The pilot intended to fly the balloon to Jacobs Well, due east of his take-off point at the Coomera Golf course. When the balloon rose to about 100 ft above ground level, he saw that extensive areas of fog covered the ground in the vicinity of Jacobs Well. He rejected the flight and landed back on the golf course in the middle of a fairway, only 70 m from his take-off point.

He called his ground crew assistant over to tow the balloon by a trailing rope to the edge of the fairway as he did not want to bring the recovery vehicle onto the fairway. His passenger had left the basket, but the ground crew member had difficulty moving the balloon. The pilot decided to swap places with her. The ground crew member operated the balloon's burners as required and the pilot towed the balloon to the side of the fairway. When the balloon touched trees, the gas was turned off at the tanks and the envelope deflated. As it did so, the basket rolled onto one side on sloping ground. The ground crew member struck her head on the burner controls lighting both burners for several seconds as the gas burnt out of the supply lines.

The ground crew member received burns to the upper part of her body, including inhalation damage to her oesophagus. The pilot received minor burns.

A witness reported that, after turning base for runway 12, the aircraft began oscillating in pitch as it continued a shallow descent. The aircraft crossed the extended centreline of the runway and struck a tree at the edge of a public car park. This caused the aircraft to break up, part of it falling on an unoccupied vehicle.

The pilot is reported to have indicated that the aircraft stalled and that he was unable to recover to normal flight before colliding with the tree.

The pilot had completed two thirds of the task of spraying a field of cotton which was bounded by a road and powerlines at one end. The pilot had been flying under the wires and had kept a watch for traffic along the road. On what turned out to be his last pass, he again lined up to fly under the wires. As he approached the wires, he saw a truck travelling along the road, on a collision course with his aircraft. Trees had obstructed the truck from view. As the pilot took avoiding action, the right mainwheel of the aircraft struck the road surface. The right main gear was bent backwards. The pilot flew his damaged aircraft to the airstrip and landed. At a slow speed it ground looped and came to rest without any further damage.

The purpose of the flight was to conduct an instrument rating renewal which included an instrument approach to Devonport. As the aircraft broke clear of cloud, the pilots became concerned that the aircraft was considerably lower than expected. Flight instrument indications appeared normal, both during and after the flight. Subsequently, the supervising pilot queried the Melbourne Regional Briefing Office (RBO) regarding the accuracy of the Automatic Terminal Information Service (ATIS) broadcast, on which the instrument approach had been conducted.

The pilot believed that the QNH was in error by approximately 12 hectopascals (hPa), resulting in the aircraft being approximately 360 ft lower than expected, and the wind was from the opposite direction.

Checks by the RBO indicated that the Bureau of Meteorology had not issued a current Devonport aerodrome Meteorological Report (METAR). This was due to the report message generated by the automatic weather station at Devonport being rejected by the Bureau of Meteorology computer.

The relevant air traffic service (ATS) officer had unknowingly broadcast an invalid Devonport METAR stored within ATS computer systems. Internal investigations by ATS revealed that as a result of a software problem, and the absence of a current Devonport METAR, the previous issue (24 hours old) had been retained and broadcast in error. Had a new, valid METAR been received it would have over-written the older, invalid message.

The QNH used for the approach was 1010 hPa in lieu of the actual 996 hPa, placing the aircraft approximately 420 ft lower than expected. The ATS computer system does not provide the origin time of the METAR. This was a fail unsafe deficiency.

The Civil Aviation Authority took immediate actions to prevent a recurrence by implementing revised procedures in the national communications centre.

The following factors contributed to the development of the occurrence:

• The Devonport automatic weather station report was rejected by the Bureau of Meteorology computer.
• ATS officer unknowingly broadcast an invalid METAR.
• ATS computer error.
• ATS computer failure to provide message origin time for metar.
• This resulted in the pilot being provided with an incorrect QNH.

Circumstances

About 20 minutes after take-off, while cruising at 3,000 ft and 128 kts with the autopilot engaged, the pilot in command heard or felt a bang which was immediately followed by a high-frequency, high-amplitude vibration. The vibration was such that the crew were unable to read the outboard instruments, both skid balls were fully deflected towards the centreline of the aircraft, and the horizontal situation indicator slaved some 60 degrees off heading and oscillated through 30-40 degrees. The co-pilot reported that the vibration through the cockpit floor made his feet go numb.

