As the aircraft was being rotated for take-off, the pilot detected a slight loss of performance from the right engine. He looked towards the engine and saw evidence of fire around the air intake on top of the cowling. The take-off was abandoned, both propellers were feathered and heavy braking was applied. The aircraft overran the strip and entered a very muddy field. The nosegear collapsed and the right engine was torn from its mounts before the aircraft came to rest 110 metres beyond the strip threshold. The pilot rapidly vacated the aircraft and waited for several minutes until rescuers arrived and extinguished the fire. The subsequent investigation did not reveal any evidence of a pre-impact fire, and all fire damage was found to have occurred after the aircraft had come to rest. No positive reason for the reported power loss was established, however tests showed that the spark from the magnetos was weaker than normal. At the point where the take-off attempt was abandoned, insufficient strip length remained in which to stop the aircraft.

At the completion of one leg of the flight, the passengers disembarked and the pilot prepared to ferry the aircraft to another aerodrome in preparation for the next day's flying. The strip in use was constructed of crushed limestone laid on black soil. The pilot taxied onto the black soil at one end of the strip as he prepared to carry out a 180 degree turn to line up for take-off. The nosegear entered a hole about 150 millimetres deep, and collapsed. The area where the nosegear collapsed had been affected by washouts, and had gradually become filled with soft silt. There was no indication to the pilot that the area was unsuitable. The owner of the property had no flying experience and was probably unaware that the condition of the strip surrounds had deteriorated.

As the pilot approached his destination he was advised that he was number three in the landing sequence. A visual, straight-in approach was made in clear, dark conditions. After receiving a landing clearance a normal flare was made, and it was not until the aircraft settled onto the runway surface that the pilot realised that the gear was retracted. At the end of the landing slide, the pilot turned off the master electrical switch and vacated the aircraft. He had made no attempt to alert the Control Tower to the fact that the aircraft was disabled on the runway. The controller, not seeing any lights indicating that the runway was obstructed, cleared a waiting Cessna 172 for take-off. Only prompt action by the instructor in this aircraft prevented a collision with the stationary aircraft.

The pilot and his passengers had arranged to fly to Wagga Wagga to attend an agricultural seminar. He had flown the aircraft from his home base to spend the night at Melrose, with a friend, before departing the following morning. Prior to DEPARTURE, the pilot obtained a weather forecast for the route to be flown. He then submitted flight details that indicated the flight would be conducted in accordance with visual flight rules. The aircraft was later observed to take-off and head towards the north-east. Approximately 40 minutes after the aircraft departed the wreckage was sighted by a passing motorist. Ground marks indicate that the aircraft had struck the ground while heading in a north-westerly direction. Both the forecast and actual weather conditions at the time of DEPARTURE and the time of the accident indicated the presence of low cloud, poor visibility and rain in the area. These conditions were below those required for flight in accordance with visual flight rules. An inspection of the wreckage revealed that the aircraft had struck the ground at a relatively low forward speed between two areas of rising terrain. No fault was found with the aircraft that could have contributed to the occurrence.

VH-TBR had been cleared to track via air route T9 from overhead Mount Hope, South Australia to overhead Narembeen, Western Australia. The aircraft had been cruising at Flight Level(FL) 350 but shortly before the incident the pilot had requested a descent to cruise at FL 290. The aircraft was recleared to decend to and cruise at FL 290 by Perth Air Traffic Control. A short time later, the Perth controller observed a radar return, from VH-TBR, on the edge of his screen. The return indicated that the aircraft was about 54 kilometres south of the cleared track and heading in a northerly direction. The controller immediately altered the course of an eastbound Boeing 727 aircraft to ensure separation between the two aircraft. It was established that the two aircraft came within 16 kilometres of each other, but at that time they were vertically separated by 2000 feet. However, during the descent made by VH-TBR, it had passed through the level of the other aircraft when both aircraft were estimated to be about horizontally separated by 32 kilometres. At this time the separation between the two aircraft did not comply with the prescribed standards. The investigation revealed that while the VH-TBR was enroute, and having just climbed to cruise at FL 350, the aircraft captain disengaged the autopilot to retrim the aircraft for level flight. When the autopilot was then re-engaged, the normal sequence was interrupted and subsequently not completed. As a result the autopilot was not re-coupled to the Inertial Navigation System(INS). This resulted in the aircraft maintaining a constant heading and under the influence of a changing wind velocity and the absence of normal enroute heading changes the aircraft diverted from the cleared track.

