The Australian Transport Safety Bureau has provided an interim report from its ongoing investigation into the derailment of a freight train north of Queensland’s Sunshine Coast earlier this year.
The Australian Transport Safety Bureau has provided an interim report from its ongoing investigation into the derailment of a freight train north of Queensland’s Sunshine Coast earlier this year.
Aurizon freight train Y279 was substantially damaged, and its driver sustained minor injuries, when the train’s two locomotives, and four of its wagons, derailed on flood-affected track at Traveston, on 23 February 2022.
Today’s interim report details the evidence collected so far in the ATSB’s transport safety investigation.
It notes a remote weather monitoring station, located about 200 m ahead of the derailment site, detected floodwaters had overtopped the track about 40 minutes before the train entered the area.
“While the remote monitoring station transmitted this information to the Queensland Rail asset management protection system, no warning or critical alarm messages were provided to the network control officer, or other relevant operational staff,” ATSB Director Transport Safety Dr Michael Walker said.
“This meant the network control officer and train driver were not alerted that floodwater had overtopped the track ahead of the train.”
Dr Walker noted the ATSB has investigated numerous accidents involving heavy rain events leading to derailments or other adverse outcomes.
This has included the derailment at Julia Creek on the Mount Isa Line in December 2015, the collision with floodwater at Banyan Creek in March 2018 on the North Coast Line, and current investigations into derailments at Nana Glen, New South Wales in February 2021 (conducted on behalf of the ATSB by NSW's OTSI), Traveston in February 2022, and Inverleigh, Victoria early this month (conducted on behalf the ATSB by Victoria's CITS).
“All such events show the importance of rail infrastructure managers having effective processes in place to manage the risk of a heavy rain event affecting the integrity of a rail line prior to a rail movement.”
With the Traveston interim report published, investigators will review and examine Queensland Rail’s integrated asset management protection system, and arrangements for the distribution of weather-related warning and alarm messages generated by the system.
“We will also be looking at procedures in place for the identification and management of a potential hazard from a weather event, and for response to warning and alarm messages,” Dr Walker said.
Procedures and training for drivers will be reviewed, both in terms of identifying and managing weather events, and egressing from a locomotive cab in an emergency.
“Investigators will also look into the training provided to network control staff and the maintenance inspections of cross track drainage systems at Traveston,” Dr Walker added.
In addition to evidence gathered, the interim report details some safety actions already taken by Queensland Rail after the derailment.
“While the ATSB will reserve its findings, and any safety issues and recommendations, for its final report, we welcome the safety action taken so far by the network operator.”
The International Confidential Aviation Safety Systems Group
The International Confidential Aviation Safety Systems (ICASS) Group promotes confidential reporting systems as an effective method of enhancing flight safety in commercial air transport and general aviation operations. The principal objectives of the ICASS Group are:
To provide advice and assistance in the startup and operation of a confidential reporting system.
To facilitate the exchange of safety related information between independent confidential aviation reporting systems.
To identify solutions to common problems in the operation of such systems.
Group membership
Membership to the ICASS Group is by invitation.
Membership - Membership with full voting rights.
Available to Reporting Systems that provide:
Voluntary reporting
Confidential protections
Operating on a regional, national or international level
Observer Status - In attendance by invitation during general business, but may be excluded from sensitive discussions.
Available to interested third party groups, eg. research institutions, airlines, service providers, manufacturers, and representatives of emerging confidential reporting systems.
For more information on confidential reporting and/or membership of ICASS, contact any one of the following programs.
Current Member Programmes
International Confidential Aviation Safety Systems Group
REPCON is a voluntary and confidential reporting scheme. REPCON allows any person who has an aviation safety concern to report it to the ATSB confidentially. Protection of the reporter's identity and any individual referred to in the report is a primary element of the scheme.
Who can make a report?
Anyone can report a safety concern confidentially to the ATSB. This means members of the travelling public or people involved in aviation.
Some examples of who has made a REPCON report in the past include:
an employee or contractor of an aviation transport operator who reported a matter under the operator’s Safety Management System (SMS) but does not believe it will be properly dealt with.
a person who has not reported under the SMS because they believe they will suffer retribution. (When submitting a report please ensure that you cannot be identified within your organisation by not copying any other person in to the report).
What may be reported?
Each of the following concerns (reportable safety concerns) in relation to the safety of aircraft operations to which the Regulations apply are examples of what may be reported under REPCON. The list is not exhaustive:
a) an incident or circumstance that affects or might affect the safety of aircraft operations;
b) a procedure, practice or condition that a reasonable person would consider endangers, or, if not corrected, would endanger, the safety of air navigation or aircraft operations, for example:
(i) poor training, behaviour or attitude displayed by an aircraft operator, airport operator or air traffic control service provider; or
(ii) insufficient qualifications or experience of employees of the aircraft operator, airport operator or air traffic control service provider; or
(iii) scheduling or rostering that contributes to the fatigue of employees of the aircraft operator, airport operator or air traffic control service provider; or
(iv) an aircraft operator, airport operator or air traffic control service provider bypassing safety procedures because of operational or commercial pressures; or
(v) inadequate airport facilities for safe operations; or
(vi) unsafe passenger, baggage or cargo management; or
(vii) inadequate traffic or weather information;
c) any other matter that affects, or might affect the safety of or aircraft operations not reportable under a mandatory reporting scheme.
If you are in any doubt whether the matter you wish to report is covered by the REPCON scheme or a mandatory reporting scheme please call us.
What is not a reportable safety concern?
To avoid doubt, the following matters are not reportable safety concerns and are not guaranteed confidentiality
matters relating to a serious and imminent threat to a person’s health or life
industrial relations matters
conduct that constitutes a criminal offence
terrorist acts. If you wish to provide information about terrorist activity you should call the National Security Hotline on 1800 123 400.
Matters which must be reported under a mandatory reporting scheme should not be reported under REPCON. This will not discharge your reporting obligations under a mandatory reporting scheme.
If you believe it would be necessary to act on information about an individual referred to in your report then you should report this directly to the Civil Aviation Safety Authority (CASA) on 1800 074 737 or the aircraft operator
What is confidential?
Personal information about the reporter and any person referred to in the report is confidential. Even if you are not concerned about keeping your identity confidential, do not copy in personnel from within or outside your organisation to the report. The integrity of the confidentiality of the reporter is the main concern of the REPCON system. If this occurs we cannot process the report within the REPCON framework.
If you think it’s necessary to act on information about a person referred to in your report, you should report this directly to the Civil Aviation Safety Authority on 1800 074 737.
Is an anonymous report acceptable?
REPCON does not accept anonymous reports. REPCON staff cannot contact an anonymous reporter to verify the report or to seek additional information. Further, REPCON staff must be satisfied that the reporter's motivation for reporting is aviation safety promotion, and that the reporter is not attempting to damage a rival or pursue an industrial agenda.
How are reports processed?
REPCON staff will assess reports for clarity, completeness and significance for aviation safety and to ensure it meets the requirements of a Reportable Safety Concern (RSC) for aviation.
The report will be de-identified to remove all personal details of the reporter and any individual named in the report. This will be passed to the reporter who must authorise the content before the REPCON can proceed further.
The de-identified text is then forwarded to the relevant organisation that is best placed to address the RSC. The organisation’s response will then be forwarded to the regulatory bodies, such as CASA, for further action as deemed necessary.
REPCON may use the de-identified version of the report to issue an information-brief or alert bulletin to a person or organisation, including CASA, which is in a position to take safety action in response to the safety concern.
What are the possible outcomes from report?
The desired outcomes are any actions taken to improve aviation safety in response to the identified concern. This can include variations to standards, orders, practices, procedures or an education campaign.
Why is REPCON important?
REPCON reports can serve as a powerful reminder that, despite the best of intentions, well-trained and well-meaning people are still capable of making mistakes. The de-identified stories arising from these reports may serve to reinforce the message that we must remain vigilant to ensure the ongoing safety of ourselves and others.
ASRS or REPCON?
REPCON is a separate scheme to the Aviation Self Reporting Scheme (ASRS). The ASRS allows for self-reports of unintentional regulatory breaches by pilots who are seeking to claim protection from administrative action by CASA. A reporter seeking protection from administrative action by CASA should consider reporting under the ASRS and whether they meet its criteria.
REPCON is a much broader reporting scheme designed to capture a wide range of aviation safety concerns from a large pool of potential reporters.
Submission of information known by the reporter to be false or misleading is a serious offence under section 137.1 of the Criminal Code. Aiding, abetting, counseling, procuring or urging the submission of false or misleading information is also a serious offence.
On 16 November 2022, a Regional Express (Rex) Saab 340B, registered VH-ZLJ, was prepared for a scheduled air transport flight from Cairns Airport, Queensland, to Bamaga, Queensland, as flight number ZL5538.
As the crew taxied the aircraft to the runway, an engineer on a nearby parking bay noticed something hanging from the aircraft and contacted the tower. The air traffic controller visually confirmed the engineer’s observations and alerted the crew, who returned the aircraft to the bay.
Aircraft parked overnight at Cairns were required to be fitted with an operator-designed bung installed in the horizontal stabiliser trim actuator cove to prevent bird nesting. The inspection revealed the horizontal stabiliser bungs had not been removed and were still installed in the left trim actuator cove.
What the ATSB found
The investigation found that the horizontal stabiliser bung was not detected during pre-flight preparations, resulting in the aircraft being dispatched with the bung still installed.
The ATSB also found that there was no procedure for the storage and accountability of the bungs after they had been removed, which differed from other bungs and covers used on Rex aircraft. Additionally, the operator did not consider aspects that would ensure the identification of an installed bung, or the safe operation of the aircraft if the bungs were not removed prior to flight.
What has been done as a result
The operator has commenced a risk assessment to formalise the procedures around the use of the horizontal stabiliser bungs. To support this, an engineering order was obtained to document and approve the manufacture of the bungs.
However, these actions did not address the issues around the storage and accountability of the bungs when they are removed or the aspects around the identification of an installed bung or the safe operation of the aircraft if the bungs were not removed. As such, the ATSB issued two safety recommendations and will continue to monitor the safety issues and provide website updates.
Safety message
‘Remove before flight’ conspicuity flags are a visual reminder to remove covers prior to flight. Failure to remove these devices may have the potential to foul or jam aircraft flight controls. In certain circumstances, the flags may not hang freely, which can reduce their visibility. Targeted inspection of locations and components, rather than relying on flags, which may not always be visible, can help to identify when these covers or devices have not been removed.
Further, when a missed item has the potential to affect the safety of flight, a secondary means of assuring the item has been removed should be employed. Similar to procedures employed for other covers on the aircraft, a means to account for what equipment has been removed from the aircraft before being stowed or retained by ground agents will provide the crew with another opportunity to detect when a bung or cover has not been removed.
On 16 November 2022, a Regional Express (Rex) Saab 340B, registered VH-ZLJ (ZLJ), was prepared for a scheduled air transport flight[1] from Cairns Airport, Queensland, to Bamaga, Queensland, as flight number ZL5538.
Ground handling services for the operator’s aircraft based at Cairns, were contracted to a third‑party provider. As part of this contract, 2 ground handlers were assigned to dispatch an aircraft, however, on the day of the occurrence one ground handler was unavailable. This meant that there were times when the available ground handler (ground handler 1) was assisted by a duty manager, prior to another ground handler commencing at 1300.
The aircraft had been parked overnight at Cairns Airport, which required the installation of horizontal stabiliser bungs (bungs) (see the section titled Use of horizontal stabiliser bungs) to prevent birds nesting in the elevator trim actuator coves. This was the first flight of the day for ZLJ, and at 1116 local time, ground handler 1 commenced removing the pitot covers, propeller straps, engine bungs and the wheel chocks from the aircraft and loaded the catering for the flight. It is likely they also attached the tail stand before leaving to dispatch another aircraft at 1131.
