Aviation safety investigations & reports

In-flight break-up involving Vans Aircraft RV-7A, registered VH-XWI, 90 km south of Charters Towers, QLD, 23 April 2021

Investigation number:
AO-2021-017
Status: Active
Investigation in progress

Preliminary report

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 23 April 2021, a Van’s Aircraft RV-7A, registered VH-XWI, was being operated on a private flight from Winton to Bowen, Queensland.

The pilot, the sole occupant and the owner of the aircraft, had been on a multi-day tour in company with three other pilots, each operating their own aircraft. Prior to departing from Winton, the pilots discussed the forecast weather conditions for the planned flight, including their arrival at Bowen. Consequently, the other pilots elected to fly to Bowen under the instrument flight rules[1] (IFR), while the pilot of VH-XWI, being restricted to operating in visual meteorological conditions[2] (VMC), departed under a daytime visual flight rules[3] (VFR) flight plan.

Witnesses stated that VH-XWI was last of the four aircraft to depart. Recorded data showed that the aircraft departed Winton Airport at about 0751 EST [4] and set a north-east course to track to Bowen, climbing to 7,500 ft above mean sea level (AMSL) for the 600 km trip (Figure 1).

Figure 1: Track of VH-XWI from Winton to Bowen
Track of VH-XWI from Winton to Bowen

 

Source: Google Earth with Aireon data, annotated by the ATSB

Near Catumnal Station, VH-XWI descended to about 500 ft above ground level (AGL) (Figure 2). At about 0820, the aircraft conducted two left orbits about 7 km to the south-west of Catumnal Station before flying closer to the station and climbing to about 1,000 ft AGL. VH-XWI conducted two right orbits, at speeds as low as 25 kt, before rapidly descending to less than
200 ft AGL.

Figure 2: Track of VH-XWI over Catumnal Station

Track of VH-XWI over Catumnal Station

Source: Google Earth with Aireon data, annotated by the ATSB

The aircraft then climbed back up to about 1,000 ft AGL before overflying the station airstrip. At about 0829, the aircraft’s airspeed reduced to about 43 kt while conducting a right turn, and descended to less than 50 ft AGL before climbing away from the station, and turning back towards Winton (Figure 3). About 11 km after turning towards Winton, VH-XWI conducted a left climbing turn, heading towards Bowen and climbing to about 10,500 ft AMSL.

Figure 3: Track of VH-XWI in the vicinity of Catumnal Station

Track of VH-XWI in the vicinity of Catumnal Station

 

Source: Google Earth with Aireon data, annotated by the ATSB

At about 290 km north-east of Winton, VH-XWI descended to about 1,000 ft AGL and then conducted a large left orbit before turning back towards Bowen and climbing to about 9,000 ft.

At about 370 km north-east of Winton, and about 90 km to the south of Charters Towers, VH-XWI conducted a right turn with a series of airspeed and altitude variations.

At about 0951, the aircraft sustained an in-flight break-up. The pilot was fatally injured, and the aircraft was destroyed.

Context

Pilot information

The pilot held a current private pilot licence (aeroplane), initially issued in August 1975. Their licence was reissued as a Civil Aviation Safety Regulation Part 61 licence on 3 May 2021, for single engine aircraft, with endorsements for manual propeller pitch change and retractable undercarriage.

The pilot’s logbook showed a total flying experience of 271.0 hours up to the last recorded flight on 22 March 2021. The majority of their total flight time (216.1 hours) was conducted prior to January 1990. The remaining 54.9 hours was conducted in VH-XWI from July 2020 to March 2021.

In July 2020, the pilot assisted a test pilot in 17 hours of initial flight testing of VH-XWI, and started familiarisation training in the aircraft in September 2020. The pilot logged 13.4 hours conversion training with a flying school in VH-XWI, before conducting a further 3.9 hours with another flying school, completing a single engine aeroplane flight review on 18 February 2021.

The pilot operated VH-XWI on numerous local and cross-country flights, leading up to the planned multi-day tour with three other aircraft.

