Unclear communication, confusion and misunderstanding of safeworking network rules resulted in a safeworking irregularity involving a freight train driver who unknowingly entered the track without protections in place near Waterfall, NSW, shortly after midnight on 21 August 2019, a new transport safety investigation notes.

The incident occurred while a driver was manually releasing hand brakes on Pacific National freight train 4WM2 following a remarshal* of the train consist to clear the main line due to a track fault on the adjoining network that prevented the train from travelling past signal W26U.

The remarshal involved dividing the train’s three locomotives from its rake of 50 wagons and manually securing the wagons’ hand brakes on the Up direction on the Up line near the signal. The locomotives then travelled to Helensburgh for a return journey towards Waterfall on the Up direction on the Up line to reattach the stabled wagons.

On arrival at the wagons, one of the two drivers from 4WM2 requested protections be put in place before entering the track on the Down line to reattach the locomotives and release the wagon hand brakes. During this time, a passenger train was diverted from the Up line to travel in the Up direction on the Down line to Waterfall to avoid the freight train.

As the driver released the hand brakes, the second driver on 4WM2 saw a passenger train approaching the driver on the Down line and signalled for the train to stop. The passenger train made an emergency brake application to stop before reaching the driver. There were no injuries.

A transport safety investigation into the incident conducted by the Office of Transport Safety Investigations, which undertakes rail safety investigations in New South Wales on behalf of the ATSB, established that the safeworking network rule and procedure for protecting activities associated with in-service rail traffic were not used effectively to ensure workers were protected from rail traffic.

The requests for protection were informal and did not detail the required activities or protection, the investigation notes. Both drivers of 4WM2 unknowingly entered the danger zone without appropriate protection and were at risk of being struck by rail traffic.

There were multiple parties involved in the communication and decision making relating to the movements of 4WM2, the investigation found. This led to confusion and misunderstanding of the required activities and likely affected the actions of the Waterfall Signaller and train crew. Additionally, not all communications were conducted in accordance with the network rules.

“Key lessons from this investigation are that rail infrastructure managers and rail transport operators must ensure that safety critical communication is conducted in accordance with network rules and that network controllers consider the potential dangers train crews are exposed to before requiring them to enter the danger zone, as part of a broader system to ensure the safety of workers entering the danger zone,” said OTSI Chief Investigator Dr Natalie Pelham.

“Workers must also ensure they have appropriate safeworking protection in place before entering the danger zone to protect them from rail traffic. Additionally, workers must ensure rest periods are utilised to manage non-work-related fatigue to complement rail infrastructure managers and rail transport operators’ fatigue management programs,” said Dr Pelham.

The rail operator and network owner have taken several proactive safety actions as result of the incident.

*Remarshal refers to changing the order of locomotives or wagons in a train’s consist.

Read the final report: Safeworking Irregularity, near Waterfall, New South Wales, on 21 August 2019

An out of gauge wagon on a freight train caused minor damage to five station platforms while travelling from Brisbane to Port Kembla, a recent ATSB investigation has found.

On the morning of 15 June 2020, wagon RKOX4055Y was unloaded at a steel facility south of Brisbane. A forklift operator had trouble unloading one of the three stacks of welded beams from the wagon, with footage from security cameras within BlueScope Steel’s Coopers Plains facility showing a corner of the wagon lifting during the unloading process before dropping back down.

With unloading completed, wagon RKOX4055Y was then shunted and attached to another 52 wagons to form Pacific National train 2BW4 for the journey to Port Kembla. Prior to departing the facility, the train underwent a full train examination and a roll-by inspection with no abnormalities detected.

At around 0430 the following morning, station staff at Grafton found damage to the station’s platform. The damage was reported to the network controller who directed the crew of 2BW4 to inspect their train on arrival at Kempsey. Another roll-by inspection was performed, however no faults were identified and the train continued its journey.

Shortly before 1100, workers at Dungog station noticed a wagon on train 2BW4 contact the platform. Network control was again advised, and the train was directed to stop at Wallarobba. On inspection, the wagon body on RKOX4055Y was found to have dislodged and was resting on the bogie.

Wagon contact damage subsequently was also found on platforms at Coffs Harbour, Taree, and Wingham.

The investigation into the occurrence, conducted on behalf of the ATSB by NSW’s Office of Transport Safety Investigations, found that during the unloading of wagon RKOX4055Y, the wagon body was likely lifted off the centre pin and dislodged as the load became stuck. The forklift operators did not notice that the wagon body had lifted and continued unloading other wagons.

