The pilot was a student on his second solo flight. During the approach and round out phase of the second circuit, the aircraft ballooned. The student pushed the controls forward and a heavy landing, nosewheel first, eventuated. The nose gear collapsed, and the propeller struck the runway. The aircraft slewed to the right and came to rest within the flight strip.

When the aircraft reported at the position reporting point after Mt Isa, it was found that it was not tracking on the route expected by air traffic controllers. There was no confliction with other aircraft, and the aircraft was recleared along the route it was tracking.

Earlier in the day the original flight plan was submitted to track via air route A575 after passing Mt Isa. This plan was later cancelled and another submitted to track via air route A464 after Mt Isa. The first route is the preferred tracking, and the amendment resulted from the possibility of adverse weather on air route R575.

Prior to departure from Brisbane information indicated that weather was now suitable on R575. The airline company operations personnel checked if the Brisbane Briefing Office held a flight plan on the aircraft, and when they were advised that the office did not hold a plan another plan was submitted for the aircraft to track via air route R575. However, as the first two plans had been submitted by the airlines base in Bangkok through Melbourne (normal practice), Brisbane was unaware of the existence of a plan for the aircraft. As a result, a cancellation message was not sent prior to the third plan being submitted.

Flight Progress Strips are prepared for each plan by two sections in the Brisbane control centre and distributed to controllers who will become responsible for the control of each aircraft. On this occasion, when the third plan was submitted it was assumed that it was a duplication of one of the previous plans, probably because no cancellation message was received, and no strips were prepared for the controllers. As a result, the controllers assumed that the aircraft would track via air route A464 after Mt Isa.

The controller who received the Mt Isa position report marked the information on the strip for the next position reporting point along air route A464 and not along R575, the point that the aircraft advised it would report at next. He then co-ordinated the Mt Isa position with the next controller responsible for the aircraft. This controller also had strips for air route A464 and was not aware the aircraft was tracking via air route R575 until the next position report from the aircraft.

FACTUAL INFORMATION

History of the flight

The flight was planned as a dual instructional flight followed by solo circuits to refamiliarise the student with the C172 aircraft and circuit procedures.

The student pilot had completed several circuits with the instructor during which some improvements to the student’s technique were made. The instructor then alighted, and the student proceeded to conduct further solo circuits.  The instructor reported that he observed two circuits and detected only minor problems in their conduct.  On the planned last circuit of the sequence, the aircraft descended and impacted the ground, some 150 m short of the runway 23 threshold.

The pilot of an aircraft taxiing at Dubbo reported seeing the C172 on what appeared to be a normal final approach followed by a rapid descent to impact the ground, nose first, from a height of approximately 50 ft.  He also reported that the aircraft did not appear to stall.  There was no fire.

The aircraft came to rest inverted.  The fuselage had broken at the baggage door frame and was folded back along the upturned forward fuselage.  The engine and propeller had separated from the airframe and were located in the general direction of the runway, approximately 12m from the main wreckage. The nose landing gear had also separated from the airframe and was located approximately 6m from the main wreckage.  The wing flaps were fully extended and the aircraft contained sufficient fuel for the intended flight.

Personnel information

The pilot held a valid student pilot licence endorsed for C172 aircraft.  He had gained approximately 45 hours in ultralight aircraft prior to his general aviation training.  He had completed approximately 16 hours in the aircraft type and had accumulated approximately 1.5 hours solo experience.  The last time he had flown, which was in the accident aircraft, was 31 days prior to the accident.

The pilot reported that he was well rested prior to the flight.

Aircraft information

The pilot reported that the aircraft had been performing normally.  The investigation found no evidence to indicate a malfunction of the aircraft or its systems.  A post-accident "strip inspection" of the engine revealed no defects which may have contributed to the occurrence.  The aircraft was fitted with a serviceable Emergency Locator Transmitter (ELT), however no emissions were reported by other aircraft in the area. The ELT switch was found in the OFF position at the accident site.

Communications

The aircraft transmissions were recorded by a voice recorder used in revenue collection administration.  These recordings were replayed with the following observations:

• The pilot used standard phraseology throughout the circuit sequence and was consistent in his transmissions.  The pilot used the term "touch and go" on approach to the runway, including the full stop landing to allow the instructor to disembark.  Similarly, although the final approach was intended to be the last for the day, the pilot called "touch and go".
• There was no other recorded traffic during the circuit sequence.  During the last circuit, however, there was another aircraft conducting an approach and an aircraft taxiing at Dubbo, both of which were communicating on the Mandatory Traffic Advisory Frequency (MTAF).  The pilot was wearing a headset to monitor the radio but was using a handheld microphone for transmitting.

Weather

The weather at the time of the accident was reported as fine and clear with a light wind from the south and a temperature of 19 degrees Celsius.  Weather is not considered as being a factor in the accident.

ANALYSIS

This was the pilots first flight after a break of 31 days.   His previous flights had been conducted over a two-day period, which included his first solo flight on the first day.

The initial circuits were conducted with an instructor and some corrections were suggested to the pilot. Similarly, the two observed solo landings had only minor problems which the instructor noted.  The circuit during which the accident occurred was planned to be the last of the session.  On this circuit there was other traffic communicating on the Dubbo MTAF.  This resulted in the pilot having to operate the handheld microphone as well as handle the aircraft and it is possible that, even though he reported being well rested, the pilot was experiencing fatigue toward the end of a reasonably demanding session.  The accumulation of these factors, coupled with the pilot’s low aeronautical experience, may have contributed to the pilot being distracted during the final approach and losing control of the aircraft at an altitude too low to effect a recovery.

CONCLUSIONS

Significant Factor

The pilot lost control of the aircraft at an altitude too low to effect a recovery.

