The pilot was tasked to fly parachutists to altitude where they would exit for a display at the Melbourne Masters Games.

Prior to any jumps, the pilot had held a safety briefing for about 50 parachutists involved in the event. According to the Safety Support Officer of the Australian Parachuting Safety Council, the safety briefing stipulated that every jumper would climb out onto the helicopter's landing gear skids and then leave one at a time at five second intervals without pushing off.

On about the eighth jump run, four parachutists climbed out onto the skids of VH-JGE. This placed two parachutists on the left skid and two on the right. The pilot flew from the right front seat, which is normal practice in a Bell 206.

When the helicopter was at 3,500 ft and 50 kts over Olympic Park, the target area, one parachutist from the left rear position departed the skid, immediately followed by the second parachutist from the left side. With the two remaining parachutists still standing on the right skid, plus the pilot in the right front, the helicopter's lateral centre of gravity limits were exceeded. According to the pilot, he was unable to prevent the helicopter from rolling to the right. At some point during the roll, the two parachutists standing on the right skid also departed. In the opinion of the pilot, the right side parachutists pushed off rather than stepping off and that the push aggravated the rate of roll. The roll continued through 360 degrees. The helicopter recovered at 70 kts after a height loss of six or seven hundred feet. The pilot advised that torque and rotor RPM limits were not exceeded during the incident.

After the incident the pilot landed and inspected the aircraft. He discovered evidence of a slight mast bump. He then flew the helicopter to Essendon where further inspections were performed by engineers. The main rotor mast was removed and checked for ovality and runout. The manufacturer was consulted during the inspections. When no fault was found with the helicopter, it was returned to service.

Just prior to the incident there had been some reorganisation of jump loads due to a six place helicopter arriving. The parachutists involved in the incident had, in rapid succession, been assigned to a four place load, then a six place load and finally to a different four place load. The Safety Support Officer subsequently determined that the two parachutists on the left side thought that all four parachutists were going to exit simultaneously on an exit count of `ready set go' given by the parachutist on the front left. The parachutists on the right side had previously briefed with a different group which had planned to exit alternatively left and right at five second intervals; they believed this was the standard briefing and had not discussed it with the left side jumpers after being reassigned to the Bell 206.

Since the incident, the Australian Parachute Federation, via a News Sheet and News Letter, has reinforced the importance of the pre-jump safety briefings, and the exit practice. Also, parachutists have been reminded of the need for extra care at special events where normal exit procedures may be varied due to operational requirements.

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

1. The pre-jump safety briefing was probably inadequate.

FACTUAL INFORMATION

A short local test flight was planned to verify scientific equipment installed in the aircraft before it embarked on an atmospheric research flight.

The take-off was normal from runway 03, and after climbing through 500 ft the pilot reduced the manifold pressure and RPM settings of both engines from take-off to climb power. Sometime after this he turned the auxiliary fuel pump switches from low to off. At 1,500 ft a vibration, which appeared to have originated in the left wing, was noticed by both the pilot and the data systems operator, who also held a private pilot licence endorsed on the aircraft type. They said that the left tip tank seemed to move through 10 - 15 mm, and the equipment pod, mounted on the underside of the left wing moved in the same plane and frequency. The right alternator warning light then illuminated.

Both pilots decided that it would be more prudent to return than continue the flight. The data systems operator suggested that because of the vibration a slow airspeed should be maintained during the descent. The pilot noticed that the airspeed indication was 115 kts, and believed he carried out the descent without any change to the power settings. He notified the control tower of his intention to return, but without advising the actual reason.

Approaching base leg for runway 03 the pilot reported that he selected 10 - 15 degrees of flap, and that the data systems operator extended the landing gear without consulting him. The data systems operator stated that it was after the aircraft had turned onto final approach, he noticed the landing gear selector lever was between the retract and extend positions and moved it to the extend position. He also attracted the pilot's attention to the airspeed, which had dropped to 82 kts, this being only several knots above the stall speed for the aircraft in its present configuration. The pilot advanced both throttles to reduce the high sink rate which had developed due to the slow forward speed, but neither engine appeared to respond. The throttles, pitch levers and mixture controls were then fully advanced, but still without any apparent response from either engine.

The pilot then realised it would be impossible to land the aircraft on the aerodrome, and a forced landing was inevitable. He thought he noticed the data systems operator selecting the flaps up at about this time, although the data systems operator could not recall doing this. As the data systems operator had more flying experience on the aircraft, and also being a glider pilot familiar without landings, the pilot considered him better qualified to carry out the forced landing, so gave him control. The data systems operator then had just enough time to ensure that the wings were level and initiate a flare, which failed to arrest the high rate of descent.