During the examination of the train the underframe was not inspected as required by Pacific National’s train examination procedure, the investigation notes. The likely dislodged wagon body was not identified and train 2BW4 departed with a rolling stock irregularity.

The investigation highlights that procedures and practices for loading and unloading rolling stock must ensure risks are identified, controlled and that the practices do not affect the safe operation of rolling stock.

Further, maintenance inspection regimes must be completed in accordance with engineering practices to identify conditions that might contribute to accidents.

Following the occurrence, both BlueScope Steel and Pacific National completed several safety actions directed at preventing a reoccurrence.

Read the final report: Wagon out of gauge on freight train 2BW4, Main North rail line, New South Wales, on 16 June 2020

Key points:

• A trainee controller’s assessment of their workload meant the pilot was not provided a requested clearance to enter controlled airspace;
• Subsequent information provided by a second air traffic controller likely resulted in the pilot deciding to descend the aircraft, despite the pilot having other safe options to transit the area or to turn back;
• Pilot most likely had not obtained required weather forecasts, and the aircraft was descended toward high terrain in visibility conditions below that required for visual flight.

The controlled flight into terrain accident of a Mooney light aircraft near Coffs Harbour in which the pilot and passenger lost their lives highlights both the importance of pre-flight planning and pilot proficiency checks, and the influence air traffic control can have on pilot decision-making, a new ATSB investigation details.

The Mooney M20J four-seat aircraft, with the pilot and a single passenger on board, was being operated on a private flight under visual flight rules from Murwillumbah to Taree on the morning of 20 September 2019. About 45 nautical miles north of Coffs Harbour at 0717 and at an altitude of 6,500 feet the pilot requested air traffic control permission to enter and transit Class C controlled airspace*, which lay in the direct track to Taree. A trainee controller working under supervision (operating from the Brisbane Centre air traffic control facility), having made an assessment of their workload, advised that a clearance was not available and provided the pilot the option to request a clearance to transit through the lower Class D airspace surrounding Coffs Harbour Airport.

The pilot subsequently contacted the controller in the Coffs Harbour control tower responsible for managing the Class D airspace, who advised that due to extensive cloud cover, a visual transit would only be possible at an altitude not above 1,000 feet. The pilot responded that the aircraft would descend to ‘not above 1,000 feet’.

The Mooney then continued on a direct track to Taree and at 0724 the pilot reported that the aircraft was operating outside controlled airspace in clear conditions at 4,100 feet and would remain on that track. Recorded air traffic control surveillance data (the aircraft was equipped with an ADS-B transponder) showed that the aircraft was then climbed to 4,500 feet before a descent was commenced, at 0732, in the vicinity of high terrain. The aircraft’s last recorded position was descending through an altitude of 3,564 feet at a ground speed of 165 knots.

When the aircraft did not arrive at Taree as expected a search was initiated. The aircraft was subsequently found to have impacted heavily wooded, steep terrain in the Dorrigo National Park at an elevation of 2,920 feet, about 26 km west of Coffs Harbour Airport. Both the pilot and passenger were fatally injured.

The subsequent investigation into the accident made a number of findings concerning both pilot proficiency and pre-flight planning, and air traffic control information, said ATSB Chief Commissioner Greg Hood.

“Information provided by air traffic control likely resulted in the pilot deciding to descend the aircraft from 6,500 feet instead of other available safe options, such as proceeding around the Class C airspace at or above 6,500 feet, diverting, or descending to the north of Grafton to proceed coastal beneath the cloud layers south to Taree,” said Mr Hood.

“The ATSB also found that the pilot was not carrying suitable navigation equipment – the pilot was likely using a handheld GPS unit while air navigation charts for the area were found stowed in a flight bag – and had most likely not obtained the required weather forecasts. These factors reduced the pilot's ability to manage the flight path changes and identify the high terrain. This led to the aircraft being descended toward the high terrain in visibility conditions below that required for visual flight, resulting in controlled flight into terrain.”

The pilot had also not completed the required flight reviews or proficiency checks, Mr Hood noted. As a consequence, the pilot did not hold a valid licence to undertake the flight, and their knowledge and skills required for effective flight management and decision‑making had likely deteriorated.

“This tragic accident emphasises to pilots the importance of flight preparation and of ensuring they have completed all required training and checks,” Mr Hood noted.

