After take off from runway 17, the aircraft commenced to roll and yaw to the right. The pilot maintained control, completed a left circuit and landed back on runway 17. Before take off, a flap setting of 20 degrees was selected and was indicating in the cockpit. Later inspection showed that at this flap selection, the right flap went to 20 degrees and the left to 40 degrees. Due to a maintenance error, when the left flap actuator was changed the hoses were re-attached to the wrong ports.

The pilot had just commenced a procedure turn at the end of a spray run, at a height of 200 feet above ground level, when the engine failed without warning. During the ensuing forced landing the aircraft landed heavily and overturned. The engine failure was caused by separation of number nine cylinder link rod end, which resulted in the piston lifting the head off the cylinder. The cause of the failure could not be positively determined, but was probably due to the link pin bush being worn away, and excessive tolerance between the link rod and link pin causing a fatigue failure of the link rod. Aircraft records showed that the engine had completed 184 hours since overhaul, but the internal appearance of the engine was that of an engine that had operated for a longer time. The reason for the unusual condition of the engine could not be established.

Circumstances:

At 1911 hours the pilot made a routine radio transmission stating that the aircraft was 20 miles (37 kilometres) north-west of Roma inbound and leaving 4000 feet on descent. He then spoke to the company at Roma on the company VHF frequency. The pilot did not respond to a traffic advisory call from Brisbane Flight Service at 1914 hours, and did not report his arrival at 1917 hours, the estimated time of arrival. Later, when the aircraft could not be located on the ground at Roma aerodrome, an aircraft which had previously departed Roma was diverted to search along the inbound track of the missing aircraft. An Emergency Locator Beacon (ELB) signal was later detected by a searching Army helicopter 19 kilometres west-north-west of Roma, and the wreckage was located at 0145 hours. The aircraft had flown into trees whilst in a shallow descent. Both engines were operating, and the wings were level at impact. The weather was fine, and the sky was clear, but it was a very dark night with no discernible horizon. There were no defects found with the aircraft that may have contributed to the development of the accident. The Minimum Safe Altitude for aircraft operating visually at night in the Roma area is 3000 feet above mean sea level (amsl). A visual descent may only be continued below 3000 feet at Roma when the aerodrome is in sight, and the aircraft is within 3 nautical miles. The accident site is approximately 1050 feet amsl. There was no evidence that the pilot was incapacitated, and the reason the aircraft descended below Minimum Safe Altitude was not determined.

Significant Factors:

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

1. The night was dark, without a visible horizon.

2. The aircraft descended below the Minimum Safe Altitude, for reasons which have not been determined.

The helicopter was being operated from a clearing in flat, tree covered terrain. It was heading into wind and had reached a height of about one metre after lift-off when it suddenly swung to the right and moved backwards. The tail skid and rotor struck the ground and the helicopter swung further right. The main rotor blades then contacted the ground and the helicopter rolled on to its side. The pilot reported that a local whirlwind had caught the helicopter just after lift-off. Overnight rain had prevented the tell-tale dust plume from developing. This accident was not the subject of an on-site investigation.

During a visual approach to Runway 32 the engine began to run roughly, to the extent that no useful power was available. The pilot made a "Mayday" call and elected to attempt a forced landing on Runway 05. In the latter stages of the approach it became obvious to the pilot that the aircraft would not reach the runway. It flew into a tall sugar cane crop and overturned at low speed. The cane cushioned the final impact. Investigation revealed that both magnetos contained leaking, obsolete coils. They had overheated, causing the ignition to fail. The coils were clear case coils which should have been withdrawn from service in the early 1970's in accordance with a specific Airworthiness Directive (AD). The AD had been withdrawn when it was considered that Licenced Aircraft Maintenance Engineers (LAMEs) in the aviation industry were sufficiently aware of the hazards posed by these coils and that all in-service clear case coils had been replaced. At engine runup, both magnetos had checked serviceable because the coils were cold. During the flight, they had heated sufficiently to cause an internal breakdown of their function, resulting in a significant power loss. The pilot misjudged the subsequent forced landing and the aircraft undershot the runway threshold.