The pilot hired the aircraft with the intension of carrying out some joyflights with his relatives in the Caboolture area. After departing Archerfield he completed a circuit and landing at Redcliffe before proceeding to Caboolture. On arrival in the circuit area the pilot stated that he carried out two low level circuits to inspect the airstrip before landing. One of the passengers then boarded the aircraft and takeoff was commenced in a north-easterly direction. When the aircraft had not become airborne with only 100 metres of the strip remaining, the pilot abandoned the takeoff attempt. The aircraft overran the strip and ran through a fence before the pilot was able to bring it to a halt. The pilot offloaded the passenger and after inspecting the aircraft took off from the strip and flew to Redcliffe. The investigation ascertained that the airstrip was 750 metres long and was unsuitable for the attempted operation.

The pilot reported that just after touchdown he felt a bump. As the aircraft slowed the nose of the aircraft sank slightly, allowing the propeller to strike the strip surface several times. An inspection of the aircraft revealed that a wallaby had struck and bent the nosegear strut. This accident was not the subject of an on-site investigation.

The pilot was conducting a flight under Night Visual Flight Rules from his property to Broken Hill. About 30 minutes after DEPARTURE the pilot reported that the aircraft engine was running roughly. Shortly afterwards he reported that the engine cowling had become detached and then that the aircraft was on fire. No further transmissions were received from the aircraft which was destroyed as a result of impact forces and fire. It was established that the No.3 cylinder became detached from the engine crankcase and damaged the engine cowling as it was forced outwards against it. The cowling blew back against, and smashed the left windshield. Engine oil escaped from the crankcase where the cylinder had been attached, and was blown onto the cabin area. The likely source of the fire was fuel escaping from broken fuel lines. Engineering investigation revealed that the lower front, half-inch cylinder hold-down nut ceased to maintain tension on the hold-down plate. Other cylinder hold-down nuts from this engine were examined and showed no signs of structural weaknesses. It is considered that the subject nut also complied to specifications, although this nut was not recovered. The engine had been overhauled 46 flight hours prior to the accident. It is considered that the nut was incorrectly torqued at that overhaul. The reason for the incorrect torquing of the cylinder hold-down nut could not be established. The subsequent severe impact with the ground was a result of the extreme distractions with which the pilot had to contend. The aircraft was cruising at 3500' AMSL when the engine disintegrated and the fire broke out. Part of the emergency procedure for this type of occurrence is to dive the aircraft in an attempt to blow out the fire. As the aircraft impacted the ground in a steep nose-down but wings near-level attitude, and only slightly off course, it is thought that the pilot was complying with that drill. However, the low cruising altitude did not afford him sufficient time to accomplish this and establish the aircraft in a more suitable attitude for a forced landing. His limited night flying experience in combination with a dark night might have resulted in him not being able to estimate his height above ground level.

The pilot reported that shortly after the aircraft became airborne, he noted a substantial change in propeller pitch noise and an associated loss of performance. Insufficient runway remained to permit a landing straight ahead. The pilot raised the landing gear and flap, however the aircraft failed to climb and the airspeed decayed to below the safe single engine speed. The take-off attempt was abandoned and a forced landing was carried out off the end of the runway. The rear fuselage impacted heavily on a dirt bank 78 metres beyond the runway threshold, following which the aircraft passed through a fence and slid for a further 78 metres before coming to rest. No fault was subsequently found with the engines or systems of the aircraft which might have explained the reported loss of performance. Calculations indicated that the weight of the aircraft at the time of take-off was close to the maximum allowable, but the centre of gravity was aft of the rear limit. Several of the passengers indicated that the aircraft rotated sharply to an unusually high nose attitude as it became airborne. The pilot's action in raising the flap when he perceived the power loss was contrary to the emergency procedures for the type, and probably resulted in sink and a further reduction in airspeed.

While the aircraft was cruising at 2000 feet above mean sea level the engine commenced to run roughly. Trouble checks failed to determine the source of rough running and the pilot elected to land at an enroute aerodrome. However before reaching this strip, the engine lost power completely and the pilot was committed to a forced landing. Because of crowds at an adjacent beach, the pilot attempted to land on a road. Touchdown was further along the road than expected because of a strong tailwind component, and the aircraft collided with a kerb before coming to rest. Investigation revealed that nuts on the various bolts and studs securing the number 3 cylinder to the crankcase had evidently not been correctly tightened. Five of the eight mounting studs/bolts had failed from fatigue during normal operations, finally allowing the cylinder to become loose. The engine had completed 83 hours time in service since an overhaul. There was no logbook record to show whether the particular cylinder had been removed or replaced since that overhaul.