The pilot reported that the engine failed during cruise at 8,500 ft. The aircraft was over water and a glide towards the coast was initiated. Aircraft ditched in the Gulf of Carpentaria. Both occupants were rescued by SAR helicopter at about 2200. The aircraft wreckage was not recovered and no indication as to the cause of the engine failure could be determined.

FACTUAL INFORMATION

History of the flight

Before departing Moorabbin for Cooma on 17 September 1994, the aircraft's main fuel tanks were filled with aviation gasoline (AVGAS) and 50 litres were added to each auxiliary tank, providing at least 515 litres total fuel on board. The auxiliary fuel tank gauges had indicated near empty before the addition of the fuel. The pilot assessed from the gauge readings that the tanks had contained a small quantity prior to refuelling and that the total fuel load was 550 litres.

The flight time to Cooma was 70 minutes. Fuel was used from the main tanks for the departure, climb, descent and arrival phases of the flight, and the auxiliary tanks were selected for the cruise. The pilot calculated the quantity of fuel used on the flight at the rate of 130 litres/hour, flight time. He estimated that 385 litres remained for the return flight to Moorabbin, which was planned for the evening of 18 September. His planned time intervals to Moorabbin, totalling 89 minutes, were calculated using a forecast wind of 250 degrees T at 30 kt. The flight plan fuel calculations allowed 15 litres for taxi, 15 % variable reserve, 15 minutes for an alternate, although no alternate was nominated, and 45 minutes fixed reserve. Flight fuel was again calculated at 130 litres/hour. The plan indicated that the fuel required, including these allowances, was 385 litres. Late in the evening the pilot prepared the aircraft for departure, but experienced difficulty when attempting to start the left engine. Unable to correct the problem, he deferred the flight until the next day.

The following morning the pilot obtained the forecast en route winds up to 10,000 ft, and the Moorabbin terminal aerodrome forecast (TAF). The forecast wind at 10,000 ft was 230 degrees T at 50 kt. The Moorabbin TAF included intermittent periods with wind gusts to 48 kt, 4,000 m visibility, 5 octas of cloud at 1,200 ft and hail showers. No other information was requested or given. The forecast required that the pilot allow for 30 minutes holding and the much stronger head winds indicated that the en route time would be significantly extended. However, without making any changes, the pilot re-activated his flight plan from the previous night.

Having obtained advice from the aircraft operator the pilot was able to start both engines without further difficulty, and departed Cooma on climb to cruise at 10,000 ft. Other than during cruise when the right auxiliary fuel tank was selected to the right engine for about 10 minutes, the flight was conducted on the main tanks. The left auxiliary tank gauge was indicating almost empty.

The pilot extended his estimated time intervals when strong headwinds were encountered during cruise. At about Eildon Weir he requested the actual weather at Moorabbin and was advised that the sky was clear. He assessed that the remaining fuel was sufficient and elected to continue. The Moorabbin Automatic Terminal Information Service (ATIS) information Tango indicated that the wind was 170 degrees M at 20 kt to 30 kt, gusting to 45 kt, with a crosswind of up to 10 kt, and 4 octas of cloud at 1,500 ft, with lower patches and showers in the area.

At about 5 km from Moorabbin the left engine surged and failed. The pilot assessed that the problem was fuel related and selected the left auxiliary tank, which restored power to the engine. By this time, he had extended the landing gear and lowered 15 degrees of flap. With runway 17L in sight, the pilot continued the approach and selected 25 degrees of flap. The tower controller advised that a squall was approaching the airfield, and the pilot recognised that this may nesessitate a go-around. On final approach at about 1.5 km from the aerodrome at a height of about 300 ft to 500 ft, the left engine failed again. The pilot increased power on the right engine but did not feather the left propeller. He assessed that the aircraft could not reach the runway and altered heading to the left, intending to land on a grassed area of the airport which he considered was within range. The pilot had not told the tower controller of either the engine failure or of his intention to land on the grass. Consequently, on seeing that the aircraft was low and well to the left of the runway, the controller instructed the pilot to go around.

At a very low height of possibly 10 ft to 20 ft, the pilot applied full power to the right engine and selected the landing gear and flaps up. The airspeed was about 94 kt, the single engine best rate of climb speed. However, with the left propeller windmilling, little altitude was gained and the airspeed decayed below 94 kt. While drifting to the left, the aircraft tracked across the airport in a south-easterly direction towards an industrial estate. The aircraft passed very low over some buildings and with the stall warning sounding, it grazed a roof and collided with two trees before impacting the ground in a steep nose-down attitude.

The pilot and the front-seat passenger were trapped in their seats by the deformation of the forward fuselage and instrument panel. The three other passengers were able to evacuate the aircraft by the main cabin door.

Wreckage examination

The aircraft had tracked about 080 degrees M from the first contact with a factory roof to where it came to rest about 80 m further on. The impact caused substantial disruption of the fuselage nose section and the left wing. Both engines were torn from their mountings.

Less than 1 litre of fuel was obtained from the left main tank. No fuel was found in the left auxiliary tank. Thirty litres were obtained from the right main tank and 8 litres from the right auxiliary tank. The reason for the engine starting difficulty was identified and found to not affect the operation of the engines or the fuel flow at engine power settings above idle. No defects were found that might have contributed to the development of the occurrence.

Performance calculations indicated that at the time of the approach, the aircraft was capable of climbing on one engine. However, this was dependent upon the correct procedures being followed, including feathering the propeller of the inoperative engine. The aircraft loading complied with the requirements of the Flight Manual.

Pilot qualifications and experience

The pilot held a Commercial Pilot Licence with a Multi-engine Command Instrument rating. He also held a Grade 2 Instructor rating with a recently granted approval to conduct multi-engine aircraft training. He had logged a total of about 1,100 hours, including about 150 hours on multi-engine aircraft. The flight to Cooma was intended to further his experience.

