Safety summary

What happened

At about 0025 on 30 May 2016, freight train 9305 derailed at a fractured welded rail joint at Katunga in northern Victoria. The train consisted of two locomotives and 37 flatbed wagons carrying empty containers. Twelve wagons located mid-consist (wagon positions 6 to 17) derailed resulting in severe damage to about 350 m of track. There were no injuries.

What the ATSB found

The ATSB found that the fracture was at a flash butt weld joining early twentieth century rail. The weld contained microscopic defects within the crystalline material structure that indicated improper material processing during flash butt welding, and had probably existed for many years.

It was concluded that the fracture was probably the result of higher than normal loading due to inadequate support of the rail. The loss of effective support was probably the result of deteriorated sleeper condition. The deferral of the replacement of select sleepers through the location had increased the potential for rail fracture, although it was not possible to directly link this decision to this fracture.

The condition of the fracture surfaces indicated that the fracture was probably present for several days prior to the passage of train 9305. After the rail’s fracture, the loosening of the track fasteners allowed the lateral misalignment of the rail ends that led to the derailment of the train. The regime that may have detected the fractured rail before the track deteriorated to an extent that would result in derailment was ineffective for this track and its condition.

What's been done as a result

V/Line has revised their Technical Maintenance Plan schedule to clarify that front of train inspections cannot be used to replace hi-rail patrols on the Tocumwal line.

Further, V/Line intends undertaking a risk review of the appropriateness of its current condition based responses for sleeper condition, as set out the V/line standard for inspection and assessment. The ATSB has recommended that V/Line completes the risk review and implements safety actions to reduce the likelihood of derailment following a rail fracture.

Safety message

Systems of inspection should be designed to ensure detection of rail fractures before track deteriorates to a condition that results in train derailment. 

The Occurrence

Train journey

At about 1915[1] on 29 May 2016, Pacific National freight train 9305 departed Tottenham Yard, Melbourne, bound for Tocumwal in New South Wales (Figure 1). The train was being operated on the V/Line broad gauge network by a crew of two and consisted of two locomotives hauling 37 flatbed wagons carrying empty containers.

Figure 1: Route of freight train 9305

Source:  Copyright Map Data Google 2016 with annotations by Chief Investigator, Transport Safety (Victoria)

The train proceeded to Craigieburn and then onto Seymour. From Seymour all trains are required to work to safeworking by train order.[2] A train order was issued at about 2215 to travel from Seymour to Shepparton and the train arrived at Shepparton without incident. A second train order was issued at about 2335 at Shepparton for the journey to Tocumwal.

At about 0025 when travelling through Katunga at about 61 km/h, the train crew felt a ‘bump’ and rough riding near the 228 km rail post. Shortly after there was a loss of brake pipe pressure resulting in a brake application. In response to this, the driver released the locomotive independent brake[3] and continued powering to maintain the train couplings in a draft condition.[4] The train then came to a stand with the lead locomotive about 295 m past the 228 km post.

Once the train had stopped, a crew member investigated the cause of the brake application. On observing the derailed wagons, the crew advised Centrol[5] and secured the train. There were no injuries to the public or the train crew.

The derailment and damage

The train had derailed at a fractured flash butt welded rail joint in the east rail at about the 227.8 km mark (Figure 2).

Figure 2: Fractured rail

Source:  Chief investigator, Transport Safety (Victoria)

The passage of train 9305 over the fractured rail had disturbed the joint sufficiently to laterally misalign the rail ends, such that a wheel flange impacted with the rail head on the Down-end. This resulted in further disarrangement of the rail and a loss of guidance for the following wagons. It is probable that the trailing axle of the leading bogie of wagon six was the first to derail.

Of the twelve wagons that derailed, wagon six, seven and eight stayed upright and generally followed the track alignment, while the rear bogie of wagon nine veered to the east of the track. The tenth wagon and the following eight wagons veered to the east of the line causing a separation between the ninth and tenth wagons. The separation caused the loss of brake pipe pressure and the subsequent application of the train brakes. The locomotive and the first nine wagons travelled about 137 m from the separated section of the train (Figure 3).

Figure 3: Separated section of train and track damage, looking towards Tocumwal

Source:  Chief investigator, Transport Safety (Victoria)

Wagons 10 to 17 ended in various states of disarrangement (Figure 4). The leading end of wagon 18 had lifted off the bogie centre bowl while the last nineteen wagons remained on the track. The derailment resulted in about 350 m of track damage.

Figure 4: Disarranged wagons separated bogies and damaged track

Source:  Chief investigator, Transport Safety (Victoria)

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[1]  The 24-hour clock is used in this report and is referenced from Eastern Standard Time (EST), UTC +10 hours.

[2]  Railway safeworking by train order involves the use of a paper instrument issued by a train controller authorising the driver to proceed into and through the nominated single-line section.

[3] An air brake system that operates on the locomotive independent of the train air brake system.

[4] A condition that maintains the coupler forces throughout the train in tension.

[5]  Central Control - The operational control centre for Victoria's regional rail network.

Context

Location

The derailment occurred on a section of tangent track about 180 m north of the Spences Road level crossing (Figure 5).

Figure 5: Derailment location in Katunga, Victoria

Source: MapInfo Professional annotated by Chief Investigator, Transport Safety (Victoria)

Infrastructure

The line between Shepparton (182 km) and Tocumwal (252.6 km) was classified by V/Line as Class 4[6] track. The V/Line standard[7] for Class 4 track construction specified timber sleepers with non-resilient fasteners, sleeper plates, 47 kg/m rail (80 lb/yd[8] for existing track) in maximum lengths of 82 m mechanically jointed. The load limit for the Shepparton to Tocumwal line was 19 t axle load at a maximum speed of 65 km/h. Higher axle loads were allowed for approved locomotives.

At the derailment location, the track (considered ‘existing track’) consisted of 80 lb/yd rail that had been welded to form approximately 27.5 m lengths that were mechanically joined by fishplates. Rail was secured to timber sleepers using base plates and dog spikes. The sleeper spacing from centre to centre was 600 mm at the location of the fracture. The rolling marks indicated that the rail through the area was manufactured in Lorain, USA in the period 1911-1913. The rolling marks on the fishplates indicated that they had been manufactured by BHP in Australia in 1958. The topography of the incident area was flat, with sand and gravel soil with good drainage. The 27.5 m section of rail at the derailment location had been fabricated by flash butt welding two 7.7 m lengths to either end of a 12.1 m length of rail.

The flash butt welding process consists of heating the rail ends by means of an electric arc struck between the ends, and when in a plastic state forcing the rail ends together to effect the weld. Flash butt welding was usually undertaken in a factory facility. The date these welds were made is unknown, but was probably within the first half of the twentieth century.

Rail traffic

From January to May 2016, the freight rail traffic in the Up direction averaged 1.2 trains per day and the average tonnage was about 2000 t, mostly loaded. Under loaded conditions, the maximum wagon axle load is about 19 t. In the same period, the rail traffic in the Down direction also averaged 1.2 trains per day and the average tonnage was about 700 t, mostly unloaded.

Metallurgical examination of rail

Rail Chemistry

The steel rail had a carbon content varying between 0.50 and 0.75 per cent. The steel also contained small percentages of manganese, silicon, phosphorus and sulphur.

The rail head hardness was typical of rail material utilised in Australia before 1985 and was appropriate for the application.

Weld fracture

The rail head at the fractured weld had been battered on both sides of the break. Both ends were battered to a depth of about 10 mm. Mechanical damage to this depth indicated the passage of bi-directional rail traffic over the broken joint after fracture. There was also significant mechanical damage to the fracture surfaces and corrosion. At the intersection of the web and the foot, the fracture surface exhibited a region of predominantly intergranular fracture where significant grain boundary oxidation was observed (Figure 6).

Figure 6: Fractured weld ends, the Up-side rail is on the left and the Down-side rail on the right. The area of intergranular fracture is identified.

Source: ALS Global annotated by Chief Investigator, Transport Safety (Victoria)

The damage to the fracture surfaces had destroyed a significant amount of the fracture detail. The undamaged fracture surfaces of the rail head and web exhibited a coarse dimpled appearance consistent with instantaneous overload fracture. These features were indicative of ductile-fast fracture.

The fractured rail was longitudinally sectioned and evaluated by macro etching. The macro etching confirmed that the rail had been flash butt welded at the failed point. The macro etching revealed that the parent material was homogenous with no significant segregation of non-metallic inclusions.

In addition to the parent material, the evaluation revealed three distinct areas; a weld fusion line, a weld flash Heat Affected Zone (HAZ) and a HAZ produced during pre-heating prior to welding (Figure 7). The two Heat Affected Zones are consistent with in-plant flash butt welding processes. The fusion line hardness of the subject rail was consistent with the parent-rail material hardness. The peak HAZ hardness was 264HV (Vickers), 2.5 mm from the break and is not excessive for the application.

Figure 7: Macro etched longitudinal section of rail on the left showing that the fracture had occurred predominantly in the HAZ adjacent to the weld fusion line. The rail prior to sectioning is shown on the right.

Source: ALS Global annotated by Chief Investigator, Transport Safety (Victoria)

Laying rail and managing stress

Mechanical joints

In jointed track, the mechanical joints have an expansion gap (Figure 8) that results in stress free rail within a defined temperature range. This longitudinal rail movement at the joint reduces the probability of rail fractures in cold temperatures due to rail contraction. Correct joint set-up and ongoing maintenance is required to ensure joints perform this function.

A mechanical joint adjacent to the fractured weld on the east rail was visually and mechanically examined (Figure 8). Based on bolt torques and wear on the fishing surfaces, the examination concluded that the rail had been expanding and contracting at the mechanical joint.

Figure 8: Mechanical joint adjacent to fractured weld on the East rail

Source: Chief Investigator, Transport Safety (Victoria)

A mechanical joint on the west rail opposite the joint on the east rail was also examined. Again, the abrasive wear on the fishing surfaces was consistent with the expansion and contraction of the rail at the mechanical joint.

V/Line construction standards[9] specified the method of laying rail to achieve design levels of maximum tensile and compressive stress. For jointed rail of 27 m length, the standard specified that the gap between rail ends should be 11 mm (the nominal maximum gap) for rails laid at a rail temperature between -2 °C to 7 °C, and fully closed (rail ends butted together) when laid at rail temperatures of 35 °C to 38 °C. The standard also specified other gap requirements for installation temperatures between 7 °C and 35 °C. If laid in this manner, at temperatures below the lower range (-2 °C to 7 °C) the rails would be in tension, and at temperatures above the upper range (35 °C to 38 °C) the rails would be in compression.

Gaps at seven pairs of mechanical joints on the Up side (towards the crossing) of the fractured weld were measured following the derailment, at an ambient temperature of about 15 °C. Gaps on the Up leg averaged 12 mm[10] and the gaps on the down leg averaged 10 mm. There was no indication that these joints had been recently lubricated, however there were signs that the joints were working.[11]

Creep measurements 

Creep is the longitudinal movement of rail caused by the motion of rail traffic on the line. Creep typically takes place on grades, where trains brake and in the direction of predominant or loaded traffic. Rail creep can affect the stress condition of the rails. Creep monitoring points (monuments) are located alongside the track (one kilometre apart) and regular measurements are taken to ensure that the longitudinal movement of the rail is within acceptable limits.