They returned to ZLJ at 1231 with the duty manager and continued the aircraft’s preparations, including connecting the ground power unit and the air-conditioning unit to the rear of the aircraft. Both ground crew then left to meet the ground handler who started work at 1300 (ground handler 2). Ground handler 2 was assigned to load luggage on to the aircraft and was occupied with this task until passengers boarded the aircraft at 1400.
The ground handling agent also provided check-in and customer services for the operator. Following a discrepancy with the number of bags checked-in for this flight, ground handler 1 left the aircraft to assist with checking-in the remaining passengers and locating the missing bag. Ground handler 1 was occupied with these tasks until returning to the aircraft at 1357 to load bags and finalise preparations.
At 1330, the flight crew arrived at the aircraft and commenced the pre-flight inspection[2] of the aircraft. The captain initially conducted an external check, walking around the aircraft. The first officer (FO) was completing their final check to line on this flight. They completed an external inspection of the aircraft as part of the aircraft’s daily inspection, in accordance with the flight crew operating manual (FCOM). They advised they paid particular attention to the rear of the aircraft, including inspecting the:
de-icing boots on the front of both sides of the horizontal stabiliser
5 static wicks on the rear of the horizontal stabiliser
depressurisation port to ensure there were no bird’s nests.
Both flight crew reported that during these checks they did not detect the tether rope with the ‘remove before flight’ conspicuity flag (Figure 2), which attached to each bung and hung under the back fuselage as a visual cue that the bungs were in place (Figure 1). The flight crew completed the internal and external checks prior to passengers arriving. At 1404, the FO completed the final external inspection.
Normally, the air conditioner[3] would have already been removed at this stage, but on this occasion, the FO observed that it was still attached to the aircraft. The ground crew were occupied with the discrepancy on the passenger list and the decision had been made to leave the air conditioner attached until the matter was resolved. The discrepancy was identified to be an administration error and the air conditioner was subsequently removed. The FO then walked under the fuselage of the aircraft to remove the tail stand and placed this in the cargo hold. During this inspection, and before closing the cargo door located at the rear of the aircraft, all straps and bungs to be retained on the aircraft were confirmed as having been removed and accounted for. The FO recalled that prior to entering the aircraft, they removed the guide strap that connected from the propeller to the passenger stairs, and the propeller guard. They also conducted a visual inspection to ensure there was nothing hanging underneath the aircraft.
As the aircraft taxied to the runway, an engineer on a nearby parking bay noticed something hanging from ZLJ and contacted the tower controller. The air traffic controller confirmed that something appeared to be hanging form the tail of the aircraft and alerted the crew who returned the aircraft to the bay.
The subsequent inspection revealed the horizontal stabiliser bungs had not been removed. The right bung was found hanging from the tail, still attached to the left bung installed in the trim actuator cove by the tether rope.
The procedure for the use of horizontal stabiliser bungs (bungs) was implemented by the operator in March 2017 at both Cairns and Townsville Airports. This followed an increase in the number of occurrences where birds had nested in the tail section of aircraft parked overnight during the warmer, humid months. The operator’s engineering department devised a solution with the design and fabrication of bungs to be installed in the elevator trim actuator coves on the upper surface of the horizontal stabilisers (Figure 1).
Source: Regional Express Pty Ltd annotated by the ATSB
The horizontal stabiliser bungs (Figure 2) were listed as site-specific equipment for use at both Townsville and Cairns. They consisted of a foam pad, which fitted into the actuator cove, attached to a board for both the right and left elevator. They were connected by a tether rope which had a conspicuity flag marked ‘remove before flight’.
The operator advised that all staff were trained and assessed in the use of the bungs prior to the bungs’ introduction. A training package was developed for contracting agents that included a presentation to familiarise ground staff with the new bungs. The training was delivered by a member of the operator’s airport services ground training department and involved the ground handler operating under supervision to obtain on-the-job training. Once assessed as competent, the ground handler would be approved for unsupervised operations. No additional training was provided by the ground handling agent because the procedure was governed by the airline.
The operator advised that the use of bungs was also covered as part of the induction training for pilots new to type.
The contractor provided ground handling services for the operator at both ports where the bungs were used. They advised that the operator’s procedures for the use of bungs were defined in the operator’s airport services manual (ASM). There was no checklist for these tasks, but ground staff followed the operator’s ASM procedures.
A presentation used by the operator’s ground training department for these pre‑ and post‑flight duties, advised ground agents that:
The horizontal stabilizer bung will be retained by the agent who will be responsible for the fitting of the bung upon termination. Similarly, the ground agent will be responsible for the removal of the bung prior to aircraft operation.
This procedure typically saw the bungs installed after the flight crew had left the aircraft and removed prior to the flight crew arriving at the aircraft the following morning.
The ground handling pre-flight duties section in the ASM provided the following guidance:
Remove bungs and propeller straps and store in designated positions in the cargo hold.
During interview, the flight crew advised that this procedure did not apply to site‑specific equipment such as the horizontal stabiliser bungs. It referred to the general instructions for the storage of items such as the pitot tube covers and engine inlet bungs, where specific storage locations were defined on the aircraft. Ground handling staff confirmed that the operator’s ASM procedures did not specify where the bungs were to be stored and that the agent stored these bungs in a container next to the parking bay. These containers were used to store several sets of bungs and were not allocated to a specific parking bay or airframe. Once the bungs were placed in the container, there was no way of knowing which bungs had been removed from what aircraft.
The training presentation, used to familiarise ground handling staff with the bungs, included the use of engine exhaust bungs (exhaust bungs) at Cairns. These exhaust bungs were also retained by the ground handling agent, however, the presentation included guidance for where these bungs should be stored (Figure 3). Similar to the horizontal stabiliser bird bungs, multiple sets were stored together in the designated storage bins.
The first officer (FO) completed their induction and commenced line training in March 2022. While familiar with the bungs at the time of the occurrence, the FO did not recall being briefed on their use during their induction. They also advised that their first exposure to the bungs was after seeing them installed on other aircraft at Cairns. Additionally, they reported having never handled the bungs before the day of the occurrence.
The airline’s primary means of communicating the use of bungs to flight crew was through the route manual where the following delegation of responsibilities appeared:
The ground agent will be responsible for the removal of the horizontal stabilizer bung prior to aircraft operation. As part of pre-flight duties, the crew MUST ensure the horizontal stabilizer bungs are removed prior to pre-flight inspections.
Additionally, the bungs appeared in the FCOM where they were listed as a check item in the external inspection of the tail area.
Both flight crew were aware of the information relating to the bung in the route manual but also believed that a company notice to air crew (NOTAC) would be provided to crew when the bungs were in use during summer months.[4] In the absence of a NOTAC on this flight, the crew believed that the bungs were not being used, although they had noticed the sporadic presence of the bungs fitted to aircraft at Cairns prior to the occurrence. The operator confirmed that while the route manual referred to the increased risk of bird nesting during the summer months, the manual also stated that the ground agent would install the bungs upon termination of service indicating that they would be used throughout the year. During interview, the ground handler confirmed that the bungs were installed every night.
The information available to the flight crew did not require them to handle the bungs but stressed that they must ensure the bung was removed before the pre-flight inspection. However, there were no instructions provided on how the crew should ensure the bungs had been removed. The flight crew advised the bungs could not be seen from the ground as the horizontal stabiliser fairings (Figure 1) obscured the bung when they conducted an external inspection, unless they moved further from the tail than would otherwise be required when completing the external inspection. In addition, the bungs could not be removed from the ground and required the crew to notify a ground handler if they were found installed during the external inspection.
The tasks required to dispatch a Rex Saab 340 aircraft were defined in the ground handling section of the company’s ASM. Access to operational information was provided to all ground handling agents to ensure the latest information was utilised with control of the documents remaining with the operator’s training department.
ZLJ terminated at Cairns the evening prior to the occurrence. The ground handling agent confirmed that while the post-flight duties were completed in accordance with the ASM, the operator’s procedures did not require a record of the installation of the bungs, and no additional details were available. As such, it could not be determined if the bung was installed correctly, or by whom, on the evening of 15 November 2022.
Video footage of ZLJ parked on the bay on the day of the occurrence, revealed that ground handling staff passed the rear of the aircraft multiple times while completing the pre-flight duties. During interview, the ground handler in charge advised that neither the bungs nor the tether rope were visible at any time. Further, they advised that they were easily detected when installed correctly and could not be missed with the conspicuity tag normally hanging below the tail and next to the rear cargo door (Figure 1).
Flight crew pre-flight procedures are documented in the company FCOM. The horizontal stabiliser bungs were identified in the external inspection, which formed part of the daily inspection. As this was the first flight of the day for ZLJ, the daily inspection of the tail area included visual checks of the following:
static dischargers
tail lights
ELT antenna
confirmation that the horizontal stabiliser bung had been removed.
Both crew members conducted external checks of the aircraft. The captain initially walked around the aircraft and noted that the bungs and associated tether rope were not visible. The FO then conducted the required external inspection in accordance with the FCOM and advised that they did not see the bungs, despite passing the tail area of the aircraft on several occasions.
Additional checks that may have identified the bungs
The Saab 340 is fitted with a gust lock system. When the handle in the cockpit is engaged, it mechanically locks the elevator, ailerons, and rudder to prevent damage in windy conditions. The gust lock is released while a stall test is conducted. The stall check is completed by the captain prior to the aircraft’s first flight of the day. During this check, the captain would release the gust lock, apply back pressure to the control column and test the stall recognition and recovery protection systems. This is achieved by applying and maintaining aft control column pressure then holding the test button to check that the stickshaker, aural alert and stick pusher activate. Once the test is complete, the gust lock is re-engaged.
The captain was unable to recall if this was the first flight of the day for the aircraft and could not confirm if this check was completed.
An additional flight control check was part of the line-up checklist and would normally have been completed prior to runway entry. It involved a co-ordinated response from the crew to release the gust lock and then check the flight controls. The captain would check the rudder and the FO would manipulate the control column to ensure full and free movement of the aileron and elevator controls. The crew confirmed that the tower controller notified them of the hanging bung before this check had been completed.
During analysis of the airport CCTV footage (Figure 4), the bung was not visible while the aircraft was being prepared, nor was it visible as the aircraft taxied away from the bay. However, the aircraft was not clearly visible in the footage. Later, when the bung was observed hanging from the aircraft, the left bung was still inserted into the trim actuator cove and the tether rope and right bung was hanging from the left horizontal stabiliser.
The operator’s engineering department designed and had the bungs manufactured. They determined that because the design did not require alteration of the airframe, a CASA approved‑ engineering order was not required.
The ATSB contacted the aircraft manufacturer to ascertain if the elevator trim actuator cove had been identified as a known area for similar nesting occurrences. Saab advised that they had only received one other report of bird nesting, and a handful of reports involving spider or insect nesting, from Australian operators. Additionally, Saab did not manufacture protection for this particular area of the aircraft, and they had not been involved in the design and manufacture of such a device. Significantly, the manufacturer provided a list of considerations that they felt would be appropriate for such a device. These included:
checklist and visual indicators to aid in identification
consequences if the cover was forgotten with regards to jamming or fouling of flight controls.
The operator confirmed that while a risk assessment had not been completed specifically for the bird bungs themselves, the decision to implement the bird bung procedure was to address the bird nesting safety concern and reduce the potential risk to passengers, crew, and the aircraft itself. There were no reports, prior to this occurrence, of aircraft dispatched with bungs installed in the trim actuator coves. However, it was reported that bungs had previously fallen out of the trim actuator cove in wind and were later found in nearby parking bays.
On the morning of the occurrence, there were significant distractions for the ground handling agent. Despite this, there were no significant time pressures during the early part of the day when the aircraft preparations began, and the ground handler removed the pitot and other aircraft covers. During this time, and later in the aircraft preparation, they were working around the rear of the aircraft on a number of occasions and the horizontal stabiliser bungs (bungs) were not detected.