“Thorough flight planning and flight reviews and proficiency checks allow pilots to develop and maintain the necessary skills to manage challenges in flight, such as inclement weather or inadvertent entry into non-visual conditions,” he said.

“Further, confirming that appropriate operational information is obtained and readily available ensures that a pilot is well prepared to anticipate in‑flight complications and successfully manage unforeseen challenges.”

The investigation also found that the pilot was not provided clearance to transit Class C airspace due to the trainee controller’s conservative assessment of their workload, although there was no conflicting traffic, meteorological factors or limiting air traffic control instructions or procedures that would have precluded providing the clearance.

The trainee’s supervisor accepted the assessment as an alternate option – transiting through Coffs Harbour Class D airspace – was provided to the pilot.

“The pilot was not provided with a clearance to transit Class C airspace despite there being no limiting meteorological factors,” Mr Hood noted.

“Instead, the Class C controller provided the option to seek a clearance at a lower altitude with an increased risk of encountering poor weather.

“Further, the limited information provided by the Class D controller to enter that airspace probably led to the pilot’s decision to descend into a hazardous area instead of opting for other available safe options.”

Since the accident, Airservices Australia has implemented a number of proactive safety actions, Mr Hood noted.

“This accident illustrates the significant influence that air traffic control can have on the conduct of a flight,” said Commissioner Hood.

“And it also serves as another reminder of the risks for visual flight rules pilots flying into non-visual conditions.

“As a former air traffic controller and private pilot myself, I urge all current controllers and private VFR pilots to read this thorough and illuminating report. It contains pertinent lessons that others can learn from.”

* Note to media – information on the classification and management of airspace in Australia can be found on the Airservices Australia website here(Opens in a new tab/window).

Read the final report: Controlled flight into terrain involving Mooney M20J, VH-DJU, 26 km west of Coffs Harbour Airport, New South Wales, on 20 September 2019

Key points:

• Rolling stock derailed then separated, coming to a stop near Glenalta
• The ATSB found a pre-existing structural crack was the genesis of the derailing sequence
• This accident highlights the importance of rolling stock managers to identify, monitor and maintain key structural risk areas of rollingstock

Rolling stock managers at Pacific National have revised their maintenance and inspection procedures and engaged an independent consultant to review repair methodology after a structural crack in the underframe of a wagon resulted in a derailment.

On 20–21 April 2018, a Pacific National freight train was travelling from Melbourne via Adelaide to Perth. A short time after commencing the downhill grade from Mount Lofty to Belair, South Australia, the train derailed and eventually separated before both portions of the train came to a stop near Glenalta.

The ATSB found that a pre-existing structural crack in the underframe of a wagon likely expanded due to in-train forces, causing the platform’s deck to bend and change angle. As the train negotiated a series of tight curves on the descending grade, a combination of wheel unloading and increased lateral forces resulted in derailment.

The ATSB found that multiple train examinations and maintenance inspections did not identify the crack, nor did Pacific National’s inspection processes identify key structural points for inspection on wagons of the type that failed.

“This incident highlights the importance of rolling stock managers considering the key structural risk areas of their rollingstock and establishing guidance methods for ensuring that these risk areas are given an appropriate level of priority when undertaking inspections,” said ATSB Director Transport Safety Dr Mike Walker.

As a result of the investigation, Pacific National altered its inspection and maintenance procedures to ensure that similar wagon types are less susceptible to this type of underframe failure, and that where detected, such cracks can be repaired.

Read the report: Derailment of freight train 6MP4, near Glenalta, South Australia, on 21 April 2018

Key points: 

• Empty wagon positioned between two loaded wagons entered rail network and derailed.
• Derailed train continued with wagon bogie dragging on the down rail of the up main line and within the six foot and foul of the down main line.
• Lead locomotive of freight train travelling on down main line collided with bogie.

A coal train collided with a wagon bogie that had been dragged across the track by another coal train following the earlier derailment and ejection of the bogie’s wheelset from an empty wagon, a new ATSB report says.

Early on the morning of 26 September 2018, train MR336 had been loaded with coal at the Moolarben loading terminal in New South Wales. During loading, a ‘wagon empty detected’ alert was triggered but the Train Loading Officer (TLO) was unable to confirm if the wagon was loaded.

