Circumstances:

During descent into Melbourne a large storm cell was detected 148 kilometres ahead on the aircraft's radar. The Captain turned on the seat belt sign and instructed the Flight Attendants to stow cabin equipment and to be seated. The aircraft was diverted right of track and passed abeam the storm cell by 37 kilometres. With no other weather returns indicating on the radar, a short duration of severe turbulence was suddenly experienced. At the time all passengers were secure in their seat belts, cabin equipment had been stowed, some of the Flight Attendants were seated with seat belts fastened and the remainder intended to secure themselves after performing appropriate cabin duties. During the turbulence encounter two Flight Attendants, who were not as yet seated, were injured. Almost immediately after the turbulence ceased, the oil filter bypass light for the number three engine illuminated. The oil filter bypass drill was carried out and number three engine was shut down. Examination of the Flight Data Recorder showed that the aircraft was flying in smooth conditions for three minutes preceding the onset of severe turbulence which lasted for 11 seconds. Vertical "G" varied from +1.57 to -0.27. Recorded Pitch Attitude values ranged between plus and minus 4 degrees while Roll Attitude values varied up to 10 degrees. Airspeed changed from 304 knots to 284 knots in one second. At the end of the turbulence encounter, smooth conditions were experienced for the rest of the flight. With the weather radar clear and inflight conditions smooth, the crew had no way of predicting the onset of severe turbulence. The illumination of the oil filter bypass light was caused by a loose piece of solder within the oil pressure switch.

Significant Factors:

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

1. The aircraft encountered unforeseen turbulence in flight.

2. A loose piece of solder within a pressure switch gave the pilots a false indication of engine oil filter by-pass. This accident was not the subject of an on-scene investigation.

Circumstances:

The aircraft had departed from Bankstown with full tanks and flown to Gunnedah. After DEPARTURE for the return flight, the pilot was unable to climb to his planned cruising altitude of 7500 feet due to weather and spent some time climbing and descending to avoid cloud. Conditions subsequently improved and he was able to maintain 7500 for a short time. The weather then deteriorated markedly with heavy rain showers and low cloud. The pilot diverted towards the coast but then became unsure of his position. Some time later the engine failed when the fuel in one tank was exhausted. After changing tanks and realising that the fuel gauge indicated less than he expected, the pilot prepared for a precautionary landing on a disused strip. The aircraft was fast on the initial approach and the pilot carried out a go around. On the next approach, the aircraft bounced after touchdown and yawed to the left. The pilot overcorrected and on the second touchdown the aircraft veered to the right, ran off the edge of the strip and over an embankment. Approximately 4 litres of fuel remained in the aircraft tanks. There was no evidence of fuel leakage, and no pre-existing fault was found with the aircraft. It was probable that the apparently higher than expected fuel consumption was due to the erratic nature of the flight combined with the leaning procedure adopted by the pilot.

Significant Factors:

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

1. Precautionary landing due to the weather and low fuel state.

2. The pilot made an improper recovery attempt from a bounced landing.

Circumstances:

The pilot reported that he had completed his pre-landing checks, that he had sighted three green lights prior to landing and that the landing gear had retracted during the landing roll. Ground markings and aircraft damage indicate that the landing gear was in the up position on touchdown and did not retract during the landing roll. A technical inspection of the landing gear did not disclose any fault which might have lead to inadvertent retraction of the gear or failure of the gear to extend when selected down. The flaps had not been extended past 10 degrees during the approach to land. It is most probable that the pilot did not correctly complete the pre-landing checks, and as a result did not select the landing gear down. The reasons why the pilot may have forgotten to extend the landing gear could not be determined.

Significant Factors:

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

1. Possible inattention on the part of the pilot.

2. Failure to extend the landing gear.

After takeoff the aircraft was flown to another property some 25 kilometres away. As the aircraft was circled around the property the pilot noticed that the engine was not delivering full power. He changed the fuel tank selection but this did not restore the lost power. The aircraft gradually lost altitude and the pilot realised it would be necessary to land. On final approach at a height of about 30 feet above the ground the engine failed completely. The aircraft was landed heavily. An inspection of the engine found that it had seized. Earlier in the year the manufacturer had issued an Advisory Circular referring to engine overheating problems with the type and recommending that a modification be incorporated. The modification was to install a cooling fin to the engine to improve the flow of cooling air. The circular also stated that modification kits would be posted out to all owners. The owner/pilot had just received his modification kit but had not fitted it.

The pilot was conducting a trial instructional flight when the aircraft experienced an engine failure approximately 50 feet above ground, and three quarters of the way along the runway. The pilot was able to clear a large ditch at the end of the runway, and landed the aircraft in a cane crop. Inspection of the engine revealed that the engine failure was caused by the failure of a gudgeon bearing housing. The neoprene housing had jammed and broken up allowing needle rollers to escape into the crankcase and cylinder. The Bureau has been advised that the engine manufacturer is to replace the gudgeon bearing in the engine type with an improved version.

The pilot reported that he was making a landing approach in strong and gusty crosswind conditions. There was considerable turbulence in the area. On very short final the aircraft encountered an updraft. The pilot reduced power almost to idle, and the aircraft then entered an area of strong sink and lost airspeed. Although substantial power was re-applied, the pilot said he was unable to prevent the aircraft from contacting the runway in a nose-low attitude. The nose gear collapsed and the aircraft slid to a halt on the runway.