In addition, while the flight crew were not expecting that the bungs would be installed, they both conducted external inspections of the aircraft, with the first officer (FO) stating they paid particular attention to the rear of the aircraft. The FO also removed the tail stand from under the tail of the aircraft where the bung conspicuity flag would have been hanging prior to entering the aircraft after the external inspection was completed. Neither pilot detected the bungs.
The ATSB analysis of the CCTV footage also did not detect the bungs while the aircraft was parked at the bay, nor as the aircraft taxied to the runway. Together, this would indicate that the bung was not installed correctly or possibly the tether rope with the ‘remove before flight’ conspicuity flag was not hanging from the horizontal stabiliser, as designed.
The training package provided to the ground handling agent indicated that the horizontal stabiliser bird bungs were to be retained by the agent, but did not specify how or where the bungs were to be stored. As the containers utilised by the agent stored multiple sets of bungs together, it could not be determined what equipment had been removed from what aircraft. This prevented any positive assurance check by ground handlers or flight crew that the bungs had been removed. This was also the case for the engine exhaust bungs.
Existing airline checklist procedures ensured that flight crew account for other covers and bungs that had been removed from the aircraft during pre-flight inspections. However, there was no pre‑flight procedure on how to check the aircraft for the installation of the horizontal stabiliser bird bungs. In the absence of a prescribed method of assurance, the flight crew walkaround inspection procedures relied on visual confirmation that the bungs had been removed by ensuring that the conspicuity flag was not visible. In this instance, when the conspicuity flag was not detected by both ground crew and flight crew, both parties would most likely have continued preparations with the belief that the bungs were not installed.
This occurrence revealed the potential for the horizontal stabiliser bungs to go undetected if incorrectly installed or not displaying as designed and identified a gap in the assurance procedures for the operator.
While a risk assessment of the bird nesting hazard led to the implementation of the procedure to install the horizontal stabiliser bungs, the operator did not conduct a separate risk analysis of the potential hazard a control surface bung could induce. Although the design incorporated features to aid in the recognition of the bungs when they were installed correctly, the evidence indicated that the design allowed for an incorrectly installed bung or one not displaying as designed to go undetected.
Existing procedural checks designed to detect fouled or jammed controls did not identify the incorrectly installed bung and there was no documented consideration given to assuring that a bung would be ejected prior to take-off, after which time it could have had the potential to adversely affect the safety of a flight.
ATSB investigation report findings focus on safety factors (that is, events and conditions that increase risk). Safety factors include ‘contributing factors’ and ‘other factors that increased risk’ (that is, factors that did not meet the definition of a contributing factor for this occurrence but were still considered important to include in the report for the purpose of increasing awareness and enhancing safety). In addition ‘other findings’ may be included to provide important information about topics other than safety factors.
Safety issues are highlighted in bold to emphasise their importance. A safety issue is a safety factor that (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.
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
From the evidence available, the following findings are made with respect to the aircraft preparation event involving Saab 340B, registration VH-ZLJ, at Cairns Airport, Queensland on 16 November 2022.
The horizontal stabiliser bungs were most likely incorrectly installed or possibly the tether rope with the ‘remove before flight’ conspicuity flag was not hanging from the horizontal stabiliser as designed. This resulted in them not being detected during pre-flight preparations and the aircraft being dispatched with the bung installed.
There were no formal procedures for the storage and accountability of horizontal stabiliser bungs after they were removed from the aircraft. (Safety issue)
The design of the horizontal stabiliser bungs did not consider aspects that would ensure the identification of an installed bung, or the safe operation of the aircraft if the bungs were not removed prior to flight. (Safety issue)
Depending on the level of risk of a safety issue, the extent of corrective action taken by the relevant organisation(s), or the desirability of directing a broad safety message to the aviation industry, the ATSB may issue a formal safety recommendation or safety advisory notice 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.
Descriptions of each safety issue, and any associated safety recommendations, are detailed below. Click the link to read the full safety issue description, including the issue status and any safety action/s taken. Safety issues and actions are updated on this website when safety issue owners provide further information concerning the implementation of safety action.
Safety issue description: There were no formal procedures for the storage and accountability of horizontal stabiliser bungs after they were removed from the aircraft.
Safety recommendation description: The Australian Transport Safety Bureau recommends that Regional Express Pty Ltd continues reviewing the use of horizontal stabiliser bungs and takes action to address the limitations associated with the current procedures around the storage and accountability of equipment removed from an aircraft.
Safety issue description: The design of the horizontal stabiliser bungs did not consider aspects that would ensure the identification of an installed bung, or the safe operation of the aircraft if the bungs were not removed prior to flight.
Safety recommendation description: The Australian Transport Safety Bureau recommends that Regional Express Pty Ltd further reviews the horizontal stabiliser bungs design and pre-flight procedures to ensure that installed bungs are readily identifiable and will not adversely affect the continued safe operation of the aircraft if not removed prior to flight.
Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to the following directly involved parties:
the flight crew of VH-ZLJ
Regional Express Pty Ltd
Aus Flight Handling
Saab Aircraft Co
Swedish Accident Investigation Authority
Civil Aviation Safety Authority.
A submission was received from:
Regional Express Pty Ltd
The submission was 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
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.
[1] The flight was operated under Civil Aviation Safety Regulations Part 121 (Air transport operations - larger aeroplanes).
[2] The roles and responsibilities of each crew member when completing the required daily internal and external inspections were defined in the flight crew operating manual.
[3] The portable air conditioner was an item of ground service equipment used to provide cool air to the cabin of the aircraft before engine start.
[4] Summer months was defined in the Rex airport services manual as the period between November and March.
Occurrence summary
Investigation number
AO-2022-058
Occurrence date
16/11/2022
Location
Cairns Aerodrome
State
Queensland
Report release date
26/10/2023
Report status
Final
Investigation level
Defined
Investigation type
Occurrence Investigation
Investigation status
Completed
Mode of transport
Aviation
Aviation occurrence category
Aircraft preparation
Occurrence class
Incident
Highest injury level
None
Aircraft details
Manufacturer
Saab Aircraft Co.
Model
340B
Registration
VH-ZLJ
Serial number
340B380
Aircraft operator
REGIONAL EXPRESS PTY LIMITED
Sector
Turboprop
Operation type
Part 121 Air transport operations - larger aeroplanes
System safety in focus following Devonport cement train runaway and derailment
Key points
At the conclusion of the investigation into a runaway and derailment in Devonport, Tasmania, the ATSB is strongly advising operators and developers of complex rail systems to apply system safety methodologies so that they can have a high level of confidence in the overall safety of the system
Final report details more than a dozen safety actions taken to address ATSB findings.
The Australian Transport Safety Bureau has released a final report detailing more than a dozen safety actions which address findings from its investigation into the runaway and derailment of a cement train in Devonport, Tasmania.
On 21 September 2018, a driver was using remote control equipment to position a TasRail train for cement loading at a siding in Railton, south of Devonport, when the train stopped responding to commands.
After a series of uncommanded emergency brake applications and releases, the train began to roll away with no-one on board.
This began a 23-minute runaway, through ten active and three passive public level crossings, beneath a highway overpass, and through five sets of points, mostly at speeds greater than the maximum track speed.
TasRail’s network control diverted the train away from public areas to a siding in Devonport Yard, where it collided with a concrete footing and surrounding fences. Fence debris struck two pedestrians nearby, resulting in minor injuries to both. Nobody else was injured.
ATSB Chief Commissioner Angus Mitchell praised the actions of TasRail network control and other staff, as well as the prompt response by Tasmania Police to keep key level crossings clear as the train passed.
The subsequent ATSB investigation found 11 contributing factors for the accident, and highlighted ten distinct safety issues (ongoing safety concerns).
“Throughout this complex and in-depth investigation, the ATSB has worked with various stakeholders and encouraged them to take safety actions aimed to ensure this type of accident does not occur again,” Mr Mitchell said.
“Pleasingly, the final report details more than a dozen safety actions taken to address these issues, by the operator TasRail, the remote control equipment
manufacturer, the rail standards board, and the regulator. All the identified safety issues either have been addressed, or are being addressed.”
Among other actions, TasRail has installed catch points at Railton to prevent uncontrolled train movements from reaching the main line, and has improved its emergency response procedures.
The ATSB found the remote control system, which is no longer in use, had several safety-related design and integration problems that were readily identifiable.
Accordingly, the ATSB’s final report emphasises the need for organisations involved in the development or operation of systems that are performing safety-critical functions to follow ‘system safety’ methodologies.
“These are techniques that can be applied throughout the design and operation of complex systems to prevent the systems from behaving in undesired ways,” Mr Mitchell said.
“Since the remote control system was designed, there have been substantial improvements in the quality and availability of systems safety guidance for complex rail systems in Australia.
“However, it is important this accident serves as a reminder for a heightened focus on systems safety from all transport operators and manufacturers, into the future.”
The report specifically notes new standards, guidance, and fact sheets published by the Rail Industry Safety and Standards Board (RISSB) in recent years, to assist rail transport operators in systems safety, systems engineering and change management.
The report also notes the Office of the National Rail Safety Regulator (ONRSR)’s enhanced focus on the importance of a system engineering approach, including a safety message published in March 2019, and two related fact sheets released in 2020, emphasising the need for a systems engineering approach in rail projects.
“The ATSB strongly advises operators and developers of complex rail systems to follow this guidance, so that they can have a high level of confidence in the overall safety of the system,” Mr Mitchell said.
This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.
The occurrence
On 14 November 2022, a Robinson Helicopter Company R22 Beta, registered VH-LOS, was being operated near the Arafura Swamp, approximately 30 km south of Ramingining Aerodrome (YRNG), Northern Territory (Figure 1). The helicopter was being used as part of an animal mustering operation, which also included multiple land vehicles.
Figure 1: Map showing location of Ramingining and accident site of VH-LOS
Source: Google Earth, annotated by the ATSB
At approximately 1800 local time, the mustering operation concluded for the day. While the land vehicles departed the swamp and headed to a camp location approximately 20 km to the west, the pilot of VH-LOS remained at the swamp with the helicopter. A witness recalled that they expected the pilot to depart the swamp soon after the land vehicles left. The pilot was expected to collect another member of the mustering operations from a location near the swamp, before returning to the mustering camp.
Meanwhile, the mustering group member who planned to meet the helicopter travelled from the swamp towards the planned meeting point, which was south of the swamp. They recalled it took about 30 minutes to reach the planned meeting point. They waited for about 10 minutes, before deciding to return to camp in their land vehicle when the helicopter did not arrive.
Figure 2: Map of Arafura Swamp and key locations, and track of VH-LOS
The yellow track shows the flight departing from Arafura Swamp at 1803 and landing south of the swamp at 1812. The red track shows the flight from the edge of the swamp to the mustering camp departing at 1837 and landing at 1854.
Source: Tracplus and Google Earth, annotated by the ATSB
When the land-based vehicles arrived at the camp, the helicopter was not there. Members of the mustering operation became increasingly concerned and commenced a land-based search at approximately 2100.
The following day, members of the mustering operation contacted some acquaintances who attended the area in helicopters and commenced an aerial search. The helicopter wreckage was located approximately 6 km from the mustering camp. The pilot was deceased, and the helicopter was destroyed.
The pilot held a Commercial Pilot Licence (Helicopter) and a valid Class 1 Aviation Medical Certificate. The pilot did not hold an instrument rating or a night visual flight rules rating. The pilot’s logbook recorded over 6,000 hours total aviation experience.
Aircraft information
VH-LOS was a 2-seat Robinson Helicopter Company R22 Beta helicopter, serial number 1715, powered by a Textron Lycoming, O-320-B2C, 4-cylinder piston engine. It was manufactured in the United States in 1991, and first registered in Australia in January 1995. The helicopter was not equipped for night flight under the visual flight rules.
Weather and environment
Witnesses involved in the mustering operations at the Arafura Swamp on the afternoon of 14 November recalled that conditions were clear. They reported that there was thunderstorm activity to east of where the group were operating, however no storms passed overhead. An analysis prepared by the Bureau of Meteorology also identified a thunderstorm to the east of the accident site, moving westward during the evening.