The pilot in command altered heading for a return to the rig. All controls appeared to be operating normally and the only warning light to illuminate was the number one elevator light which went out when the system was reset.

Speed was reduced to 60 kts and the aircraft was descended to 200 ft as a precaution in the event of a failure. The change in airspeed and power and the manipulation of the controls did not alter the frequency or level of the vibration.

About 30 minutes later, the vibration stopped as abruptly as it had started. The aircraft felt completely normal, and all controls worked normally. The pilot in command increased speed to 100 kts. As the aircraft passed another rig, which was considered to be unsuitable for an emergency landing, it was observed by the rig crew, who reported that everything appeared normal.

About 2 minutes after the vibration stopped, it started again at the same frequency, but at a higher amplitude. A very short time later, the aircraft suddenly yawed to the right and tail rotor control was lost. The pilot in command closed the throttles and the yaw stopped. He then placed the aircraft in an autorotational descent, using cyclic control to counter yaw. The pilot in command reported that the tail rotor controls felt as if they were rubbing against something when he operated them following the tail rotor failure.

During the subsequent flare, as the pilot in command was about to lower the nose and cushion the landing, the aircraft commenced an uncommanded pitch nose-down, even though the pilot in command was still holding full back cyclic control. The pilot in command increased the collective pitch and the co-pilot activated the floats. The aircraft was pitching nose-down and rolling to the right as it touched down on the water. It continued to roll to the right until it was upside down. All doors were opened by the impact. Both pilots left the partly submerged, overturned aircraft by their respective doors and surfaced at about the same time.

The pilots observed that the tail boom, held on the surface by a partially inflated flotation bag, was about 40 m from the main fuselage. The left main fuselage flotation bag was fully inflated. The right bag was inflated except for the centre section.

Both the tail and main fuselage sections subsequently sank in 85 m of water.

A search of the seabed failed to locate the tail section. The main fuselage section was located, inspected and videotaped using a remotely piloted underwater vehicle.

Inspection of the video and of photographs taken before the fuselage sank indicated that the tail boom broke off approximately 1.5 m aft of the boom attachment bulkhead. The boom appeared to have fractured upwards and then sideways to the right. One main rotor blade had marks indicating a fuselage strike. The other blade was shattered.

There was no evidence of failure of the longerons adjacent to the boom attachment bulkhead (a known problem).

No photographs of the tail boom were available.

The helicopter was maintained in accordance with requirements in force at the time of the accident.  There was no evidence of pre-existing defects which could have contributed to this occurrence.

Analysis

The vibration was reported by the crew as high frequency and high amplitude indicating that it was most likely associated with tail rotor components rather than engine accessories. Both sets of components rotate at high speed and therefore could induce high frequency vibration. However, it is unlikely that an engine accessory could introduce a high amplitude vibration such as that described by the crew. In addition, the vibration caused the horizontal situation indicator (HSI) to slave off heading. As the compass sensor for the HSI is located in the tail boom this indicates that the vibration was probably centred in that area. The vibration did not vary with power or speed indicating that it was not associated with uneven aerodynamic loading (of the tail rotor). Vibration associated with a previously reported longeron failure was reported as low frequency.

During the period of the initial vibration, and during the break from it, the aircraft controls appeared to respond normally. The pilot lost tail rotor control shortly after the onset of the second period of vibration. The tail rotor drive rotates at a relatively constant speed and the drive components are located inside the fuselage structure. As a result, it is likely that vibration associated with these components would remain relatively constant at all power settings and speeds. The one unusual aspect of the failure is that all vibration ceased for a period and flight returned to normal. As the tail boom and tail rotor components were not found, the precise nature of the failure could not be determined. Available information indicates that the vibration was possibly associated with a failure of either the tail rotor drive shaft and/or its mountings or one of the two tail rotor drive gearboxes and/or its mountings.

The damage to the main fuselage in the area of the tail boom fracture and to the main rotor blades indicates that the boom probably failed following contact with the water, during the landing flare, and as a result of a main rotor blade strike. The fact that a tail boom flotation bag partially inflated also indicates that the boom was still attached on touchdown.

VH-HSP departed Sydney five minutes before VH-TJP. Both aircraft were tracking via Wollongong and T18 to Eildon Weir. On first contact with sector control, VH-HSP was cleared to climb as planned to flight level (FL) 350. VH-TJP was also planned at this level but on first contact with sector control, VH-TJP was cleared to climb to amended FL 330. At this stage, VH-TJP was closing on VH-HSP at 110 knots and was 13 miles behind.