The pilot's PA 31 endorsement training was conducted about 6 months before the accident. The training included engine failures after take-off and single engine approaches during which he had been instructed that the minimum safe altitude from which to conduct a single-engine go-around was 300 ft.

Engine fuel flow management

During the endorsement training, the endorsing pilot cited an example of a PA 31-310 which he knew to have an average or block fuel consumption of 140 litres/hour. Subsequently, the pilot hired VH-NNN from another operator who conducted a check flight with him. The instructor drew the pilot's attention to a placard which had been placed in the aircraft. The placard listed take-off, climb and cruise power settings. It also gave an exhaust gas temperature (EGT) setting of 1,400 degrees for the cruise. The pilot understood that the owner wanted these settings to be strictly followed. On subsequent flights in VH-NNN the pilot complied with the placarded power settings, including setting the EGT to 1,400 degrees F. The aircraft's engine management instrumentation included electronic digital fuel flow indicators, in addition to the standard fuel flow gauge. However, the pilot was not instructed in the use of the digital indicators.

The PA 31-310 Pilot Operating Handbook provides information on fuel mixture leaning procedures. The handbook indicates that for best economy the mixture should be set at peak EGT, provided 1,650 degrees F is not exceeded. To obtain the best power fuel flow setting, the handbook recommends setting the fuel flow to achieve an EGT of 125 degrees less than peak EGT. The best power fuel flow is considerably greater than that which results from the use of the best economy setting. Consequently, many operators use fuel flow settings between best power and best economy, typically 50 degrees F less than peak EGT.

The setting of 1,400 degrees as placarded, did not necessarily provide the pilot with a reference for peak EGT, which may vary between engines. By not establishing the reference peak EGT, the pilot did not verify the relevance of the 1,400 degree setting to the required fuel flow. The aircraft owner advised that the placard had been fitted for his own reference only.

Following analysis of information from previous flights of VH-NNN, and testing of the left digital fuel flow indicator, the investigation found that the standard fuel flow gauges were not accurate. Fuel consumption was calculated using the digital flow indicators, together with the manufacturer's information on fuel consumption for take-off, climb and descent. These indicated that the left engine required a total fuel consumption for the flight to Cooma and return to Moorabbin of almost all the fuel in the left main tank and the 50 litres added to the left auxiliary tank. However, the fuel flow achieved by setting the mixture control to 1,400 degrees EGT was higher than would have occurred using the best power setting.

By not establishing the fuel quantity on board prior to take-off from Cooma, the pilot was unable to confirm the fuel consumption rate for the engine settings used, and the actual fuel available for the return flight. However, he was confident that the aircraft contained sufficient fuel for the flight. His decision to not add fuel at Cooma was also influenced by his concern for better aircraft performance in the event of an engine failure.

Final flight path

Airport tower personnel reported that the aircraft initially appeared to be established on final for runway 17L. However, it then became apparent that the aircraft had deviated to the left of the extended runway centreline. The deviation to the left continued after the pilot was instructed to go around. The flight path carried the aircraft past the threshold of runway 17L in a shallow arc, briefly paralleling runway 13L, before crossing the aerodrome eastern boundary.

The difference in distance to run between the grass area nominated by the pilot, and the threshold of runway 17L, was found to be minimal.

ANALYSIS

Appropriate pilot decision making and adherence to established procedures are vital to the effectiveness of the response to an emergency situation. The circumstances of this occurrence did not reflect a standard of operational practice and decision-making consistent with the qualifications held by the pilot. This is apparent both in his flight fuel management, and in his response to the resulting asymmetric condition.

Fuel management

The pilot's fuel management relied on assumptions of fuel flow rates, placing an undue reliance on a block fuel consumption rate of 130 litres/hour, and on leaning the mixture to 1,400 degrees EGT. While these parameters may individually be appropriate in other circumstances, he did not verify that they were valid for this flight. By not confirming the aircraft's fuel state at Cooma, the pilot could not have known if sufficient fuel remained, and that his fuel management was appropriate.

Despite the forecast of winds considerably stronger than those for which he had planned, and the requirement to allow for possible holding at Moorabbin, the pilot did not reassess his fuel requirements or use a more appropriate engine management technique. He recognised that the initial failure of the left engine was due to fuel exhaustion and that the left auxiliary tank, which he then selected, contained little fuel. However, he did not appear to realise that a further failure of either or both engines due to fuel exhaustion could be imminent.

Asymmetric operations

The pilot demonstrated a lack of understanding of the fundamentals of multi-engine aircraft performance. This is evidenced by his not feathering the left propeller, his inability to maintain the aircraft on the runway alignment during approach, and his non-adherence to a decision height.

Following the first failure of the left engine, the pilot did not appear to understand the need to minimise drag and conserve height until assured of a safe landing. Although unable to maintain directional control during the approach, and despite having assessed that the aircraft had insufficient performance to reach the runway threshold, the pilot attempted to go around. Had he recognised the importance of nominating and maintaining a decision height, he would not have attempted to comply with the instruction to go around.

It is likely that the pilot's decision to land on the grass was made as a result of inadequate asymmetric technique rather than inadequate aircraft performance.

CONCLUSIONS

Findings

1. The pilot was appropriately licenced to conduct the flight.
2. The aircraft weight and balance were within the Flight Manual limitations.
3. The pilot did not allow for the provision of holding fuel and did not replan for the stronger headwinds and the resultant greater total fuel consumption.
4. The pilot did not establish the actual quantity of fuel on board the aircraft prior to departure from Cooma.
5. The aircraft fuel flow gauges provided erroneous readings.
6. The pilot was not familiar with the operation of the digital electronic fuel flow indicators and did not reference them during the flight.
7. The pilot did not establish whether the fuel flow management settings shown on a placard in the aircraft were appropriate to the flight.
8. The left engine failed at a late stage of the landing approach due to fuel exhaustion of the left main and auxiliary tanks.
9. The pilot did not advise the Moorabbin tower controller of the engine failure.
10. The prevailing wind conditions increased the pilot's workload.
11. The tower controller instructed the pilot to go around when, during final approach, the aircraft deviated from the runway alignment.

