More than usual forward trim was required during and after take-off. The autopilot trim actuator ran out of forward trim and then ran continuously to full aft. The crew were unable to adequately manually trim forward. The aircraft returned for a normal descent and landing.

The autopilot Mach trim actuator was found to be inoperative. The actuator had been fitted during overnight maintenance and the observed problem occurred on the first flight after installation. Ground test procedures after installation had not shown up any problems.

Workshop rectification found anomalies with the backlash on the jackscrew and with the actuator length. The manufacturer advised that these anomalies would not have caused the problem that was experienced.

The actuator was refitted four days after the workshop check and has since operated satisfactorily. The cause of the inflight problem was not discovered.

While VH-CZE was lining up a helicopter was cleared for take-off from the southern end of the parking areas to the west of the runway. The helicopter was instructed to remain west of the flight strip and to cruise not above 500 ft.

The helicopter pilot maintained the runway heading for about one mile past the end of the runway before slowly moving left to track around the coast to his destination adjacent to the Cairns city area. When he started to move left VH-CZE was in the latter stages of the take-off. As the crew had expected the helicopter to remain west of the centreline and it had now drifted into their path, they abandoned the take-off. The helicopter was maintaining 400 ft at that time.

The tower controller intended that the helicopter should remain west of the runway until he instructed otherwise. The helicopter pilot was new to the area and did not fully understand the intent of the instruction.

The two aircraft departed Bundaberg on flights scheduled for the same time. Both intended tracking direct to Brisbane at 9000 ft. The same flight pattern had been operated for some months. As a general rule VH-FCU departed first because of the start procedures required by VH-XFO. Because VH-XFO was faster in flight it was normal for that aircraft to overtake VH-FCU during the latter stages of the climb. Both aircraft would continue at their planned altitude with the crews knowing that the faster aircraft was in front and that the distance between the two aircraft was increasing.

On this occasion VH-XFO was overtaking VH-FCU and when about two miles behind that aircraft was turned onto a southerly heading. When the crew were satisfied that they had passed VH-FCU they turned to intercept their direct track (151 degrees). The climb was continued, and some turns were made to remain in visual flight around cloud build-ups. After reaching 9000 ft and cruise speed the crew of VH-XFO advised that their ground speed was 215 kts. The speed of VH-FCU was 200 kts in the cruise.

Some time later, after VH-FCU came out of cloud, VH-XFO was seen at the same level and about 50m to the right. The crew of VH-FCU immediately turned left and descended. The crew of VH-XFO saw the other aircraft and commenced a climb to 10000 ft. VH-FCU was subsequently returned to 9000 ft.

Examination of recorded radar data confirmed the pilots' reports. The two aircraft were less than one mile apart before VH-XFO turned right to increase their spacing. When the aircraft reached their cruising altitude, they were about 4 NM apart and VH-XFO was starting to move ahead of VH-FCU. When the crew of VH-XFO commenced their return to the planned track they conducted an intercept of about 30 degrees. This was later increased to 45 degrees when some manoeuvring around cloud was made. During this period the ground speed also reduced by up to 20 kts. As a result, when VH-XFO was turning, having intercepted the desired track, the two aircraft were in very close proximity to each other.

SIGNIFICANT FACTORS

1. Both flights scheduled to depart at the same time.

2. Both flights elected to utilise the same cruising altitude.

3. The crew of VH-XFO did not realise the implications of:

• diverting off track;
• manoeuvring around weather; and
• making a large-angle intercept of track.

4. The crews did not maintain adequate surveillance on their relative positions.

The pilot reported that during the take-off roll the aircraft accelerated to rotation speed. It was then that the pilot felt that the aircraft performance was not normal and rejected the take-off. The aircraft overran the end of the 1100 m strip and struck a log hidden in grass. The left main gear collapsed.

The crew of VH-MVW reported that the Mackay-Proserpine leg was flown OCTA. They requested traffic from Flight Service prior to descent and were given no IFR traffic. Transfer to Proserpine MTAF was made at 15 DME and an inbound call made with no reply. A further call was made on entering downwind for runway 11. Again, there was no reply. When VH-MVW was on short final approach for runway 11, a Cessna aircraft was seen crossing from right to left at low altitude over the other end of the runway. As the aircraft turned off the runway, a parachutist was seen descending into the aircraft parking area opposite runway 06/24. The crew were not previously aware of the aircraft or the parachutist.

The pilot of the parachuting aircraft reported that he had been cleared to climb into controlled airspace to 8500 ft for the drop. He was given VH-MVW as traffic Mackay-Proserpine. His aircraft was equipped with only one VHF radio. He transferred to MTAF frequency three minutes prior to the drop advising intentions. After the drop, he transferred to the MTAF passing 4000 ft and advised his intentions. At no time did he hear a call from VH-MVW.