Sunset at Ramingining on 14 November 2022 was 1905 and the end of civil twilight (last light)[1] was 1927. Civil nautical twilight[2] was 1953 and astronomical twilight[3] was 2020. The moon was a waning gibbous, rising at 2337 with about 71.3% of the visible disk illuminated.
Site and wreckage
Examination of the wreckage indicated that VH-LOS collided with terrain at approximately 45° nose-down pitch and 30° left angle of bank. There was a short wreckage trail of about 13 m, with all helicopter parts present at the accident site and no evidence of an in-flight break-up. One main rotor blade was liberated in the collision and was found about 30 m to the right of the wreckage trail.
The tail cone and tail rotor assembly remained connected to the fuselage, however presented as deflected down and curled under the helicopter. Site examination showed that both fuel tanks remained intact and contained fuel. Damage signatures to engine rotating components indicated that the engine was operating prior to the collision with terrain. There was no post-impact fire.
Recorded data
The helicopter was fitted with an aircraft tracking unit, which recorded and transmitted the position of the aircraft to a server. The ATSB obtained records showing the recorded tracks of VH-LOS on the afternoon of 14 November, and on other dates prior to the accident. The final recorded position of the helicopter was at the mustering camp, and the aircraft tracking unit did not record the position of the helicopter prior to it colliding with the terrain at the accident site.
The ATSB recovered a handheld GPS unit from the wreckage. Preliminary analysis indicated this unit did not capture the flight on the afternoon of 14 November.
The aircraft was not fitted with a flight data recorder or cockpit voice recorder, nor was it required to be.
The investigation is continuing and will include further review and examination of:
pilot records and medical information
aircraft maintenance and flight records
aircraft wreckage
witness information
meteorological data
recorded aircraft tracking data.
Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken.
A final report will be released at the conclusion of the investigation.
Acknowledgement
The ATSB wishes to acknowledge the support provided by the Northern Territory Police Force during the ATSB deployment to the accident site. The accident site was in a very remote location and the Northern Territory Police Force provided substantial logistical support to facilitate ATSB access to the accident site and the activities at the site.
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
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.
[1] Geoscience Australia (GA) defined the ending of civil twilight as the instant in the evening when the centre of the sun is at a depression angle of 6° below an ideal horizon. At this time in the absence of moonlight, artificial lighting or adverse atmospheric conditions, the illumination is such that large objects may be seen but no detail is discernible.
[2] GA defined the ending of evening nautical twilight as the instant in the evening when the centre of the sun is at a depression angle of 12° below an ideal horizon. At this time in the absence of moonlight, artificial lighting or adverse atmospheric conditions, it is dark for normal practical purposes.
[3] GA defined the ending of astronomical twilight as the instant in the evening when the centre of the sun is at a depression angle of 18° below an ideal horizon. At this time the illumination due to scattered light from the sun is less than that from starlight and other natural light sources in the sky.
On the afternoon of 14 November 2022, a Robinson Helicopter R22 Beta, registered VH-LOS, was being operated near the Arafura Swamp, Northern Territory. The helicopter was being used as part of an animal mustering operation, which also included multiple land vehicles.
After the mustering operation had concluded for the day, recorded data indicated that the helicopter returned to the mustering camp. When members of the mustering operation returned to the camp, the pilot and the helicopter were not there. Realising that the pilot was missing and becoming increasingly concerned about the pilot’s welfare, the mustering group commenced a search using land vehicles.
On the morning of 15 November members of the mustering operation organised an aerial search. The wreckage of VH-LOS was located at about 1300, about 6 km from the mustering camp. The pilot was deceased, and the helicopter was destroyed.
What the ATSB found
The ATSB found that the pilot of VH-LOS operated the helicopter after the end of nautical twilight in cloudy conditions and away from the direction of sunset. There was no celestial or terrestrial lighting, and as such the flight occurred in dark night conditions. The pilot did not have an appropriate qualification, and the helicopter was not suitably equipped, for night flight. While flying in dark night conditions, the pilot likely became spatially disoriented which led to a collision with terrain.
A pathologist’s report found that the injuries sustained by the pilot in the collision were probably not fatal, and that the pilot probably succumbed to environmental exposure. VH-LOS was equipped with a manually activated personal locator beacon. However, the beacon was secured to the inside of the helicopter, and the pilot was probably unable to access it once outside the helicopter after the collision.
When members of the mustering operation identified that the pilot and the helicopter were missing, they considered that the pilot may have landed and would either return the following day, or would be waiting nearby. As a result, they did not contact emergency services. In combination with the absence of a distress signal from the personal locator beacon, this led to delays in initiating a formal search and rescue response and subsequent location of the accident site.
The ATSB found that the combination of the personal locator beacon not being activated and authorities not being notified when the aircraft was missing resulted in a delay to the pilot being located before succumbing to environmental exposure after sustaining survivable injuries in the accident.
Safety message
Various ATSB research and investigation reports refer to the dangers of flying after last light without the appropriate qualifications and equipment. Day visual flight rules (VFR) pilots should carefully consider the timing of last light when planning flight near the end of the day. The Civil Aviation Safety Authority Visual Flight Rules Guide provides guidance to pilots on methods for determining the timing of last light, and pilots should also consider the influence of nearby weather that may cause the onset of darkness to be earlier than expected. The requirement to only operate under the VFR in daylight conditions, and to return 10 minutes before last light, provides a reliable method for ensuring visual cues are available for safely operating an aircraft.
Dark night conditions provide no useable external visual cues and in these environments all VFR pilots, including those with endorsement to operate under the night VFR, will experience an increased risk of spatial disorientation. The ATSB’s Avoidable Accidents publication Visual flight at night accidentsprovides further discussion of these risks and how they have contributed to other accidents. The ATSB encourages all VFR pilots to take note of the tragic consequences associated with dark night flight in this accident.
The accident also highlights that when operating in remote locations, there is an increased risk of fatal consequences from otherwise survivable accidents. Pilots operating in remote locations should carefully consider the use and location of equipment such as a personal locator beacon, to maximise the likelihood it will be accessible to them in the event of an accident. The Visual Flight Rules Guide provides guidance on the use of emergency locator beacons.
Figure 1: Map of the Northern Territory showing the location of the accident site and nearby locations
Source: Google Earth, locations labelled by ATSB
At about 1800 local time, the mustering operation concluded for the day. The pilot of VH-LOS instructed a member of the mustering group to drive a grader vehicle to the southern edge of the swamp. The pilot planned to collect the grader driver and fly them back to the mustering camp, located about 20 km to the west.
Other members of the mustering operation departed the swamp in land vehicles, heading towards the camp. A witness recalled that VH-LOS was on the ground when the group departed, and they expected the pilot would depart soon after they left.
Figure 2: Map of Arafura Swamp and key locations, and track of VH-LOS
The yellow track shows the flight departing from Arafura Swamp at 1803 and shutting down south of the swamp at 1818. The red track shows the flight from the edge of the swamp to the mustering camp departing at 1837 and landing at 1854.
Source: Google Earth, with aircraft tracking plots overlayed by ATSB based on records obtained from recorder onboard VH-LOS
The grader driver travelled from the swamp towards the planned meeting point, which took about 30 minutes. They waited for about 10 minutes before deciding to return to camp on the grader when the helicopter did not arrive. The grader did not have a radio capable of communicating with the helicopter.
The other members of the mustering operation arrived back at the camp and noticed that neither the helicopter pilot nor the grader driver were there. One witness recalled it took about an hour to return to camp, and that the group arrived when it was close to dark, but not ‘pitch black’. Another group member recalled that they arrived after dark, at about 1945 to 2000.
The grader driver arrived at the camp at about 2100. Members of the mustering operation became increasingly concerned about the wellbeing of the helicopter pilot and commenced a search using land vehicles from about 2100 until 0100 on 15 November.
The mustering group members then contacted some acquaintances who attended the area in helicopters and commenced an aerial search from about 1100. The helicopter wreckage was located at about 1300, about 6 km from the mustering camp. The pilot was deceased, and was found outside and resting against the helicopter. The helicopter was destroyed.
The pilot held a Commercial Pilot Licence (Helicopter) and a valid Class 1 aviation medical certificate. The pilot also held a single engine helicopter rating, and a low level rating with aerial mustering (helicopter) and sling endorsements. The pilot did not hold an instrument rating or a night visual flight rules (VFR) rating.
The pilot’s logbook recorded over 6,200 hours total aviation experience, however no records had been made of flights conducted after March 2022.
Events prior to the accident
The pilot flew VH-LOS to Ramingining on 10 November 2022 and operated around the Arafura Swamp in the days prior to the accident. Aircraft tracking records showed that the helicopter was operated until 1859 on 11 November and until 1931 on 12 November. It is likely that these flights were conducted near or after the end of civil twilight (see Celestial illumination information).
Post-mortem examination and medical information
A post-mortem examination of the pilot was conducted by a qualified pathologist, on behalf of the Northern Territory Coroner. The pathologist’s report indicated that their examination was impeded due to the elapsed time between the accident and the recovery of the pilot’s body to a suitable mortuary facility. Only limited toxicology analysis could be performed, and although a high concentration of alcohol was detected the analysis could not determine if some or all of the measured alcohol (0.18%) was the result of post-mortem changes.
The pathologist’s report identified that the pilot sustained multiple injuries, including a fracture to the left femur, however the injuries were likely survivable. The report found that death was most likely the result of environmental exposure following the collision, with the left femur fracture contributing to reduced mobility.
The pathologist also observed no obvious evidence of injury consistent with being caused by a harness or seatbelt.
Witnesses recalled that the pilot was fit and healthy prior to the accident, and there were no indications that the pilot was experiencing any unusual stress. No witnesses recalled the pilot consuming alcohol or other drugs in the days before the accident.
Aircraft information
VH-LOS was a Robinson Helicopter Company R22 Beta helicopter, serial number 1715, powered by a Textron Lycoming, O-320-B2C, 4-cylinder piston engine. It was manufactured in the United States in 1991, and first registered in Australia in January 1995, and was equipped and maintained to a day VFR standard. The R22 has 2 seats, with the pilot flying from the right seat, and each seat was fitted with a seat belt and inertia reel shoulder strap, similar to those used in motor vehicles. VH-LOS did not have doors fitted at the time of the accident.
VH-LOS was not fitted with a flight data recorder or cockpit voice recorder, nor was it required to be.
The operator of VH-LOS tracked the aircraft using a system configured for the TracPlus tracking service. The system consisted of a RockAir device located in the helicopter, which was capable of transmitting the aircraft location using satellite and cellular networks. Registered users could log into the TracPlus website to view the aircraft track and position.
At the accident site, the ATSB found the RockAir unit outside the helicopter. A data card recovered from inside the unit included records showing the recorded tracks of VH-LOS on the afternoon of 14 November, as well as log files for the RockAir system. The files showed the final recorded position of VH-LOS was at the mustering camp location at 1925.
The manufacturer of the RockAir reviewed the log file from the day of the accident and noted the following:
The pilot of VH-LOS did not manually deactivate the aircraft tracker.
The RockAir was performing normally on the day of the accident.
The device was in a mode where it would deactivate if external power was removed, unless it detected the aircraft was moving above a speed threshold.
The RockAir automatically deactivated at 1925 when the device lost power.
There were 36 other instances on the day of the accident where the device lost power for 2-5 seconds, however the unit reverted to battery power because the aircraft was moving.
It was not possible to determine the reason for the power supply interruptions, with mechanical movement of the power supply being a possibility.
Weather and environment
Weather
Members of the mustering operation recalled that conditions were fine while they were operating around the Arafura Swamp on the afternoon of 14 November, with no storms overhead. The grader driver recalled conditions as being cloudy, and that it was dark that night.
An analysis prepared by the Bureau of Meteorology (BOM) identified a thunderstorm to the east of the accident site at about 1730, which moved west during the evening. The analysis stated that outflow from the thunderstorm could have produced variable direction winds with gusts up to 35 kt. Near the thunderstorm, heavy rainfall with reduced visibility and broken low cloud were possible.