Creep measurements recorded at the 228 km point between 2009 and April 2016 indicated a slow movement of the rails in the Up direction (towards Melbourne). The location of the weld fracture (227.8 km) was between the Spences Road level crossing and 228 km. The creep measurements indicated movement towards the fixed point of the crossing.

Track inspection

V/Line’s track inspection and maintenance procedure required track patrol inspections, general inspections and detailed inspections to be carried out at specified frequencies. For the Shepparton to Tocumwal line, track patrol inspections were required to be performed by road-rail vehicle or front of train riding once a week. General inspections by track walking and detailed inspections by a track geometry recording vehicle were to be carried out annually. Ultrasonic testing using a rail flaw detection (RFD) vehicle was to be conducted every two years.

The maintenance procedures provided specific guidelines for the assessment of non-welded joints (mechanical) and welded joints. Cracks in fishplates, loose or damaged bolts, rail-end batter and joint gaps are identified as areas for assessment in mechanical joints. For general inspection of rails and welded joints, corrosion, gauge corner or other cracking, piped rail, corrugations, shelling, rust streaks, and damaged rail were specified areas of assessment.

The most recent track patrol inspection before the incident was completed on 24 May 2016. This inspection, conducted from the front of a train, did not identify any defects at the derailment location.

A ‘Work Order’ for the most recent track walking inspection before the derailment for this section (182 to 253 rail km) records that it was completed on 30 October 2015 with no noted defects at the derailment location.

Measurement of the track geometry was carried out in March 2016 and no abnormal readings were recorded in the vicinity of the broken rail weld (227.8 km).

Rail flaw detection

The annual ultrasonic testing for internal rail defects involved operating an RFD vehicle. When a defect was detected by the RFD car, the location was noted and a manual inspection using hand-held ultrasound equipment was carried out. The defect was then categorised according the class of rail line, type and size of defect.

The last RFD inspection on the Shepparton to Tocumwal section of track was carried out about 12 months before the derailment on 5 May 2015 and no defects were observed at the location of the weld fracture. Following the derailment, recordings of the ultrasonic response at the fracture location were reviewed and there were no identifiable indications of microscopic material defects at the fracture location.

Detailed track condition inspection

A detailed asset inspection was conducted in 2014. The inspection identified 13 ineffective sleepers from 227.700 and 228.000 km, including three nominally within 50 m of the fractured weld. The Work Orders to replace the sleepers were subsequently cancelled, and V/Line advised that the sleeper replacement did not occur.

Train and crew information

Pacific National freight train 9305 consisted of two locomotives XR553 and XR554 hauling 37 flatbed wagons carrying empty containers. The containers were interspersed evenly on the wagons along the train. The trailing load of the consist had a total mass of 971 t, and the total mass including locomotives was 1215 t. The total length of the train was 768 m.

Train 9305 was crewed by two drivers who were appropriately qualified and certified for the route. The drivers were tested for the presence of alcohol after the derailment and returned zero results.

Post-incident rolling stock inspection

Inspection of the leading bogie of the first wagon that derailed identified the presence of wear in the friction wedge pockets. This wear was within condemning limits[12] and there were no signs that the bogie had been hunting. Wheel tread damage was the result of the derailment. The condition of the rolling stock did not contribute to the derailment.

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[6]  Categorised as a Major Freight Line.

[7]  Use and Laying of Rail, Document No: NIST 2650.

[8]  About 40 kg/m.

[9]  Use and Laying of Rail – NIST 2650, p.13.

[10]  While the nominal maximum (nominal) joint gap is 11 mm, greater gaps can exist in practice due to variations in bolt diameter and wear or elongation of rail holes. It is not uncommon to find joints that can extend to a gap of 15 mm.

[11]  Expansion and contraction of the rail at the mechanical joint.

[12]  A permissible limit determined by the use of a specific gauge.

Safety analysis

Derailment

The derailment occurred as a result of a fracture at a flash butt welded rail joint. The condition of the fracture surfaces indicated that the fracture had occurred prior to the passage of train 9305. Battering of the fractured rail indicated bi-directional traffic across the fracture, and corrosion and fracture surface damage suggested the fracture had been present for several days.

The battering of rail head ends indicated that vertical displacement of the rail had been possible in the period following the fracture. In addition, dog spikes on the Up-side of the fracture had been lifted and were loose suggesting that the passage of trains had resulted in the deterioration of rail fixings around the fracture. This deterioration was sufficient to allow the development of a lateral discontinuity at the fracture during the passage of train 9305 resulting in the derailment of the train.

Weld fracture mechanism

The fracture occurred predominantly in the Heat Affected Zone adjacent to the weld fusion line and fracture surfaces were consistent with instantaneous overload fracture.  

Pre-existing defect

Metallographic examination of the fracture exhibited a mixed mode (transgranular and intergranular) cracking mechanism. The fracture surface at the foot-web intersection of the fractured weld exhibited a predominantly intergranular brittle fracture mode (Figures 6 and 9).

Figure 9: Photomicrograph of the etched microstructure of the rail fracture surface. The foot-web intersection of fractured weld exhibited an intergranular fracture mode.

 

Source: ALS Global annotated by Chief Investigator, Transport Safety (Victoria)

Intergranular brittle fracture occurs by separation at or adjacent to the grain boundaries (where significant oxidation was observed). This type of fracture is indicative of improper material processing during flash butt welding.

History of weld failures

V/Line advised that there were about 330,000 flash butt welds and about 180,000 thermit welds[13] on their operating network. From 2005 to 2015, there were 59 flash butt weld failures, 27 thermit weld failures and a range of other fractures (Figure 10). The flash butt failures represented 15 per cent of the total annual rail failures and the failure rate is similar to other welded connections on the network.

Figure 10: Rail failures from 2005 to 2015.

Source: V/Line Pty Ltd, annotated by Chief Investigator, Transport Safety (Victoria)

Loading of rail

Rail tension

There was no evidence to suggest that rail creep or frozen joints had resulted in higher than normal rail tension. The rail joints between the fracture and level crossing were ‘working’ and so provided for rail expansion and contraction. In addition, the recorded rail creep was southwards towards the crossing making high rail tension in cold weather less likely.

Temperatures recorded at Tocumwal (24 km from Katunga) indicated low overnight temperatures during the last week of May, with a minimum of 3 °C. Considering the measured joint gaps between the fracture and the crossing, these low overnight temperatures probably resulted in some tension in the Up (east) rail. However, this tension is unlikely to have been excessive and would have been within the normally expected range. It was therefore concluded that excessive rail tension was not likely to have contributed to the fracture.

Bending stress

In the absence of excessive rail tension, higher than normal bending stress within the rail most likely led to the fracture. The failure mechanism by instantaneous overload, as confirmed by metallurgical examination, is consistent with this loading scenario.

Bending stresses are developed in a rail during the passage of a train and increase when the support provided to the rail is inadequate or uneven. Site observations identified that support of the rail was probably compromised by the deteriorated condition of sleepers.

Following a period of dry weather, the month of May received more than double its normal rainfall and this may have had some influence on the condition of the support.

Asset condition

Inspections

A walking inspection seven months prior to the derailment and weekly track patrols were scheduled in accordance with network procedural requirements and there was no specific deficiency in the application of the inspection regime identified.

However, in this instance these inspections did not identify a deterioration in track support at the derailment location. The absence of any rail top defects or other track geometry anomalies through this location may have reinforced a belief that sleepers were providing adequate support.

Deferment of sleeper replacement

Asset assessments in 2014 had identified several ineffective sleepers through this location and work orders were raised for sleeper replacement. V/Line advised that these work orders were subsequently cancelled. It was not possible to identify whether those sleepers identified for replacement directly influenced the rail fracture leading to this derailment. However, the action to defer sleeper replacement probably increased the risk of rail fracture through the location.

The documentation clarifying the rationale for cancelling the replacement of sleepers could not be identified by V/Line. Several factors might influence decisions to cancel work orders including judgements as to the serviceability of the track, risks associated with the type and volume of traffic, funding and resource allocation. In this instance, the rationale for the deferment of the work program could not be ascertained due to the lack of documentation. Assessing the risk of deferring a work program and documenting the process is crucial to ensuring a verifiable and transparent decision making process.

The fracture

Pre-fracture weld defect

It is unlikely that the defects found within the weld would be detected by ultrasonic testing used in an automated RFD vehicle or currently available train borne monitoring equipment. The defects that were located on grain boundaries within the crystalline material structure were small and discontinuous and would produce specular multi-directional ultrasonic responses. These responses would produce a multi peak indication similar to lower level ‘noise’ signals and would be expected to be below the threshold that would cause a defect alarm. The microscopic defects observed would need to propagate by fatigue to produce a macroscopic planar defect before a detectable ultrasonic return signal could be produced. While some microscopic fatigue was observed, it had not progressed to macroscopic levels in this case.

Fracture detection

The condition of the fracture surfaces indicated that the fracture was probably present for at least two days prior to the derailment. Rail fractures cannot be completely eradicated and the network has about 30 fractures per annum. Therefore, there is a strong imperative to identify the presence of the fracture before the track deteriorates to a condition that could cause derailment.

The fracture was present during the passage of several trains. In the previous 48 hours, three Melbourne-bound and one Tocumwal-bound trains had traversed the location, one in daylight hours. There were about two trains per day preceding this. However, there were no rough riding or track irregularities reported by train drivers prior to the derailment even though other trains had travelled over the fracture. Given the section was jointed, it may have been difficult for train crew to detect the presence of the fracture.

A track patrol inspection was carried out by front of train riding on 24 May 2016, six days before the derailment. It is unknown whether the fracture was already present, although track patrol by hi-rail may have been a more effective means of detecting the fracture. If the fracture occurred after this patrol, there were no other means of identifying this fracture.

Once the rail had fractured, the configuration and condition of the track meant that dog spikes probably became dislodged relatively quickly reducing the opportunity for the fracture to be identified by track patrol prior to the loss of gauge. Risk mitigation measures used to identify fractured rail were not effective for the configuration and condition of this track.

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[13]      Exothermic welding using molten metal to join rail ends. This method of connection is normally conducted on site and
 uses an Aluminothermic reaction to create the heat necessary to melt the joining metal.

Findings

The following findings are made with respect to the derailment of freight train 9305 at Katunga, Victoria on 30 May 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Safety issues, or system problems, are highlighted in bold to emphasise their importance. A safety issue is an event or condition that increases safety risk and (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.

Contributing factors

• There were microscopic defects within the weld zone that were probably the result of improper material processing during the flash butt welding of the joint.
• The loading of the rail at the weld was probably higher than normal due to inadequate support of the rail, and this inadequate support was not identified.
• The rail fracture was not detected before the passage of train 9305.
• The inspection regime to identify rail fractures was ineffective for the condition of this track. [Safety Issue]
• During the passage of train 9305, the rail ends at the already fractured weld laterally misaligned resulting in the derailment of the train.

Other factors that increase risk

Remediation works to replace deteriorated sleepers was deferred by V/Line. 

