The Jabiru aircraft was departing Cairns for a dual training flight. At approximately 200 ft AGL during the initial climb, a loud bang was heard, and the aircraft began to vibrate violently. The pilot immediately reduced engine power and was able to land the aircraft straight ahead on the remaining runway without further incident.

Later examination found that the right rear cylinder on the engine had partly detached from the crankcase. The cause for the detachment was traced to the fatigue failure of two of the cylinder tie down bolts. Specialist examination of the bolts by the manufacturer determined that the bolt design was probably inadequate. The manufacturer has since redesigned the bolts.

The aircraft ballooned during the flare out to land. In attempting to correct the flare, the pilot pushed forward the control column which resulted in the aircraft landing heavily and the nosewheel and propeller striking the runway. The pilot appears to have reacted spontaneously by pushing the control column forward instead of overshooting from the approach. The pilot's low aeronautical experience may have contributed to his actions.

Factual Data

This incident involved the RAAF Roulettes aerobatic team operating in close proximity to a media helicopter during an aerobatic display.

During the week prior to the occurrence, the RAAF Roulettes aerobatic team had coordinated plans to provide an aerobatic display during the launch of a Frigate at Williamstown (WMS) naval dockyard. Parties involved in the planning/coordination were the Roulettes administration officer, the Essendon Tower (EN TWR) team leader and the Melbourne Ops District Office Support Specialist (DOSS) staff.

The plan was for the Roulettes to arrive and hold at Freeway Overpass (FWO) at 3000 feet, weather permitting and then to proceed to WMS for the display. The airspace required for the display was a three nautical mile radius around WMS up to 4000 feet. A temporary restricted area was promulgated by NOTAM up to 2000 feet to cover the OCTA portion, the CTA base at WMS being 2000 feet. The controlling authority was EN TWR.

Both the EN TWR team leader and the ML Terminal Area Controller (TAC) were advised of the reason for the NOTAM and the intentions of the Roulettes, including the possible need to operate up to 4000 feet.

When the Roulettes arrived at FWO, the weather was marginal for holding at 3000 feet, so they were cleared to hold at 2000 feet. When they were ready to proceed to WMS for the display, they were cleared by EN TWR to "commence their run". The clearance did not include any reference to an airspace release (i.e. altitude limits) for the display nor a transit altitude for the run-in from FWO to WMS.

A media helicopter, VH-HWA, was operating over WMS at 2500 feet on Radar Advisory Service (RAS) frequency in Departures South (DEP S) airspace with DEP S concurrence. EN TWR passed traffic advice to Roulettes on VH-HWA, but VH-HWA was not advised of the intentions of the Roulettes. On arrival at WMS the Roulettes commenced an aerobatic display which took them to approximately the same altitude as, and in close proximity to, VH-HWA. Although the Roulettes did not acknowledge traffic advice on VH-HWA, they later confirmed they were aware of and maintained separation from, VH-HWA, during the display.

The pilot of VH-HWA was unaware that the Roulettes had him in sight and were maintaining visual separation from him during the display, but he did not report the matter to RAS. Because transponder codes were garbled with the aircraft in close proximity to each other, the Melbourne Approach Control Unit (ACU) were unaware that the Roulettes had conducted their display in close proximity to VH-HWA until after the event when advised by EN TWR.

The incident occurred during a high traffic load at EN TWR and a moderate to high traffic load in DEP S. In addition, there was ADC training in EN TWR that necessitated the ADC letting the trainee take control of the situation, with the ADC providing as little assistance as possible.

Analysis

Melbourne Area Approach Control Centre (AACC) controllers had no specific handover in the morning from the TAC to make them aware that the Roulettes would be conducting a display at WMS and requiring ML Terminal Area (TMA) airspace. They received the NOTAM on the restricted area but thought it was only to protect the launch of the ship, even though the NOTAM actually stated, "due air display". Details of the air display, including the controlling authority and possible airspace requirements, had previously been advised to the TAC who had made an appropriate annotation in the daily diary. However, the daily diary had not been checked by the oncoming morning TAC. In addition, there was nothing in the handover/takeover sheet advising of the Roulettes display.

