its engine running.

The pilot of VH-CJR was conducting a flight from Prosperpine to Gladstone via Rockhampton. After passing over Charon Point he decided to track to the west of his planned track and overfly Marlborough enroute to Rockhampton and thus remain well clear of the restricted area to the east. The pilot did not advise Rockhampton Air Traffic Control of his revised tracking details. When the aircraft was 36 kilometres north-west of Rockhampton, the pilot contacted Rockhampton Tower and requested a clearance to cross the Rockhampton Contol Zone. The tower controller cleared the aircraft to track to Rockhampton remaining at least two kilometres to the east of the Rockhampton to Marlborough railway line, at an altitude of two thousand feet. The controller did not advise the pilot that the clearance was an amendment to his planned tracking details, as is required. However, the pilot acknowledged the clearance without query. This clearance was given to VH-CJR to provide lateral separation with VH-TJJ, which was about to depart Rockhampton. The pilot of VH-TJJ subsequently reported that the aircraft had departed and passed through 3000 feet. Some two and a half minutes later the pilot of VH-CJR reported the position of the aircraft as five kilometres north-west of Rockhampton at 2000 feet. Neither pilot reported sighting the other aircraft. The pilot of VH-CJR, who was inexperienced in the Rockhampton area, did not comply with the terms of his clearance.

The southbound aircraft, BA 11, was cruising at FL330. The northbound aircraft, MH 24, had been cleared to climb to and cruise at Flight Level(FL) 350, with a requirement to reach the assigned level by 1801 hours local. Shortly afterwards BA 11 requested a diversion to the right of track. The aircraft was cleared to divert up to 90 kilometres to the right of track. The tracks flown by the aircraft were laterally separated by approximately 80 kilometres. About five minutes after being given approval to divert from his cleared track, the pilot of BA 11 requested a clearance to climb to FL 350. This request was denied by the Perth controller and the aircraft was given approval to divert either to the left or right of track, as required. At 1811 hours local the Perth controller gave BA 11 a clearance to climb to FL 350, at 1816 hours local. The aircraft acknowledged the clearance and during the subsequent climb advised sighting another aircraft, MH 24, an estimated two kilometres to the right and 1400 feet above his level. The investigation determined that the Perth controller had mistaken the time MH 24 had been required to reach FL350, 1801 hours, for the time he had calculated that the aircraft would pass. He had thus applied the required separation standard to this time instead of the calculated time of passing of 1818 hours local.

Both pilots were at Horsham to compete in the annual "Horsham Week" gliding competitions. On the day of this accident no task had been set but both pilots had taken the opportunity to make pleasure/familiarisation flights of the area. At the time of the accident the two aircraft were at approximately 5000 feet above sea level. VH-HDY was flying towards Horsham on a constant heading of approximately 330 degrees. The aircraft was in a descent and the pilot estimated he was about 1000 feet below the cloud base. Cloud cover was reported as six eights of cumulus type cloud. VH-KYO was flying in the opposite direction to VH-HDY, also on a constant heading at the same altitude. The pilot of VH-HDY reported that he had just completed a scan of his instruments when he looked up to see the other glider head on. He pushed the control column forward to try and avoid a collision but this was not successful. The pilot of VH-KYO reported that he had also looked up from concentration on another task, to sight the other aircraft head on at the very last moment. He had no time to take any avoiding action. The right wing of VH-HDY hit the nose/cockpit area of VH-KYO, smashing the canopy, dislodging the instrument panel and damaging the nose. VH-HDY lost two metres of its right wing and became uncontrollable. The pilot abandoned the aircraft and parachuted to the ground. The pilot of VH-KYO received injuries to his right foot and face in the collision but was able to maintain control of the aircraft and fly it back to Horsham where he made a safe landing in a paddock beside the aerodrome. At the time of the accident both aircraft were operating in an environment where the pilots were responsible for maintaining separation from other aircraft on the basis of see and be seen. In this accident both aircraft were approaching head on, both were gliders with thin wings and narrow fuselages, both were essentially white in colour when viewed from head on and both were against a background of whitish coloured cloud. Such circumstances would have made it very difficult for each pilot to sight the other's aircraft.