Safety issues and actions

The safety issues identified during this investigation are listed in the Findings and Safety issues and actions sections of this report. The Australian Transport Safety Bureau (ATSB) expects that all safety issues identified by the investigation should be addressed by the relevant organisation(s). In addressing those issues, the ATSB prefers to encourage relevant organisation(s) to proactively initiate safety action, rather than to issue formal safety recommendations or safety advisory notices.

Depending on the level of risk of the safety issue, the extent of corrective action taken by the relevant organisation, or the desirability of directing a broad safety message to the rail industry, the ATSB may issue safety recommendations or safety advisory notices as part of the final report.

Rail fractures

Safety issue number: RO-2016-007-SI-01

Safety issue description: The inspection regime to identify rail fractures was ineffective for the condition of this track.

Safety recommendation description: The ATSB recommends that V/Line completes the risk review and implements safety actions to reduce the likelihood of derailment following a rail fracture.

Additional safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

V/Line has advised that, since the derailment of freight train 9305, a joint servicing program has been completed, with all mechanical joints lubricated, bolts repaired, and fishing surfaces lubricated. V/Line has also redeveloped its ultrasonic inspection and assessment standard to include more specific instructions and requirements for ultrasonic testing, including a requirement to report non-sizable defects in more detail. Further, it has conducted ultrasonic inspections of an additional 100 flash butt welds and 50 thermit welds on the Tocumwal line. They reported that no defects were detected during these inspections.

Sources and submissions

Sources of information

The sources of information during the investigation included:

• V/Line Pty Ltd
• ALS Industrial Pty Ltd
• Asciano Limited
• Speno Rail Maintenance Australia Pty Ltd

References

Use and Laying of Rail – NIST 2650 – V/Line Procedural document.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

Submissions were received from V/Line Pty Ltd and The Office of the National Rail Safety Regulator (ONRSR). The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2017 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

What happened

On 5 June 2016, the pilot of a Cessna 206 floatplane, registered VH-NTK, was taking off from the Southport Broadwater about 6 km south-east (SE) of Southport Airport, Queensland, for a charter flight with two passengers on board.

The wind was blowing from the west-north-west (WNW) at about 18 kt, with gusts of variable speed. The take-off direction to the north-west (NW) was too restrictive due to the presence of boats in the area, so the pilot elected to begin the take-off towards the south-west (SW) (Figure 1). Taking off to the SW would be through a jet-ski course and a crosswind from the right. Once clear of the jet-ski course, the pilot intended to veer right onto a more westerly (into wind) heading to complete the take-off.

The pilot set 20° flap and left the water rudders^[1] in the down position to assist with directional control at the start of the take-off run. The pilot applied full power to start the take-off run and the aircraft pitched^[2] backwards into the plowing position.^[3] The pilot retracted the water rudders about five seconds into the take-off run, and about two seconds later, pitched the aircraft forward from the plowing position into the step position.^[4] As the aircraft pitched forward onto the step it veered to the left onto a south-south-west (SSW) heading (this increased the crosswind experienced – see textbox 4 in Figure 1). The pilot maintained the aircraft on this heading until they sighted barrels in the water that were used to mark the jet-ski course.

The pilot could not prevent the veer to the left, even with full right rudder, so after sighting the jet-ski course barrels, the pilot pitched the aircraft backwards into the plowing position to improve directional control on the water.^[5] The pilot then alternated pitching the aircraft between the plow and step position in order to gradually veer to the right onto a more westerly heading (textbox 5 in Figure 1).

As the aircraft was passing a SW heading and was turning towards WSW, the right wing lifted and the aircraft rolled^[6] to the left. The roll continued, despite the application of full right aileron by the pilot, until the left wing impacted the water. The aircraft rotated to the left through about 270° and the nose and propeller ploughed into the water. The aircraft then came to a stop in an upright position, facing in a westerly direction (Figure 1).

The pilot assessed the condition of the aircraft and elected not to evacuate the passengers. The aircraft was then towed to shore by a jet-ski. There were no injuries and the aircraft was substantially damaged (Figure 2 and 3).

Figure 1: Approximate take-off path and key events

Source: Google earth modified by ATSB

Figure 2: VH-NTK left wing damage

Source: Owner

Figure 3: VH-NTK rear strut fracture (view of the left float facing forwards)

Source: Owner

Pilot comments

The pilot provided the following comments:

• the force that veered the aircraft to the left occurred when they pitched the aircraft forward from the plow position to the step position
• they were turning the aircraft right through SW towards WSW when it rolled
• they were holding full into wind (right) aileron control and therefore expected the left wing to lift prior to the right wing
• when they rolled to the left they were ‘shocked’ by the crosswind and ‘surprised’ they could not control the floatplane
• they estimated the strength of the gust that lifted the right wing was about 8–10 kt
• they had about 110 litres of fuel in the left wing tank and about 60 litres in the right wing tank, which may have contributed to the left roll
• the floatplane rolled left at about 30–35 kt airspeed
• the crosswind limit is 20 kt
• the take-off speed is 41 kt with 20° flap set.

Left turn effect

There are four distinct propeller forces, each of which produce a left turning force on an aeroplane, as follows:

• Torque effect: As the engine internal parts and propeller rotate clockwise, as viewed by the pilot, an equal force tries to rotate the aircraft in the opposite direction. This force places more weight and consequently more hydrodynamic drag on the left float of a floatplane.
• Slipstream effect: The clockwise spiralling motion of the propeller slipstream means that the slipstream strikes the left side of the vertical fin. This produces a yawing^[7] moment to the left.
• P-factor: In a nose high attitude the ‘bite of air’ of the downward moving blade of the propeller is greater than the ‘bite’ of the upward moving blade, which moves the centre of thrust to the right side of the propeller disc. This also produces a yawing moment to the left.
• Gyroscopic effect: The rotating propeller behaves like a gyroscope. As such, any time a force is applied to deflect the propeller from its plane of rotation, the resultant force is 90° ahead in the direction of rotation, and in the direction of the effective force (Figure 4). As such, the gyroscopic effect results in a yawing motion to the left when the aircraft is pitched forward from the plow position to the step position.

Figure 4: Gyroscopic effect

Source: FAA pilot’s handbook of aeronautical knowledge

Additional information is available from the United States Federal Aviation Administration (FAA) Pilot’s handbook of aeronautical knowledge, chapter 5: Aerodynamics of flight.

Crosswind take-off

According to the FAA Seaplane operations handbook, crosswinds can present special difficulties for floatplane pilots. If the aircraft turns towards the wind during a crosswind take-off, then centrifugal force will combine with the wind force to produce a rolling moment in the opposite direction to the turn (Figure 5). If strong enough, the combination of wind and centrifugal force may lift the upwind wing and submerge the downwind float, rolling the aircraft until the downwind wingtip strikes the water. This is known as a water‑loop (Figure 6).

Centre of gravity^[8] location also affects the floatplane’s handling characteristics on the water. If the centre of gravity is located to one side of the centre-line, such as a fuel imbalance between the tanks, one float must support more weight and therefore displace more water than the other float, resulting in more water drag on that side (Figure 7).

Figure 5: Effect of wind force and centrifugal force

Source: FAA seaplane operations handbook

Figure 6: Water-loop

Source: FAA seaplane operations handbook

Figure 7: Effect of fuel imbalance on centre of gravity

Source: FAA seaplane operations handbook

ATSB comment

The pilot reported that it was the force from the forward pitching motion of the aircraft from the nose-high plowing position to a nose-level step position that resulted in the aircraft veering left from the planned take-off path. The force that produces this motion is the gyroscopic effect. At the time of the uncommanded roll to the left the aircraft was turning right with a strong crosswind from the right and more fuel distributed in the left tank than in the right tank. These factors probably combined to elevate the risk of submerging the downwind float and lifting the upwind wing, resulting in a water-loop.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Operator

As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety actions:

Changes to operating procedures

The operator is updating their operations manual to incorporate the following procedural changes:

• The channel at the operating base is orientated north-south, which restricts movements orientated east-west, therefore if the wind is forecast to gust more than 20 kt from the west, or within 30° either side of west, the take-off must be rejected.
• If the aircraft veers to the left during the take-off run and requires full control inputs, then reject the take-off.

Safety message

This accident highlights the risk of a water-loop event during a crosswind take-off in a floatplane. The combined forces acting on a floatplane have the potential to significantly reduce the margin of control available to the pilot. The FAA Seaplane operations handbook provides several recommended crosswind take-off techniques, including the considerations associated with arcing manoeuvres during take-off. If an arcing manoeuvre is to be attempted then the FAA handbook recommends placing the centrifugal force and wind force on opposite sides, and reducing the radius of the arc as the floatplane speed increases.

Refer to the FAA Seaplane operations handbook for a detailed explanation of the recommended crosswind take-off techniques.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Retractable control surfaces on the back of each float that can be extended downward into the water to provide more directional control when taxiing. They are attached by cables and springs to the air rudder and operated by the rudder pedals in the cockpit.
2. The term used to describe the motion of an aircraft about its lateral (wingtip-to-wingtip) axis.
3. A nose high, powered taxi characterised by high water drag and an aftward shift of the centre of buoyancy. The weight of the floatplane is supported primarily by buoyancy, and partially by hydrodynamic lift.
4. The attitude of the floatplane when the entire weight of the aircraft is supported by hydrodynamic and aerodynamic lift, as it is during high-speed taxi or just prior to take-off. This position, which is also referred to as the planing position, produces the least amount of water drag.
5. When on the step position the keel of the floats tend to resist turning motion.
6. Term used to describe movement of an aircraft about its longitudinal axis.
7. Term used to describe the motion of an aircraft about its vertical or normal axis.
8. Point through which resultant force of gravity acts, irrespective of orientation; in uniform gravitational field, centre of mass.

What happened

At 0856 Central Standard Time (CST) on 25 May 2016, a Piper PA-32, registered VH-NKA (NKA), departed Darwin Airport, Northern Territory (NT) for a business flight to Oenpelli Airport, NT. On board were a pilot under supervision, a supervising pilot and two passengers. The pilot under supervision was the pilot flying (PF), with the supervising pilot acting as pilot monitoring (PM),^[1] observing the flight and providing assistance.

At 0926, a Cessna 210, VH-SQT (SQT), departed Jabiru Airport, NT, for a scenic flight over Kakadu National Park and the East Alligator River, NT. On board were the pilot and five passengers. SQT initially proceeded in an easterly direction before progressing north along the river (Figure 1).

At about 0930, the PF in NKA assessed the expected weather conditions at Oenpelli and elected to make a straight-in^[2] approach to runway 12. At this time, the PF made an inbound broadcast on the Jabiru-Oenpelli common traffic advisory frequency (CTAF), advising their position as 50 NM west of Oenpelli. The PF then descended the aircraft from the cruising altitude of 9,500 ft and made a further broadcast on the Jabiru-Oenpelli CTAF as the aircraft reached 15 NM from Oenpelli. The pilots of NKA received no response to these broadcasts.

Figure 1: Overview of incident location

Source: Google Earth, annotated by ATSB

As SQT reached Cahill’s Crossing, 7 NM south of Oenpelli Airport, the pilot broadcast on Jabiru-Oenpelli CTAF, advising that they would be tracking north via the East Alligator River towards Flying Fox Island and operating not above 800 ft. The pilot did not receive a response to this broadcast.