A ‘wagon empty alert’ was also triggered as the train passed over the weighbridge. Unable to visually confirm if the wagon was loaded, the TLO requested the Coal Handling Preparation Plan (CHPP) Supervisor check the 28th wagon. The supervisor and technician drove to the front of the loading train, counted back from the first wagon, and confirmed that the 27th, 28th and 29th wagons were loaded. Loading was complete and the train advised to depart.

 At about 160 km from the terminal, the leading wheelset of the trailing bogie of the 25th wagon derailed on the up main line at Antiene. The wheelset ejected from the bogie and came to a rest about 3 kms up the track. The train continued in a derailed state for 9 km, dragging the bogie across the down track until it collided with the lead locomotive of train WC915, which was travelling in the opposite direction.

The collision resulted in WC915’s lead locomotive and two wagons derailing and the 25th, 26th and 27th wagon of MR336 tipping on their sides away from the down line. There were no injuries to the drivers on either train.

A transport safety investigation into the incident by the Office of Transport Safety Investigations (OTSI), which undertakes rail safety investigations in NSW on behalf of the ATSB, established that the wheelset derailed due to an empty wagon positioned between two loaded wagons being allowed to enter the rail network.

OTSI Acting Chief Investigator Mick Quinn said empty or light loaded wagons positioned between loaded wagons running on the rail network is a known risk that can have severe consequences.

“In this instance, trailing in-train longitudinal forces lifted the empty wagon and its trailing bogie, resulting in the leading wheelset of the trailing bogie mounting the rail and dismounting in a derailed state. The wheelset then ejected from the bogie and the train continued with the bogie dragging on the down rail of the up main line within the six foot and foul of the down main line,” said Mr Quinn.

The investigation found the 25th wagon of MR336 was not loaded due to a malfunction of a ‘stop loading sensor’ in the automatic loading system being commissioned at the terminal.

“Reduced confidence in the alarm from several false empty wagon alerts during the commission process meant the TLO was pre-occupied when the alarm sounded and the opportunity to see and confirm the wagon was loaded was missed,” Mr Quinn noted.

“Other opportunities to check the wagon were also missed due to low light conditions at the terminal and the CHPP supervisor check requested by the TLO based on a check of the wrong wagon.

“This investigation highlights the need for coal loading terminals and rolling stock operators to review their processes to prevent empty or lightly loaded wagons being positioned between loaded wagons and entering the rail network.”

In response to the incident the Moolarben loading terminal corrected the malfunctioning sensor and implemented a more detailed verification process to ensure both the TLO and Control Room Operators verify trains are loaded within their specifications before advising train operators loading is complete.

A review of the terminal's risk assessment for additional train loading has implemented several actions including empty wagon detection by two independent methods, improvements in lighting, and increased monitoring of weighbridge performance. A review and update of training the train loading manual and training package has also been conducted.

Read the final report: Derailment and collision between coal trains, Ravenan (25 km from Muswellbrook), New South Wales, on 26 September 2018

Key points:

• Ballast loss from a mud hole reduced track lateral resistance
• Longitudinal compressive forces were also present in the rail due to the day’s hot conditions
• Track buckled under the dynamic load of the train, with the leading bogie of one wagon derailing

A freight train wagon’s lead bogie derailed when passing over track that buckled and deformed under the train likely due to a loss of supporting ballast due to a mud hole and compressive forces within the rails due to hot weather, a new transport safety investigation report details.

On 21 January 2019, SCT Logistics freight train 6BM9, consisting of two locomotives and 31 wagons, was travelling south from a logistics terminal in Barnawartha, Victoria to Altona in Melbourne, with temperatures expected to reach 39°C.

At 1530, the train passed through Creighton travelling at about 100 km/h. About 500 metres after crossing Creighton Siding Road, the lead bogie of the third-last wagon derailed a short distance before a small rail bridge. The driver noticed a plume of dust towards the rear of the train in the rear view mirror, and observed a loss of brake pipe pressure.

The train was brought to a stop and network control notified. The crew then inspected the train and identified the derailed wagon. An immediate site inspection by maintenance personnel from the track manager, the Australian Rail Track Corporation (ARTC), found significant lateral misalignment of the track.

A transport safety investigation into the incident conducted by the office of Victoria’s Chief Investigator, Transport Safety, which undertakes rail safety investigations in Victoria on behalf of the ATSB, established that the wagon derailed at a section of track with a  mud hole* and an associated loss of ballast, resulting in a reduction of track lateral resistance.