The aircraft was cruising at 400 feet above the ground when it suffered a complete engine failure. The pilot stated that the engine had cut out in a manner similar to being switched off. There was no rough running or misfiring, before the engine stopped. A single air restart was attempted without success. The pilot then elected to land in a dry creekbed, the only available cleared area within gliding distance. During the forced landing, the right main landing gear struck a rock. This resulted in a severe swing to the right during which the aircraft struck trees lining the creekbed. The aircraft was transported to a workshop at Mt Isa, where a successful attempt was made to restart the engine. The engine ran at low power settings, for some time with out fault. The owner restarted and ran the engine a further four times without incident. However, the engine fuel filter was later found to have been substantially contaminated with foreign debris. The fuel filter had previously been reinstalled in the reverse sense by the aircraft owner. This effectively contained all incoming contaminants on the inside of the filter screen tube, which caused a restriction to the fuel flow.

The pilot was spraying a bean crop in a valley. During a procedure turn the aircraft began to sink towards trees on the side of the valley. The pilot immediately applied full power and dumped the load, but the sink could not be arrested and the aircraft struck the trees. When the sink was encountered the pilot was committed to continue the turn to avoid terrain. The surface wind in the valley was a light southerly breeze, but there was a strong south-easterly at 2000 feet. The pilot had sprayed the field on previous occasions, and was familiar with the local area. The sink experienced on this occasion was considered to be the result of the strong wind at height combined with the local topography. This type of situation is documented in the Agricultural Pilots Manual. No faults were found with the aircraft that may have contributed to the occurrence. It was evident that when the sink occurred the performance available from the aircraft was insufficient to enable the pilot to avoid collision with the trees.

Circumstances:

The operator submitted an ICAO format flight plan direct to the Civil Aviation Authority (CAA) telecommunications network on the evening prior to the flight. This flight plan took into account a temporary change of routes in the Mackay area due to decommissioning of the Mackay VHF omni-directional radio range (VOR). The operator also advised the CAA Mackay briefing office of the sectors to be flown by the crew who would obtain briefing at Mackay. When the crew arrived for briefing the Briefing Officer had a set of notams and flight sector sheets available for collection. The crew advised him that they would be using the plan submitted by their company. The sectors for the crew that day were Mackay - Rockhampton - Brisbane - Townsville - Brisbane. All legs were flown uneventfully until the Townsville - Brisbane sector. The clearance for the aircraft was to track Townsville - Bowen then planned route. Radar coverage from Townsville is lost at 90 nautical miles just prior to Bowen. The aircraft was flown from Bowen to Mackay with the next point being Corio instead of Bowen to Hamilton Island then to Corio. The error was detected when the Hamilton Island position report was requested by Townsville Control. The investigation disclosed that the crew did not read the Notams received at Mackay. Those Notams contained a typed note concerning amended routes around Mackay due to decommissioning of the Mackay VOR and readers were directed to a Brisbane FIR Notam number 3600. That Notam was not in the package given to the crew. In any event it had been superseded by Brisbane FIR Notam 3667 on 1 August, and it was not given to the crew either. The company navigation officer is responsible for the routes flown by company aircraft. He had ensured that the flight plans relating to flights around Mackay took the amended routes into account. The pilots have two other sources of route data available. These are the flight planning books available at each CAA briefing office and the Flight Management Computer (FMC) sector details programmed into each aircraft. Neither of these were altered due to the effort required and the temporary nature of the changed routes. The only route effectively altered by the changes was the tracking of flights between Townsville and Hamilton Island instead of Townsville and Mackay. When the crew were checking the legs in the FMC on the ground at Townsville, they used the sheet given to them by the Mackay briefing officer. Since this agreed with the FMC legs, they had no reason to question the planned route. Had the flight plan been used as a check the different track would have been noted.

Significant Factors:

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

1. The Briefing Officer did not provide a full Notam list for pre-flight briefing.

2. The operating company did not highlight discrepancies in route information to crews.

3. The pilots did not read the Notams.

4. The pilots did not use the ATC flight plan to check FMC data.

Recommendations:

1. When an aircraft is given an airways clearance the route to be flown is usually specified to the first turning point or a point along the cleared track. If the first reporting point was nominated all parties concerned would have a final check on the track the aircraft would fly. At the first reporting point the next segment of the route would normally be confirmed by the pilot's position report or the radar track of the aircraft. It is recommended that the Civil Aviation Authority amend the format of airways clearances to include the first reporting point instead of the first turning point or tracking point along a cleared route.

The pilot reported that the aircraft was flying at 50 knots at about 500 feet above the ground when the engine stopped. He pulled the engine start cord and the engine restarted. The aircraft was then climbed to 2000 feet as the pilot was concerned about operating over rough terrain. A short time later, the engine stopped again and rather than attempt another restart, the pilot concentrated on landing the aircraft. Substantial damage resulted from the landing on unsuitable terrain. Examination of the engine revealed that the carburettor was misaligned and that the piston at the magneto end of the engine had failed. The piston exhibited signs of detonation which was probably the result of an overly lean fuel/air mixture. Recent advice from the engine manufacturer included the recommendation that super grade petrol be used instead of unleaded petrol with ehtyl alcohol added. Further, new engines are fitted with a baffle or air guide under the cylinder cowl and have a new carburettor setting. This accident was not the subject of an on-site investigation.