At 0952, the PF in NKA established the aircraft on a 5 NM final approach leg to the runway at Oenpelli Airport at an altitude of 1,000 ft and configured the aircraft for landing. At the same time, the pilot of SQT continued to follow the East Alligator River north making continuous shallow turns left and right to maximise their passenger’s view. As SQT began a right turn, the pilot observed the shadow of another aircraft (subsequently determined to be NKA) tracking towards the shadow of their own aircraft. The pilot of SQT continued the right turn and assessed the position of the sun in relation to the shadow on the ground to establish the position of NKA. The pilot of SQT sighted NKA in close proximity and instinctively descended the aircraft to avoid a collision.

At this time, the PM in NKA, observing the high workload of the PF, elected to broadcast advising they were 4 NM from Oenpelli conducting a straight-in approach for runway 12.

At about the same time, the pilot of SQT broadcast on the CTAF to establish contact with NKA and advise of the near collision. The pilots of each aircraft communicated without difficulty following the incident.

The pilot of SQT estimated that the aircraft passed at the same altitude and a distance less than 100 m at the closest point. The pilots of NKA did not see SQT.

The pilots and passengers of both aircraft were not injured in the incident and the aircraft were not damaged.

Pilot Comment

The pilot of VH-NKA:

The supervising pilot of NKA provided the following comments:

• No radio calls were heard from the pilot in SQT prior to the incident, despite having experienced no communication difficulties prior to, or after the incident.
• Their view of SQT would have been obscured by the aircraft’s right wing as SQT approached their aircraft.
• The change to the Jabiru-Oenpelli CTAF was made slightly later than the usual distance of about 70 NM from Oenpelli Airport. This may have led to the pilots missing the departure call from the pilot in SQT.
• The pilot in command expressed concern at the planning of a low-level scenic flight through the extended centreline^[3] of an aerodrome at a distance of 3 NM.

The pilot of VH-SQT:

The pilot of SQT provided the following comments:

• No radio calls were heard from the pilots in NKA prior to the incident despite hearing calls from other aircraft. The radio in use was tested immediately afterward and found serviceable.
• The incident occurred at the point they would normally make a radio call for transiting abeam Oenpelli Airport. The pilot spotted the shadow of NKA just as they were about to make the call.
• The avoiding action required was forceful, inducing slight negative ‘G’.^[4] Had the pilot taken no avoiding action the two aircraft would have collided.
• The pilot did not expect an aircraft on approach to Oenpelli airport at a distance of 4 NM from the runway to be as low as 800 ft.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Operator of VH-SQT

As a result of this occurrence, the operator of SQT has advised the ATSB that they have taken the following action:

Communications procedure

The communication procedures for scenic flights using this route have been changed. They will now include a broadcast when the aircraft are 3 NM from Oenpelli Airport, stating that the aircraft will be passing through the extended centreline of runway 12, operating at not above 800 ft.

Safety message

This occurrence highlights the importance of effective communications. Where this effectiveness is compromised, pilot lookout becomes increasingly important. The ATSB publication Limitations of the See-and-Avoid Principle provides information on developing effective lookout techniques.

The Civil Aviation Safety Authority (CASA) publication CAAP 166-2(1) Pilots’ responsibility for collision avoidance using ‘see-and-avoid’ provides information which can increase the probability of sighting traffic.

Fly neighbourly advice

ERSA - GEN - SP contains a fly neighbourly advice for pilots operating in the Kakdau National Park. Pilots intending to fly over Kakadu National Park should obtain, read and comply with the Kakadu Fly Neighbourly Agreement.

Aviation Short Investigations Bulletin - Issue 51

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Pilot Flying (PF) and Pilot Monitoring (PM) are procedurally assigned roles with specifically assigned duties at specific stages of a flight. The PF does most of the flying, except in defined circumstances; such as planning for descent, approach and landing. The PM carries out support duties and monitors the PF’s actions and aircraft flight path.
2. An approach directly to the runway from the present position of the aircraft without joining the standard approach circuit or overflying the aerodrome.
3. A theoretical line drawn out from and in line with the runway. The aircraft is required to be aligned along this extended centreline at a point no less than 3 nm from the runway threshold during a straight-in approach.
4. The unit of measurement for measuring vertical acceleration within an aircraft. 1 G is equal to the force of gravity at the earth’s surface. In flight, g load values represent the combined effects of flight manoeuvring loads and turbulence. This can be a positive or negative value.

What happened

On 20 May 2016, the pilot of an Airbus Helicopters EC 130 T2 helicopter, registered VH-ZVO (ZVO), was conducting a ferry flight from Port Kembla to Bankstown Airport, New South Wales, with an engineer, who was also a crewmember, on board. At about 1437 Eastern Standard Time (EST), the pilot of ZVO contacted Bankstown Tower air traffic control (ATC), advising they were at 2RN approach point at 1,000 ft and inbound to Bankstown (Figure 1). The aerodrome controller (ADC) cleared ZVO to track to Bankstown via the Choppers South approach point at 500 ft.

Figure 1: Bankstown Airport and Choppers South

Source: Airservices Australia, annotated by the ATSB

At the same time, an instructor and student of a Piper PA-28-181 aeroplane, registered VH-MJT (MJT), were conducting circuit training on runway 29 left (29 L) at Bankstown Airport. At about 1438, the instructor advised the ADC that they were on the downwind circuit leg for a glide approach,^[1] and a touch-and-go landing. The ADC cleared MJT for the touch-and-go landing in response. Soon after, the instructor set the throttle to idle to simulate an engine failure, and the student commenced a glide approach.

At about 1439, the pilot of ZVO called at Choppers South at 500 ft and the ADC cleared ZVO to overfly the runways midfield (which included crossing all three runways – 29 left, centre and right), at 500 ft and then to join the circuit on the downwind leg for a landing at taxiway N1 (Figure 2). The ADC also advised the pilot of ZVO of traffic, which was another helicopter then overhead the runways and outbound via Choppers South. The pilot of ZVO saw, and reported sighting, that helicopter.

The ADC reported that they then observed MJT on final approach, about 100 m short of the runway threshold, and assessed that they were on a normal approach path. The ADC also observed ZVO pass the outbound helicopter and then, concerned about the outbound helicopter’s proximity to restricted airspace (R555), had a brief look at the tower situational awareness display (TSAD) to check their track.

The instructor of MJT reported that as the aeroplane approached the runway threshold on final approach, it was still at about 400–500 ft above the runway, which they assessed as too high to safely complete the landing. The student therefore commenced a go-around^[2] procedure, applied full power, and moved to the left of the runway centreline. The radar data showed MJT descended to about 300 ft during final, and an off-duty controller who observed the incident, estimated MJT then continued to descend to between 100 and 200 ft on short final before conducting a go-around.

The controller looked up from the TSAD and sighted MJT in the go-around. The controller estimated that MJT was at about 250–350 ft above the runway and about 250–300 m beyond the runway threshold.

As ZVO crossed the airport boundary, the engineer sighted the aeroplane (MJT) and alerted the pilot. The pilot then saw MJT in the go-around, at the same height as ZVO, and immediately conducted a left turn to increase separation between the helicopter and the aeroplane. MJT was about midfield (half way along the runway) when the instructor sighted the helicopter (ZVO) taking avoiding action.

At about 1441, the controller advised the pilot of ZVO of MJT as relevant traffic, and watched as the helicopter turned through 360° and passed MJT.

At that time, the instructor of MJT reported that they broadcast, stating that they were going around. On the recorded audio from the ADC frequency, about 8 seconds after the ADC advised ZVO of MJT, the instructor of MJT can be heard to start to broadcast, but was then over-transmitted by another radio broadcast.

The instructor of MJT estimated that the helicopter was within about 30–50 m horizontally and at the same height as MJT. The pilot of ZVO estimated the aeroplane was about 200 m away, and the ADC estimated the proximity to be about 120 m.

ZVO then continued to land at N1 as cleared. MJT continued to conduct circuits.

Figure 2: Bankstown Airport showing indicative tracks

Source: Airservices Australia, annotated by the ATSB

Aerodrome control and radio frequencies

There were two tower frequencies and ADC positions at Bankstown, with ADC1 having responsibility for arrivals and departures on runways 29 right/11 left and 29/11 centre; ADC2 was responsible for the training circuit with runway 29 left/11 right. However, these were combined when the traffic volume allowed. When not combined, the two aerodrome controllers were required to coordinate with each other if helicopters were operating inbound or outbound via Choppers South and therefore crossing the circuit traffic midfield over the runways.

The two Tower frequencies at Bankstown were combined at the time of the incident, and one controller occupied the ADC position. When combined, pilots of aircraft operating on either the circuit Tower frequency or the other Tower frequency would have been able to hear transmissions on the other frequency. Although the pilots of ZVO and MJT had different radio frequencies selected, they were combined such that the transmissions on both frequencies could be heard on either.

Pilot comments

Instructor of VH-MJT

The instructor of MJT commented that they were not aware of ZVO before sighting it after the pilot of ZVO had taken avoiding action and the ADC had issued the traffic alert. Despite having heard a couple of radio calls regarding helicopters, they were not aware of ZVO tracking via Choppers South or that they would be crossing the runways at 500 ft.

There was a tailwind component, which may have contributed to the aircraft being high on final. The automatic terminal information service (ATIS) current at the time indicated an occasional downwind of 4 kt. The ATIS was changed about 10 minutes after the incident, and the runway direction changed to 11, with the wind reported to be from 150° at 8 kt.

The instructor stated that if an approach is unstable,^[3] conducting a go-around is standard procedure. The instructor also stated that it would be valuable for aircraft in the circuit to be advised by ATC if a helicopter is approaching from Choppers South and crossing midfield at 500 ft. Additionally, advising the helicopter pilot when there is an aircraft on final would be valuable information.

After the incident, the instructor spoke to the Tower controller by telephone, and reported that they were advised that to avoid a similar situation, pilots should broadcast that they are going around before commencing the go-around. The instructor commented that a pilot’s priority is to aviate first and control the aircraft, then to communicate later.

The instructor also commented that at a non-towered aerodrome, there would not be an aircraft passing across the midfield at 500 ft (without a broadcast). The procedure could be addressed such that either the helicopters do not pass directly through the circuit, or the aircraft on final approach and the helicopter pilot are both given traffic information regarding each other.

Pilot of VH-VZO

The pilot of VZO provided the following comments:

• They did not hear any call from the pilot of the aeroplane, nor was there any call from Tower that the aeroplane was conducting a go-around.
• Even if a pilot broadcasts conducting a go-around, sometimes the aircraft can be hard to see on finals. They did not see the aeroplane at first, but their passenger saw it going around. They do not expect to see another aircraft at the same height when crossing the runways at 500 ft.
• They were not aware of the other aircraft at all before they saw it – they had not heard a call and were not aware of any aircraft in the training circuit. They did not know to look there for other aircraft traffic.

Controller comments

The aerodrome controller reported that they were monitoring an outbound helicopter on the TSAD when MJT commenced the go-around. As soon as they sighted the potential conflict, VZO had commenced a left turn and the ADC gave MJT as traffic to VZO.