“The combination of reduced track lateral resistance from the mudhole and longitudinal compression within the rails due to the hot weather was sufficient for the track to misalign under the dynamic loading of the freight train, and for one wagon to derail,” said Chris McKeown, Chief Investigator, Transport Safety.

“In this case, the wagon derailment only resulted in minor track damage, however, had the wagon not derailed an XPT passenger service 80 minutes behind the freight train would have encountered the track misalignment and possibly derailed,” he said.

The mud hole had been identified and recorded in maintenance work orders for at least two years prior to the derailment, but no remedial work had been undertaken and it was not identified as a special location for the monitoring of track stability in ARTC’s Track Stability Management Plan, the investigation notes.

“The loss of ballast profile at the derailment location probably required a more significant level of response than being monitored, such as a temporary speed restriction or repair,” Mr McKeown said.

The longitudinal compressive forces were due to the hot conditions of that day, and possibly localised low stress-free-temperatures in the rails near the rail bridge, the investigation notes.

“In continuously welded rail, longitudinal compression forces occurs regularly during summer, as the rail expands longitudinally and it may buckle if there is inadequate track lateral resistance,” said Mr McKeown.

“In this instance, the rail bridge likely acted as a fixed point, with deformed track creating an ‘S’ buckle that went from the derailment site to the bridge.”

In response to the derailment, ARTC has reviewed its Track Stability Management Plan and included the affected section of track as a special location for the monitoring of track stability.

“This investigation highlights the importance of rail infrastructure managers having systems in place to identify track sections vulnerable to lateral instability during the summer period,” Mr McKeown said.

* Mud holes occur when ballast becomes contaminated (or fouled) with fine materials. This can be due to poor ballast, a breakdown of the ballast material or the formation (the track base) rising up through the ballast. The fouled ballast retains water (appears like mud), prevents effective drainage, and can result in poor track geometry.

Read the report: Derailment of freight train 6BM9, at Creighton, Victoria, on 21 January 2019

Key points:

• Flight crew inadvertently lined-up and commenced take-off roll on Canberra Airport’s runway 30, rather than the assigned runway 35
• Flight crew advised they were ready for take-off before checks were complete

A Virgin Australia ATR72 inadvertently lined-up on the wrong runway at Canberra Airport for a night time departure, a new ATSB report details.

The flight crew of the 25 September 2019 flight to Sydney had elected to depart Canberra Airport’s runway 35 from intersection G (‘Golf’), based on aircraft performance considerations, environmental conditions and the short distance between their parking bay and the runway holding point.

While taxiing to the holding point at intersection Golf, the flight crew completed their departure review. Just before reaching the holding point, the flight crew advised ATC they were ready for take-off. After clearing the aircraft for take-off, ATC deactivated the stop bar and the lead-on lights were illuminated. The aircraft then crossed the holding point and started turning through the intersection and inadvertently lined-up with the centreline of runway 30, which is considerably shorter in length than runway 35.

ATC saw the aircraft moving on runway 30 and immediately instructed the flight crew to stop. At about the same time, the flight crew rejected the take-off.

A review of airport closed-circuit television and recorded flight data showed the aircraft lined-up on runway 30, paused and then briefly accelerated and braked suddenly. The aircraft then exited the runway and departed from intersection ‘N’ (November) for runway 35 as per ATC instructions, without further incident.   

Acting ATSB Director Transport Safety, Kerri Hughes said that using intersection Golf for runway 35 meant the flight crew only had about 90 seconds to complete the preparatory tasks for departure. This resulted in the flight crew advising ATC they were ready for take-off prior to completing the before take-off procedure.  

“The first officer reported being focused on the before take-off checks as they approached the holding point, while the captain was focussed on the runway lead-on lights,” Ms Hughes said.

“The challenge and response nature of the before take-off procedure would have required some of the captain’s focus. This likely resulted in the captain taxiing the aircraft through the intersection with divided attention, while the first officer’s attention was focussed inside the cockpit.”

Ms Hughes explained that intersection Golf leads to the intersection of the Canberra Airport's two runways, 12/30 and 17/35, and is listed in airport documentation as a known runway incursion hotspot due to this complex layout. There are few airports in Australia where a taxiway leads to the intersection of two runways.

Further, when the stop bar at intersection Golf was deactivated, the lead-on lights to both runway 30 and 35 were illuminated, increasing the risk of confusion.