A very inexperienced trainee was operating the position under the supervision of a rated controller. The controller was distracted from his supervision task for a short period and when he returned his attention to the screen, he noted that VH-TJP was now only five miles behind VH-HSP and 200 feet below.

The controller told the trainee to turn VH-TJP onto 150 degrees. The trainee instructed VH-TJP to turn right onto 150 degrees but immediately corrected this to turn left onto 150 degrees. The crew then queried the direction of turn. The controller took over from the trainee, told the crew to turn left and gave them traffic information on the other aircraft. Separation reduced to a minimum of three miles at the same level.

Both the controller and the trainee indicated they were not very familiar with the performance of VH-HSP and that the climb performance achieved had been less than they anticipated. The controller expected that VH-HSP would reach flight level 350 before longitudinal separation was lost. Separation would then be maintained vertically which was the reason VH-TJP was assigned amended FL 330.

Significant Factors

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

1. Inadequate knowledge of the performance of VH-HSP.

2. The controller did not maintain an adequate monitor of the situation to ensure that the separation strategy devised, actually achieved its aim.

The flight was an attempt by the pilot to achieve the 500km Goal Flight. During the flight the pilot was unable to find continuing lift and an outlanding became necessary. During the landing the right wing struck grass at the boundary of a paddock and the glider ground looped.

The pilot had misjudged the approach and overshot his intended touchdown point. He had also forgotten to lower the landing gear.

The chief flying instructor was conducting initial multi engine endorsement training for a commercial pilot.  It was the student's fourth session.  After practising simulated engine failures at about 3000 ft in the training area, the aircraft was flown to Tyabb for circuit training.

On the third circuit, on base for landing to the south on the 1000 metre airstrip, the instructor failed the right engine by placing the mixture lever into the idle cut-off position. He told the student not to feather the right propeller but to continue with a touch-and-go landing, thereby experiencing an approach and landing with a failed engine and an unfeathered propeller.  The student selected two stages of flap and, on final, placed both propeller pitch levers into the full fine position.  She closed both throttles before touchdown.  During the landing roll the instructor raised the flaps and advanced the right mixture lever to the full rich position.  Then the student advanced both throttles fully, expecting take-off power on both engines.  At this point the indicated airspeed was about 70 knots. The minimum control speed for single engine operations is 69 knots.  The left engine produced take-off power but the right engine failed to deliver power.

Initially, when the aircraft began to yaw to the right, the instructor thought the student was having difficulty with directional control which she had experienced on previous landings. However, when the aircraft yawed further right, he identified a failed right engine and quickly took over the controls.  By then a collision with runway lights, gable markers and a shallow drainage ditch was imminent, despite the application of full left rudder by the instructor.  He chose to maintain full power on the left engine and become airborne, hoping to avoid the obstacles immediately ahead and find a clearer area to land. The aircraft flew for about 290 metres at a low height in a southerly direction within the airfield boundary but outside the runway gable markers with the instructor struggling to maintain control.  Then the right wing collided with a two metre high pile of old stumps.

The outboard section of the right wing, including the outboard fuel tank, was torn off.  The aircraft turned right through about 260 degrees while remaining upright. It then settled onto the ground and slid backwards, coming to rest about 30 metres beyond the stumps.  As the aircraft came to rest it caught fire.  The right-wing spar was completely broken, and the right engine was torn out of the airframe.  The pilot and the student escaped through flames.  Fire quickly gutted the cabin.

In the seconds between taking over the controls and impact with the stumps, the pilot did not attempt to feather the propeller of the failed engine because of the difficulty he encountered controlling the aircraft at low airspeed. If the RPM of the windmilling propeller had decreased below 800, which it probably had, then feathering would have been prevented by the design of the propeller mechanism.

The airframe was subsequently examined by engineers who found no fault which may have contributed to the accident.  No fault was found with the left engine which had produced take-off power on demand. No fault was found with the right engine.  Aviation gasoline was found in the fuel lines and in the fuel tanks.  There was adequate fuel on board for the flight. The cockpit switches were destroyed by fire.

From the time the instructor selected the mixture to idle cutoff until the student attempted to achieve take-off power during the attempted touch-and-go landing was probably less than two minutes.  The reason the fuel injected engine did not restart when the mixture lever was advanced was not determined.   Witnesses reported hearing a "backfire", probably from the right engine, at about the time full power was selected.