The pilot was required to carry out a rope laying operations for the purpose of transmission line installation, between pylons. After take-off the pilot established a 20 feet hover, 10 metres west of one of the pylons. A worker standing on the ground was observed to be walking towards the helicopter holding in his right hand the rope attached to the pylon. As the rope became taut, it was struck by the the main rotor blades. Control of the helicopter was lost. The investigation was carried out by the Department of Civil Aviation Malaysia.

During ridge soaring operations, areas of sink were encountered and the aircraft descended over forested terrain. The only area suitable for an outlanding was a small deer enclosure. The pilot initially overshot the area and during the turn to re-position the aircraft for landing the right wing struck the fence surrounding the enclosure. The aircraft yawed through 90 degrees before impacting the ground in a level attitude. Although general soaring conditions were poor, the pilot had elected to leave the ridge-line to conduct a sight seeing flight. During this flight a wind change moved through the area. On return to the ridge-line the pilot, who had not detected the wind change, persisted with efforts to find an area of lift. The proximity of the aircraft to the tops of the trees and the small size of the deer enclosure precluded the pilot sighting the clearing in time to conduct a straight-in approach.

On arrival at a sloping helipad, the pilot overflew the pad to ascertain that it was clear, and made a final approach to the pad. During the landing two of the main rotor blades struck the surface of the slope. The investigation was carried out by the Department of Civil Aviation Malaysia.

The pilot was departing into strong and gusty wind conditions. The aircraft was observed to climb steeply to about 200 feet above ground level. It then entered a descending turn to the right, at a low airspeed. The descent continued with the aircraft in a nose high attitude, and a wing was seen to drop shortly before ground impact. The pilot subsequently reported the engine was delivering full power throughout the flight. Another pilot who had flown a number of flights in the area during the day, reported that he had encountered pronounced areas of sink to the north of the strip. It was considered that while attempting to fly out of similar conditions, the pilot had allowed the airspeed to decay and the aircraft had stalled. There had been insufficient height available for the pilot to effect recovery. This accident was not the subject of an on-scene investigation.

Circumstances:

The pilot was undergoing a check flight with an instructor, as he was contemplating purchasing this type of aircraft. This was the first occasion that the pilot and instructor had flown together. A series of exercises was carried out, during which the pilot was asked to demonstrate a power on stall at a height of approximately 500 feet. During this exercise, the pilot did not lower the nose sufficiently during the recovery. The pilot was not accustomed to practising stalling at such a low altitude, and during his previous training this had been carried out at 1500 feet. After some discussion another stall recovery was carried out, and on this occasion the pilot used the correct technique. The instructor then decided to return to the strip to carry out some circuits and landings as he assessed the pilot to be unsuitable to fly solo. The flying technique required by the instructor was generally at variance to that previously experienced by the pilot, and it would appear that the check flight was rather vigorous without the opportunity to become accustomed to the environment. During the return flight, the instructor described the circumstances which could cause the aircraft to stall during a forced landing with no power. To demonstrate this, he then closed the throttle at a height of between 300 and 500 feet, and asked the pilot to adopt a glide attitude, initiate a stall and then effect a recovery without the use of engine power. The pilot did not lower the nose sufficiently after the stall symptoms appeared, and he was told to further lower the nose, as a steep nose down attitude is required to effect this type of recovery. When the pilot did not commence to ease the aircraft out of the ensuing dive, the instructor called that he was taking over, but he was unable to move the controls. The pilot had become rigid at the controls, the instructor was unable to correct the situation, and the aircraft remained in a pronounced nose down attitude until ground impact.

Significant Factors:

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

1. The instructor was carrying out stalling practice at a low height.

2. The pilot mishandled the controls, probably due to misapprehension.

3. The pilot apparently panicked and became rigid on the controls when the aircraft was in a steep nose down attitude near the ground.

4. The instructor was unable to regain control of the aircraft before it struck the ground.

Recommendations:

The Civil Aviation Authority in conjunction with the Australian Ultralight Federation, should consider specifying minimum heights above ground level for ultralight aircraft engaged in stalling, spinning and unusual attitude recovery practice.