“The complexity of some airport runway and taxiway layouts can be exacerbated by reduced visibility conditions, such as at night or in poor weather, which can easily increase flight crew confusion,” Ms Hughes said.

“This investigation highlights the need for flight crews to familiarise themselves with complex runway layouts, particularly any unique designs, and ensure effective flight crew co-ordination is employed to minimise the risk of a runway incursion.”

The investigation also found that Virgin Australia’s ATR72 before take-off procedure did not specify when the crew were to advise ATC they were ‘ready’ for take-off . Further, runway verification checks using external cues were not included in procedures for all their aircraft. 

“The ATSB notes that, while Virgin Australia no longer operate the ATR72 aircraft, they have developed a new runway verification procedure for inclusion in their Flight Crew Operating Manual for their Boeing 737 fleet.”

Read the final report: Runway incursion and take-off commenced on incorrect runway involving GIE Avions de Transport Régional ATR72, VH-VPJ, Canberra Airport, Australian Capital Territory, on 25 September 2019

Key points:

• Passenger train struck the end of a steel coil which had fallen off a freight train travelling in the opposite direction
• Coil’s securing straps likely failed due to direct contact with a supporting cradle, which was missing a rubber mat
• Two crew on the passenger train sustained minor injuries as train traversed damaged track

A passenger train had begun making an emergency braking application when it struck the tail of a steel ‘jumbo’ coil which was obstructing rail track in both directions on the Sydney-Melbourne main line near Winton, Victoria on 30 March 2018, after the coil had dislodged from a freight train, a new ATSB investigation report notes.

The Melbourne to Albury V/Line passenger train service was travelling at about 110 km/h when it struck the unrolled tail of the 1.9 metre diameter, 16 tonne coil of rolled steel.

The coil had fallen from the 35th wagon of a Pacific National freight train, which was travelling from Port Kembla to Melbourne with a consignment of steel products from Blue Scope Steel, after passing the Seven Mile Creek Bridge near Winton. After falling from the wagon, the coil impacted ballast between the tracks at least twice, misaligning the east and west tracks, and damaging 39 trailing wagons (including damage to steps, handbrakes, brake cylinders and bearing caps), before coming to rest between the two tracks.

About 10 minutes later, the V/Line passenger service, which was travelling in the opposite direction, impacted the unravelled tail of the coil and entered the damaged track, but did not derail.

Two train crew members standing in the buffet car were thrown sideways as the train traversed the damaged tracks, sustaining minor injuries. The train’s locomotive received superficial damage.  

“While no injuries to passengers were reported, this investigation highlights the importance of robust load restraint systems to protect against movement of loads during transport, which is particularly important for heavy loads,” said ATSB Director Transport Safety Dr Stuart Godley.

“Should heavy loads like jumbo coils fall from train wagons they pose a significant risk to the safety of passengers and train crew of other rail vehicles.”

After striking the coil, the driver brought the passenger train to a stop, and advised train control that they had struck a steel coil. After applying signal blocks to both tracks, train control requested the drivers of the freight train to stop and inspect their train.

The subsequent ATSB investigation into the incident found that the coil had likely fallen from the wagon due to the absence of a rubber mat from one of the two faces of the cradle that supported the coil. The mat’s absence meant some of the coil’s metal unitising securing straps were in direct metal-to-metal contact with the cradle, increasing the risk of the straps failing, and allowing the coil centre to telescope (where the inner rolls of the coil move laterally relative to the outer layers). This reduced the coil’s lateral stability, and increased the risk of it falling from the cradle.

While it could not be conclusively determined when the straps broke it was likely that at least some broke during transit, reducing the ability of the remaining straps to maintain the coil as a unit. Subsequently, the remaining straps either also broke due to the forces imposed on them or were insufficient to prevent the coil from telescoping. Two broken steel straps were found either side of the track where the coil had fallen from the train.

Photographic evidence showed that the mat had been missing from the wagon's cradle since at least June 2017.

“The missing mat resulted in steel-on-steel contact between the coil and the cradle,” said Dr Godley.

“This increased the likelihood of wear on the coil’s securing straps, particularly if the radial straps were positioned within the contact area, which was permitted by the operator’s loading rules. Consequently, the risk of securing straps breaking during the journey was increased.”