Significant factors

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

1. The pilot did not ensure that the aircraft contained sufficient fuel for the flight.
2. The pilot did not establish that the engine control settings used were appropriate for his planned fuel consumption rate.
3. After the failure of the left engine the pilot did not maintain directional control of the aircraft.
4. The pilot made an inappropriate decision to attempt to go around from a very low height and did not feather the left engine propeller.

SAFETY ACTION

The investigation found that there are no specific CAR or CAO requirements with respect to essential training or testing prior to granting a multi-engine training approval. During the investigation of another occurrence (9402804) similar safety deficiencies were identified.

There is no approved or prescribed syllabus of training, or training approval test requirements for these aircraft categories. It is not a requirement to demonstrate to a CAA FOI or an approved ATO, knowledge and understanding of all systems and procedures essential to the safe operation of the aircraft, in all flight regimes, prior to the granting of a check and training approval.

Under CAR 217, a pilot is not required to hold an instructors rating in order to hold a check and training approval. Such approval is covered by the delegation under Part 5 of the CARs and includes the delegation to conduct training for endorsement and also to issue a certificate of endorsement. The delegation leaves the test requirements and parameters to the discretion of the testing FOI.

As a result of the investigation into occurrence 9402804 the Bureau issued interim recommendation IR950063 to the Civil Aviation Authority. It stated:

The Bureau of Air Safety Investigation recommends that the Civil Aviation Authority provide a syllabus of prescribed test requirements as a standard for the testing of an applicant for the granting of a check and training approval on a specific aircraft type. The test should ensure that the applicant has adequate knowledge and understanding of all systems essential to the safe operation of the aircraft, in all flight regimes, and that the applicant has the ability to pass on such detail to a student.

The CAA response stated:

Guidance on the conduct of check pilot approvals including flight test requirements are contained in MAOC Vol 1 Part A Ch 10 Appendix C3.  The Authority agrees with this recommendation and has commenced a project to produce a standard flight test report form for candidates, both instructors and trainers, seeking multi-engine training approval. In support of this form the Authority will also produce a syllabus and a test-conduct guide.

The Bureau has classified this response as CLOSED/ACCEPTED.

During cruise the pilot stated that the aircraft had experienced stronger than expected headwinds, so he allowed the left fuel tank to run dry in order to maximise endurance before changing to the right tank, the contents gauge of which indicated about 6 US gallons remaining.

A few minutes later the engine failed, and although the pilot performed all the necessary emergency procedures, he was unable to restore power.

He made "Mayday" transmissions on the Area and CTAF frequencies, then looked for a clear area to carry out a forced landing. There being no suitable areas within gliding range he was committed to stalling the aircraft into the treetops. The emergency locator beacon activated.

An investigation of the aircraft revealed there was no fuel in the left tank, and as the right tank had suffered damage at impact it was not possible to determine if there had been fuel in it prior to the accident. Fuel stains were noted behind both tank filler caps, indicating that some fuel syphoning may have occurred in flight.

Circumstances

This incident involved the loss of a sling load, namely four 205 litre drums of hydraulic oil from a pallet in a cargo net, while cruising at 90 knots at 800 ft above the ground (AGL).  The incident was the subject of an internal investigation by the operator.  The Bureau was asked to review the operator's investigation and provide comment as considered necessary.  For this purpose, a Bureau investigator attended the scene of the occurrence and visited the operator's base.

Tarmac assistants prepared a sling load consisting of four 205 litre drums of hydraulic oil standing upright, bungs uppermost, on a standard wooden forklift pallet.  A cargo net surrounded the base of the pallet and the bottom half of the drums.  The four corners of the net were gathered to one point above the drums.  A shackle attached the net to a wire strop about 3 metres long.  A swivel attached the wire strop to the cargo hook on the helicopter.

After a normal take-off was performed with the 770 kg (approx.) sling load attached, the pilot asked the crewman, sitting on the right side of the helicopter beside the sliding door, and the tower controller, how the sling load was hanging inflight.  Both advised that the load was trailing at about 10 to 15 degrees off the vertical and not swinging or rotating.  The sling load felt to the pilot as though it was trailing nicely.  The load could not be viewed by the pilot because the helicopter was not fitted with a pilot sling load viewing mirror.

Without warning, while cruising at 800 feet AGL at 90 knots, the pilot felt a jolt through the airframe and the helicopter began to climb with no change being applied to the power setting or the inflight attitude of the helicopter. It felt to the pilot as if the sling load had dropped off.  The pilot instructed the crewman to visually check the load. The crewman saw that the four drums were missing but the net, containing the pallet, was still attached to the cargo hook.  The pilot immediately returned to the Longford heliport with the net still attached. On arrival at Longford heliport, engineers discovered that when the drums fell out of the cargo net the pallet/cargo net had swung back far enough to contact the tail boom of the helicopter. The boom was not dented but a slight smear of paint from the wooden pallet was left on the tail boom.

The drums were almost identical to Jet A1 or AVGAS drums with one main difference - the top of each drum included an extra press-fit bung approximately 8 cm in diameter. Hydraulic oil, which was subsequently found on the webbing of the cargo net, appeared to be confined to one corner of the load.  There was enough stain on the net to accept that at least one of the drums had vented oil in flight.  The most likely source of venting was from a dislodged press fit bung.  Tensioned-up around the four drums was a thin stainless-steel strap.  The main function of the tensioned strap was to make the drums less likely to fall off the pallet during forklift handling.  However, the strap also should have made the drums less likely to topple out of the cargo net in flight.  The strap/band was never found after the incident.  This configuration of drums in a sling load had been successfully used by the operator in the past.