An off-duty controller, who was in the ATC tower at the time of the incident, commented that in Class D airspace, pilots have responsibility to see and avoid VFR aircraft and ATC has a responsibility to provide relevant traffic information to assist them to do that. In normal circumstances, an aircraft in the circuit and a helicopter tracking across the runway at 500 ft would not need to know where each other was as they are ‘segregated’. Additionally, providing traffic information that was not useful, may lead pilots to switch off to essential information. However, in the go-around procedure, they were relevant traffic and the controller would pass the traffic. Usually their response would be to pass traffic to the helicopter first as they were generally in a stage of flight with a lower workload and are more manoeuvrable than fixed wing aircraft.

En Route Supplement Australia

The ERSA entry for Bankstown included the following under the heading Class D:

‘CAUTION: HELICOPTERS OVERFLY RUNWAYS MIDFIELD AT 500FT.’

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Airservices Australia

As a result of Airservices internal investigation into the occurrence, a Standardisation Directive (SD) has been developed for publication on 28 June 2016. The SD aims to educate controllers on the key lessons learned from the occurrence.

Specifically, the SD Clarifies that

• an aircraft cleared to land is also cleared to conduct a go-around
• helicopter tracking which crosses an operational runway as described in ERSA must not be relied on to assure segregation of overflying helicopter traffic from the possible go-around or missed approach of aircraft using the runway
• where the possible go-around or missed approach path of a landing aircraft is in potential conflict with a helicopter overflying, controllers are required to provide traffic to both aircraft in anticipation of the possible go-around or missed approach rather than in response to the go-around or missed approach.

Operator of VH-MJT

As a result of this occurrence, the operator of MJT has advised the ATSB that they are taking the following safety actions:

Induction training amendment

Company induction training will be expanded to cover more details with regards to helicopter activities at each base.

Safety message

The possibility that an aircraft will go around from an approach should always be considered by ATC and pilots, with respect to the separation of air traffic.

The adage ‘aviate-navigate-communicate’ remains a fundamentally effective prioritisation guide for pilots. Nonetheless, under some circumstances, it may be prudent to broadcast intentions early, particularly when those intentions vary from an expected or anticipated course of action. This may be particularly important where the potential for a conflict with other traffic is elevated, such as in an area of high traffic density. Timely broadcasts provide greater opportunity for other pilots to focus their lookout, and for ATC to react to the changing circumstances.

The Civil Aviation Safety Authority booklet, Class D airspace, advises pilots that when operating in Class D airspace, they must sight and maintain separation from other aircraft. Pilots and ATC have a dual responsibility to maintain situational awareness of other traffic.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Throttle set to idle to simulate an unpowered approach.
2. A flight path taken by an aircraft after an aborted approach to landing.
3. An unstabilised approach is an approach during which an aircraft does not maintain at least one of the following variables stable: speed, descent rate, vertical/lateral flight path and in landing configuration, or receive a landing clearance by a certain altitude.

Safety summary

What happened

On 15 May 2016, at approximately 1056 Australian Eastern Standard Time (AEST), an unmanned ‘675 J class’ tram (‘J’ class) collided with a ‘1054 Nagasaki’ tram (Nagasaki) at Sydney Tramway Museum (STM) in Loftus, New South Wales. The Nagasaki was approaching Loftus after completing a tourist operation between Sutherland and Loftus, when the crew noticed the unmanned ‘J’ class moving towards them on the same track. The crew responded by stopping the Nagasaki and evacuated all 16 passengers safely before the collision occurred.

What the ATSB found

The ATSB found that the ‘J’ class was parked on a downhill gradient towards Sutherland prior to the runaway and collision. It was also found that the tram’s handbrake had not been applied and instead, a hardwood wheel chock had been placed under the tram’s front wheel to restrain the vehicle’s movement.

What's been done as a result

Since the incident, STM has adopted a number of changes to manage the risk of tram runaway. These include but are not limited to the following:

• STM has made the application of handbrakes mandatory.
• STM’s Safety Management System (SMS) now requires trams to be stabled on level track.
• STM has included yellow markings to delineate level track from a descending gradient.
• STM has stopped using hardwood wheel chocks to stable its trams.

Safety message

Rolling Stock Operators need to consider the limitations of rolling stock brake systems, including brake retention times, when designing stabling procedures and locations to park rolling stock.

The risk of rolling stock runaway should be assessed, taking into account the context of the organisations railway operations, and should examine all existing and available risk controls.

Additionally, any changes made to a risk control should follow a change management process to ensure that the change does not reduce the risk control’s effectiveness.

Figure 1: 675 ‘J’ class and 1054 ‘Nagasaki’ class tram collision

Source:   ATSB

The occurrence

At 0815 on the day of the incident, the driver and a second crew member signed on for work and boarded the Nagasaki tram in readiness for a tourist service. The crew completed the required pre-operation safety checks and moved the tram out of the running shed area (Figure 3). It was then halted at a stop board outside the running shed where the Nagasaki’s horn was sounded twice in accordance with STM’s procedures.

Figure 2: Incident location at Loftus

Source: Geoscience Australia, annotated by the ATSB

The crew then moved the Nagasaki in the Down^[1] direction towards the Royal National Park (RNP) and stopped just before the Princes Highway level crossing (Figure 3). At the level crossing, the crew completed an inspection of the level crossing lights and prepared to move the Nagasaki in the Up direction (towards Sutherland) to the Railway Square Waiting Shed (RSWS) (Figure 3). While the crew of the Nagasaki were at the level crossing, another tram (611 ‘Y’ class) departed the running shed with two crew members on board. The ‘Y’ class was moved adjacent to the RSWS to on-load passengers for its operation to Sutherland and then the following journey to the RNP (Figure 3). Soon after this, the Nagasaki was moved from the level crossing and parked behind the ‘Y’ class.

Another tram (‘J’ class) also departed the running shed to the RSWS and was parked behind the Nagasaki (Figure 4). The ‘J’ class driver applied the air brakes^[2] but did not apply the handbrake when stabling it adjacent to the RSWS which was on a level gradient. A single hardwood wheel chock was placed under the ‘J’ class’s left-hand leading wheel.

Figure 3: Yellow dotted line shows the depot mainline, red dotted line shows bidirectional lines, and blue dotted line shows the Up and Down mainlines at Loftus

Source: Google maps, annotated by the ATSB

The first tram in the sequence (‘Y’ class) departed for Sutherland at approximately 1005 and returned to Loftus at approximately 1013. The ‘Y’ class then departed for the RNP at approximately 1015.

Figure 4: Sequence of trams parked before the ‘Y’ class departed to Sutherland

Source: Sydney Tramway Museum, annotated by the ATSB

The ‘Y’ class returned to Loftus from the RNP at approximately 1040. It was then parked behind the ‘J’ class, which was parked behind the Nagasaki. At approximately 1048, the Nagasaki departed for Sutherland with 16 passengers and two crew members on board.

The track from Loftus to Sutherland begins as a double line track (Up and Down mainline) and then merges into a single bidirectional line further towards Sutherland (Figure 3). The safeworking system implemented on the bidirectional line was ‘staff and ticket’^[3]. The Nagasaki driver was provided a staff (metal token) before departing in the Up direction towards Sutherland. This provided Nagasaki with exclusive access to the bidirectional line for that journey in the Up direction.

At approximately 1050, the ‘J’ class was moved forward towards Sutherland and parked just before Cross St junction to line up with a kerb (Figure 5). The air brakes were used to stop the tram however, the handbrake was not applied. In lieu of the handbrake, a STM staff member placed the hardwood wheel chock used previously under the front left-hand wheel of the ‘J’ class. The ‘J’ class was parked on a falling gradient facing towards Sutherland with the control key removed and was left unattended.

Figure 5: Sequence of trams parked while the Nagasaki tram was heading to Sutherland

Source: Sydney Tramway Museum, annotated by the ATSB

Shortly after arriving at Sutherland, the Nagasaki departed at approximately 1054 on its return trip to Loftus.

At approximately 1055, a STM staff member noticed that the unmanned ‘J’ class had begun to roll down the falling gradient towards Sutherland. The ‘J’ class left the Up mainline and crossed onto the bidirectional line towards Sutherland (Figure 3). The ‘J’ class then headed towards the Nagasaki that was travelling in the opposite direction on the same line.

As the crew of the Nagasaki negotiated a small curve, they noticed the unmanned ‘J’ class heading towards them. The Nagasaki driver immediately applied the emergency brake, which brought the Nagasaki to a halt. The driver then instructed all passengers to evacuate immediately and opened all doors. The crew assisted passengers to exit the Nagasaki as quickly as possible. All passengers and crew had exited the Nagasaki safely before the ‘J’ class collided with the Nagasaki.

The ‘J’ class had travelled in an unmanned state for approximately 283 m. Marks on the rail indicated that the collision force moved the ‘Nagasaki’ 13.5 m back towards Sutherland.

As a result of the collision, there was minimal damage to the steel-bodied exterior of the Nagasaki. The ‘J’ class’s floor hoist (support) was compressed and the wooden floor panels were damaged. The front exterior face of the ‘J’ class was damaged and broken wood was observed within and around the trams (Figure 6).

Immediately after the impact, the crew confirmed that there were no injuries and checked that all passengers had exited the Nagasaki. The driver then reported the incident to the STM shift manager. While waiting for assistance, the crew secured the Nagasaki by disconnecting its power feed pole and applying the service brake and handbrake.

Figure 6: Damage to the 675 ‘J’ class tram

Source:   ATSB

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1. Down direction: Facing away from Sutherland, Up direction: Facing towards Sutherland.
2. Air brakes: A braking system which uses air pressure to stop or slow the tram.
3. ‘Staff and ticket’ is a method of safeworking where trams are given exclusive entry into a track section only if the driver is provided a unique staff (metal token) or observes the unique staff and is provided a ticket.

Safety analysis

This section examines the failed risk controls and likely contributing factors that resulted in the ‘J’ class running away unmanned and colliding with Nagasaki tram.

675 ‘J’ class tram braking systems

Air brake system

The ‘J’ class service brake uses a manual lapping air brake system. This system uses air pressure to stop or slow the tram. It functioned by directing air from a main air reservoir through a main brake pipe to driver controlled air valves. On command by the driver, the air valves direct a volume of pressurised air into the brake cylinder. The air pressure within the cylinder extends the brake cylinder rod, applying a force through the brake rigging and onto the brake shoes. Friction braking occurs when the brake shoes contact the wheel tread face on all four wheels (Figure 7). The driver may increase braking effort by feeding more air into the brake cylinder and similarly reduce it by releasing air. An electrically powered air compressor provides compressed air to the main air reservoir. A pressure sensitive switch will automatically stop and start the compressor to maintain the brake pipe pressure.

The driver control for the air valves on the ‘J’ class had three positions. These were:

1. Release (releases air from the brake cylinder) – Turned right.
2. Lap (does not release or feed any air into the brake cylinder) – Middle position.
3. Brake (feeds air into brake cylinder) – Turned left.

The manual lapping air brake system on the ‘J’ class does not retain air in its brake cylinder indefinitely. In the lap position, air gradually releases from the system and braking effort reduces over time after application. Therefore, a service brake application is not suitable as a park brake. This is different to a self-lapping air brake system where the air valve automatically feeds air into the system as brake cylinder pressure.