BOM also supplied observations for the evening of 14 November and the morning and afternoon of 15 November, at Milingimbi (about 60 km north of the accident site) and Bulman (about 130 km south-west of the accident site). BOM advised that these observations should be used as an estimate only for conditions at the accident site. These observations showed it was a hot and humid night in north-east Arnhem land, with temperatures from 27 to 33°C and humidity of 35 to 90% recorded.
Conditions became hotter and less humid during the day on 15 November. At 1300, when the helicopter wreckage and pilot were found, Milingimbi and Bulman recorded 33°C and 55-60% humidity. Witnesses recalled that conditions that day were hot.
Sunset at the location of the mustering camp on 14 November 2022 was 1835 and the end of civil twilight (last light)[1] was 1858. Nautical twilight[2] was 1924 and astronomical twilight[3] was 1951.
The moon was a waning gibbous, rising at 2337 on 14 November with about 71.3% of the visible disk illuminated. There was no environmental lighting in the vicinity of the accident site.
Accident site and wreckage information
The accident site was located 6 km east of the mustering camp, in a flat clearing scatted with small trees and anthills. There were no sources of terrestrial light. None of the trees had damage consistent with a helicopter rotor strike, and there was no evidence of a bird strike or indications of a post-impact fire.
The helicopter was found on its left side, with significant compression of the nose and underside of the forward left section of the fuselage (Figure 3). The compression damage indicated that the helicopter collided with terrain at about 45° nose-down, and 30° left side low. There was a short wreckage trail extending about 13 m, with all helicopter parts present at the accident site and no evidence of an in-flight break-up.
Indentations on the terrain nearby indicated a main impact point about 6 m aft and 4 m right of where the helicopter was found. Anthills forward of the main impact point showed damage consistent with having been struck by the rotor blades, and both rotor blades presented with evidence of ground strikes. One main rotor blade was liberated as the result of a ground strike, and was found about 30 m to the right of the wreckage trail. The cockpit windscreen had shattered and remnants were scattered around the accident site along with the contents of the aircraft.
The tail cone and tail rotor assembly remained connected to the fuselage, however presented as deflected down and curled under the helicopter. Site examination showed that both of the bladder-type fuel tanks remained intact and contained fuel. Examination of the helicopter’s flight control system and drive train did not indicate any pre-existing defects that could have affected the control or function of the helicopter. Damage signatures to engine rotating components indicated that the engine was operating at the time of the collision with terrain.
The pilot was found in a reclined position on the north-western side of the aircraft (next to the right helicopter seat), with their head rested against the helicopter. There was a large water bottle on the ground nearby. The screw-cap lid had been removed and the drinking spout exposed, suggesting it was likely the pilot was capable of opening and drinking from the water bottle after the accident.
Helicopter restraints
Both helicopter seatbelts were found to be buckled. The lap belt was in its normal secured position at the base of the seat, while the shoulder belt (which connected from the top right to the lower left), was pulled behind the seat base.
The seatbelt assembly had three anchor points, with the two lower anchor points connected to the pilot’s seat frame. The pilot’s seatbelt was found to be secured to its anchor points. The pilot’s seat had been significantly disrupted, pulled in the direction of impact away from the helicopter structure. The separation of the seat structure was very likely a result of the forces generated by the pilot restrained by the seat belt and being propelled in the direction of impact.
Regulatory information and guidance
Visual flight rules
Flight under the VFR must be conducted in conditions that enable the pilot to determine the aircraft’s position by visual features in the external environment. VFR flights are only permitted at night if:
the pilot in command is authorised to conduct a flight under the instrument flight rules or at night under the VFR, and
the aircraft is appropriately equipped for flight at night.
The CASA VFR guide stated that ‘night is that period between the end of evening civil twilight and the beginning of morning civil twilight... last light (is) the end of civil twilight’. The guide further stated that cloud cover or poor visibility may cause daylight to end at a time earlier than the forecast time, and allowance should be made for these factors when planning a flight near last light.
Civil Aviation Order 20.18 described the requirements for helicopters operating under the instrument flight rules (IFR) or at night under the VFR. Among other requirements, for a helicopter operating at night where attitude cannot be maintained using visual external surface cues, the helicopter must also either equipped for IFR flight with an autopilot or automatic stabilisation system, or be operated by a qualified 2 pilot crew. VH-LOS was not equipped for night flight under the VFR.
A member of the mustering operation who had flown with the pilot did not recall the pilot using procedures or routines for determining a ‘last flight’ time to avoid flying in the dark. They recalled that the pilot had emphasised the importance of having a visible horizon while flying in near dark conditions, to provide a reference for the position of the terrain.
Additional guidance for night VFR flight in dark night conditions
Dark night conditions exist when there is little or no celestial illumination, in locations where no significant ground lighting is available.
The CASA advisory circular Night VFR rating provided guidance to pilots conducting operations under the night VFR (NVFR). This guidance highlighted that while suitably endorsed pilots may safely fly visually in night conditions where there is adequate celestial illumination or other sources of light, visual flight is significantly more hazardous in dark night conditions.
There may be times when there is bright moonlight or extensive ground lighting available, making a night operation only a little more difficult than flying in daylight. However, there may be dark night conditions (i.e. without moonlight or significant ground lighting) that can make it very difficult to discern the natural horizon and maintain control of the aircraft by reference to external visual references.
The absence of a visible horizon during dark night conditions is a particular hazard. As highlighted by Gibb and others (2010), seeing a horizon is ‘crucial for orientation of the pilot’s sense of pitch and bank of the aircraft’. The Night VFR rating advisory circular identified this risk, noting:
CASA strongly recommends that NVFR operations take place only in conditions that allow the pilot to discern a natural visual horizon or where the external environment has sufficient cues for the pilot to continually determine the pitch and roll attitude of the aircraft.
The ATSB’s Avoidable Accidents publication Visual flight at night accidentsidentified that of 26 accidents during night visual meteorological conditions (VMC),[4] almost all occurred on dark nights. Visual flight at night accidents highlighted that:
When flying over land or oceans without light sources, on dark nights with no visible moon, visual flight at night is essentially the same as instrument flight.
Requirements for emergency locator transmitters
An emergency locator transmitter (ELT) is designed to send a distress signal to a network of satellites in an emergency. The Civil Aviation Safety Regulations Part 91 (General Operating and Flight Rules) Manual of Standards (MOS) required aircraft to be fitted with an ELT. For flights such as that conducted by VH-LOS, aircraft may be equipped with an automatic ELT, which is fixed to the aircraft and designed to automatically activate in the event of a severe impact (g) forces. Alternatively, the ELT can be a manually activated and removable survival ELT, also referred to as personal locator beacons (PLB). The MOS required that if an ELT is a PLB, the pilot in command must ensure it is carried either on their person, in or adjacent to a life raft, or adjacent to an emergency exit.
VH-LOS was equipped with an ACR ResQLink 400 PLB. To activate the ResQLink, the user needed to first lift the antenna and expose the on/off button, then press the on/off button for 2 seconds.
The ATSB observed that the PLB remained inside the helicopter post-accident, and was attached to the helicopter's centre console. There was no apparent damage to the unit, and the battery was in-date. The antenna was in the folded-down position with the on/off button covered. There was not evidence that the pilot had attempted to operate the PLB after the accident.
Figure 4: ResQLink activation instructions (left) and condition in-situ at VH-LOS accident site (right). The image on the right shows the antenna and power button guard remained in the down position
Requirements for search and rescue notification
The Part 91 MOS required that for VFR flights conducted in a designated remote area, the pilot must submit a flight plan, nominate a SARTIME (search and rescue time) for arrival, or leave a flight note with a responsible person. The Airservices Australia publication En Route Supplement Australia showed designated remote areas within Australia. The Arafura Swamp, the accident site, and all other areas the helicopter was operating in in the days prior to the accident were within a designated remote area.
The Part 91 MOS described the requirements of the holder of a flight note, including that they must immediately contact the Joint Response Coordination Centre (JRCC) if the flight becomes overdue.
The pilot of VH-LOS did not leave a formal flight note, however, it was understood the pilot would meet the grader driver at a particular location. When the helicopter did not meet the grader driver or return to the camp on the evening of 14 November, it was understood by the members of the mustering operation that the pilot was overdue. However, they did not contact any authority that night. The first call to emergency services (a 000 call) was made after the helicopter wreckage had been found on the afternoon of 15 November.
One member of the mustering operation recalled that it was not uncommon for the pilot of VH-LOS to arrive later than expected, as the pilot sometimes conducted additional unplanned flights. They also recalled that there had been occasions that the pilot had landed in an out-location and not returned until the following day.
When the helicopter did not return as expected on 14 November, members of the mustering group considered the possibility that the pilot had landed and were hopeful of the pilot returning the following day. They also considered the possibility that the pilot encountered problems and landed, and would be waiting to be found by road vehicles. In this context, members of the mustering group reported that they did not become highly concerned about the pilot until the morning of 15 November.
Related occurrences
Since the 2013 publication of Visual flight at night accidents, the ATSB has investigated multiple fatal accidents involving light helicopter pilots operating on dark nights in areas that did not contain any local ground lighting. Examples include:
AO-2014-144: The ATSB found that the pilot, who did not hold a night VFR rating or instrument rating, continued flying towards the destination after last light (end of civil twilight), then in dark night conditions without local ground lighting, inadvertently allowed the helicopter to descend into terrain.
AO-2016-031: The ATSB found that the pilot, who was only qualified to operate in day-VFR conditions, departed on a night flight and continued towards the destination in deteriorating visibility until inadvertently allowing the helicopter to descend into water.
AO-2021-006: The ATSB found that the pilot, who did not hold a night VFR rating or instrument rating, continued flying towards their destination after last light, through the period of civil twilight and into astronomical twilight. In dark night conditions without local ground lighting the pilot inadvertently allowed the helicopter to descend into terrain.
The helicopter collided with terrain sometime after 1925 on 14 November 2022. There was no indication of any mechanical problem contributing to the collision with terrain, the helicopter had sufficient fuel on board, and there was no evidence of collision with a bird or another objects. A post-mortem examination indicated the pilot probably survived the accident, and there was no evidence of medical factors that would have resulted in the pilot becoming suddenly incapacitated.
Although the timing of the accident could not be precisely determined, aircraft tracking records indicate that the accident flight took place after nautical twilight. The pilot did not have a rating to fly at night under the VFR. VH-LOS was not equipped for flight by reference to the aircraft instruments, and the pilot did not have a rating for flight under the instrument flight rules.
The accident occurred in an extremely remote location with no nearby terrestrial lighting. On the evening of the accident, the moon rose late and provided no illumination for the accident flight. Depending on how long the aircraft flew prior to the collision with terrain, conditions would have become darker later in the evening, and cloudy conditions associated with a westerly-moving storm system may have further reduced visibility. Considering the last recorded position of the aircraft and the accident location, it is likely that the accident flight was in an easterly direction, meaning sunset was behind the direction of travel. As such, the ATSB concluded that the accident flight was conducted in dark night conditions due to the absence of both celestial and terrestrial lighting.
Spatial disorientation describes the phenomenon of a pilot becoming unable to correctly perceive the position, movement and orientation of their aircraft. When flying under the VFR, pilots rely on external visual cues to maintain spatial awareness, including the orientation of the aircraft (which way is up), and the proximity to terrain. In dark night conditions, when there is no celestial illumination and no nearby terrestrial lighting, there are no external visual cues available to pilots. In such circumstances, spatial disorientation is highly likely unless pilots have access to and utilise aircraft instrumentation. This risk was highlighted in Visual flight at night accidents:
In very dark environments, VMC is essentially the same as IMC[5] in terms of available external visual information. The only real difference is that lights on the ground may be seen in VMC. In remote areas where there are no lights or ambient illumination, there is essentially no difference. Pilots cannot see the ground and have no external visual cues available to assist with their orientation.