VH-RMG was cleared to land on runway 19. VH-HSS was cleared to line up after VH-RMG had landed and told to expect an immediate takeoff clearance. At about this time VH-TJQ was approaching final and about 12 kilometres from the runway. At the end of its landing roll VH-RMG turned into a highspeed exit and stopped with the rear of the aircraft over the runway and with the entire aircraft infringing the flight strip. The radio transmitter of VH-RMG then started to operate continuously thus preventing effective communication between the Tower and any aircraft. The crew of VH-RMG attempted to call on the Surface Movement Control(SMC) frequency but the transmitter continued to operate continuously. At the same time the pilot of VH-TJQ was attempting to ascertain from the Tower if his aircraft was cleared to land. He also called on the SMC frequency but that frequency was jammed at that time by the continuous transmissions from VH-RMG. By this stage the pilot of VH-TJQ had decided to land if they did not obtain a landing clearance. When the aircraft was at about 200 feet above ground level the crew noticed that VH-HSS was lined up on the threshold of the runway. An immediate go-around was carried out. The rear section of VH-RMG still infringed the runway. During the above sequence the Tower Controller had been attempting in vain to both instruct VH-TJQ to carry out a go-around and to have VH-HSS vacate the runway. Neither aircraft had received these instructions because of the continuous transmissions from VH-RMG. The sighting of VH-HSS on the runway threshold was made more difficult for the crew of VH-TJQ by the fading light and the fact that the white aircraft was aligned with the white threshold markings. Subsequent checks of the radio systems in VH-RMG failed to find any faults with the systems.

Several gliders were thermalling in one area during a cross-country flight. VH-IZE departed for the next thermal and the pilot, having determined that he was clear of other aircraft, began a left turn in the thermal. He then heard a loud bang and the glider pitched steeply down, however he was able to parachute to the ground. The left wing of VH-IZE had severed the fuselage of a second glider, VH-GKN, and the tail wheel area had struck the upper right wing and cockpit. The pilot of VH-GKN had been thrown from his seat but did not operate his parachute. The relative positions of the two gliders prior to the start of the manoeuvring which resulted in collision could not be established. However, the apparent relative impact attitudes of each aircraft indicate that just prior to impact VH-IZE would most probably have been in the two o'clock low position in the field of view from the cockpit of VH-GKN. VH-GKN would have most probably appeared in the seven o'clock high position in the field of view from the cockpit of VH-IZE. It is likely that the pilot of VH-GKN was incapacitated as a result of the collision.

Circumstances:

The two gliders were taking part in a cross-country skills development exercise with a team leader in a third glider. The team leader was ahead of the other two and waiting for them. VH-GGT was established in a thermal when the pilot sighted VH-GEZ tracking towards him. The pilot of VH-GGT levelled the wings to allow VH-GEZ to join the thermal. He then banked and resumed circling in the same direction. He heard a bang and felt the glider lurch and realised that the two gliders had collided. Both pilots carried out handling checks, and the team leader carried out a visual check of the damage. The pilots then elected to fly 30 kilometres back to Tocumwal. The pilot of VH-GGT stated that his glider felt "funny" just before landing, and as he stepped out of the cockpit after landing the entire rear fuselage folded upwards, held by a double thickness of fibre glass only a few centimetres across. VH-GEZ was found to have considerable compression failures on the underside of the wing.

Circumstances:

The two aircraft were on identical tracks, with the slower aircraft (VH-ITF) in front and maintaining 8000 feet. VH MWX was faster and maintaining 10000 feet. Due to military flying activity, they were unable to fly from Ballidu direct to Perth but obtained a clearance to track via Clackline. VH-ITF obtained a clearance to enter controlled airspace (65 nautical miles from Perth) at 6000 feet, while VH-MWX was cleared to enter at 5000 feet. Although both aircraft had reported at Ballidu at the same time, the pilots were unable to see the other aircraft. VH-ITF descended to 6000 feet and the pilot of VH-MWX elected to descend to 7000 feet until he could maintain visual contact with the other aircraft. If he had not seen the other aircraft before entering controlled airspace (CTA) he intended orbiting outside CTA until separation was obtained. The pilot of VH-MWX saw the other aircraft about 13 kilometres before the airspace boundary and commenced descent to 5000 feet. He was overtaking to the left of the other aircraft and at the same altitude when VH-ITF was instructed to make a left orbit by the controller. This action was halted when the pilot of VH-MWX advised the other pilot and the controller against the turn because his own aircraft was in the way. VH-MWX subsequently descended to 5000 feet and VH-ITF was instructed to orbit to gain lateral spacing with the other aircraft. Identification of VH-MWX on radar was completed at 57 nautical miles (103 kilometres) from Perth, after the pilot had reported at 5000 feet.

Significant Factors:

The following factor was considered relevant to the development of the incident:

1. The controller used a poor technique in allocating clearances. This incident was not the subject of an on-scene investigation.

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