Since the incident, a number of actions have been taken to reduce the risk of a similar occurrence, the ATSB investigation report notes. These include Pacific National updating their freight loading manual to require the use of a minimum of two radial and two circumferential straps to secure coils. The operator also updated its wagon maintenance manual to include a requirement to 'consider the condition of load mats during inspection and maintenance', and to repair or replace as required.

However, the ATSB has identified two safety issues from the investigation that remain unaddressed, and so has issued two formal safety recommendations to Pacific National. The first recommendation concerns the risk presented by continuing to allow the loading of jumbo coils in such a way that radial securing straps can contact the wagon’s support cradle. The second concerns ensuring that cradles sufficiently restrain jumbo coils against lateral accelerations to prevent their moving and falling during transit.

“Load restraint systems should include assessments and documentation that demonstrate appropriate load cases, design requirements, operational and loading requirements have been met, to ensure that the safety of the load restraint is maintained over time,” said Dr Godley.

Read the final report: Track obstruction due to loss of freight involving train 6WM2 and subsequent impact of passenger train 8615 with track obstruction, near Winton, Victoria, on 30 March 2018

Key points:

• Boeing 787 experienced uncommanded right engine shutdown
• A blocked inlet filter in a fuel metering valve servo assembly resulted in the electronic engine control being unable to control flow of fuel to the engine, resulting in the shut down
• Replacement of fuel pump and hydro-mechanical unit now required in event of maintenance messages indicating lack of FMV control

A Boeing 787 experienced an uncommanded shutdown of its right Rolls-Royce Trent 1000 engine while the aircraft was on descent into Perth Airport due to a blocked inlet filter in a fuel metering valve servo assembly, an ATSB investigation report details.

Operated by Scoot Airways, the Boeing 787-9, registered 9V-OJE, departed Singapore on 11 October 2018 on a regular scheduled flight to Perth, with 11 crew members and 356 passengers on board. About 2 hours into the flight the fight crew received status messages indicating abnormalities with the right engine, and later told the ATSB that the engine was slow to respond to commanded inputs and that engine performance continued to decline. At 9,000 ft, severe thrust asymmetry developed, and the autopilot made a rudder input. Shortly after, the right engine shutdown uncommanded.

The flight crew issued a PAN and air traffic control provided a clearance to level-off at 5,000 ft and vectored the aircraft off the approach to allow time for the completion of the quick reference handbook checklist, which required the crew to decide whether they should attempt to relight the engine. With the close proximity of Perth Airport and the aircraft’s capability to land safely with one engine, the flight crew decided not to attempt an engine restart. They then completed their landing performance calculations and advised air traffic control they were ready to land. The aircraft subsequently landed safely at 1909 local time and passengers disembarked as normal.  

ATSB Director Transport Safety Stuart Macleod, said the investigation highlights the importance of flight crews being familiar with their emergency procedures.

“In this case the flight crew worked effectively to assess the situation and took appropriate action to minimise risk in line with the operator’s flight crew manual,” said Mr Macleod.

To determine the cause of the uncommanded engine shut down engine manufacturer Rolls-Royce conducted a review of flight data information from the electronic engine controller (EEC), the report explains.

“A series of maintenance messages were found indicating a gap between the commanded and actual position of the fuel metering valve (FMV) – part of the hydro-mechanical unit (HMU) used to control the supply of fuel to the engine – that increased until the engine shut down,” Mr Macleod said.

“The first message showed that the flight metering valve was taking longer than needed to reach the position as specified by the EEC, subsequent data showed that after a later commanded declaration the FMV moved below the idle position as directed and did not move back as directed reducing fuel to the engine and it shutting down.”

Before the aircraft’s non-revenue flight to return to Singapore for further maintenance the right engine’s HMU was replaced. Similar maintenance messages were generated during a later flight but without an in-flight engine shutdown.

“Examination of the two HMUs showed evidence of a blocked inlet filter in the FMV servo assembly from worn journal bearings the engine’s secondary high pressure fuel pump, limited the EEC’s ability to effectively manipulate the FMV position and therefore the flow of fuel to the engine,” said Mr Macleod.

In response to the incident Rolls-Royce have updated its Fault Isolation Manual to include the removal of the fuel pump and HMU in the event of maintenance messages indicating the FMV not moving as commanded position.