At approximately 1050, the ‘J’ class was parked adjacent to Cross St junction on a falling gradient with the air brakes applied and the driver controlled air valve in the lap position. The ‘J’ class was then left unattended. Air within the brake system likely released, which gradually reduced the ‘J’ class’ available braking effort. The braking effort holding the ‘J’ class from moving likely reduced to a point where the brake could not hold the mass of the tram on the downhill gradient and relied on the chock to restrain its movement. At approximately 1055, the ‘J’ class started to roll down the gradient.

The time between brake application and the tram rolling down the grade suggested the retention time of air within the brake cylinder was less than five minutes. STM later advised the retention time was approximately four minutes and thirty seconds.

The ATSB found the tram system was not equipped with a gauge to measure air pressure within the brake cylinder. The ATSB also found that at the time of the incident, the tram crew were not aware of the allowable air retention times and the possible effects on braking.

Handbrake

The handbrake on the ‘J’ class consisted of a gooseneck handle attached to a chain winch. A chain was fitted between the hand-driven chain winch and the brake rigging (Figure 7). To engage the handbrake, the driver was required to feed air into the brake cylinder (apply brakes) which engaged all the brake shoes on the tram and put slack in the chain. The driver was then required to wind the gooseneck handle, which removed slack from the chain. The retrieval of the chain applied a tension force to the brake rigging to maintain a friction force between the brake shoes and the wheel tread faces (Figure 7). The handbrake was locked in position by using a locking pawl and ratchet system.

To release the handbrake, the pawl was required to be unlocked, which released the tension in the system, and allowed the chain winch to unwind. The driver was required to exercise caution when releasing the handbrake to avoid injury from contact with the unwinding gooseneck handle.

The ATSB found that the handbrake was not applied to the tram prior to it running away on the falling gradient.

Emergency braking

Emergency braking on the ‘J’ class is completed by engaging the traction motor reverser. The reverser forces the motor to move the tram wheels in the opposite direction to their direction of travel. This braking system may only be applied when the tram is manned and therefore, could not be applied to the ‘J’ class.

A similar system exists on the Nagasaki and was used by the driver to stop the tram prior to the collision with the ‘J’ class.

Figure 7: Air brake and handbrake system on the 675 ‘J’ class tram. The yellow arrows denote force direction for applying braking effort

Source: Sydney Tramway Museum, annotated by the ATSB

675 ‘J’ class tram maintenance

The ‘J’ class was built in 1904 in Sydney with the tram’s electrical systems and air brake equipment originally imported from the United States of America (USA). The bogie was a Brill 21E type also imported from the USA. The tram was decommissioned in 1935 and was fully refurbished by Bendigo Tramways in 2007.

STM procured the tram from Bendigo Tramways in 2008 and completed further work for passenger operations at STM.

STM asset management system requires the ‘J’ class to undergo an intermediate inspection annually and an overhaul inspection every 20 years. The tram crew were also required to complete pre-inspection checks before operating the tram.

The last annual inspection for the ‘J’ class was completed on 30 April 2016 and the tram was certified fit for operations. The pre-inspection checklist completed on the day of the incident also supported that the tram was fit to operate.

The ATSB determined that STM had completed all of the required inspections on the ‘J’ class in accordance with their standards.

Tram operations and stabling

General operations

The museum operated approximately 5 out of their 20 operational ready trams annually. Trams scheduled for passenger operations were moved out of the running shed onto the depot mainline. Once on the depot mainline, the trams were moved in the Down direction towards the RNP. The trams then crossed over onto a bidirectional mainline. Once on the bidirectional mainline, crews were then required to change the direction of the roof-mounted power supply pole and proceed to the opposite end of the tram to operate it in the Up direction towards the RSWS. The trams were then parked, in single file, on the Up mainline opposite the RSWS. The trams were then operated in that order to Sutherland and back. Upon returning, trams then operated to the RNP and back to the RSWS (Figure 3).

The total length of track at STM was 3.6 km. The track comprised of a double line section (Up and Down mainlines) and bidirectional line sections on either ends (Figure 3). The bidirectional line sections were protected by the ‘staff and ticket’ method of safeworking, with each bidirectional line having its own unique staff.

A maximum of two trams were permitted to enter the same bidirectional line section as long as they travelled in convoy (the same direction). The first tram driver to enter a bidirectional line section was shown the unique staff (metal token) for that section and was provided a ticket permitting entry into that section of track. The second tram driver trailing behind the first was then provided the staff and permitted to enter the same section. Convoy operations were conducted at low speed (20 km/h) and both tram crews were required to be in sighting distance of each other.

For single tram operations on the bidirectional lines, tram crews were provided the unique staff for that bidirectional line section only. This gave the crew operating the tram exclusive access to that section. This was the process applied on the day of the incident.

Tram crewing requirements

STM required at least two crew members (driver and conductor) to be on board trams during operations. Some trams required a third person (observer), where the conductor could take control of the tram if the driver became incapacitated. The Nagasaki and ‘Y’ class trams required two crew members, while the ‘J’ class required three.

ATSB found that STM complied with the crewing requirements for the ‘Y’ class and Nagasaki trams, but not for the ‘J’ class. Two crew members were on board the ‘J’ class for its journey between the running shed and the RSWS. In addition to this, it was found that movements near the RSWS on the double line track for the ‘J’ class were completed by one crew member only.

The ATSB determined that although the crewing requirements were not complied with for the ‘J’ class, the absence of the third crew member was not a contributing factor to the incident.

Stabling of the ‘J’ class tram near the RSWS

The track between depot junction and the RNP end of the RSWS was on a falling gradient towards Sutherland. The track then levelled out between the RNP end and Sutherland end of the RSWS. The track then continued on a falling gradient after that towards Sutherland (Figure 5).

Prior to the runaway, the ‘J’ class was moved and parked on the falling gradient adjacent to Cross St junction (Figure 5). The service air brake was applied and a single hardwood wheel chock was placed under the front left-hand wheel. The handbrake was not applied when parking the ‘J’ class both times on the day of the incident.

STM’s operating procedure specified that unattended trams, which were parked at the kerb near Cross St Junction (falling gradient), were required to either be chocked or have the handbrake applied. The operating procedure also specified that drivers were required to release air from the brake cylinders or they would release over time. The ‘J’ class crew complied with the requirements of the operating procedure with respect to applying a chock but did not release air from the brake cylinders.

The ATSB found that STM complied with the operating procedure requirement with respect to placing a chock under the ‘J’ class wheel, however did not release the service brake (air from the brake cylinders). If the service brake had been released, the driver would have likely had an opportunity to identify that the chock could not sufficiently restrict movement of the ‘J’ class on the gradient. This would have been a better outcome than the brakes gradually releasing and the ‘J’ class rolling when it was unmanned.

The ATSB also found that although the falling gradient near Cross St junction had been identified within its SMS documents, it was likely difficult for drivers to observe visually.

Chocks

The ATSB identified that the chock type used to stable the ‘J’ class on the day of the incident was newly adopted by STM. It was a triangular wedged hardwood chock (Figure 8). Applying this type of chock required the crew member to visually line up the wedge with the curve tread face of the wheel.

ATSB investigators noted that the ‘J’ class had a lowered footboard which hindered the access to install the chock. This meant that lining up the triangular wedged hardwood chock with the wheel would have required the crew to get down lower than usual to visually line it up and place it against the wheel.

The ATSB replicated the process to install the hardwood chock under the ‘J’ class. The ATSB found that the chock could not be installed against the wheel adequately due to the chock fouling the brake gear. The ATSB determined it was likely the chock was incorrectly installed and did not function as intended.

The older chock type was a 600 mm long rectangular softwood block (Figure 8). Applying this type of chock required the crew member to place it under the wheel and ensure that the wheel flange deformed the softwood to provide a tight wedge. The new design chock being hard wood did not likely provide this tight wedge as it would not have deformed like the softwood chock. The large longitudinal face of the older chock enables reliable contact with the wheel tread face. In comparison, the new design chock’s narrow contact area required precision when installing the chock against the wheel tread face. At the time of the incident, STM were using both soft and hardwood wheel chocks.

After the incident, the chock was found in the four foot with witness marks on it consistent with that of a tram having driven over it at an angle (Figure 8). This was likely due to the ‘J’ class wheel rolling over the chock.

STM’s change management procedure (STM6012) requires risks to be assessed for any changes to operations made which can affect safety. The procedure required a change request form to be completed and approved by the rail safety manager. All changes which were made were also required to be entered into a change register (STM6170) which is reviewed by the board periodically. Based on the evidence provided, it was not evident that STM complied with its change management procedure when it adopted the new hardwood chock.

It is likely that if the change management procedure had been followed, STM would have had an opportunity to identify the risks associated with the newly adopted hardwood chock.

Figure 8: Comparison of the old and new type chock

Source: ATSB

Handbrake use

STM staff advised that it had become a work place practice not to apply the handbrake due to the risk of a wrist injury when releasing it. STM’s operating procedure did not require tram crews to apply both a handbrake and install a wheel chock.

The ATSB also found that the training program for tram crews did not include information on the correct use of handbrakes.

The ATSB determined that it is likely that the handbrake was not applied due to insufficient training on its correct use, as well as, the lack of a requirement to do so. It is likely that the ‘J’ class would not have rolled away when the air brakes released had the handbrake been applied correctly.

Risk management

Risk assessment

The ATSB reviewed STM’s risk register and found that STM had identified the risk of ‘unmanned tram runaway and collision’. The risk controls listed by STM included;

1. Trams to be parked on a level surface
2. Trams chocked
3. Trams attended (Person on tram unless stable)
4. Driving key secured (Ensures only qualified staff can move the tram).

Risk controls one to three failed on the day of the incident and risk control four was implemented but was not applicable to the unmanned runaway of the ‘J’ class.

All STM operational ready trams have a working handbrake (an existing risk control), which was not captured in the risk register. Additionally, STM’s operational procedures only required staff to either install a chock or apply a handbrake when stabling trams.

The ATSB found that the use of handbrakes was avoided by STM tram crews because of:

1. The lack of a requirement to do so as long as chocks were applied
2. The risk of injury when releasing the handbrake.

Risk control effectiveness

The ATSB found that STM did not appropriately manage risk control effectiveness for the risk controls protecting the ‘J’ class from running away with respect to the following:

• Although an incline near Cross St was referenced in SMS documentation, it was likely difficult for drivers to determine where the flat gradient ended and the incline began to safely park trams.
• It was not evident that STM had followed its change management process when adopting the new hardwood chock and installing it under the ‘J’ class.
• It was not evident that tram crews had been adequately trained in the correct use of handbrakes.
• Drivers were unaware of the retention times for air within the tram’s brake cylinder and the consequences of air escaping.

Findings

From the evidence available, the following findings were made regarding the unmanned runaway of the ‘J’ class which collided with Nagasaki at Loftus NSW on 15 May 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Safety issues or system problems are highlighted in bold to emphasise their importance. A safety issue is an event or condition that increases safety risk (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.