All the drums impacted the ground within an area of about 60 metres diameter.  The site was open, flat, heathland well clear of all buildings and human occupation.  No livestock were nearby.  The four impact points were so close that it is highly probable that all of the drums departed the cargo net during one sudden event in flight.

The damaged drums were dumped at the tip before being examined.  Later attempted retrieval of the damaged drums from the tip was unsuccessful.  Careful inspection of the damaged drums may have confirmed whether or not the central press-fit bung(s) had come loose in flight.  The drum which vented hydraulic oil may have sustained different impact damage to the others.

The operator carried out an internal investigation of the incident.  At the request of the operator, a Bureau investigator reviewed the findings of the operator.

The main cause of the incident was that the cargo net was not large enough to enfold the drums. Had the net been large enough the drums could not have escaped despite a probable loss of hydraulic oil from at least one drum and the possible loss in flight of the tensioned metal strap around the four drums.

Findings by the operator

1. The tarmac assistants who prepared the load had not been specifically trained in rigging sling loads.
2. Only one type/size sling/cargo net was available for use.
3. The sling/cargo net did conform to Department of Labor and Industry (DLI) cargo and lifting gear testing certification standards.
4. No company procedures were in place to guide personnel on how to properly rig a sling load.
5. Tarmac assistants were trained in ground to air communications procedures and the correct method of hooking up a load to a hovering helicopter.
6. The sling/cargo net, shackles and swivel used were all in excellent condition.
7. Cargo lifting equipment was controlled and maintained according to National Association Testing Authority (NATA) standards. Significant Factors

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

1. The sling net was not large enough to fully enfold the drums.
2. Hydraulic oil vented from one of the drums in flight.
3. As the oil vented, a drum may have partially collapsed in flight as a result of the weight of the other drums and the action of the tensioned steel strap, thereby altering the geometry/stability of the load.
4. An undetermined event caused the drums to lose stability in flight.  This, coupled to the fact that the sling net was not able to fully enfold the drums, caused the drums to topple out of the cargo net and fall to earth.

SAFETY ACTION

The following internal recommendations were made to management:

1. That no further sling loads of 205 litre drums take place until alternative methods of transport are investigated and approved.
2. That if a suitable method for airlifting of 205 litre drums is selected, only drums with screw top lids be approved for transport.
3. That an appropriate course of training be provided for tarmac assistants.  (Such as a five day rigging course with the Air Movement Training Development Unit at Richmond, NSW.)
4. That consideration be given to incorporating all slings, shackles and sling nets into the present system administered by the Barrys Beach Marine Terminal (BBMT) sling store.
5. That any special lifting equipment, such as cargo nets, lifting frames or baskets be incorporated into the company cargo and lifting gear manual because many people may be involved in preparing a sling load as it passes from the point of preparation (warehouse, contractor etc.) through the helipad to the field.
6. That detailed procedures be developed by the helipad, in co-operation with their freight interface to ensure that any potential underslung loads are appropriately prepared and readied for transportation.

The BASI investigator added the following safety observations:

1. It is very wise to have a pilot sling load viewing mirror attached to a helicopter for all sling load operations. (With previous helicopter types flown by the operator, mirrors were fitted.)
2. At present there is no Sikorsky company-approved sling load mirror for the S76.  However, Helicopter Resources Pty. Ltd. of Victoria is now operating the Sikorsky S76A in the Antarctic with a pilot sling load viewing mirror attached.  The Helicopter Resources mirror does have Civil Aviation Authority (CAA) Regulation 35 approval.
3. According to the flight manual, with a sling load of 862 kg or less, the maximum airspeed allowed in the S76 is136 knots up to 6000 feet. This is a very high airspeed for sling loading.  It is accepted that every different sling load may have its own maximum optimum speed after which it may sway, spin, trail too far aft, even try to fly beside the helicopter, etc.  It is also accepted that the manufacturer is very thorough in flight testing a helicopter before the flight manual becomes an approved document.  However, it is logical to expect that the higher the airspeed the more dramatic a problem is likely to be when/if an unusual inflight sling load event occurs.  For example, if the drums had departed the cargo net from VH-EXQ at 136 knots, it is suspected that the tail boom would have been significantly damaged by the trailing pallet.  Several other helicopter types have a maximum airspeed of 80 knots for sling load operations, presumably to minimize the hazard in the event of a mishap with a sling load.

As a result of the review by the Bureau investigator, the company is considering the following advice:

1. Fit an approved pilot sling load mirror to the S76 for future sling operations.
2. Despite information contained in the flight manual maximum airspeed versus weight supplement, consider a lower company sling load airspeed limit and include it in the company operations manual for CAA approval.
3. Use relevant, qualified experts to ascertain appropriate safe standards for sling equipment and ascertain any occupational health and safety implications.
4. Try to adopt one practical standard for sling equipment, if possible, for simplicity and to avoid confusion.

CIRCUMSTANCES

History of Flights

VH-JJQ taxied at Kalgoorlie at 0805 and departed at 0809. The crew had planned to cruise at 24,000 feet (FL240) and track via Southern Cross. VH-AZW reported at the Southern Cross position at 0808 at FL270, with an estimate for Kalgoorlie of 0829. At time 0819, with VH-JJQ maintaining FL200 and VH-AZW on descent, VH-AZW passed approximately 500 feet below VH-JJQ on a reciprocal track. Neither crew took evasive action.

Personnel Information

The occurrence involved flight crew, as indicated earlier in the report, an air traffic controller (ATC) responsible for the control of Perth sector 4 (SEC4), controlled airspace (CTA) between Perth and Kalgoorlie, and a flight service officer (FSO) working Perth flight information service position 8 (FIS8) and providing IFR traffic information and coordination for uncontrolled airspace (OCTA) around and to the north of Kalgoorlie.

