Aviation safety investigations & reports

VFR into IMC and controlled flight into terrain involving Pilatus Britten-Norman BN2A, VH-OBL, 98 km west-south-west of Hobart Airport, Tasmania, on 8 December 2018

Investigation number:
AO-2018-078
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final

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What happened

On 8 December 2018, the pilot of a Pilatus Britten-Norman BN2A-20 Islander, registered VH‑OBL and operated by Airlines of Tasmania, was conducting a positioning flight from Cambridge Airport to Bathurst Harbour, Tasmania, under the visual flight rules. The aircraft departed Cambridge and was scheduled to arrive at Bathurst Harbour about 45 minutes later to pick up five passengers for the return flight. The aircraft did not arrive and the Australian Maritime Safety Authority received advice that an emergency locator transmitter allocated to VH-OBL had activated. That evening, the wreckage was located near the Western Arthur Range in the Southwest National Park. The pilot was fatally injured and the aircraft was destroyed.

What the ATSB found

The ATSB found that the pilot was using a route through the Arthur Range due to low cloud conditions and had continued over a saddle in the range at a lower altitude than previous flights. During this, the pilot likely encountered reduced visual cues, as per the forecast conditions. This led to controlled flight into terrain while attempting to exit the range.

Specific guidance provided by Airlines of Tasmania to their pilots for the Bathurst Harbour operations was primarily given verbally and was not well documented. This resulted in the pilots having varied understanding of the expectations regarding in-flight weather-related decision-making at the Arthur Range saddle.

Although not contributory, the ATSB identified that Airlines of Tasmania’s safety management processes for identifying hazards extensively relied on safety occurrence reports. This limited the opportunity to proactively identify the risks in all operational activities and assess the effectiveness of any controls in place.

Further, and also not contributory, the Civil Aviation Safety Authority did not conduct any formal surveillance activities relating specifically to the operator’s safety management system, despite having repeat safety findings system and hazard identification in the year prior to the accident. However, it was noted that there were ongoing communications with the operator throughout this time. In addition, it was identified that the Civil Aviation Safety Authority’s processes for acquitting repeat safety findings were not effective in ensuring that earlier findings were appropriately assessed prior to the current findings being acquitted.

What has been done as a result

In January 2020, the operator introduced specific guidance for the south‑west operations, which introduced visibility requirements for pilot’s using the direct route through the Arthur Range saddle. Additionally, further information and guidance has been added to the training syllabus, and the safety management system around weather assessment criteria and seeking further guidance when required. The operator has also implemented a number of changes to make the safety management system more proactively assess risks from sources other than safety reports.

Safety message

This accident highlights the hazards associated with flying in mountainous terrain, the challenges of in-flight weather-related decision‑making and the importance of maintaining an escape route. Further, it demonstrates the importance of using multiple sources to identify the hazards potentially affecting the safety of an organisation, rather than relying on one key source. Such sources include safety occurrence reports, inspections, audits, flight data, and expert judgment. Likewise, it is equally important to monitor and evaluate the ongoing effectiveness of existing risk controls to ensure that they remain appropriate.

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The occurrence

Context

Safety analysis

Findings

Safety issues and actions

Glossary

Sources and submissions

Appendix

Australian Transport Safety Bureau

Update

Updated: 6 December 2019 

The investigation into the collision with terrain involving Pilatus Britten-Norman BN2A, VH-OBL, 101 km west-south-west of Hobart, Tasmania, on 8 December 2018 is continuing. A preliminary report outlining the then known facts of the investigation was published on 4 February 2019.

Since the publication of the preliminary report, the investigation team has gathered information from, or related to the accident, to build a detailed picture of the event including:

  • recovered aircraft components and available electronic data
  • aircraft maintenance documentation
  • weather conditions
  • pilot qualifications and experience
  • operator procedures
  • research and similar occurrences.

The investigation team is currently examining and reviewing the evidence to determine its relevance, validity, credibility and relationship to the accident and other pieces of evidence. Based on this analysis, the team is developing and testing a series of hypotheses to determine the safety factors that could have contributed to the accident or increased the risk of the accident occurring and will form the basis of the ATSB final report.

Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant stakeholders so appropriate and timely safety action can be taken.

Preliminary report

Preliminary report published 4 February 2019

What happened

On 8 December 2018, a Pilatus Britten-Norman BN-2A-20 Islander, registered VH-OBL, operated by Par Avion, was conducting a positioning leg under the visual flight rules[1] from Cambridge Aerodrome to Bathurst Harbour, Tasmania. The aircraft departed the aerodrome at 0748 Eastern Daylight Time (EDT),[2] and was scheduled to arrive at Bathurst Harbour about 0845 to pick up five passengers for the return flight to Cambridge Aerodrome.