The decision by the day VFR qualified pilot to operate a helicopter which was not equipped for night flight after last light was inherently unsafe and increased the risk of unintentional collision with terrain. The dark night conditions on the night of the accident meant that regardless of the pilot’s ability to fly using external visual cues at night, there were none. In these conditions, the pilot likely became spatially disoriented, and unintentionally allowed the helicopter to descend into the terrain.
The significant nose-down and left-side down attitude of the aircraft wreckage, and the short wreckage trail, were consistent with the pilot flying at slow speed and developing an unusual aircraft attitude in the moments prior to collision. The wreckage, being only 6 km from the last known position of the helicopter, indicates that the disorientation and collision occurred soon after the commencement of the flight in dark night conditions.
Survivability
The post-mortem examination identified that the pilot was probably not fatally injured by the collision with terrain. The damage to the helicopter seat indicated that the pilot was at least partially restrained by the seatbelt during the collision. However, considering to the absence of observed bruising associated with a seatbelt, it is possible that the pilot was either only partially restrained (by the lap belt only), or slipped out of the seatbelt in the collision. The direction of impact (lower left) and shoulder belt orientation (top right to lower left), are consistent with the latter explanation. After the collision, it is likely the pilot manoeuvred out of the buckled restraint, outside of the damaged helicopter which was laying on its side. With injuries reducing the pilot’s mobility, the pilot likely planned to wait for rescue.
The post-mortem report further identified it was likely that the pilot succumbed to environmental exposure. There were up to 17.5 hours from when the helicopter collided with terrain and when the pilot was found deceased the following day. Although the pilot likely had a water bottle available and was shaded by the helicopter on the morning of 15 November, conditions were hot and humid. Therefore, this analysis examined the safety systems that could have led to the earlier recovery of the pilot.
Personal locator beacon
The mandatory carriage of emergency locating equipment is a risk control used to facilitate the prompt identification of aircraft accidents, and the timely and accurate response by emergency services. VH-LOS was equipped with a manually-activated PLB, however the pilot did not activate this beacon following the accident. Had the pilot activated the PLB, it is almost certain that a search and rescue response would have located the aircraft, increasing the likelihood the pilot would have survived the accident.
To ensure the PLB is accessible after a collision, regulations require the PLB is carried on the person of the flight crew or adjacent to an emergency exit. The PLB carried in VH-LOS was secured to the centre console, which, in a small helicopter such as a Robinson R22, is nearby the aircraft exits and the pilot’s seated position.
When the helicopter collided with terrain, conditions were dark and the pilot may not have been able to locate the PLB. Once outside the helicopter, in poor visibility and with limited mobility (due to the significant leg injury), the location of the PLB inside the helicopter was effectively inaccessible to the pilot. This highlights the advantage of carrying a PLB on the person of pilots, particularly in one-person operations.
VH-LOS was not equipped with an automatically activated ELT. As in this accident, manually activated PLBs may not be effective in situations where a pilot survives an accident but is incapacitated or is otherwise unable to access the PLB. An automatic ELT will provide another opportunity to alert search and rescue authorities in these situations.
Notification to emergency services
Regulations within the aviation industry require pilots to notify responsible persons of the details of flights, including a planned departure and landing time. The requirements then follow that the Joint Response Coordination Centre (JRCC) should be notified of a potentially missing aircraft, so that a search and rescue response should be initiated.
In this instance, members of the mustering operation at Ramingining became increasingly concerned about the wellbeing of the pilot during the night of 14 November. They conducted a land-based search on the night of 14 November, hoping that the pilot had landed and could be seen from the road. Becoming significantly concerned on 15 November, they requested some acquaintances to conduct an aerial search, which led to the identification of the deceased pilot. Throughout this time, no calls were made to appropriate authorities.
When the pilot was first identified as missing, the level of concern and the perceived urgency of the situation was influenced by previous experiences where the pilot had returned much later than expected. The mustering operations, being conducted in an extremely remote environment, involved a necessity to frequently resolve problems without the assistance of formal authorities. Furthermore, the members of the mustering operation (other than the pilot) had limited engagement with aviation systems and regulation.
While noting the circumstances which contributed to emergency services not been immediately notified in this instance, a prompt formal notification of a missing aircraft is the most effective action personnel on the ground can take. Emergency calls will result in the JRCC being notified, and the JRCC are capable of deploying very capable assets for finding a missing aircraft with minimal delay or at first light the next day.
Findings
ATSB investigation report findings focus on safety factors (that is, events and conditions that increase risk). Safety factors include ‘contributing factors’ and ‘other factors that increased risk’ (that is, factors that did not meet the definition of a contributing factor for this occurrence but were still considered important to include in the report for the purpose of increasing awareness and enhancing safety). In addition ‘other findings’ may be included to provide important information about topics other than safety factors.
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
From the evidence available, the following findings are made with respect to the collision with terrain involving Robinson R22 Beta, VH-LOS, near Ramingining, NT on 14 November 2022.
The pilot did not activate the personal locator beacon, which was probably inaccessible to the pilot once they left the helicopter after the accident. In addition, authorities were not notified when the aircraft was missing. In combination, this resulted in a delay to the pilot being located before succumbing to environmental exposure after sustaining survivable injuries in the accident.
Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to the following directly involved parties:
the aircraft owner and operator
the aircraft manufacturer
the aircraft tracking device manufacturer
the aircraft tracking service provider
No submissions were received.
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
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
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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.
[1] Geoscience Australia (GA) defined the ending of civil twilight as the instant in the evening when the centre of the sun is at a depression angle of 6° below an ideal horizon. At this time in the absence of moonlight, artificial lighting or adverse atmospheric conditions, the illumination is such that large objects may be seen but no detail is discernible.
[2] GA defined the ending of evening nautical twilight as the instant in the evening when the centre of the sun is at a depression angle of 12° below an ideal horizon. At this time in the absence of moonlight, artificial lighting or adverse atmospheric conditions, it is dark for normal practical purposes.
[3] GA defined the ending of astronomical twilight as the instant in the evening when the centre of the sun is at a depression angle of 18° below an ideal horizon. At this time the illumination due to scattered light from the sun is less than that from starlight and other natural light sources in the sky.
[4] Visual Meteorological Conditions (VMC): an aviation flight category in which visual flight rules (VFR) flight is permitted – that is, conditions in which pilots have sufficient visibility to fly the aircraft while maintaining visual separation from terrain and other aircraft.
[5] Instrument meteorological conditions (IMC): weather conditions that require pilots to fly primarily by reference to instruments, and therefore under instrument flight rules (IFR), rather than by outside visual reference. Typically, this means flying in cloud or limited visibility.
The Australian Transport Safety Bureau has released a preliminary report from its on-going investigation into a fatal helicopter accident near Maitland last month.
On 6 October 2022, the pilot and sole occupant of a single-engine, five-seat Bell 206 JetRanger was conducting a ferry flight from northern New South Wales to Warnervale, on the Central Coast.
About two and a half hours into the flight, the helicopter collided with terrain, coming to rest on a muddy river flat east of Maitland. The pilot was fatally injured and the helicopter was destroyed.
ATSB investigators attended the scene and conducted an initial assessment of the aircraft in situ, before it was moved to higher ground for further examination due to rising water levels.
“Today’s preliminary report details factual information established in the investigation’s early evidence collection phase,” ATSB Director Transport Safety Stuart Macleod said.
“It has been prepared to provide timely information to the industry and public, and contains no analysis or findings, which will be detailed in the final report.”
The preliminary report notes recorded data indicated the pilot was following the inland visual flight rules (VFR) lane west of Williamtown Airport when, approaching Tocal, the aircraft started to climb, and conducted a right 180‑degree turn.
“Data showed that over the next 20 minutes, the helicopter conducted a number of turns, a climb up to 3,100 ft, and a descent to around 120 ft above ground level, and exited and re-entered the VFR lane on a number of occasions,” Mr Macleod said.
“It was then observed by six witnesses, who reported it heading towards the Hunter River, descending slightly, and possibly initiating a turn when it rolled markedly and descended rapidly, colliding with the riverbank.”
ATSB investigators were able to account for all major aircraft components at the accident site, and examination of the aircraft’s flight controls, engine and structure did not identify any pre-existing defects.
Bureau of Meteorology data for Maitland Airport 15 minutes before the accident reported 8 kt of wind with scattered cloud at 4,000 ft and 4,500 ft, and overcast cloud at 7,800 ft above the airport.
“To date, the ATSB has assessed the wreckage, interviewed witnesses and collected external data sources related to weather, air traffic communications, and flight tracking,” Mr Macleod said.
“Moving forward, the investigation will include further review and examination of aircraft maintenance documentation and operational records, recorded data,
weather information, air traffic communications, and the pilot’s medical records, qualifications, and experience.”
A final report will be released at the conclusion of the investigation.
“However, should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” Mr Macleod concluded.
Fracture of the propeller bolts was likely related to a loss of bolt tension
Emergency training practice and recurrence increases the likelihood of pilots achieving a safe outcome
The incident highlights the importance of pilots remaining vigilant to transient or persistent changes to the normal operation of their aircraft.
The propeller of a Jabiru aircraft separated in-flight due to fractured propeller bolts likely due to a loss of bolt tension, an ATSB investigation has found.
A student pilot had departed on a training area solo flight in the Jabiru J170-C aircraft from Muchea Greenside airfield, north of Perth, on 22 December 2021. On return to the airfield, during the downwind leg of the circuit, the pilot commenced configuring the aircraft for landing when a vibration from the engine was felt.
The engine gauges read as normal and the vibration reduced with throttle reduction.
Shortly after, while on final approach, the pilot observed emus crossing the runway around the normal touchdown point and conducted a go-around. While on climb at around 800 feet, there was a loud ‘bang’ and the pilot observed that the propeller had separated from the aircraft.
The pilot elected to land ahead and conducted an uneventful forced landing in a paddock, approximately 2.5 km from the end of the runway. The aircraft suffered minor damage during the landing, and the pilot was uninjured.
“The ATSB’s investigation found that the propeller separated as a result of fracture of the propeller bolts that was likely related to a loss of bolt tension,” said ATSB Director Transport Safety Dr Stuart Godley.
“However, as the propeller was not able to be found, the mechanism for the loss of bolt tension was not determined.”
The investigation also noted that the student pilot’s actions were positively influenced by having recently undertaken several hours’ worth of flight emergency training, contributing to the safe outcome.
“When faced with an in-flight emergency, emergency training practice and recurrence will increase the likelihood of pilots achieving a safe outcome,” Dr Godley said.
The incident also highlights the importance of pilots remaining vigilant to transient or persistent changes to the normal operation of their aircraft, which may be indicative of an impending failure of a critical component or system.
“Landing as soon as practicable and having the aircraft inspected is a prudent course of action.”
Dr Godley noted that the ATSB did not typically investigate incidents and accidents involving recreational category aircraft. However, as Australia is the state of design and state of manufacture for the Jabiru aircraft, and the same aircraft model are registered with CASA and is also operated internationally, the ATSB conducted the investigation to determine if there were broader lessons for the aircraft type.
On 8 November 2022, a De Havilland Canada DHC-8-202 aircraft, registered VH‑TQS and operated by QantasLink, was conducting a passenger flight from Lord Howe Island to Sydney, New South Wales. During the descent, the flight crew noticed failures of the traffic alert and collision avoidance system, the ground proximity warning system as well as the radio altimeter.
During landing, the beta lockout system horn activated and then both engine manual warnings illuminated. With the engines in manual mode, the captain advanced the power levers to maintain the propeller speed above their restricted range. After stopping at a holding point about halfway through the taxi, the captain noticed a degradation in the braking performance. Braking performance continued to deteriorate as the aircraft was taxied and the brakes failed and ignited. The captain initiated an evacuation, during which no-one was injured.
