Circumstances:

The aircraft had been modified by the installation of an air driven winch for the purpose of towing gunnery targets and was operating in conjunction with a warship for scheduled sea/air gunnery practise. Weather conditions in the area were reported as overcast at 4000 feet, wind 060 degrees / 15-20 knots and visibility of 15-20 kilometres. At about 1717 hours the aircraft was instructed to commence carrying out gunnery tracking runs at an altitude of 1000 feet with the sleeve target not deployed. Between 1720 and 1735 hours the aircraft carried out two such runs from the west and east. The aircraft then tracked to the south, away from the ship to a distance of about 10 kilometres. At about 1738 the aircraft was instructed to turn inbound for a run from astern. At about 1739 hours the pilot reported engine problems and about one minute later advised "I've got problems, Mayday, I'm going in". Crewmen stationed near the stern of the ship, reported seeing the aircraft dive into the sea. The warship was immediately turned back towards the crash position. Other warships and aircraft were also ordered to the crash position. The only wreckage sighted was at the crash datum and was believed to have been a section of wing. This wreckage was located about two metres below the surface and sank before it could be recovered. The approximate depth of water at the crash position is 450 fathoms. No trace of the aircraft or its occupants has been discovered to date. The subsequent investigation established that the flight crew were properly qualified to conduct the flight, and that the aircraft was appropriately certified and maintained. The flight was conducted in accordance with the conditions of the operating contract. At the time of the occurrence the aircraft had not deployed the sleeve target, and no firing was being carried out. No evidence was found to suggest an in-flight structural failure or fire. The installation of the target towing equipment was not considered to have been a factor in the development of the accident. There was a loss of control of the aircraft following an apparent engine malfunction. The precise reasons for the accident have not been established.

Significant Factors:

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

1. Apparent engine failure or malfunction.

2. Control of the aircraft was lost for reasons which have not been determined.

Circumstances:

The aircraft, being flown by a pilot who had just completed type endorsement, was enroute Canberra - Talbingo - Albury at 6000 feet. Approaching Talbingo, the pilot noticed that the fuel gauges, which had each indicated three quarters full at Canberra, were indicating that only a small quantity of fuel remained. Suspecting that either a severe leak had developed, or he had made a serious error in fuel planning, the pilot elected to carry out an emergency landing in the Carabost area. To accurately report his position, the pilot attempted to tune the radio navigation aids to the Albury VOR, DME and ADF, without success. He then initiated descent and attempted, unsuccessfully, to transmit a MAYDAY call to Wagga Flight Service, Albury Tower and to broadcast on 121.5 MHz. On final approach to the selected landing point the pilot applied power, but the engine failed to respond. The aircraft touched down short of the intended landing point, bounced over a fence, and landed heavily in a paddock, collapsing the landing gear. The occupants evacuated the aircraft without assistance. Inspection of the aircraft the next day revealed that it had an adequate quantity of clean, water-free fuel in the tanks. Sufficient battery voltage was available to raise the flaps. The landing gear tracks on the ground indicated that the main landing gear had extended but had not locked down prior to landing. The descent had been carried out with throttle closed, mixture rich, carburettor heat on and cowl flaps open. To conserve fuel the pilot did not warm the engine during the descent. Consequently, low engine temperature, possibly combined with fouled spark plugs, prevented the engine from responding when the pilot sought power on final approach. The indication of low fuel quantity, combined with the inability to receive navigation aids and to transmit a radio message, plus the failure of the main landing gear to lock down are consistent with an electrical malfunction or low battery voltage. Overnight, the battery could have recovered sufficient charge to permit the flaps to be raised. Thus, an electrical malfunction and/or a loss of battery voltage, affecting the fuel quantity indicating system and misleading the pilot into believing that his fuel state was critically low, may have occurred.

Significant Factors:

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

1. An electrical malfunction and/or a low battery voltage may have occurred in flight.

2. The pilot was inexperienced.

3. The pilot misinterpreted the symptoms of the electrical problem as a low fuel state.

4. The pilot elected to carry out a forced landing in difficult terrain.

5. Following a prolonged descent at idle power with rich mixture, the engine suffered a loss of power on final approach. This accident was not the subject of an on-scene investigation.

Circumstances:

The pilot planned a pleasure flight which commenced in calm conditions. By the time the aircraft arrived back at the airstrip the wind was gusting north westerly at about 15 to 25 knots. The pilot assessed the wind direction and elected to land on the shorter north-south strip (about 330 metres long). On final approach the aircraft encountered strong turbulence and downdrafts. The pilot who had little experience in these conditions continued the approach until just prior to touchdown when he decided to go around and commenced a right turn. Whilst executing this manoeuvre the aircraft struck a log which was about 150 metres to the right and south of the strip.

Significant Factors:

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

1. A strong north westerly wind generated considerable turbulence making aircraft control near the ground difficult.

2. The pilot was inexperienced in windy and turbulent conditions.

3. The pilot attempted to go around from a low height.

4. The aircraft collided with a log.

Prior to takeoff the aircraft was cleared to track via a Standard Instrument Departure procedure referred to as (Runway) 21 Clackline 1. After takeoff the aircraft was observed to make an early left turn. The Tower controller kept the aircraft in sight to ensure that there was no confliction with another aircraft which was in the vicinity. It was determined that the crew of GIA 879 had flown a 21 Clackline 2 departure procedure. This procedure was on the adjacent page of the relevant document to the 21 Clackline 1 procedure.