In addition, when on 1 November 2018, another Scoot Boeing 787 generated maintenance messages related to the HMU during start-up, the engine was inspected, and some wear was found on some journal bearings. To search for similar maintenance messages, Rolls-Royce examined all maintenance data across the fleet of Trent 1000 Package B and Package C engines and monitored ongoing flights. Six other events were found, five with Scoot-operated aircraft, but none resulted in an in-flight shutdown. The majority occurred between late 2018 and early 2019.

The report notes Rolls-Royce considered a number of factors to explain the incidences of journal bear wear on Scoot operating aircraft but due to the number of variables they were unable to identify a dominant factor that could explain their susceptibility to pump bearing wear; however, Rolls-Royce identified and implemented a number of interim measures such as engine data monitoring to address the risk from low life wear of bearings.

“This occurrence highlights that positively identifying all factors that contribute to technical failures can be difficult and time consuming but that it is possible for manufacturers and operators to implement interim risk mitigation measures as done in this case,” said Mr Macleod.

“Rolls-Royce have advised the ATSB they will continue to monitor maintenance messages and the condition of unserviceable fuel pumps and are investigating the possibility of using flight data to detect fuel pump journal wear before its effects on valve operation becomes apparent.”

Read the final report: Engine failure involving Boeing 787, 9V-OJE, Perth Airport, Western Australia, on 11 October 2018

Key points:

• Aircraft stalled and entered a spin while overflying a rural property’s landing area
• The pilot was unable to recover control of the aircraft before it impacted terrain
• Accident highlights the need for pilots to minimise the risk of stalling, particularly when in proximity to the ground

A Liberty XL-2 two-seat light aircraft likely stalled at low speed and at a height that limited an effective recovery before it collided with the ground at a rural property near Braidwood, NSW on 4 August 2019, fatally injuring the pilot, an ATSB investigation has found.

The Liberty had flown from Moruya to the property in company (i.e. following but not in formation) with a second light aircraft with the view to landing at the property, or if the landing area was deemed unsuitable, continuing on to Camden. The pilot of the other aircraft, a recreational category aircraft better suited to operating from unprepared landing strips due to its landing gear configuration and higher propeller clearance, successfully landed at the property, but then called the Liberty pilot via mobile phone to advise that the runway was not suitable for their aircraft.

Recorded data from a flight planning app on the Liberty pilot’s iPad showed that the aircraft approached the landing area from the south-east, overflew the homestead before turning left to circle the landing area with a slowing airspeed.

On a second orbit of the strip, at about 400 ft above ground level, and after crossing the marked end of the landing area, witnesses observed the left wing drop and the aircraft enter a steep rotating descent. The pilot was unable to recover control of the aircraft before it impacted terrain.

“The ATSB investigation found that the aircraft departed controlled flight after slowing and turning downwind with no flap selected,” said ATSB Director Transport Safety Dr Mike Walker.

“The left wing stalled, and this resulted in the aircraft entering into an upright spin at an altitude that limited an effective recovery.”

The ATSB has investigated a number of accidents where light aircraft have stalled and impacted terrain. A stall/spin will result in a steep pitch down and rotation towards the stalled wing. Recovery takes a considerable amount of height, the magnitude of which is dependent on the reaction time of the pilot, and the use of appropriate recovery technique.

“This investigation highlights the need for pilots to minimise the risk of stalling, particularly when in proximity to the ground, such as during take-off and landing,” Dr Walker said.

“Turning manoeuvres at or close to the aircraft’s critical angle of attack, if mishandled, can lead to a stall that may result in the aircraft entering a spin.

“Pilots can limit their risk of losing control in flight by maintaining situational awareness of the aircraft state while conducting turns, maintaining adequate airspeed through appropriate power application during increased bank angles, and by selecting altitudes to operate at that provide sufficient height to recognise and recover from a stall.”

The investigation established that the aircraft’s stall warning system, which was designed to provide aural warning of impending stall conditions about 5 kt above the expected stall speed, was most likely functional at the time of the accident. However, it is unknown if and for how long this warning may have sounded. How the pilot reacted to the warning before the aircraft stalled is also unknown.

Separately, the investigation found that the aircraft’s maintenance release was invalid due to an airworthiness directive (AD) requiring inspection of the muffler having not being acted upon. Dr Walker noted that the overdue maintenance did not contribute to the accident, however, the invalid maintenance release should have precluded further flight in the aircraft until the AD was addressed.

Read the final report: Collision with terrain involving Liberty Aerospace XL-2, VH-XLK, 9 km north-east of Braidwood, New South Wales, on 6 August 2019