What the ATSB found
The ATSB found that the failure of the radio altimeter led to the subsequent failures of the traffic alert and collision avoidance system and the ground proximity warning system, as these systems rely on data from the radio altimeter. The radio altimeter failure also resulted in the beta lockout system relying solely on the weight on wheels sensors. This meant that, when the weight on wheels indicated a momentary ‘in-air’ indication during landing, the beta lockout was triggered. The beta lockout activation resulted in a dual engine manual condition. With the engines in manual mode, the captain had to manually advance the power levers to avoid the ground operating restricted range of the propellers. This increased the amount of wheel braking required, combined with a long taxi of over 5 km, resulted in the brakes overheating, failing and igniting.
Operational guidance contained in the Quick Reference Handbook did not adequately inform the flight crew of the flow-on implication of the radio altimeter failure on the beta lockout system. Nor did it adequately provide guidance on responding to a dual engine manual condition.
Although not contributory, it was also found that the Bromo Chloro di-Fluoromethane (BCF) fire extinguisher was used on the high temperature brake fire, potentially increasing the risk of exposure to hazardous by-products.
What has been done as a result
QantasLink has advised they have made changes to both the DHC-8-200 Quick Reference Handbook and Flight Crew Operating Manual, including:
providing further information about the beta lockout system
new checklists for a radio altimeter failure and dual engine manual condition scenario.
The operator also published a technical advisory bulletin to DHC-8-200/300 flight crew outlining this event and learnings from this event.
Safety message
This occurrence highlights the importance of appropriate operational guidance, particularly in modern aircraft with complex integrated systems. Procedures for managing an equipment failure should consider factors that may influence the performance of other operational systems. In this occurrence, the flow-on effects of the radio altimeter failure on the beta lockout system. Fortunately, the flight crew were able to successfully troubleshoot the system errors and carry on the flight safely. Increased safety margins in procedural documentation can also help ensure flight crew make appropriate decisions when managing unexpected events. In this case, even a one second change in the timing of retarding the power levers could have prevented the occurrence.
The investigation
Decisions regarding the scope of an investigation are based on many factors, including the level of safety benefit likely to be obtained from an investigation and the associated resources required. For this occurrence, a limited-scope investigation was conducted in order to produce a short investigation report, and allow for greater industry awareness of findings that affect safety and potential learning opportunities.
The occurrence
Approach to Sydney
On 8 November 2022, a QantasLink De Havilland Canada DHC-8-202 aircraft, registered VH‑TQS departed Lord Howe Island on a scheduled passenger flight to Sydney, New South Wales with 3 crew and 23 passengers on board. The first officer (FO) was the pilot flying (PF)[1] and the captain was the pilot monitoring (PM).
At about 1658 local time, while descending through flight level (FL)[2] 175 on approach to Sydney (Figure 1), the flight crew were alerted to a failure of the traffic alert and collision avoidance system (TCAS)[3] as well as the ground proximity warning system (GPWS).[4] Shortly after, they noticed the radio altimeter (RadAlt) had also failed.
Figure 1: ADS-B[5] derived flight data showing the approximate location of the radio altimeter failure on approach to Sydney
Source: FlightRadar24 and Google Earth, annotated by the ATSB
The FO continued flying the aircraft while the captain consulted the Quick Reference Handbook (QRH) for the GPWS, TCAS and RadAlt failure procedures. The flight crew then informed air traffic control of the TCAS failure, and the FO continued with a visual approach to runway 34R[6] at Sydney.
Landing and taxi
After touching down, the FO retarded the power levers into beta range[7] to use the propellers to help slow the aircraft, as was standard procedure. When this happened, the beta lockout warning horn sounded. The power levers were brought forward to flight idle, which silenced the horn. Shortly after, the captain took over as PF as the aircraft’s nose-wheel steering tiller is located on the left (captain’s) side of the cockpit.
As they vacated the runway, the flight crew noticed that the GPWS and TCAS faults were resolved, but also identified that both the #1 and #2 engine manual caution lights were now illuminated, indicating that the electronic control units (ECU) of both engines were now in manual mode. The ECU normally controls the under-speed governing of the propellers during ground operations. However, when in manual mode, the power levers must be manually advanced by the flight crew to control the propeller speed and avoid the prohibited range[8] below 780 revolutions per minute (RPM). It also meant that reverse thrust would not be available to assist with slowing the aircraft during landing and the taxi.
As the captain advanced the power levers to maintain the propeller speed above 780 RPM, they noted that additional wheel braking was required to maintain a normal taxi speed. While the captain was taxiing the aircraft, the FO consulted the QRH checklist for the engine manual warnings, however, the checklist was prescribed for only a #1 or #2 engine manual caution light, not both simultaneously.
After about 3.3 km of taxiing, the aircraft reached the bravo 8 holding point (Figure 2). The captain brought the aircraft to a stop as air traffic control had instructed them to hold. While stopped, the flight crew contacted engineering support seeking advice on the dual engine manual condition. However, engineering was unable to provide advice within the available timeframe.
Once permitted, the taxi continued towards the domestic terminal. From this point, the taxi had a slight downhill slope and the captain started to notice the response from the brakes reducing. The braking performance continued to deteriorate, and during the final turn into the domestic 1A area (Figure 2), after about 5.5 km of taxiing, there was no braking response and the captain verbalised, ‘We’ve lost brakes’. The captain manoeuvred their aircraft to avoid colliding with another aircraft that was turning into a bay, and then brought the aircraft to a stop. At that time, the cabin crew reported via the interphone that there was fire, including visible flames, from both sides of the aircraft. The captain initiated an evacuation at which point the FO referenced the checklist in the QRH. They then exited the aircraft with the fire extinguisher. As the passengers disembarked, the FO went to both landing gear and attempted to extinguish the fires. A short time later, emergency services arrived and extinguished both fires using foam fire retardant.
No crew or passengers were injured during the evacuation.
Post-flight inspection
Following the occurrence, the aircraft was inspected by maintenance personnel. That inspection identified that all 4 main wheels and brakes were heat affected. Several of the brake and wheel components were replaced as a result of the brake fires. Maintenance testing could not replicate the RadAlt fault and the reason for its failure remains unknown.
Figure 2: ADS-B derived flight data showing the track of the aircraft on the ground at Sydney and the location of the brake failure
Source: FlightRadar24 and Google Earth, annotated by the ATSB
Context
Flight crew information
The captain had been flying for over 10 years and had about 5,000 hours of aeronautical experience with 2,272 hours on DHC-8 aircraft. The FO had been flying for about 9 years and had about 2,400 hours of aeronautical experience, of which 1,734 were on the DHC-8.
Aircraft information
General
VH-TQS was a high-wing, pressurised aircraft manufactured by De Havilland Canada in 1995. It was powered by 2 Pratt & Whitney Canada PWC123D turboprop engines, each driving a Hamilton standard 14-SF-23 4-blade, feathering and reversible, constant speed propeller. QantasLink had been operating the aircraft since 2011.
Radio altimeter
The aircraft was fitted with a radio altimeter (RadAlt). The RadAlt measures the height of the aircraft above terrain immediately below the aircraft, known as the radio altitude, and typically has an operating range of between 0 and 2,500 ft. The RadAlt system on the DHC-8-200 consists of a transmitter/receiver unit mounted under the cabin floor and 2 antennas on the underside of the fuselage. It is integral to the operation of the TCAS and GPWS, as well as the beta lockout system.
Beta lockout system
The power levers on the DHC-8-200 operate in 2 zones, flight mode and beta mode. In flight mode, the levers control engine speed between flight idle and take-off power. While in beta mode, the power levers control propeller pitch directly. The beta range is used for ground operations such as slowing the aircraft after landing and for ground manoeuvring. While in beta range, the ECUs regulate power to provide under-speed governing of the propellers.
As the levers are retarded in the flight mode towards flight idle, a flight idle gate prevents unintentional movement of the levers into the beta region. The gate is overridden by raising gate release triggers, allowing the power levers to be moved further aft to the ‘DISC’ detent. At this point, the propeller blade angle is at +1.5° which is used to slow the aircraft after touchdown. For ground manoeuvring, the levers can be retarded further to maximum reverse, at which point the propeller angle reaches -11.0°.
To ensure the beta condition is not activated in-flight, the system is disabled by the beta lockout while the aircraft is airborne. The beta lockout system is disabled from ground to 50 ft above ground level by the radio altimeter, or from an on-ground indication from the weight on wheels (WoW) system. Both the RadAlt and WoW are interlinked to the beta lockout system to prevent activation of beta lockout in the event that the aircraft bounces slightly during landing.
Weight on wheels system
The WoW system on the DHC-8-200 consists of proximity sensors on each of the landing gear and prevents the gear from retracting while on the ground. The proximity sensors register an on‑ground condition when the suspension compresses due to the weight of the aircraft. The beta lockout system requires the consensus of the main landing gear sensors, whereas the flight data recorder requires the consensus of all 3 gear (both main and nose) to provide a WoW indication in the recorded flight data. Further, it is possible for a sensor to record an in-air condition due to a decompression of the landing gear suspension, even when the wheel remains in contact with the ground.
Engine control unit
On the DHC-8-200, each aircraft engine is fitted with an ECU. The primary function of the ECU is for fuel flow regulation and torque management to optimise performance while protecting the engine from operational hazards such as exceedances of certain engine parameters, including temperature and RPM. In the event of a fault, the ECU will drop offline, and engine management will revert to manual control, as indicated by the illumination of the ECU manual light on the caution panel. In manual mode the flight crew must manually control fuel flow and there will normally be a difference between the 2 engine power lever positions for the same torque.
There are limitations on the use of lower power lever settings, particularly after landing, as the ECU normally controls the engine under-speed governor. With this, in manual mode, the flight crew must manually advance the power levers to maintain the propeller RPM above the ground operating restricted zone. Consequently, reverse thrust is no longer available for the affected engine.
Operational information
Landing procedures – power levers
The QantasLink Flight Crew Operating Manual (FCOM) contains landing procedures. Regarding the setting of the power levers during landing, the FCOM stated that:
Set the power levers to disc after touchdown.
Quick Reference Handbook guidance
The DHC-8-200 QRH did not have guidance in the event of a failure of the radio altimeter. Neither was there any information regarding the implications that the failure would have on the beta lockout system. There was some pertinent guidance available in other manuals. For example, the Operating Data Manual stated:
If the RADALT is inoperative or scrolling ensure positive WOW prior to the selection of discing on touchdown
However, the flight crew would not be expected to access this manual during this phase of flight.
The QRH contained guidance on the GPWS and TCAS failures, but there was no reference to radio altimeter failures. In addition, the QRH contained no information for a dual engine caution condition, however, it did include guidance on an individual #1 or #2 engine manual caution.
Evacuation procedures
Both the Aircrew Emergency Procedures Manual and the QRH contained guidance on actions and flight crew responsibilities in the event of an evacuation. Both documents required the FO to exit the aircraft with a fire extinguisher and torch.
Fire extinguishers
The DHC-8-200 was fitted with a Chubb Bromo Chloro di-Fluoromethane (BCF) fire extinguisher. The Aircrew Emergency Procedures Manual, available in the flight crew’s electronic flight bag, contained guidance on the use of the BCF, which was for general use on most fires except some burning metals. The manual specifically stated that:
Warning: Some metals react adversely with BCF extinguishant (e.g. titanium and magnesium) however they need to [be] at extreme temperatures to react adversely, e.g. brake fire on the Q200/Q300).
The Chubb material safety data sheet stated that hazardous decomposition products:
May evolve bromine, chlorine, fluorine, halogen acids and carbonyl halides when heated to decomposition.
In response to a draft of this report, the operator advised that their annual emergency procedures training for flight crew covers BCF extinguisher description, serviceability, operation and precautions. This included a discussion on the warning, as noted above, and that the extinguisher can be used on in-flight fires.
Flight crew comments
During interview, both flight crew stated that they had never used a BCF fire extinguisher before. Both recalled from their training that the BCF extinguisher should not be used on some metal fires. However, they could not recollect that they were not to be used on brake fires on the DHC-8-200 aircraft. After the evacuation, the FO considered whether to use the BCF extinguisher on the brake fires. Aware that passengers were evacuating, and as the response time of the emergency services was unknown at that point, they elected to deploy the extinguisher on both fires.