The aircraft impacted the ground heavily on a golf course adjacent to the runway threshold. Both main gear legs failed and separated, the nose gear leg remaining in situ still extended. The aircraft continued along a fairway for 230 m in a direction of 023 degrees, colliding with an automatic sprinkler system control unit, which buried deep into the left-wing root area. The aircraft then struck two small trees. This turned the aircraft to the right before it came to a stop on a heading of 090 degrees. The pilot and data systems operator sustained minor injuries.

The landing gear was found to be extended, with its selector in the corresponding down position, and the flaps retracted with its selector in the up position.

Ground slash marks, and damage to all propeller blades indicated that the engines were operating at impact. The right propeller had all blades bent back, one blade severely bent, with lesser bending on the other two, indicating that each blade had contacted the ground before the engine stopped. Two of the blades also had forward bending tendencies, but marks on the blades indicated they had been buried in the ground when stationary, and this bending occurred as a result of the aircraft turning at the end of the ground run. All blades on the left propeller were bent back in a gradual curve, the bending again corresponding with each blade contacting the ground before the engine stopped.

Witnesses who observed the aircraft on its final approach reported hearing engine noise. Black smoke was also noticed coming from the right engine, and several backfiring sounds were heard.

After the accident, when the pilot was securing the cockpit and turning off electric power, switches, and fuel, he noticed that an auxiliary fuel pump switch was in the high position. He could not recall this pump being turned on at any time during the flight. An inspection revealed that the right engine exhaust pipes had deposits of soot, but none at the outlet or along the underside of the nacelle. There was no soot in the left engine exhaust pipes.

All fuel filters were found to be clear of contamination, there were no obstructions in the fuel lines from the tanks to engines, and normal quantities of fuel were found at the engines in the fuel control units and distributor valves. Laboratory testing found no problems with the fuel.

No faults were found with the ignition systems which may have caused both engines to fail.

All external pods and probes were correctly attached, and no damage or defects could be found which may have contributed to the reported inflight vibration.

Both engines were inspected and no defects found which could have affected their operation. They were then installed in an engine test stand and ran normally at all power settings, responding correctly to all throttle movements.

The aircraft had been operated in the private category. The flight manual states that pilots required to operate the aircraft must be trained and approved to fly this particular aircraft when configured for atmospheric research with external pods, pylons and probes fitted. The pilot had undergone several hours of familiarisation training 12 months previously but had not flown the aircraft since. The operator did not conduct recency checks or give continuation training for pilots.

ANALYSIS

An inspection of the aircraft and its ancillary pods, pylons and probes failed to find any looseness, faults or any other airframe problems which may have caused the inflight vibration. It is possible that slight turbulence may have produced the effect. Illumination of the right alternator light was not considered as having contributed to the accident.

Both engines were found to be serviceable and capable of delivering full power. The propeller slash marks in the ground and damage suffered by the propeller blades before the engines stopped indicated that they were developing power at impact.

It is possible that the right auxiliary fuel pump was accidentally turned on as the pilot turned the pump switches from low to off during the climb. This would have produced a rich mixture in the right engine with associated rough running and vibration. It would also account for the deposits of soot in the right engine exhaust pipes, and the smoke seen by the witness.

While returning to the aerodrome the pilot stated that he did not adjust the engine power settings for the descent to circuit height. Due to possible task saturation, he probably reduced the power without realising it, otherwise, with its engines operating normally, the aircraft would have accelerated. During this time however, the airspeed deteriorated from 115 kts to 82 kts.

The pilot selected 15 degrees of flap on base leg, and then after turning final was warned of the slow airspeed by the data systems operator, who had extended the landing gear, causing more drag. The aircraft would have been near its stall speed, with a subsequent high rate of descent. This would have been exacerbated if the data systems operator had raised the flaps, which he could not recall doing.

When the pilot opened the throttles, he may have gained the impression that the engines were not developing power as the aircraft would have continued its rapid descent. With all the unusual activity going on it is possible that the pilot failed to register an increase in engine noise. The application of power probably prevented a stall developing, with subsequent loss of control.

There was no evidence found to indicate that both engines had suffered failures simultaneously and were not capable of responding to throttle movement.

SIGNIFICANT FACTORS

1. A possible rich mixture on the right engine may have caused an inflight vibration.
2. The pilot and data systems operator became worried about a vibration, and did not monitor the aircraft's progress adequately.
3. The pilot was not current on the aircraft and allowed the airspeed to deteriorate with the aircraft developing a high rate of descent.

The glider was on an aero tow take off. On the ground roll the right wing contacted the ground and the glider veered to the right of the tug. Corrective control inputs were applied and the glider moved to the left side of the tug. The glider pilot pulled the release. The glider went through a cartwheel manouver and the nose struck the ground heavily.