The ATC was correctly licensed to operate sector 4. There was no evidence that shift cycles, fatigue, working conditions or console workload, affecting the ATC, were factors in the occurrence.

The FSO was experienced having been initially rated in 1989. He had completed nine shift cycles, including two ten-hour shifts, in the ten days preceding the occurrence shift and he had one rostered day off. There had also been a number of late changes to the FSO's shift program during the ten-day period. The FSO indicated that during the seven weeks since he had returned from leave the workload on FIS8 had not reached the levels that it had at the time of the occurrence. He also indicated that although fatigue had not been a factor in the occurrence there were several other ongoing personnel issues that he believed could have affected his performance. These were low morale resulting from length of shifts, shift amendments, lack of breaks, staff shortages and the use of contract staff.

The FSO had not undergone a performance check during the preceding twelve months. Communications

Communication frequencies and agencies applicable to the incident were:

1. 134.3 mhz Perth control (SEC4) and 2. 122.1 mhz Perth flight service (FIS8).

The crew of VH-JJQ reported that they did not hear some transmissions made by the pilot of VH-AZW on frequency 122.1 mhz and they had difficulty contacting FIS8 on that frequency on their VHF communication transceiver No. 2. No fault was reported or found with the transceiver.

The following is a summary, with remarks, of the recorded communications relating to the traffic confliction between VH-JJQ and VH-AZW.

Recorded of Communications

Time (hours minutes seconds) 

Summary - Remarks

0806.07

FIS8 advised SEC4 that VH-JJQ was taxiing at Kalgoorlie for Perth.

-SEC4 had coordinated VH-AZW's estimate for Southern Cross (0809) with FIS8 shortly after the aircraft departed Perth at 0731. This information should have alerted FIS8 that VH-AZW was potential traffic for VH-JJQ once descent had been initiated.

-When FIS8 coordinated the taxi advice on VH-JJQ to SEC4 and in anticipation of completing the departure coordination, FIS8 ticked VH-JJQ's Flight Progress Strip (FPS) to indicate that the action was completed. However, the coordination did not take place and there no longer existed a cue to indicate to the operator that the action was outstanding.

0809.03

The pilot of VH-AZW contacted SEC4 with his Southern Cross position and gave it as Southern Cross 08, FL270, Kalgoorlie 29. SEC4 then asked the pilot of VH-AZW to report established inbound on the Kalgoorlie VOR with advice of the inbound radial.

0809.07

The crew of VH-JJQ reported to FIS8 that they had departed Kalgoorlie at time 08, that they were tracking 256 degrees for Perth, and they had left 5000 ft in the climb.

0809.31

FIS8 called SEC4 on intercom with the comment, 'one for you'. SEC4 replied with 'two for you' and immediately began to give VH-WCE's descent time but was then interrupted by the pilot of VH-AZW stating that he was on the Kalgoorlie 225 radial.

-FIS8 was about to give VH-JJQ's departure information to SEC4 but was interrupted and did not do so. A review of the tapes indicated that the SEC4 operator used the interruptive technique, when answering the intercom, on more than this occasion.

0810.26

SEC4 asked the pilot of VH-AZW where he expected to be on his normal descent profile at time 20.

• SEC4 was attempting to calculate a time of passing and whether it would be inside or outside controlled airspace.

0811.08

SEC4 and FIS8 re-established intercom, FIS8 asked for VH-WCE's descent time and then gave other traffic (VH-HSW) taxiing at Leonora but still did not give VH-JJQ's departure.

• By this time the FPS for VH-JJQ had been incorrectly notated to indicate that the coordination actions had been completed.

0811.22

The pilot of VH-AZW called SEC4 and gave FL160 as his expected level at time 20.

• When SEC4 received the taxi report on VH-JJQ, he calculated a rough time of passing with VH-AZW of 0820 based upon a projected departure time for VH-JJQ of 0810. SEC4 than asked the pilot of VH-AZW which level he would be at on descent at time 0820 and when the pilot indicated he would be at FL160, SEC4 correctly concluded that the conflict would occur OCTA (the base of CTA is FL200).

0811.49

FIS8 asked for SEC4's additional traffic and SEC4 gave VH-AZW, at Southern Cross 08, FL270 Kalgoorlie 0829 with an estimated top of descent 12, and indicated that he would give the pilot of VH-AZW traffic information on VH-JJQ.

• SEC4's closing comment was misleading in that it supported FIS8's misconception that VH-JJQ's departure information had been given to SEC4. SEC4, having indicated that he would provide traffic information to VH-AZW on VH-JJQ did not request departure information from FIS8.
• FIS8 did not notate VH-AZW on VH-JJQ's FPS in anticipation that traffic information would be required.
• FIS8 incorrectly entered the estimated descent time as 0822 on VH-AZW's FPS.

0812.44

The pilot of VH-AZW requested descent and SEC4 stated 'leave control area on descent. IFR traffic for descent JJQ a BAe 146, taxied Kalgoorlie for Perth at time 06 will be on climb and a rough estimated time of passing with that aircraft 20'.

• As SEC4 had not received a departure report on VH-JJQ from FIS8 the aircraft was not, in ATS terms, traffic for VH-AZW. SEC4 was attempting to give the pilot of VH-AZW early information on possible traffic. The advice from SEC4 did not include a destination altitude as would be provided in a normal traffic information message. For VH-JJQ to be traffic SEC4 needed to have the VH-JJQ's Kalgoorlie departure time.
• When the pilot of VH-AZW was given traffic on VH-JJQ, SEC4 included the time of passing as a guide to the pilot. The aircraft was transferred to FIS8 frequency 122.1 as soon as descent was commenced. However, the pilot of VH-AZW did not communicate directly with the crew of VH-JJQ to establish an accurate awareness of the traffic situation.
• The pilot of VH-AZW indicated that he based much of his judgement on the rough time of passing advised bySEC4.
• Although the time of passing was not given as definite the pilot of VH-AZW had been told to expect VH-JJQ to pass his aircraft at about 0820. Standard operating procedures allow SEC4 to wait 10 minutes before following up an anticipated departure coordination.