At 0829, the Australian Maritime Safety Authority (AMSA) received advice that an emergency locator transmitter (ELT) allocated to VH-OBL had activated. AMSA advised the Tasmanian Police and the aircraft operator of the activation, and initiated search and rescue efforts. The rescue efforts included two helicopters and a Challenger 604 search and rescue jet aeroplane. The Challenger arrived over the beacon signal location at around 0925; however, due to cloud cover it was unable to visually identify its precise location. Multiple attempts were made throughout the day to locate the accident site, however, due to low-level cloud, the search and rescue operation was unable to confirm visual location of the aircraft until about 1900. The aircraft wreckage was located in mountainous terrain near the Western Arthur Ranges in the Southwest National Park. The search and rescue crew determined that the accident was unlikely to have been survivable. The search and rescue helicopter crew considered winching personnel to the site; however, due to a number of risks, including potential for cloud reforming, the time of day and lighting, and other hazards associated with the mountainous location, the helicopter departed the area. The aircraft wreckage was accessed the following day, when it was confirmed that the pilot, the sole occupant of the aircraft, was fatally injured.

Position and altitude information was obtained from FlightAware, which recorded a combination of ADS-B[3] and Spidertracks[4] data. The data showed the aircraft tracking to the southwest towards Bathurst Harbour (Figure 1). At approximately 0816, the aircraft entered a valley near the West Portal in the Western Arthur Ranges, and proceeded to conduct a number of turns. The final ADS‑B data point recorded was at 0828.

Figure 1: Track of VH-OBL from Cambridge Aerodrome towards Bathurst Harbour, showing the accident location

Figure 1: Track of VH-OBL from Cambridge Aerodrome towards Bathurst Harbour, showing the accident location. Source: Google earth and FlightAware, modified by ATSB

Source: Google earth and FlightAware, modified by ATSB

Site and wreckage

ATSB investigators travelled to Hobart, Tasmania as part of this investigation. However, due to the remote location and access difficulties, and other risks associated with the mountainous location of the wreckage, the ATSB did not attend the accident site. Investigators conducted numerous interviews, gathered relevant information and worked closely with the Tasmanian Police to gain an understanding of the accident. A number of items recovered from the wreckage and detailed photographs by the Tasmania Police forensic investigators will be examined by the ATSB.

Figure 2: Accident location of VH-OBL in the Western Arthur Ranges

Figure 2: Accident location of VH-OBL in the Western Arthur Ranges. Source: Tasmania Police

Source: Tasmania Police

Pilot information

The pilot held a current Commercial Pilot Licence (Aeroplane) and had completed a flight review on 25 May 2017. The pilot also held a Class 1 Aviation Medical Certificate that was valid until 26 February 2019. The available information indicated that the pilot had about 540 hours total aeronautical experience, with 82.5 hours on Islander aircraft.

Ongoing investigation

The investigation is continuing and will include examination of the following:

  • recovered components and available electronic data
  • aircraft maintenance documentation
  • weather conditions
  • pilot qualifications and experience
  • operator procedures
  • research and previous occurrences.

Acknowledgements

The ATSB acknowledges the support of Tasmania Police for their assistance during this investigation.

_______________

The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this report. As such, no analysis or findings are included in this update.

 

__________

  1. Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
  2. Australian Eastern Daylight Time (EDT): Coordinated Universal Time (UTC) + 11 hours.
  3. 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.
  4. Spidertracks is a commercial satellite based tracking system, enabling the aircraft position to be monitored remotely. It includes an SOS button, which can be manually activated by the crew in an emergency.

Safety Issues

Go to AO-2018-078-SI-01 - Go to AO-2018-078-SI-02 - Go to AO-2018-078-SI-03 -

South-west operations guidance

Airlines of Tasmania did not provide any documented guidance for the south-west operations, despite encouraging pilots to commence the flight, even when forecasts indicated they may be likely to encounter adverse weather en route. This resulted in the pilots having varied understanding of the expectations regarding in‑flight weather‑related decision making at the Arthur Range saddle, and increased the risk that some pilots continued into an area of high terrain in marginal conditions, where options to escape were limited.

Safety issue details
Issue number: AO-2018-078-SI-01
Status: Closed – Adequately addressed

Hazard identification

Airlines of Tasmania's safety management processes for identifying hazards extensively relied on safety reports. This limited the opportunity to proactively identify the risks in all operational activities, and assess the effectiveness of any controls in place.

Safety issue details
Issue number: AO-2018-078-SI-02
Status: Closed – Adequately addressed

Regulatory management of repeat safety findings

The Civil Aviation Safety Authority’s acquittal process for repeat safety findings was not effective in ensuring that all previous findings of a similar nature were also appropriately assessed prior to the current and all associated safety findings being acquitted.

Safety issue details
Issue number: AO-2018-078-SI-03
Status: Open – Safety action pending
General details
Date: 08 December 2018   Investigation status: Completed  
Time: 0828 AEDT   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): 98 km west-south-west of Hobart Airport   Investigation phase: Final report: Dissemination  
State: Tasmania   Occurrence type: Controlled flight into terrain (CFIT)  
Release date: 20 December 2021   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Pilatus Britten-Norman Ltd  
Aircraft model BN2A-20  
Aircraft registration VH-OBL  
Serial number 2035  
Operator Airlines of Tasmania Pty Ltd operating as Par Avion  
Type of operation General Aviation  
Sector Piston  
Damage to aircraft Destroyed  
Departure point Cambridge Airport, Tasmania  
Destination Bathurst Harbour aeroplane landing area, Tasmania  
Last update 08 February 2022