Loss of control

Circumstances:

The flight from Orchid Beach was to transport three passengers to Hervey Bay where they were booked on a scheduled flight departing at 1215 hours. The aircraft arrived at Orchid Beach at about 1200 hours, and the pilot hastily loaded the aircraft and departed. The take-off appeared to be normal. The aircraft was seen to make a right turn at about 250 feet above the ground, level with a ridge to the southwest of the aerodrome. The turn was made abruptly, with about 45 degrees of bank. Witnesses then saw the bank angle reduce, and at the same time the aircraft began to lose height. The aircraft was last seen when it was diving in a 45 degree nose down attitude. The aircraft impacted the ground near the base of the ridge. The impact angle was 58 degrees below the horizontal, with a bank angle of 118 degrees and an aircraft speed at impact of approximately 80 knots. No defects were found with the aircraft that may have contributed to the development of the accident. The wind at the time was easterly at about 35 knots, and this would have generated considerable mechanical turbulence in the vicinity of the aerodrome due to the local topography. The behaviour of the aircraft during the moments preceding impact was consistent with a stall leading to loss of control. The wind conditions, excessive bank angle, and control manipulation may have all been contributory.

Significant Factors:

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

1. The pilot was in a hurry to depart and did not climb to a safe height before making a turn downwind in turbulent wind conditions.

2. The pilot apparently did not maintain sufficient airspeed for continued flight under the prevailing circumstances.

Circumstances:

The student pilot was carrying out a touch-and-go landing on his first solo flight. He stated that soon after touchdown the aircraft swerved to the left of the runway centreline and did not respond to his efforts to correct the situation. The aircraft left the runway and travelled for some distance across the grass verge before demolishing a fibreglass boundary marker. The nose gear then separated as the aircraft came to a halt against the bank of a drainage ditch, approximately a hundred metres from the runway. The pilot stated that the aircraft speed was between 70 and 75 knots at touchdown. He said that as soon as the aircraft had settled onto the runway, he retracted the flaps and was in the process of advancing the throttle for take-off when the aircraft veered to the left. Examination of the tyre marks showed that the aircraft was wheelbarrowing and skidding sideways when it left the runway. The elevator trim was found positioned approximately midway between the neutral and the nose down position.

Significant Factors:

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

1. The pilot was inexperienced.

2. The pilot mishandled the flying controls and caused the aircraft to wheelbarrow.

3. The pilot lost directional control of the aircraft.

Circumstances:

The pilot, who was relatively inexperienced, was engaged in pasture spraying, operating from an airstrip located on the property being sprayed. He had been on duty approximately seven hours when commencing his nineteenth flight. After take-off, the pilot initiated a shallow climbing turn onto a southerly heading, affording himself little time in which to review his flight pattern before gaining alignment for the spray run. He began spraying at tree height until the area became sufficiently open to permit descent to about one metre above ground level. Approaching the fence which formed the southern boundary of the treatment area, the pilot initiated a climbing turn to the right, to follow a "racetrack" pattern. Soon after commencing the turn the pilot realised that the aircraft could not climb fast enough to maintain clearance from the hill beginning on the southern side of the treatment area. The pilot dumped the hopper load, and with full throttle attempted to turn across the face of the hill. The aircraft mushed onto the hillside, coming to rest 41 metres from the initial impact and 150 metres from the fence pull-up point. A left turn following pull-up would have taken the aircraft over lower terrain.

Significant Factors:

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

1. The pilot turned toward terrain, the gradient of which exceeded the performance capability of the aircraft.

2. The pilot gave himself insufficient time for adequate flight review.

3. The pilot may have been subject to some skill fatigue.

Circumstances:

The aircraft was being flown for a visual night circuit to runway 11 after completing an instrument approach. The wind was reported as 5 to 10 knots from the south-west. The pilot reported that after touchdown the aircraft commenced to veer to the right. Although left braking and steering was applied, the aircraft continued to veer until it lurched to the right and stopped, as though the right wheel had become bogged. After vacating the aircraft, the pilot found the right main gear oleo had broken away and the aircraft was resting on the right main gear mount, which had dug into the runway surface. A metallurgical examination of the landing gear showed that the inner oleo strut tube had failed as a result of the propagation of a fatigue crack to a critical length. No manufacturing fault was detected; however, the landing gear had a high total time in service history. No other failures of this type are contained in Civil Aviation Authority records, and it is considered that it may have been a "one-off" event.

Significant Factors:

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

1. The landing gear had a high total time in service.

2. Tensile failure of bronze filler in a fatigue and/or large loading environment.

3. Fatigue fracture of inner oleo strut tube.

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.