Significant Factors

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

1 Probable inappropriate control inputs by the glider pilot.

During the landing roll, at about 60 kts, the pilot inadvertently selected the gear up when he intended to raise the flaps.

The nose and left main gear collapsed. The aircraft came to rest on the runway near a taxiway.

The glider was nearing the end of a 190 km cross country flight. The weather was fine, with good visibility and light west to north westerly winds. At about five km from the airfield the pilot decided to descend from 3,500 ft by increasing airspeed to 116 kt, some 3 kt less than the maximum airspeed limit.

The pilot reported that initially the glider was flying normally at this speed, but suddenly the control stick was pulled from his grasp and vibrated back and forth, banging against its stops. He managed to regain his hold on the stick and began to raise the nose of the aircraft to reduce airspeed. At this point the glider rolled into an inverted attitude.

Believing that the aircraft had suffered a major structural failure, the pilot elected to escape from the cockpit and make a parachute descent. Initially, he experienced difficulty in releasing the canopy, but once open he fell freely from the glider. The pilot made a successful parachute descent, whilst the glider proceeded to land in bushes, sustaining minimal damage.

During a subsequent airworthiness inspection by the gliding authority, it was found that the mass balance of the tailplane was beyond limits. The out of balance condition had apparently occurred some three years previously when the glider had been rebuilt. As a result, elevator flutter had occurred as the aircraft reached its maximum airspeed limit. Under normal circumstances the critical airspeed for the onset of elevator flutter should have been well in excess of the maximum airspeed limit. 

The gliding authority has advised that it has taken action to prevent a recurrence by issuing an airworthiness directive, and conducting surveillance of the maintenance organisation concerned.

The student pilot was conducting a solo navigation exercise. On arrival in the Goulburn circuit area, he elected to land on runway 04, having observed that the wind was northerly at about 10-15 kts. Shortly after turning onto base leg the pilot realised that the wind was gusting.

During the landing flare the aircraft was struck by a strong wind gust which caused it to be displaced from the runway alignment. While the pilot was attempting to re-align the aircraft with the runway a second wind gust caused the left wing to drop and strike the runway grass verge.

The pilot recovered control of the aircraft and completed the landing without further difficulty.

Significant factor

1. The pilot did not conduct a go-around following the first upset.

Kiwi 52, an A4 Skyhawk, on a missed approach from a runway 35 ILS approach, had been issued with missed approach instructions to maintain runway heading and maintain 6000 feet. When Kiwi 52 was about four miles north of the aerodrome, the aircraft was instructed to turn right heading 070 degrees and to climb to and maintain 6500 feet. The altitude restriction was to maintain separation with VH-PZL, overflying at 7500 feet.

As Kiwi 52 approached VH-PZL, Kiwi 52s altitude readout reached 7400 feet. When asked to confirm his level, the pilot of Kiwi 52 reported maintaining 6500 feet. Kiwi 52 was passed traffic information on VH-PZL. Shortly afterwards Kiwi 52s altitude readout returned to 6500 feet. The two aircraft closed to about two miles radar separation with Kiwi 52 passing behind VH-PZL.

Factors

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

1. The pilot of Kiwi 52 failed to follow an air traffic control instruction to maintain an altitude.

The right side of the strip was temporarily unavailable for take-off due to a glider with an unserviceability returning for a landing. A tug aircraft was parked off the left side of the strip. Following a discussion with the pilot of the parked tug a decision was made to take off on the left side of the strip. During the ground run the left wing dropped to the ground, the glider veered to the left and the wingtip struck the left main gear tyre of the parked tug. The glider was substantially damaged.

The aircraft landed beside the strip during light rain. The pilot said that he thought that he had lined up to land on the strip to the right of markers on the left side. What he had seen were the right side markers and inadvertently landed on rough ground to the right of the marked strip. The aircraft struck an obstacle (not identified) in the long grass and was substantially damaged.

The pilot later said that he felt fatigued after a full day's flying.

The aircraft was taking off from a bush strip. The pilot said that the take-off run took about 600 m of the 800 m available. However, the aircraft failed to climb away so the pilot rejected the take-off at a late stage. The aircraft was landed beyond the end of the strip, amongst saplings and trees.

The pilot attributed the lack of performance to a partial power loss, although he had not heard a change in engine note, nor had he noticed any abnormal engine indications. During subsequent testing of the engine, full power was able to be achieved. Two other pilots later stated that the strip surface was affected by soft sand, and only had a usable length of about 500 m. The aircraft performance charts indicated that a take-off roll of approximately 600 m was required under the prevailing conditions.

It is considered likely that the pilot attempted to fly the aircraft off the ground prematurely. As a result, the aircraft climb performance was adversely affected by induced drag.