Circumstances:

The PA-44 aircraft was cleared to take-off and given a clearance which included the instructions to maintain runway heading and to call Adelaide Approach airborne. At about the same time, the TB20 was approaching Adelaide at 2,000 feet from Parafield to conduct a practice Adelaide/Parafield non-directional beacon (NDB) approach, which uses the Adelaide NDB. The TB20 pilot was cleared to conduct the NDB approach. The PA-44 did not commence its take-off run until about 110 seconds after lining up and being issued with the clearance. During this period, Adelaide Approach East issued a restriction of 2,000 feet for the PA-44, which Tower passed on to the pilot. Once the PA-44 became airborne, Tower advised Approach East that Tower was able to co-ordinate the separation between both aircraft. Approach East then directed Tower to amend the PA-44 clearance to direct to Port Stanvac at 2,000 feet. Tower could not raise the PA-44 as the pilot had changed to Approach radio frequency as instructed. Approach East then reported that he had issued the revised clearance to the PA-44 pilot. Almost a minute passed before Tower advised Approach East that a conflict was rapidly developing between the PA-44 and the TB20. The TB20 pilot, on the outbound leg of the NDB, reported sighting the PA-44 at a distance of about 30 metres, level, on his right and tracking from right to left.

Significant Factors:

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

1. The PA-44 aircraft held on the ground for almost two minutes before commencing take-off.

2. Both Tower and Approach controllers allowed a situation to develop where neither was certain which section was responsible for separation between the two aircraft.

Recommendations:

1. The CAA might consider this incident as the basis of an article to illustrate to pilots the reasoning behind RAC/OPS-0-52 which states in part that if the pilot calls "ready" he should be prepared to "make a roll-on take-off in one continuous movement if take-off clearance is given". The implication is that the take-off should be commenced without delay and that the Tower controller will assume the aircraft is ready for immediate take-off.

2. The CAA should examine procedures at Adelaide to ensure that there is no doubt which controller is controlling which aircraft. Special attention should be paid to the Adelaide/Parafield NDB procedure and full traffic information should be given to pilots "under the hood" conducting instrument training. The CAA has agreed to prepare an article in response to the first recommendation for publication in the Aviation Safety Digest. The second recommendation was actioned by the CAA during the process of the investigation.

The pilot of VH-HCE was preparing to conduct solo circuits and landings, using runway 11 Right. The aircraft had stopped facing northwards on the bitumen section of runway 36 Right, just south of taxiway Lima, while the instructor vacated the aircraft. The Piper VH-EMZ had previously landed and was taxiing westward along taxiway Lima. As VH-EMZ approached the runway 36 Right intersection, VH-HCE began to cross taxiway Lima, heading towards the holding point for runway 11 Right. The two aircraft collided in the middle of the taxiway. The pilot of VH-EMZ subsequently reported that she had difficulty seeing along the taxiway because of the late afternoon sun. The pilot of VH-HCE reported that he had looked along taxiway Lima prior to moving forward, but had not seen the other aircraft.

Both aircraft were conducting scenic flights over North Stradbroke and Moreton Islands. Neither the pilot of VH-WAS nor the pilots in VH-DMB submitted a flight plan (nor was it a requirement) and were operating NOSAR, NO DETAILS outside controlled airspace on a "see and be seen" basis. No routine radio transmissions were heard from either aircraft when they were in the South Passage Bar area. VH-DMB had flown over Moreton Island and was turning left at an angle of bank of 25 degrees when it collided with VH-WAS at 1500 feet above mean sea level over the South Passage Bar. The pilot of VH-WAS stated that his aircraft was turning through east, in a shallow right turn when he felt and heard an impact. It was immediately obvious to him that a wingtip section from the left wing was missing, but he was unaware of what his aircraft had struck. An uncontrolled, left, descending turn ensued and the aircraft descended about 1200 feet before the pilot managed to level the wings after reducing the engine power to idle. He transmitted a brief MAYDAY call during the recovery. The pilot successfully ditched the aircraft some 4 kilometres east of Reeders Point, Moreton Island. After the aircraft came to rest, it floated for about a minute before sinking in 7-8 metres of water. The pilot and his passenger escaped from the wreckage and each clung to a separated aircraft wheel. They then began to swim for the shore on the incoming tide. VH-DMB plummeted out of control and impacted in a near vertical dive on a shallow sand bank some 800 metres from the shore of North Stradbroke Island. Inspection of the wreckage found that the left wingtip of VH-WAS had struck the cockpit area of VH-DMB. It is probable that this impact disabled both the front seat occupants of VH-DMB. The left mainwheel of VH-WAS had severed a 1.2 metre section of the left wing of VH-DMB. The investigation determined that both aircraft were in a position to have been visible from the cockpit of the other aircraft for at least 10 seconds before impact. Several factors affect a pilots ability to observe other aircraft. In this case it is likely that the relative position of each aircraft to the other meant that they were in a constant position in the other pilots field of view. The pilot of VH-WAS was also looking in the direction of the sun and VH-DMB was coloured such that it would not have contrasted with the backdrop of a high overcast. Although the pilots in VH-DMB were looking down-sun it is possible that the small frontal cross-section presented by VH-WAS would have been lost against the background of the island and the horizon. Because of the nature of the sight-seeing flights being undertaken by both aircraft it is also possible that all pilots may have been partially distracted from their lookouts by passengers. As a result of a previous accident involving a mid-air collision, the Bureau of Air Safety Investigation has undertaken to conduct an evaluation and prepare a report on the practicality of the "see and be seen" principle.

Circumstances:

Both pilots were conducting solo navigation exercises for the removal of the area restriction from their Private Pilot Licences. The pilot of VH-JGG, following a brief refuelling stop at Mudgee, took off from runway 04 and climbed to circuit height prior to setting heading from the downwind leg. At about the same time, VH-DAF entered the downwind leg for runway 04, after approaching the circuit area from the west. Both pilots made the required radio calls but possibly may not have heard each other due to preoccupation with their respective arrival and DEPARTURE procedures. An eyewitness reported seeing one aircraft being overtaken by a second aircraft which appeared to be taking evasive action. The right wing of the overtaking aircraft struck the left wing of the leading aircraft. The overtaking aircraft, which was subsequently identified as VH-DAF, lost its right wing in the collision and spun to the ground about two kilometres northwest of the aerodrome. The other aircraft was landed successfully in a paddock about two kilometres southeast of the aerodrome, despite extensive damage to the left wing which rendered aileron and flap systems inoperative and airspeed indications unreliable. At the time of accident, the weather was fine with scattered cloud at 4000 feet and visibility in excess of 10 kilometres.

Significant Factors:

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

1. The pilots of both aircraft failed to see each other for reasons which could not be determined.

2. VH-DAF overtook and collided with VH-JGG.

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.