Recorded flight data
The aircraft was fitted with an L3[9] FA2100 flight data recorder and L3 FA2100 cockpit voice recorder. Both units were transferred to the ATSB technical facilities in Canberra for download. Figure 3 shows a portion of the flight data recorded during the touchdown phase of the flight.
The data showed that the WoW system indicated an on-ground condition on initial touchdown (black track in Figure 3). One second later, the system recorded an in-air condition for one second, before returning to the on-ground condition for the remainder of the landing sequence. In that one second period in which the WoW returned to the in-air state, the data showed (red and green traces in Figure 3) that both propellers were placed into the beta mode. Coincident with this, the data showed the master caution (orange trace) activating.
Figure 3: Recorded flight data showing the timing of weight on wheels indication in relation to when the propellers were placed into beta mode
Both the TCAS and GPWS relied on data from the RadAlt. Thus, the failure of the RadAlt resulted in the subsequent failures of the TCAS and GPWS. Further, the beta lockout system was interlinked with both the RadAlt and WoW systems to prevent the beta range from activating in‑flight. This meant that once the RadAlt had failed, the beta lockout system was relying solely on the WoW indication.
Weight on wheels
The flight data showed that, in the same second the power levers were retarded to beta range, the WoW sensors recorded a momentary ‘in-air’ condition. With the system registering an ‘in-air’ condition while the power levers were in beta range, the beta lockout system activated. The activation of the beta lockout resulted in engine manual caution warnings for both engines as the ECUs reverted to manual mode. Consequently, as the ECUs were not providing the under-speed governing during ground operations, this meant that reverse thrust was not available to slow the aircraft during the landing and subsequent taxi.
Brake failure
With both engines in manual mode and the requirement to avoid the ground operating restricted range, the flight crew had to manually advance the power levers on both engines to an increased propeller speed above 780 RPM. This subsequently increased the amount of wheel braking required.
The flight crew were able to safely stop the aircraft at the bravo 8 holding point, after about 3.3 km of taxiing. It was only after this point the braking performance deteriorated, eventually failing, igniting and initiating the evacuation. The combination of the additional burden placed on the brakes due to the increased thrust required to avoid the restricted propeller speed, as well as the length of the taxi with a downhill component, likely both contributed to the brakes overheating then failing, and igniting.
Operator guidance – engine manual warning and RadAlt
After the failures of the GPWS, TCAS and RadAlt, the flight crew consulted the DHC-8-200 QRH finding guidance for the TCAS and GPWS failures, but none for the RadAlt failure. Had the QRH contained information regarding the flow on effects of the RadAlt failure on the beta lockout system, it was likely the flight crew would have delayed the movement of the power levers into beta range during the landing until weight on wheels was assured.
Similarly, when the flight crew observed the engine manual caution warnings on both engines, they again consulted the QRH, finding guidance for only a #1 or #2 engine manual warning. Had the QRH provided additional guidance on dual engine manual cautions, the flight crew could have safely terminated the taxi at the bravo 8 holding point, or at any point prior, likely avoiding the brake failure, fire, and subsequent evacuation.
Fire extinguisher usage
Before evacuating the aircraft, the FO consulted the QRH and in accordance with the checklist exited the aircraft with the BCF fire extinguisher. Cognisant of the proximity of evacuating passengers, and unaware of the response time of the emergency services, the FO elected to deploy the BCF on both brake fires. Although no-one was adversely affected in this occurrence by the use of the BCF fire extinguisher, their use on high temperature metal fires (such as a brake fire on the DHC-8-200 as noted in the Aircrew Emergency Procedures Manual), can result in the production of a number of toxic fumes.
Guidance on the use of the BCF extinguisher was provided in the Aircrew Emergency Procedures Manual, however, it was unlikely that flight crew would review this manual during an emergency evacuation. This information was not covered in the QRH, which was reviewed by the flight crew immediately prior to the evacuation. While the FO exited with the extinguisher, they could not specifically recall that it was not to be used on this type of fire. Therefore, it was likely that, in this occurrence, additional guidance in the QRH could have prevented the use of the BCF on the high temperature brake fire.
Findings
ATSB investigation report findings focus on safety factors (that is, events and conditions that increase risk). Safety factors include ‘contributing factors’ and ‘other factors that increased risk’ (that is, factors that did not meet the definition of a contributing factor for this occurrence but were still considered important to include in the report for the purpose of increasing awareness and enhancing safety). In addition ‘other findings’ may be included to provide important information about topics other than safety factors.
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
From the evidence available, the following findings are made with respect to the brake failure and fire involving DHC-8-202, VH-TQS, Sydney Airport, New South Wales, on 8 November 2022.
Contributing factors
The radio altimeter failure led to the beta lockout system relying solely on the weight on wheels to prevent the activation of the beta lockout system.
During the touchdown, in accordance with standard operating procedures, the power levers were moved into the beta range. As this occurred when the weight on wheels sensors momentarily recorded an in-air condition, the beta lockout system and engine manual condition activated. This meant that reverse thrust would not be available to assist in decelerating the aircraft during the landing and taxi.
The increased power setting required to avoid the restricted zone while in engine manual mode combined with the long taxi, increased the amount of wheel braking required, resulting in the brakes overheating, failing and igniting.
The operator did not provide adequate guidance on how to respond to a dual engine control unit or radio altimeter failure on the de Havilland Canada DHC-8-200 aircraft, leaving flight crew without sufficient resources to appropriately deal with such failures.
Other factors that increased risk
During the evacuation of the aircraft, the Bromo Chloro di-Fluoromethane (BCF) fire extinguisher was used on a high temperature brake fire, increasing the risk of exposure to hazardous by-products.
Safety actions
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.
Safety action by QantasLink
In response to this occurrence, on 4 October 2023, the ATSB was advised by QantasLink that the following actions had been undertaken:
They published a technical advisory bulletin to DHC-8-200/300 flight crew outlining the event and learnings from the event, including relevant technical explanations, such as the radio altimeter failure and the flow-on implications with the beta lockout system.
Further information about the beta lockout system will be added to the DHC‑8‑200/300 Flight Crew Operating Manual Section 4 in an upcoming amendment.
A new QRH checklist is also being produced for a radio altimeter failure. This new QRH checklist will assist to identify a radio altimeter failure and will provide appropriate actions and considerations. In particular, it will include the following note from the De Havilland Operating Data Manual:
If the Radio Altimeter is inoperative or scrolling, ensure positive WOW prior to the selection of Discing on touchdown.
They are developing a new QRH checklist for a ‘#1 ENG MANUAL and #2 ENG MANUAL (Caution Lights)’ scenario. This new checklist will provide guidance in the event both engines operate in manual mode, including considerations such as maintaining propeller RPM outside the prohibitive range and limiting taxi duration, with consideration given to being towed to the bay (where possible). Specifically:
After landing, shutdown both engines as soon as practical. Taxi duration must be limited to avoid excessive braking caused by high power settings.
Additional guidance regarding the use of brakes has been added to the Flight Crew Operating Manual.
Sources and submissions
Sources of information
The sources of information during the investigation included:
Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to the following directly involved parties:
the flight crew
QantasLink
De Havilland Aircraft of Canada Limited
Civil Aviation Safety Authority
The Transportation Safety Board of Canada
Transport Canada.
Submissions were received from QantasLink. The submission was 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
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Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
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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.
[1] Pilot flying (PF) and pilot monitoring (PM): 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 the aircraft’s flight path.
[2] Flight level: at altitudes above 10,000 ft in Australia, an aircraft’s height above mean sea level is referred to as a flight level (FL). FL 175 equates to 17,500 ft.
[3] Traffic alert and collision avoidance system: a type of airborne collision avoidance system (ACAS).
[4] Ground proximity warning system: a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle.
[5] ADS-B: Automatic dependent surveillance–broadcast is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked.
[6] Runway number: the number represents the magnetic heading of the runway. The runway identification may include L, R or C as required for left, right or centre.
[7] In beta range, the power lever directly controls propeller blade angle during ground operations. Beta range of operation consists of power lever positions from flight idle to maximum reverse.
[8] During ground operations, the propeller speeds must be maintained above 780 RPM to avoid resonance in the propellers, which can result in excessive airframe vibrations.
[9] L3: now L3Harris Technologies, Inc. Melbourne, Florida, USA.
Occurrence summary
Investigation number
AO-2022-056
Occurrence date
08/11/2022
Location
Sydney Airport
State
New South Wales
Report release date
20/02/2024
Report status
Final
Investigation level
Short
Investigation type
Occurrence Investigation
Investigation status
Completed
Mode of transport
Aviation
Aviation occurrence category
Fire
Occurrence class
Serious Incident
Highest injury level
None
Aircraft details
Manufacturer
De Havilland Canada/De Havilland Aircraft of Canada
Model
DHC-8-202
Registration
VH-TQS
Serial number
418
Aircraft operator
EASTERN AUSTRALIA AIRLINES PTY LTD
Sector
Turboprop
Operation type
Part 121 Air transport operations - larger aeroplanes
ATSB releases interim report from Saab 340 interrupted engine start and evacuation incident
Key points
During an interrupted engine start procedure for the left engine, flame and smoke were visible
Interim report details factual information to provide timely information to the industry and public
Subsequent safety action taken by the operator includes the provision of a training package and guidance to ground staff about dispatch procedures and hand signals.
The ATSB has released an interim report from its ongoing investigation into an incident where passengers were evacuated from a Saab 340 after flame and smoke were briefly observed from the rear of the aircraft’s left engine during an interrupted engine start.
The aircraft, operated by Regional Express, was being prepared for departure on the morning of 5 April 2022 for a flight from Melbourne to King Island, with two pilots, a flight attendant and 23 passengers on board.
“Drawing upon a preliminary review of CCTV footage, on-board recordings and interviews with the crew, the report details the incident’s sequence of events during the engine start-up sequence,” said ATSB Director Transport Safety Dr Mike Walker.
After the right engine was started, and as the crew began to start the left engine, a ground staff member disconnected the ground power unit from the aircraft prior to receiving the signal from the flight crew to do so, the report details. This interrupted the start-up sequence.
The captain then initiated the interrupted engine start procedure for the left engine, which included motoring (using its starter to rotate the engine with fuel and ignition switched off) to remove any residual fuel from inside the engine.
As the left engine propeller began to rotate, flame and smoke were visible coming from the rear of the left engine for about 3 seconds.
A marshaller, positioned at the front of the aircraft, noticed the flames and began to signal to the flight crew to stop the engine start using the appropriate hand signal. However, the marshaller could not recall the hand signal for fire and instead communicated to the flight crew by mouthing the words ‘smoke’ and ‘flame’ and gesturing to the left engine.
The captain ceased motoring the left engine. At about this time, the flight crew noted that the left engine interstage turbine temperature (ITT) was still rising and in response the captain decided to make a second attempt at motoring. At this time, the marshaller continued to signal to the flight crew that there was a problem.
The report then details the actions of the flight crew, including actioning the engine fire emergency checklist and commanding an evacuation.
Two passengers received minor injuries in the evacuation, which took about 4 minutes.
The report details safety action taken by the operator as a result of the incident, including the development of a new hand signal to indicate an interrupted engine start, and providing ground staff with a training package about dispatch procedures and hand signals.
“This interim report details factual information established in the investigation’s early evidence collection phase, and has been prepared to provide timely information to the industry and public,” said Dr Walker.
“It contains no analysis or findings, which will be detailed in the investigation’s final report.”
The continuing investigation will include a review and examination of flight crew failure management procedures, crew communication and coordination; flight crew, flight attendant and ground staff recurrent training; and on-board recordings.
“Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” Dr Walker noted.
![Figure 1: ADS-B[5] derived flight data showing the approximate location of the radio altimeter failure on approach to Sydney](/sites/default/files/inline-images/AO-2022-056%20Figure%201.jpg)