Contributing factors

• The ‘J’ class tram was parked on a downhill gradient and left unattended.
• The tram’s manual lapping air brake system was not designed to automatically feed air into its brake cylinder and therefore braking force could not be restored when air leaked to atmosphere.
• STM did not follow its change management process for adopting the new hardwood chock type. Subsequently, the hardwood chock could not be applied reliably under the ‘J’ class wheel and could not restrict its movement [Safety Issue].
• STM did not follow its operations handbook when stabling the ‘J’ class with respect to releasing air from the brake cylinder.
• STM did not comply with its risk control in ensuring that trams were attended when parked [Safety Issue].
• STM did not require the application of all available and reasonably practicable risk controls when parking trams with respect to their location and handbrake application [Safety Issue].

Other factors that increased risk

• There was no delineation separating inclined and level surfaces, and drivers were required to visually determine gradients.

Safety issues and actions

The safety issues identified during this investigation are listed in the Findings and Safety issues and actions sections of this report. The Australian Transport Safety Bureau (ATSB) expects that all safety issues identified by the investigation should be addressed by the relevant organisation(s). In addressing those issues, the ATSB prefers to encourage relevant organisation(s) to proactively initiate safety action, rather than to issue formal safety recommendations or safety advisory notices.

Depending on the level of risk of the safety issue, the extent of corrective action taken by the relevant organisation, or the desirability of directing a broad safety message to the rail industry, the ATSB may issue safety recommendations or safety advisory notices as part of the final report.

All of the directly involved parties were provided with a draft report and invited to provide submissions. As part of that process, each organisation was asked to communicate what safety actions, if any, they had carried out or were planning to carry out in relation to each safety issue relevant to their organisation.

The initial public version of these safety issues and actions are repeated separately on the ATSB website to facilitate monitoring by interested parties. Where relevant the safety issues and actions will be updated on the ATSB website as information comes to hand.

Change management process implementation for safety critical changes

Safety issue number: RO-2016-006-SI-02

Safety issue description: STM did not follow its change management process for adopting the new hardwood chock type. Subsequently, the hardwood chock could not be applied reliably under the ‘J’ class wheel and could not restrict its movement.

Attending parked trams

Safety issue number: RO-2016-006-SI-03

Safety issue description: STM did not comply with its risk control in ensuring that trams were attended when parked.

Use of all available and reasonably practicable risk controls when parking trams

Safety issue number: RO-2016-006-SI-04

Safety issue description: STM did not require the application of all available and reasonably practicable risk controls when parking trams with respect to their location and handbrake application.

Sources and submissions

Sources of information

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

Any submissions from those parties will be reviewed and where considered appropriate, the text of the draft report will be amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2019 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

What happened

On 21 May 2016, the pilot of a Kavanagh Balloons E-240, registered VH-VBM (VBM), planned to conduct a one-hour scenic flight from Bundoora, Victoria (Vic.) with nine passengers. Prior to commencing the flight, the pilot obtained the relevant weather forecasts and observations. The wind was from the north to north-west at 5 to 10 kt. The pilot therefore assessed the balloon would track in a southerly direction and nominated potential landing sites at Burnley and Dendy Park in Brighton (Figure 1).

Figure 1: Approximate track of VH-VBM and relevant locations^[1]

Source: Google earth, annotated by ATSB

At about 0700 Eastern Standard Time (EST), the balloon departed Bundoora in company with five other balloons. About 35 minutes later, the balloon arrived overhead Burnley. The pilot of VBM elected to continue to Dendy Park, along with another balloon from the same operator, to extend the flight to one hour. At that time, the pilots of four other balloons, which had been operating in company with VBM, elected to climb into a more westerly wind to track to Moorabbin Airport, Vic.

At about 0800, the balloon in company with VBM landed safely at Dendy Park. The wind speed was about 10 kt as VBM approached Dendy Park. As the balloon descended to land, the pilot sighted a light pole directly in the balloon’s path (Figure 2). The pilot then lit the balloon’s burners to climb over the pole, however, a second light pole stood directly in the balloon’s path on the far side of the available landing area. Due to the balloon’s height and the wind, the pilot assessed that the balloon may collide with the second pole if the pilot attempted a landing and therefore elected not to land in the park.

Figure 2: Dendy Park showing light poles

Source: Google earth, annotated by ATSB

The pilot then attempted to land in a golf course beyond the park, but the balloon did not track towards a safe landing area. The balloon continued at low level over parkland, however, the pilot also assessed this area to be unsafe for landing.

At about 0820, the balloon crossed the coast and tracked out over Port Phillip Bay. The pilot commenced a climb into a more westerly wind to track towards land. At about 0825, the pilot contacted air traffic control (ATC) and requested a clearance to climb to 5,000 ft. About 90 seconds later, the pilot advised that they were now at 4,000 ft and may require emergency assistance. At that time, the pilot stated that the balloon had an estimated 30 minutes of fuel remaining.

At about 0830, the balloon tracked back over land. The pilot advised ATC that in the 5 minutes it would then take to descend and land, the balloon would track back over water. The pilot elected to descend to conserve fuel and prepared for a water landing. The pilot briefed the passengers and descended about 1 km from shore. The pilot then enacted the company emergency procedures. Air traffic control recordings showed that at 0841, when asked by ATC if it was their ‘intention to ditch the balloon at the moment’, the pilot confirmed that it was.

At about 0845, the pilot established contact with the crew of a nearby vessel. The pilot coordinated with the crew of the vessel to arrange the evacuation of passengers. The passengers evacuated one or two at a time onto the vessel over the next 30 minutes (Figure 3).

After evacuating the passengers, the pilot conducted a climb to about 2,000 ft back into more favourable winds and subsequently landed safely at Mount Martha, Vic. (Figure 1).

The pilot and passengers were uninjured, and the balloon was not damaged.

Figure 3: Evacuation of passengers from VBM to vessel

Source: ABC News

Pilot comments

The pilot provided the following comments:

The ground crew assisting the balloon which landed before VBM, were available to assist the landing at Dendy Park. The pilot felt that a successful landing could not be assured even with the assistance of ground crew.

The company emergency procedures for conducting a water landing were available and clear. This greatly reduced stress and ensured the pilot and passengers were well prepared for a possible water landing.

• It was not their sole intention to ditch the balloon. Ditching was one possible scenario and the pilot was preparing the balloon and passengers for that situation should it eventuate.

If they encountered similar weather conditions in future, the pilot would launch from further east. The north-easterly surface wind experienced was not forecast. In the future, the pilot would look for indicators of this wind prior to selection of a launch site.

Landing in a 10 kt wind is normally manageable, however, the light pole was in the balloon’s path (at Dendy Park).

At the time the emergency was declared, the estimated endurance was 30 minutes. Once the passengers had been evacuated the balloon endurance was greatly increased.^[2]

Carriage of life jackets

No life jackets were carried on board VBM for this flight.

As the planned flight, including the expected departure and approach paths, did not include an over water component, there was no requirement to carry life jackets based on Civil Aviation Order 20.11.

Civil Aviation Safety Authority (CASA) comments

CASA provided the following comments:

• While the evacuation was conducted in an appropriate manner, the locality of a suitable vessel with competent crew may have had a significant positive effect on the safe rescue, which under the circumstances, was a fortunate rather than a well-planned emergency procedure.
• The company’s operations manual requires that, as soon as the balloon crosses the coastline, the ground crew be contacted and an emergency telephone call made. Immediately after this, a MAYDAY^[3] is to be declared. This did not occur until the balloon was 1km out over the bay. As the pilot did not did not make a PAN or MAYDAY call as required, ATC did not have notice to apply the appropriate degree of severity to the incident. This was confirmed by Victoria Police during their incident debrief where it was highlighted that there was no communication or coordination between ATC and ground-based emergency services.

Safety message

This incident provides a good example of the value of effective emergency procedures. Despite having completed thorough pre-flight planning and preparation including weather and field selection, a number of factors combined to create a difficult situation for the pilot. Thorough emergency procedures along with regular training greatly reduced workload in the incident and assisted the pilot in achieving a safe outcome.

Declaring an emergency early, through the use of standard phrases such as ‘MAYDAY’ is vital in clearly communicating a requirement for emergency assistance or advising of an emergency situation. This enables ATC to provide assistance and coordinate emergency services without delay. The Airservices Australia safety bulletin What happens when I declare an emergency? provides further information on the actions taken by ATC once an emergency is declared.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Approximate track based on GPS and radar data.
2. The reduced weight of the balloon without passengers on board required less fuel use to remain aloft, resulting in an increase in endurance.
3. MAYDAY is an internationally recognised radio broadcast for urgent assistance.

What happened

On 22 April 2016, at about 1440 Eastern Standard Time (EST), an instructor and student were conducting circuit training in a Robinson R22 helicopter, registered VH-JKH (JKH), at Ballina Byron Gateway Airport, New South Wales. The helicopter was positioned about two thirds of the way down runway 06 (Figure 1) when the crew broadcast on the common traffic advisory frequency (CTAF) that they were rolling for take-off on runway 06.

Very soon after that broadcast, the pilot of another helicopter operating at the aerodrome alerted the crew of JKH that there was an aircraft rolling for take‑off on runway 06 behind them, and suggested that JKH expedite clearing the runway.

A Cessna 182 aeroplane, registered VH-YKM (YKM), had entered the runway at the intersection of taxiway A (Figure 1), and was taking‑off on runway 06, towards the helicopter (which was still on the runway). The instructor in JKH took control of the helicopter from the student, rejected the take-off and vacated the runway to the northern grass, as the aircraft continued its take‑off run.

Although the pilot of YKM was unaware at the time, their broadcasts on the CTAF prior to commencing take‑off had not been successfully transmitted. As the aeroplane climbed through about 400 ft above ground level, the pilot sighted the helicopter (JKH) to their left over the grass.

The pilot of YKM later found that although the aircraft radio was on, and was set to the CTAF, the radio microphone was not fully plugged in. In this condition, none of their broadcasts on the CTAF had been successfully transmitted.^[1] The pilot of YKM had not heard any broadcast from JKH and did not see the helicopter on the runway, despite checking to see that the runway was clear before entering.

Figure 1: Ballina Byron Gateway Airport diagram

Source: Airservices Australia – annotations by the ATSB

Operator comment

The operator of JKH commented that after the event, they checked from the position on the taxiway where YKM entered the runway to verify if they could see where the helicopter would have been. They established that they could – but advised that this needs to take into consideration that they knew what they were looking for.

ATSB comment

The pilot of the helicopter who alerted the crew of JKH to the aircraft rolling for take-off on runway 06 is commended for their situational awareness, and speaking up when the potential for a collision became apparent. That pilot may have played an important role in averting a more serious occurrence.

Safety message

Pilots are encouraged to check the performance of radio communications systems as part of their pre-flight procedures. Aerodrome frequency response units at non-towered aerodromes allow pilots to confirm that they have the correct frequency selected, and that their radio communications system is transmitting. Nonetheless, as this incident highlights, an AFRU does not necessarily provide an indication to a pilot that their transmissions are inaudible or otherwise ineffective. Additionally, this incident highlights the importance of a thorough lookout prior to entering a runway. Not hearing any broadcasts on the CTAF does not necessarily mean that other aircraft are not operating in the area.

