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Summary

Summary

Updated: 25 July 2017

Additional information regarding the occurrence that was recently brought to the attention of the ATSB has been assessed, and the draft investigation report is being finalised prior to review by the ATSB Commission. It is now anticipated to be approved for release to directly involved parties (DIP) for comment in August 2017. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than October 2017.

 

Updated 19 April 2017

The draft investigation report is being finalised prior to review by the ATSB Commission. It is now anticipated to be approved for release to directly involved parties (DIP) for comment in May 2017. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than July 2017.

 

Updated 19 December 2016

Completion of the draft investigation report has been further delayed by the involvement of the investigator in charge on other aviation safety investigations and tasks. It is now anticipated for release to directly involved parties (DIP) for comment in March 2017. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than May 2017.

 

Updated: 7 September 2016

Completion of the draft investigation report has been further delayed by the involvement of the investigator in charge on other aviation safety investigations and tasks. It is now anticipated for release to directly involved parties (DIP) for comment in January 2017. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than March 2017.

 

Updated: 14 June 2016

Completion of the draft investigation report has been delayed by competing priorities and workload of the investigator in charge. It is now anticipated for release to directly involved parties (DIP) for comment in October 2016. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than December 2016.

 

Updated: 11 November 2015

At approximately 0830 Eastern Standard Time[1] on 3 September 2015, four low capacity twin engine turboprop aircraft flew towards Mount Hotham Airport, Victoria, as part of a passenger charter involving a number of different operators. On arrival at Mount Hotham the weather conditions were below that required for a visual approach. As a result, it was necessary for each aircraft to carry out a published Global Navigation Satellite System (GNSS) instrument approach, in order to navigate clear of cloud before landing (Figure 1).

Figure 1: GNSS instrument approach chart for Mount Hotham Airport
 Figure 1: GNSS instrument approach chart for Mount Hotham Airport


Source: Airservices Australia

The first aircraft to arrive in the Mount Hotham area was Beech Aircraft Corp. B200 King Air, registered VH-OWN. The pilot of that aircraft commenced the GNSS approach from the south-east and, having descended below the specified altitude of 7,700 ft overhead initial approach fix HOTEC, experienced tracking difficulties approaching the intermediate fix HOTEI. In response, the pilot discontinued the approach and climbed the aircraft in a north-easterly direction (Figure 2). Having climbed back to the lowest safe altitude for that area, the pilot of VH-OWN commenced manoeuvring in the airspace above the Mount Hotham Airport as the other charter aircraft progressively arrived in the area and commenced the instrument approach.

Figure 2: VH-OWN partial radar tracking during the first approach
(Note: the climb back to the lowest safe altitude is not displayed)

Figure 2: VH-OWN partial radar tracking during the first approach (Note: the climb back to the lowest safe altitude is not displayed)

Source: Airservices Australia, modified by the ATSB

The second aircraft arrived at Mount Hotham on the same track as VH-OWN. The pilot of that aircraft conducted the GNSS approach and landed on runway 29.

The third aircraft to commence the approach was another B200 King Air, registered VH-LQR, which tracked inbound from the north-east at 8,000 ft. During this time the pilot of VH-OWN continued manoeuvring in this area at 7,700 ft and the two aircraft passed in close proximity of each other with a vertical separation of approximately 300 ft.

The pilot of VH-OWN then conducted a second approach and experienced similar tracking difficulties. The pilot reported becoming visual and clear of cloud during the approach and continued to descend. VH-OWN was then observed to carry out significant manoeuvring while on short final to the runway before landing.

The airspace around Mount Hotham was designated as uncontrolled Class G airspace. Civilian radar coverage was unable to track all parts of the flight, and there was no control tower or certified air/ground radio service at the airport. Neither VH-OWN nor VH-LQR were fitted with airborne traffic avoidance equipment such as the Traffic Collision Avoidance System. The primary means of separation was the use of radio communication between the pilots and flight in accordance with the published instrument approach chart.

The investigation is continuing and will include examination of the:

  • navigation and autopilot system fitted to VH-OWN
  • recorded radio and radar data
  • planning and conduct of the multiple aircraft charter operation
  • air traffic services provided in the Mount Hotham area.

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The information contained in this web update 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 web update. As such, no analysis or findings are included in this update.

 

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  1. Eastern Standard Time (EST) was Coordinated Universal Time (UTC) + 10 hours.
 
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