0813.11

The pilot of VH-AZW called SEC4 indicating that he was leaving FL270. SEC4 then instructed the pilot of VH-AZW to call FIS8 and to report leaving FL200 on that frequency.

• SEC4 did not advise FIS8 that VH-AZW had left FL270 on descent nor did he complete the process of passing traffic information on VH-JJQ to the pilot of VH-AZW.
• Up to this point VH-JJQ had been listening out on FIS8's and the Kalgoorlie MTAF frequencies and had not heard any of the exchanges between SEC4 and VH-AZW. VH-AZW had been listening out on SEC4 and Perth Approach's frequencies and had not heard any of the exchanges between VH-JJQ and FIS8.

0813.59

The pilot of VH-AZW reported to FIS8 that he had left FL260 on descent and he was at 83 DME from Kalgoorlie. FIS8 confirmed with the pilot of VH-AZW that SEC4 had provided traffic information on VH-JJQ.

• The pilot of VH-AZW indicated that he made this call expecting the crew of VH-JJQ to hear it. The crew ofVH-JJQ were listening out on FIS8 frequency by this time, but did not hear the call. The pilot of VH-AZW did not follow up on the lack of response.

0814.36

FIS8 attempted to call the crew of VH-JJQ to pass traffic on VH-AZW but was interrupted by another aircraft.

0815:02

FIS8 commenced passing traffic on VH-WCE to VH-JJQ, but quickly realised that this was an error.

• For some reason FIS8 had entered VH-WCE on VH-JJQ's strip and ticked it to indicate traffic had been passed. VH-WCE was an aircraft tracking between Perth and Mount Morgans and was not in conflict with VH-JJQ.
• During the period from 0812.02 to 0815.27 FIS8 was also busy dealing with other traffic and had attempted to call the crew of VH-JJQ on at least two occasions, to give them traffic information on VH-AZW, without success.

0815.27

FIS8 passed traffic on VH-AZW to VH-JJQ; however, it included advice that VH-AZW was maintaining FL270 and an incorrect descent time of 0822.

• The pilot of VH-AZW was listening out on FIS8 frequency at that time but did not register the incorrect descent time that was given to VH-JJQ.
• FIS8 passed traffic on VH-AZW to VH-JJQ at 0815.27, and included a descent time of 0822 as was indicated on the strip. Although VH-AZW had been on descent for two and a half minutes, the crew of VH-JJQ were led to believe that there was no urgency in establishing contact with VH-AZW. The pilot-in-command of VH-JJQ thought there was something odd about the descent time and estimated time of arrival at Kalgoorlie; however, following discussion with the first officer it was accepted. No attempt was made to confirm the information with FIS8.
• The crew of VH-JJQ was passed traffic on VH-AZW 3 minutes 35 seconds after SEC4 coordinated the Southern Cross position with FIS8. During this time frame FIS8 asked the crew of VH-JJQ if they had traffic on VH-AZW. Although there was no reply FIS8 did not pursue VH-JJQ's lack of response. He proceeded to perform low priority coordination tasks, and it was not until the crew of VH-JJQ prompted FIS8 that he provided traffic on VH-AZW.
• Although busy, FIS8 had the opportunity to anticipate the traffic confliction between VH-AZW and VH-JJQ and pass the traffic information earlier. He could have done this when the pilot of VH-AZW called that he had left FL260 on descent. Instead FIS8 afforded other actions a higher priority. When VH-AZW was passed as traffic to the crew of VH-JJQ, FIS8 did not notate the FPS to indicate it had been done.

0817.17

The crew of VH-JJQ requested an airways clearance from SEC4. SEC4 asked the crew of VH-JJQ to stand by then acknowledged a descent time given by VH-LBZ.

• SEC4 then attempted to calculate the respective positions of VH-AZW and VH-JJQ so he could give VH-JJQ clearance to enter controlled airspace. The aircraft passed before this was completed.
• VH-AZW was still listening out on SEC4's frequency and should have heard this call. This call should also have confirmed to SEC4 that VH-JJQ had departed Kalgoorlie. A review of the SEC4 tape indicates that the SEC4 controller spent some time, following the request for a clearance from the crew of VH-JJQ, attempting to resolve the time and altitude of passing, because of his responsibilities in relation to traffic information and separation, without contacting either aircraft or FIS8 to resolve outstanding issues such as VH-JJQ's departure time from Kalgoorlie.

0818.40

The pilot of VH-AZW made a general broadcast to FIS8 and the crew of VH-JJQ indicating that the aircraft was at 56 DME Kalgoorlie and on descent through FL200.

• VH-AZW passed beneath VH-JJQ approximately 20 seconds later.
• The pilots had not communicated with each other to arrange separation.

Medical

There were no predisposing medical conditions other than the possibility of short- or long-term fatigue/stress resulting from the conditions imposed on the FSO, by the roster arrangements and working environment.

Workload

Both SEC4 and FIS8 had high workload situations at the time of the occurrence. Although there were only eight active aircraft in FIS8's area, there were several items of coordination to process, traffic information was required to be passed to several aircraft, and there were communication difficulties with an aircraft on high frequency (HF) radio. Most of the traffic in the sector was in an area to the north of Kalgoorlie. FIS8's attention was focused on this traffic at the time VH-JJQ departed from Kalgoorlie.