A significant aspect to this incident was that VH-MVW was on Flight Service frequency while the parachuting aircraft was on the area control frequency. The indications are that each aircraft crew was complying with procedures in terms of MTAF operations although it is puzzling that VH-MVW did not receive any of the calls reportedly made by VH-DBP on returning to the circuit area. The situation was exacerbated by the pilot of VH-DBP having only one VHF radio and not being able to maintain a continuous listening watch on the MTAF.

Parachuting has been in operation at Proserpine for approximately two months. At this stage, the relevant maps and charts do not display the parachuting symbol at the Proserpine location.

Safety Action

1. An arrangement has been established whereby the parachuting organisation will advise Flight Service when parachuting operations are going to take place. This will enable Flight Service to advise IFR aircraft of such operations.

2. The parachuting organisation has undertaken informally to ensure that aircraft engaged in parachuting operations are dual VHF equipped.

3. The question of map and chart amendment to show parachuting operations at Proserpine has been referred to Air Traffic Services.

The pilot was taxiing the aircraft for take-off. The taxiway runs adjacent to the verandah of the Wagin Aero Club. As the aircraft passed the Aero Club, a book that the pilot was using fell to the cockpit floor. The pilot reached down to retrieve the book and as a result his attention was distracted from control of the aircraft. The left wing, outboard leading edge, collided with a verandah post causing substantial damage.

Because of the condition of the strip, the technique the pilot used for take-off was to set 20 degrees flap and apply almost full back elevator control to lift the aircraft off the ground at low airspeed and to then accelerate in ground effect before climbing away. On this occasion, after lift-off at 55 kts, the control column became jammed near the fully back position. The aileron control was partially jammed.

At about 300 ft, with the aircraft in a high nose attitude and the airspeed decreasing through 40 kts, the pilot reduced engine power and the nose attitude decreased. He was able to climb the aircraft to about 500 ft and maintain pitch control through the use of engine power and flap. The rudder was used for roll control.

The pilot conducted a straight-in approach to Inverell and landed safely.

Post-flight inspection revealed that a multi-pin plug had become detached from an ADF indicator unit in the instrument panel. The plug had lodged in the slide channel for the control column, thus causing the restriction.

The aircraft was departing Bundaberg on the second leg of a ferry flight from Brisbane to Rockhampton. The take-off was rejected, during the initial stages of the ground roll, after the pilot noticed a low manifold pressure indication for the left engine.

During the subsequently ground run to determine the cause of the low manifold pressure, smoke was observed coming from the left engine compartment. The engine was immediately shut down and the engine fire extinguisher activated.

Later examination of the engine found that the right exhaust collector for the turbocharger had broken away, near a slip joint coupling. Hot exhaust gases escaping past the broken section caused extensive heat damage to the lower inboard engine nacelle skin and the right engine bearer.

Specialist metallurgical examination of the failed pipe has concluded that the exhaust pipe had failed due to high temperature corrosion. It further concluded that the failure was initiated by localised hot pitting attack (corrosion) on the inner surfaces of sections of the exhaust system. In one section of the pipe, pitting had led to the perforation of the weld deposits in the lap joints. A second failed section showed extensive pitting around the circumference of the pipe which led to separation of that section. The report advised that the development of the pitting attack responsible for the failure of the exhaust system was dependent on the combination of a number of factors.

The deposition of oxides from the products of combustion, predominately lead oxide.

The reaction of these oxides with the oxide film formed by the heat-resistant alloy in response to exposure to elevated temperatures.

Operating the engine under conditions which result in the temperature of elements of the exhaust system exceeding the melting point of the oxide mixture.

Features of an exhaust system, such as bends and slip joints, that increase the temperature locally or concentrate the products of combustion may also contribute to the development of localised pitting attack.

During the investigation other evidence was obtained which indicates the engines for this aircraft may have been operated for extended periods at excessively lean settings. It is probable that this lean operation provided the elevated temperatures which was one of the contributing factors in the initiation of the localised pitting attack (corrosion).

The aircraft was engaged in spreading Gypsum from an airstrip with an elevation of 3,200 ft. Take-offs and landings were conducted towards the west, with the wind varying from the northwest to the southwest and increasing in strength. The pilot reported he had encountered high sink rates and turbulence in the treatment area on previous flights.

Acceleration and lift off during the next take off appeared normal but the aircraft almost immediately began to sink. The pilot lowered the nose and activated the load dump system. However, the sink could not be arrested, and the aircraft collided with a fence. The engine and both wings were torn off.

About 10 minutes after departing Bankstown for a local flight, the pilot noticed a reduction in engine RPM. Believing the throttle friction had become loose, he increased the throttle setting and tightened the friction. Soon after, the RPM again decreased so the pilot commenced to turn back towards the airport. During the turn the engine oil pressure indication decreased to zero. The pilot advised the tower of the problem, and of his intention to land on an abandoned airstrip. The engine was shut down after it began to vibrate, and the pilot informed the tower that a forced landing would be carried out in a field. During the subsequent landing the nosewheel entered a drain and the aircraft overturned.

Investigation later revealed that a connecting rod bolt had failed, resulting in a loss of oil pressure and subsequent engine failure.