On the flight plan received from the Roulettes there was no mention of an air display nor any request for a higher level at WMS. When ML RAS requested from DEP S a level for VH-HWA to operate at WMS, both controllers agreed that 2500 feet would give the required tolerance with the restricted area. ML DOSS had informed the EN team leader of the proposed restricted area and the Roulettes requirements. The team leader had prepared a briefing note, but the EN aerodrome controller (ADC) was busy supervising a trainee and had not assimilated the information in the note, in particular the possible need for a climb above the restricted area.

Regarding ML TMA, the TAC handover/takeover sheet did not give a reason for the restricted area (upper limit 2000 feet) and the daily diary was not checked. The Airways Data Systems Officer (ADSO) staff did not show the flight plan to the TAC, however, the flight plan did not indicate any air display at WMS.

The EN ADC did not specify any altitudes in his clearance to the Roulettes when he cleared them to “make their run", nor did he ascertain their requirements. In addition, the Roulettes then accepted a clearance, without question, that included no reference to altitudes. VH-HWA was not passed traffic information on the Roulettes because ML RAS were unaware, they would be operating above 2000 feet, the upper limit of the restricted area. Further, VH-HWA and the Roulettes were on different frequencies.

There had been no coordination between EN TWR and DEP S regarding the possibility (or intentions) of the Roulettes to operate above the upper limit of the restricted area (2000 feet) in DEP S airspace.

Factors

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

1. The restricted area at WMS was only promulgated to the base of CTA. Had it been promulgated to 4000 feet (the original highest planned operating altitude for the Roulettes) then it would have been under one controlling authority and VH-HWA would not have been over WMS at 2500 feet at the same time the Roulettes were conducting an air display.
2. The Roulettes were not given a proper clearance by the EN ADC to proceed to WMS and to conduct the display. The clearance was deficient in that no altitudes were specified, either for transit to WMS or for the display at WMS.
3. The Roulettes accepted a clearance that did not specify altitudes. This was probably as a result of an expectancy that they could operate up to 4000 feet, such expectancy being created by the planning for the event that occurred the previous week.
4. There were numerous breakdowns in communication/coordination between elements of ATC because controllers failed to follow standard procedures which would have averted these breakdowns. In failing to follow such procedures, certain elements of ATC were unaware of the intentions of the Roulettes.
5. The flight plan received from the Roulettes made no mention of an air display at WMS and contained no request for a higher level at WMS. Consequently, the flight progress strips were prepared without this knowledge.
6. The pilot of the helicopter was not given traffic information on the Roulettes. This was because ML RAS was unaware that the Roulettes would be operating above the upper limit of the restricted area.
7. The incident occurred during a high traffic load at EN TWR when ADC training was in progress. In addition, there was a moderate to high traffic load at DEP S.

Safety Action

All controllers involved were counselled. The counselling included a reminder of the need not to be complacent, to ensure that all control instructions are correctly carried out and coordinated so that no controller is left in any doubt.

ML DOSS and Manager Ops Support were consulted to ensure a standardised method of advice to all relevant parties, including the contents of NOTAMS, the way information is disseminated and the need with the initial briefing to ensure the responsibilities of the controlling authority are understood. Had the NOTAM included the vertical limits with the relevant tolerances, this incident may have been avoided.

A standardisation item is to be issued to highlight the need for precise descriptions of airspace releases plus a reminder that performance characteristics need to be considered when formulating airspace releases.

A standardisation item is to be issued highlighting the importance of being specific when defining a route clearance.

The ML TMA Stream Specialist conducted counselling for all ML TACs to ensure that correct handover/takeover procedures apply. In addition, TMA staff were to be reminded of their responsibilities for ensuring a correct handover is carried out.

All controllers were to be reminded of the separation requirements for formation flights.

ADSOs were to be reminded of their responsibilities to pass this type of flight plan to the TAC.

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.