Initially when the right engine failed to deliver power, there was sufficient remaining runway ahead for the pilot(s) to have closed the throttles and stopped the aircraft safely before the end of the runway.  The student, who considered closing the left throttle, did not dare to do so once the instructor took over.  Having taken over the controls, the instructor was confronted with obstacles immediately ahead, which he cleared by becoming airborne. He was then confronted by another obstacle, the pile of stumps which he was unable to avoid.

Four or five times in this aircraft, recently, the instructor had successfully performed a touch-and-go landing after shutting down an engine with the mixture lever during multi-engine endorsement training; once per candidate towards the completion of their endorsement.  On all previous occasions the shutdown engine produced full power when the mixture lever was advanced, and the throttle opened fully.  The instructor's hope was that the training exercise would be a valuable experience for the students.  However, in hindsight he realised that the exercise enhanced the chances of an accident occurring if the shutdown engine did not restart quickly during the touch-and-go.

Since this accident it has become apparent that many multi engine flying instructors, approved testing officers and flying operations inspectors have varying opinions as to whether engines should be shut down completely in the circuit or at low level, as opposed to selecting zero thrust settings appropriate to the particular aircraft.

CONCLUSIONS

Findings

1. The instructor and student were properly licenced and qualified for the task.
2. The aircraft was serviceable and after the accident no faults were found that may have contributed to the accident.
3. The right engine did not deliver power when the mixture and throttle levers were advanced for the touch and go landing. The reason why the right engine did not restart was not determined.
4. The flying instructor underestimated the risk involved versus the training advantage of shutting down one engine at low level followed by a touch-and-go landing.

Significant factors

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

1. The instructor shut the right engine down during approach.
2. The instructor briefed the student to fly the approach and land with the engine shut down and the propeller windmilling.
3. During the subsequent touch and go landing, the engine did not restart/deliver power when the mixture and throttle levers were advanced.
4. When the aircraft then began yawing to the right the instructor initially believed the student was having ongoing difficulty with directional control.
5. When the instructor identified that the yaw was due to asymmetric power and took control of the aircraft, the situation with aircraft performance, runway remaining and surrounding terrain was such that an accident was inevitable.

SAFETY ACTION

The following safety action is being taken:

1. The Civil Aviation Safety Authority (CASA) will release a Civil Aviation Advisory Publication containing an initial multi engine endorsement training syllabus.
2. The Bureau of Air Safety Investigation will conduct a research project on advanced training accidents.
3. Since this accident, CASA has held industry symposiums to discuss standardisation of multi engine training procedures.

Whilst turning onto a right base leg for runway 16R, with the autopilot disconnected, right rudder input was unsuccessful, and the rudder appeared 'frozen'. After two unsuccessful attempts to deflect the rudder to the right the pilot applied left rudder which responded, although requiring the application of higher-than-normal force on the rudder pedal. Subsequent application of right rudder was successful but felt extremely stiff. A light 'tramping' was also felt through the pedals. The number 1 yaw damper was disconnected temporarily with no apparent change in control feel or response. The aircraft subsequently landed without further incident.

An investigation found seized bearings at the pilot's aft rudder input quadrant, requiring excessive input forces for rudder deflection. The bearings, shaft and support frame assembly were changed, which resulted in the system returning to normal operation.

There had been a history of rudder input problems since the aircraft's last scheduled maintenance in the United Kingdom in February, when the quadrant shafts had been changed as an inspection sampling program requirement.

The aircraft was cleared for a visual approach to the duty runway (RWY) 11 and joined a 7km final from a right base position. The crew were advised by ATS of several military fighter aircraft taking off from RWY 29.

The captain advised ATS of his position and that a traffic confliction was about to occur as he saw two of the six fighter aircraft pass above and to the left of his aircraft. The last of the section of fighters passed within 1,000 metres of the aircraft at the same level.

Subsequent investigation revealed that a request for the use of a non-duty runway (RWY29) had been agreed to previously for the military aircraft, but there had been a delay with their departure. The radar controller failed to note that a non-duty runway was marked on the flight strips. Reflected radar returns were being experienced on the Surface Movement Radar and the controller misidentified these reflected returns as those of the military aircraft, and being relatively inexperienced cleared the military aircraft to take off in confliction with the approaching aircraft.