The aircraft had been issued with an airways clearance to track from Ballidu to Perth. It was observed on radar to be diverging from this track until queried by Perth Air Traffic Control. The aircraft then turned in the appropriate direction but did not track directly for Perth until radar vectors were supplied. Maximum displacement from the cleared track was about 31 kilometres. The situation was constantly monitored by Air Traffic Control and no confliction occurred with any other aircraft. After landing the Captain advised that the primary navigation aid the Inertial Navigation System was giving erroneous information as to the actual position of the aircraft. Subsequent ground checking of the equipment failed to reveal any serious fault. It was considered that either the original computerised programme loaded into the aircraft system at Djakarta was faulty or the crew might have inadvertently introduced an error. Nevertheless other navigation equipment was apparently operating satisfactorily and would have indicated that the aircraft was not on the desired track. The procedures used by the crew to cross-check navigation information were not established. It was determined that the pilot who was a senior pilot in the company was conducting training to allow a First Officer to be promoted to Captain. It was possible that while concentrating on the training task the Captain allowed his attention to be diverted from the operation of the aircraft.

The pilot reported that he was flying straight and level at 200 feet above ground level(AGL) and about 55 knots when the aircraft sideslipped to the left and nosed over. The nose continued to drop to the almost vertical position and the speed built up to 60 knots. At about 100 feet AGL, the pilot attempted to pull out of the dive but the aircraft did not respond and struck the ground in the almost vertical nose down attitude. Eyewitnesses reported that the aircraft was in the circuit area when they saw a wing drop and the nose of the aircraft fall sharply. The AUF Safety Officer reported that the flying surfaces of the aircraft were undamaged and he suspected that a stall/spin DEPARTURE was experienced by the pilot. In addition to cuts and bruises, the pilot suffered compound fractures to both legs and his right arm. This accident was not the subject of a formal on scene investigation.

The pilot reported that he made a normal approach to land into a 10-15 knot wind. The flare for landing was initiated but the aircraft landed heavily, making first contact on the right mainwheel. The initial touchdown was some 8 metres beyond the boundary fence, 96 metres short of the strip end and 166 metres short of the marked threshold. The aircraft then bounced and touched down again on the strip 220 metres beyond the initial touchdown point. The pilot recalled that at this point he heard the landing gear warning horn sound and noticed that the right main gear safe indication light had gone out. The right wing then collapsed slowly and the aircraft slewed through 180 degrees as it came too rest on the wingtip about 550 metres from the first ground contact. There was some evidence that the approach was lower than usual and that windshear was present on the approach path. The right main undercarriage leg collapsed due to an overload failure of the bellcrank lugs.

The pilot had refuelled the aircraft to full tanks the previous day and then flown a total of 1.6 hours. On the day of the accident he completed a flight from Darwin of 1.1 hours duration. Four minutes after leaving Cooinda, at an altitude of 1000 ft, the engine failed and the pilot's attempts to restart the engine were unsuccessful. A forced landing was attempted into a short clearing but the aircraft over-ran the clearing and collided with trees. Investigation established that the pilot used the left tank but mistakenly recorded flying on the right tank for 1.6 hours the previous day and used the left tank again for 1.1 hours on the trip to Cooinda. On-site investigation established that the intact left tank was empty and right tank, although leaking, contained a significant amount of fuel. Other evidence established that the fuel gauges were not serviceable and the pilot did not select the electric boost pump to ON after changing tanks in his attempt to restart the engine. A series of engine run tests carried out after the accident showed no fault with the engine, and that the engine would recover after fuel exhaustion on one tank if the electric boost pump was selected ON after changing tanks.

As the aircraft became airborne the pilot heard a loud bang and upon inspection noticed that the left flap was holed and buckled. The elevator trim had also been damaged and was immovable. This resulted in the aircraft tending to fly in a nose high attitude. The pilot assumed that one of the mainwheels had been dislodged and decided to fly the aircraft to Townsville where emergency services were available. Enroute he was contacted by radio from Scartwater Station and advised that the aircraft was missing a mainwheel. After the pilot received advice from a flying instructor, the aircraft was successfully landed at Townsville. An inspection of the aircraft revealed that the left landing gear torque link bolt had failed as a result of fatigue cracking which had originated from a poorly machined lubrication groove.

The pilot had only recently regained flying currency and was inexperienced on type. He had suffered some frustration in gaining dispensation to return to Alice Springs without radio, and in having to vary his plans to stop off en route with his passengers who were also disappointed at the change in itinerary. On arrival at Alice Springs, the pilot joined the circuit for the non-duty runway which was out of wind. During the attempted cross-wind landing, the aircraft bounced and ballooned and the pilot did not take the correct recovery action. The aircraft landed heavily on the right wheel and then onto both main wheels. The pilot reported that he did not attempt to go-around off the bounced landing because he lacked the confidence to execute this manoeuvre with the aircraft configured with full flap. A subsequent inspection revealed damage to the right maingear leg which required replacement.