A number of witnesses observed the aircraft operating in the accident area. A common observation was that it was operating at a lower height (probably between 500 and 1000 feet above ground level) than was usually seen of other light aircraft flying over the area. The aircraft was seen to complete a number of level orbits over a chicken farm and then to head south for about two kilometres. While this was occurring the engine sound died and picked up again a few times, as if the pilot was practising setting the aircraft into a glide. The aircraft then flew a level left turn through about 270 degrees before suddenly entering a 30 to 40 degree dive. At close to tree-top height it abruptly changed attitude and entered a steep, perhaps vertical, climb. Some witnesses felt that the pilot was about to fly a loop. As the aircraft climbed, the speed rapidly decayed. During these manoeuvres, the engine note was heard to die and pick up twice. The aircraft was then observed to fall, nose first and right wing slightly low, into a near vertical dive. Apart from completing one or possibly two rotations, it remained in this attitude until lost from sight amongst trees. The aircraft impacted the ground in a 90 degree nose down attitude. When recovered from the wreckage the airspeed indicator was indicating 105 knots. It was established that the engine was operating at impact. No evidence was found of any abnormality in the aircraft or its systems which may have contributed to the accident. No explanation was found for the apparent operation of the aircraft at a relatively low height, or for the dive to a very low level followed by the steep climb. The carburettor fitted to the engine was equipped with an accelerator pump. A characteristic of carburettors of this type is that rapid or "slam" opening of the throttle can temporarily over-fuel the engine and cause the RPM to fluctuate for a short time. It could not be determined whether this characteristic may have been associated with the engine note dying and picking up twice as heard by witnesses in this instance. Investigation established that the the passenger occupying the front right-hand seat had flown 33 hours dual and 3.5 hours solo on Cessna 152 aircraft during 1983/84. The front seats of the aircraft were adjustable fore-and-aft along rails attached to the floor. Examination of the cockpit revealed the adjustment of the front left-hand seat (occupied by the pilot-in-command) at impact to have been five notches from the front. The front right seat was positioned in the forward-most notch. Tests of these seating positions were conducted in another PA28 aircraft using persons of the same height as those involved in the accident. These tests indicated that the right seat occupant should have been able to comfortably manipulate the engine and flying controls of the aircraft. However, the left seat appeared to be too far to the rear for the pilot-in-command to have been in a normal flying position in relation to the controls. Specific flying techniques are required to recover an aircraft from an extremely nose-high attitude at low speed. The aircraft involved in this accident was observed to develop such an attitude accompanied with low speed, and the low height at which this occurred would have increased the level of pilot skill required to return the aircraft to a safe flight environment. It was established that the pilot-in-command had received no training in the flying techniques required to recover aircraft from unusual attitudes. The seating position tests suggested that the pilot-in-command may not have been manipulating the controls during the final stages of flight, and it is also probable that the person occupying the right-hand seat had not received any training in recovery from unusual attitudes. It is considered probable that once the aircraft had reached the nose-high attitude at low speed, that it was beyond the experience level of either of the front seat occupants to effect a safe recovery, particularly in view of the low height of the aircraft at the time.

Until the day prior to the accident the pilot had not flown for over three months. He was carrying out a period of touch-and-go landings. On about the third or fourth landing the aircraft was apparently caught in an area of sink at the approach end of the strip, and touched down in a flat attitude and bounced slightly. The aircraft was recovered and touched down again in a normal attitude. The pilot lowered the nosewheel onto the strip, then applied power to go-around. The aircraft was observed to become light on the mainwheels and commence a swing to the left. As the swing increased the right wingtip hit the ground and the nosegear leg broke off. The aircraft slid to a halt on the mainwheels to the left of the flight strip.

Circumstances:

During a period of low operational activity, the pilot was contracted to spray a crop in open, flat terrain. Having almost completed the irregular shaped area, the pilot positioned his aircraft to make a run over a very small corner of the crop, towards a clump of trees, some of which were up to 25 metres high. The pilot mis-judged his turn onto the run alignment, necessitating a steep approach. Once settled at spray height, he was faced with a very steep climb-out to clear a large tree. During the pull-up, the aircraft stalled and collided with the tree. The nose pitched down, and the aircraft impacted the ground in a near vertical attitude, before rolling inverted. The pilot extinguished a small fire.

Significant Factors:

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

1. The pilot attempted to spray an area which was only marginally suitable for aerial treatment.

2. The pilot mis-judged his approach to the area.

3. The aircraft stalled during the pull-up.

Recommendations:

The Civil Aviation Authority reassess recency requirements for agricultural pilots to place emphasis on hours flown during the preceding 90 days. This assessment should take into consideration the type of operation the pilot is to return to following an extended break, or period of very low operational intensity.

The pilot had landed at the one-way agricultural strip in order to deliver covers for a load of superphosphate. The subsequent take-off was normal until the point where the tail of the aircraft was raised. At this time the aircraft was affected by a strong wind gust, and the pilot was unable to maintain directional control. The aircraft ran off the side of the strip and struck scrub and a steel fence post. The wind at the time was relatively strong, giving a substantial downwind/crosswind component. Although the pilot had operated from this strip on numerous occasions, he had not worked from it for about 12 months. The strip posed difficulties because it changed direction to the right over the crest of a hill. Due to a strong left tailwind, the pilot had to maximise the take-off run available. The path chosen, combined with the prevailing wind, took the aircraft off the right side of the strip before it had attained flying speed.

The glider was being winch-launched from strip 36. During the launch, the left wingtip dropped into lush vegetation covering the strip. The glider rolled rapidly to the left around the wingtip, until it was inverted. It impacted heavily in this attitude and came to rest 96 metres from, and 15 metres to the left of the take-off point. A 15-20 knot north-easterly wind was blowing at the time and the right wing was seen to lift as the left wing contacted a reasonably heavy cover of dandelions which were 30-40 centrimetres tall. The pilot had activated the manual release and the winch operator stopped the launch when the glider adopted the acute roll angle, but both of these actions were too late for recovery to be achieved prior to impact. Due to soggy conditions, the gliding club had not used the strip for the previous 2 months, and had not mown the surface prior to recommencement of operations.