Technical Equipment

There were no direct technical/equipment failures identified as having occurred during the course of the incident. However, flight service staff identified a number of potential factors which may have caused distraction. Examples were noise in the room, lighting deficiency, air conditioning faults, headset problems, HF/ VHF frequency problems, and location of the map display. At the time of the incident a number of Perth flight service area frequencies were combined on the FIS8 console through the use of the retransmit facility. Whilst the retransmit facility helps to reduce ATS operator workload by queuing aircraft calls as if only one frequency existed, it can increase pilot workload by increasing the number of non-applicable transmissions aircrew have to monitor.

Airspace Procedures and Requirements

The provision of IFR/IFR traffic information to aircraft outside controlled airspace is a feature of the current airspace system. Aeronautical Information Publication (AIP) RAC 11.6, titled Traffic Information Outside Controlled Airspace, contains the following statements:

• '11.6.1. Outside controlled airspace a traffic information service is provided to IFR and MLJ [Military Low Jet] aircraft about other conflicting IFR or MLJ aircraft...'
• '11.6.2. An IFR or MLJ aircraft reporting taxiing or airborne at an aerodrome within an MTAF or CTAF area will be advised of conflicting IFR or MLJ traffic which is not on MTAF or CTAF'.
• '11.6.3. An IFR or MLJ aircraft inbound to an aerodrome within an MTAF or CTAF area will be advised of conflicting IFR or MLJ traffic regardless of whether the confliction will occur inside or outside the MTAF/CTAF area...'
• '11.6.9. Pilots intercepting broadcasts from aircraft in their vicinity which are considered to be in potential conflict must acknowledge the intercept by transmitting callsign and, as appropriate, aircraft type, position, actual level and intentions'.

With the traffic alerting system operating correctly, it is reasonable for flight crews to anticipate that they will be provided with a directed flight information service on other conflicting IFR aircraft. It is reasonable for them to expect that such information will be provided at a time that will facilitate the resolution of any traffic conflictions. However, it is also important that pilots accept responsibility for maintaining continued situational awareness as per paragraph 11.6.9 and being prepared to intercept and acknowledge pertinent broadcasts.

ANALYSIS

Flight Service Officer Performance

The FSO on position FIS8 made a number of procedural errors during the period leading up to the occurrence.

These errors led to a failure to provide accurate and timely traffic information to IFR aircraft on opposing tracks. Whilst the FSO was unable to pinpoint any specific reason for his failure to perform at optimum level there were a significant number of workload, environmental, human performance and organisational issues that probably contributed. The FSO indicated that he may have been suffering from a level of long and/or short-term stress as a result of the environmental, human performance and organisational issues.

The FSO's procedural errors may not have been due to a recent reduction in his overall performance. It is possible that his performance had deteriorated over a period of time and the lower levels of activity on the consoles he operated, during previous shifts, did not disclose this. The lack of a performance check also meant the deterioration was not disclosed in time for remedial action to be taken before it led to an air safety occurrence.

Air Traffic Controller Performance

The SEC4 ATC answered intercom calls in a dominating manner, resulting in caller's priorities being altered, and in a manner not in accordance with standard operating procedures. This situation can lead to failure of the calling party to achieve complete information transfer. SEC4 did not coordinate VH-AZW's descent to FIS8, and this possibly contributed to an incorrect situational awareness of the crew of VH-JJQ and FIS8 when assessing traffic information parameters. SEC4 did not complete the exchange of traffic information to the pilot of VH-AZW, and he did not avail himself of all the information that was available when attempting to resolve the time and altitude of passing parameters.

Flight Crew Performance

It is apparent that each aircraft had been alerted to the operation of the other. However, the opportunity for the flight crew to recognise the problem and take corrective action was diminished by a number of factors. In the case of VH-AZW, the information provided on VH-JJQ was incomplete in that advice of the departure of VH-JJQ was not provided. In the case of VH-JJQ, the information was flawed, in that an incorrect descent time and an incorrect statement that VH-AZW was maintaining FL270 were provided, and the crew did not hear critical radio transmissions.

Environmental Issues

A number of environmental issues were identified, and these may have degraded the FSOs performance at the time of the occurrence. These were:

• noise in the room;
• lighting deficiencies;
• air conditioning faults;
• headset problems;
• HF/ VHF frequency problems and- the location of the map display.

Human Performance/Organisational Issues

A number of human performance and organisational issues were identified which may have contributed to the occurrence. These were:

• low morale;
• length of shifts;
• shift amendments;
• lack of breaks;
• staff shortages;
• the use of contract staff and
• the failure of the performance checking system.

The aircraft was established in normal cruise at 7,000 ft when the pilot heard a loud bang from the right engine. The pilot believed that the right engine had failed, but as he commenced the propeller feathering procedure, he realised that the propeller was missing. On closer inspection it was clear that the entire right propeller, including the hub and spinner, had detached. The aircraft returned to Darwin where a safe landing was accomplished.

A metallurgical examination of the crankshaft revealed its failure was consistent with the development of an abnormally high force during flight. The engine bearers had been broken, and the engine was supported only by control linkages, cables and the engine cowling. This damage was consistent with the separation of one propeller blade, or portion of a blade. The resulting imbalance causing an overload failure of the engine bearers and crankshaft.

The propeller was not recovered.

VH-UJF was enroute Eildon Weir to Moorabbin at 3000 ft in controlled airspace and was approaching the reporting point Academy when the approach radar controller observed VH-AZQ approaching Academy from the Moorabbin direction at 2800 ft. VH-AZQ had penetrated controlled airspace while awaiting an airways clearance. The approach controller advised VH-UJF of the conflicting traffic and turned VH-UJF onto a heading of 270 degrees. At the same time VH-AZQ called Melbourne radar advisory service (RAS). The RAS controller advised VH-AZQ of the conflicting traffic and verified the level of VH-AZQ as 2500 ft. Both aircraft came within 2 NM of each other in visual meteorological conditions.