Most occurrences reported to the ATSB at non-towered aerodromes involve conflicts between aircraft, or between aircraft and ground vehicles. In particular, active runways should be approached with caution. The ATSB publication A pilot’s guide to staying safe in the vicinity of non-towered aerodromes, stated that a large number of the conflicts between aircraft involved:

• ineffective communication between pilots operating in close proximity
• the incorrect assessment of other aircraft’s positions and intentions
• relying on the radio as a substitute for an effective visual lookout
• failure to follow published procedures.

Aviation Short Investigations Bulletin - Issue 51

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. An ATSB review of CTAF recording suggested that there was a number of attempted transmissions around six minutes prior to the incident. These transmissions were little more than a momentary carrier wave or microphone ‘click’, and they were followed by a ‘beep-back’ response from the aerodrome frequency response unit (AFRU). The ATSB could not ascertain if those transmissions were attempts by the pilot of YKM to broadcast on the CTAF.

What happened

On 15 May 2016, a Qantas Airways Airbus A380 aircraft, registered VH-OQD, operated flight QF7 from Sydney, New South Wales to Dallas-Fort Worth, Texas, United States.

About two hours prior to the aircraft’s arrival in Dallas-Fort Worth, a passenger alerted the cabin crew to the presence of smoke in the cabin. The cabin crew then initiated the basic fire drill procedure.

Two of the cabin crew proceeded to the source of the smoke with fire extinguishers. At the same time, the customer services manager (CSM) made an all stations emergency call on the aircraft interphone to alert flight crew and other cabin crew to the presence of smoke.

The cabin crew located the source of the smoke at seat 19F, in Zone F, on the upper deck (Figure 1). The crew removed the seat cushions and covers from seat 19F while the CSM turned off the power to the centre column of the seats. When the seat was further dismantled, the crew found a crushed personal electronic device (PED) wedged tightly in the seat mechanism. The cabin crew assessed that the crushed PED contained a lithium battery.

Figure 1: Cabin diagram showing the seat from where the smoke emanated

Source: Qantas, modified by ATSB

By that time, the PED was no longer emitting smoke, however, a strong acrid smell remained in the cabin. The crew then manoeuvred the seat and freed the PED (Figure 2). The crew placed the PED in a jug of water, which was then put in a metal box and monitored for the remainder of the flight.

The flight crew did not receive any abnormal indications or warnings.

No passengers were injured, and the aircraft was not damaged in the incident.

Figure 2: Crushed PED after removal from seat

Source: Qantas

Operator comments

The aircraft operator commented that it has been estimated over one billion lithium batteries are transported by air every year, with potentially hundreds carried on single sectors on large aircraft. As such, both cabin crew and passenger education remains a key component to managing these events. Raising passenger awareness of the potential hazards of PEDs commences at check-in, through to the pre-flight safety demonstration, and aims to minimise the risk of PED thermal runaway events.

Qantas Airlines’ basic fire drill is based on a teamwork approach, with the division of duties between three central crew and as many supporting crew as available and required. This division of duties allocates the responsibilities of fighting the fire, retrieving equipment and ensuring lines of communication with the flight deck remain uninterrupted.

ATSB comment

Similar occurrences

The ATSB has received 17 notifications of similar incidents of lithium battery thermal events in aircraft over the past 6 years.

The ATSB investigation AO-2014-082 details an example where a short circuit between lithium batteries initiated a fire in an aircraft cargo hold.

Safety message

This incident provides an excellent example of an effective response to an emergency situation. The crew were able to quickly implement the basic fire drill procedure which defined the roles and responsibilities of the responding crew. This enabled a rapid and coordinated response to the smoke event using all available resources. The effective implementation of this procedure also ensured the flight crew were kept informed as the situation developed.

This incident also highlights the hazards of transporting lithium-ion battery powered PEDs. The Civil Aviation Safety Authority web page Travelling safely with batteries and pamphlet Is your luggage safe? provide information on the safe carriage of lithium-ion batteries and lithium-ion powered devices aboard aircraft.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

What happened

On 16 May 2016, the pilot of a Maule MT-7-235 aircraft, registered VH-DRS, conducted a private flight from Greenfields airstrip (near Noosa), Queensland, with two passengers on board.

The aircraft departed Greenfields airstrip at about 1220 Eastern Standard Time (EST) and flew to Gympie ALA, where the aircraft was refuelled. The aircraft then departed from Gympie and flew north towards Maryborough before returning to Greenfields along a coastal route.

The aircraft joined the circuit at Greenfields on the downwind leg for runway 09. The pilot turned on to the final approach at about 800 ft above ground level, with an airspeed of about 70 kt. The pilot noticed they were getting low on the approach and at about 500 ft, they increased the power to regain their approach path. The pilot subsequently assessed that the aircraft was too high and lowered the nose to re-intercept the approach path.

The pilot flared the aircraft for landing, the aircraft landed heavily and bounced into the air. As the aircraft landed again, the nose wheel touched down first (before the main landing gear) with sufficient force that the nose wheel strut fractured. The nose landing gear and propeller then dug into the ground and the aircraft rotated over its nose and slid a short distance inverted before coming to rest.

The pilot and one passenger were uninjured, the other passenger sustained minor injuries, and the aircraft sustained substantial damage (Figure 1).

Figure 1: Accident site showing damage to VH-DRS

Source: Aircraft owner

Pilot comments

The pilot provided the following comments:

• they taxied the full length of the strip before departure from Greenfields and noted the grass surface was in good condition
• they had flown about five flights, totalling about 20 hours in the last 12 months
• the pilot’s previous flight was about 4 to 5 weeks prior to the accident flight
• the pilot had not operated the Maule aircraft with more than one passenger on board prior to the accident flight
• the pilot thought that the higher all-up-weight of the aircraft with an extra passenger on board contributed to a higher sink rate on final than they expected
• the pilot commented that they should have performed a go-around, rather than continuing with the landing manoeuvre.

ATSB comment

Currency versus proficiency

At the time of the accident the pilot was current for passenger-carrying operations, having conducted at least three take-offs and three landings in the last 90 days. However, it was more than one month since their last flight, which was also a local area scenic flight. The take-off and landing phases of flight are critical phases of flight, since the aircraft is operating closer to the stall speed and with less height to recover from a control problem, relative to cruise flight. The requirement for three take-offs and three landings in the last 90 days is a regulatory requirement of currency, but this does not guarantee proficiency. When flying infrequently, proficiency in take-offs and landings can be improved by dedicating a portion of the flight to practicing circuits. The United States Federal Aviation Administration safety briefing September/October 2010 described this as ‘imbuing the quantity of all your flying, however limited, with quality.’

Safety message

Go-around

The pilot commented that conducting a go-around could have prevented an unstable approach and initial bounce from escalating to an accident. General aviation pilots should set their own criteria for when to conduct a go-around manoeuvre, so that they can recognise and respond to the conditions in a timely manner. This will assist pilots to develop a mindset, which the Flight Safety Foundation (FSF) refers to as ‘go-around-prepared’. FSF Approach-and-landing Accident Reduction (ALAR) briefing note 6.1 emphasises the need to be ‘go-around-prepared’ or ‘go-around-minded’ because the execution of a go-around is an infrequent manoeuvre. FSF ALAR briefing note 7.1 provides further information on unstable approaches and how to develop personal lines of defence.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

What happened

On 13 May 2016, the student pilot of a Cessna 172S aircraft, registered VH-EWZ (EWZ), was conducting solo circuits at Moorabbin Airport, Victoria. The runway in use was runway 35 right (35R), and the wind was west to north-westerly at 10 to 20 kt. At the same time, the pilot of a Cessna 172R aircraft, registered VH-SYH (SYH), was also conducting circuits. SYH was the aircraft immediately ahead of EWZ in the circuit.

The student pilot of EWZ completed eight circuits. During that time, the wind, in particular the crosswind, increased and was subsequently reported as 9 to 15 kt from the left of runway 35R.

At the completion of their circuit training, the pilot of SYH landed and taxied clear of runway 35R, stopping on taxiway E facing north-west (Figure 1). Soon after SYH landed, at about 1059 Eastern Standard Time (EST), EWZ was on the final approach for another touch-and-go landing.^[1]

The pilot reported that during the landing, EWZ touched down heavily to the left of the runway centreline.^[2] The pilot then applied full power to continue the take-off. As the power increased, the aircraft yawed to the left and ran off the runway. At that time, the pilot of EWZ sighted SYH on the taxiway, reduced the power to idle and applied full right rudder in an effort to avoid SYH.

Figure 1: Moorabbin Airport showing location of collision

Source: Google earth – annotated by ATSB

The underside of the left wing of EWZ contacted the top of the right wing of SYH (Figure 2). EWZ came to a stop on the grass to the left of runway 35R. Both aircraft sustained minor damage and the pilots were uninjured (Figure 3).

Figure 2: Damage to right wing of VH-SYH

Source: Aircraft operator

Figure 3: Damage to left wing of VH-EWZ

Source: Aircraft operator

Pilot comments

Pilot of VH-EWZ

The pilot of EWZ provided the following comments:

• In the previous circuits, they had conducted a go-around^[3] when they were not comfortable with the approach. On the accident circuit, they assessed that the approach was normal, and elected to continue to land.
• As they applied power to take-off, the aircraft yawed^[4] left. They assessed that they may not have applied sufficient rudder input to counter the yaw effect of the increase in power.
• They were using a higher power setting than normal on final approach to maintain the desired approach path due to the crosswind.

Operator comments

Operator of VH-SYH

The operator of VH-SYH provided the following comment:

• In their experience on this aircraft type, yaw induced by crosswind has the potential to be significantly greater than left yaw induced by propeller effects. They suggested that the left yaw induced by the reported crosswind from the left, coupled with not so strong left yaw from propeller effects, combined to create the strong left yaw reportedly experienced.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following safety action in response to this occurrence.

Operator of VH-EWZ

As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety actions:

Company instructors have reviewed the landing technique they were using and teaching. A video demonstration of approach and landing technique was recorded, both for staff training purposes and as a training tool.

Safety message

This incident highlights the importance of knowing your own limits. Pilots should use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors including weather conditions that may affect aircraft handling.

This incident also underlines the importance of applying correct technique during all phases of flight, including take-off and landing. The CAA NZ – Flight Instructor Guide - Crosswind Circuit provides useful information for crosswind operations.

Aviation Short Investigations Bulletin - Issue 50

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2016 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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^[1]     Touch-and-go landing is a manoeuvre which is common when learning to fly fixed-wing aircraft. It involves landing on a runway and taking off again without coming to a full stop. Usually the pilot then circles the airport in a defined pattern known as a circuit and repeats the manoeuvre. This allows many landings to be completed in a short time.

^[2]     The ATSB obtained recorded data from the incident flight for EWZ. The data showed the aircraft touched down slightly to the right of the runway centreline.

^[3]     A go-around, the procedure for discontinuing an approach to land, is a standard manoeuvre performed when a pilot is not completely satisfied that the requirements for a safe landing have been met. This involves the pilot discontinuing the approach to land and may involve gaining altitude before conducting another approach to land.

^[4]     Term used to describe the motion of an aircraft about its vertical or normal axis.