The pilot held a valid basic class 2 medical certificate, with the last examination conducted on 1 February 2021. This type of certificate is based on the standard required for a commercial driver licence declaration, verified by a general practitioner.

Aircraft information

General

The Van’s Aircraft RV-7A is a low-wing, all-metal, high performance, experimental amateur-built aircraft. It is supplied in kit form and is designed to be constructed for the education and recreation of the owner. The RV-7A is suitable for cross-country flying, with speed ranges from 56 to 200 kt, and can be operated between +6 g and -3 g,[5] making it suitable for flying aerobatic manoeuvres.

Pilots and passengers of experimental aircraft in Australia accept the risk that the aircraft may not meet the same airworthiness safety standards as certified aircraft and operate these aircraft on the basis of informed participation.[6]

VH-XWI was fitted with a Dynon Skyview HDX primary flight display. The Skyview system incorporated various communication and GPS navigation systems, including a two-axis autopilot.

Airworthiness

The Special Certificate of Airworthiness issued to VH-XWI on 26 August 2020 indicated in the annexure, among other requirements, that the aircraft be operated ‘by day and under VFR only’.

The most recent entries in the aircraft and engine maintenance logs were on 10 April 2021, about 13 days prior to the accident. They showed that the aircraft had accumulated 84.8 hours total time in service.

Fuel

The aircraft operated on aviation gasoline (AVGAS) and had the capacity to carry 159 L in two 80 L wing tanks. The aircraft was refuelled prior to departure from Winton, with records indicating that about 75 L was uplifted.

Meteorological information

Bureau of Meteorology forecasts indicated there was significant cloud, reduced visibility and adverse weather predicted for the duration of the flight. While generally better weather conditions existed to the west of the east coast of Queensland, these were forecast to deteriorate from greater than 10 km visibility down to about 1,000 m in isolated thunderstorms with showers, rain and broken cloud from 800 ft to above 10,000 ft. Severe icing and turbulence were expected with isolated thunderstorms and cumulonimbus in the area.

A witness along the flight path at Catumnal Station, about 100 km north-east of Winton, heard an aircraft overhead the station for a period of time, consistent with recorded data from VH-XWI; however they were unable to visually identify the aircraft due to the presence of fog.

A witness at Pajingo Station, about 15 km from the accident site, recalled hearing an aircraft operating in the vicinity; however they did not see the aircraft in flight. That witness described the presence of steady continuous light rain for most of the morning prior to hearing the aircraft nearby.

Wreckage information

The accident site was located almost directly below the last known reliable radar data point. The wreckage of VH-XWI was located on partially vegetated, open bushland with the ground significantly softened by recent rainfall. The wreckage was distributed over a distance of about 1.5 km (Figure 4), with the larger and heavier aircraft sections located closer to each other, and lighter, smaller sections of wreckage found to the north-west of the main wreckage, consistent with the forecast wind direction.

Figure 4: Accident site scatter pattern

Accident site scatter pattern

Source: Google Earth, annotated by the ATSB

The engine, propeller and forward airframe sections (Figure 5) departed the main aircraft structure in flight and impacted the ground at high speed, resulting in substantial surface disturbance.

Figure 5: VH-XWI engine location

VH-XWI engine location

Source: ATSB

The left wing and cockpit section (Figure 6) were located a short distance from the engine, with significant downwards bending of the right main spar occurring in-flight, resulting in the separation of the right wing from the airframe.

Figure 6: VH-XWI left wing and cockpit section

VH-XWI left wing and cockpit section

Source: ATSB

Other information

One of the pilots travelling in company with the pilot of VH-XWI indicated that all the pilots discussed the weather prior to departure from Winton as a point of concern. Witnesses recalled that the weather at Winton was clear with no fog or cloud, however significant weather was expected closer to the coast. Prior to departure, it was offered to the pilot of VH-XWI that, should the weather be too bad for VFR flight, one of the group would return to pick them up and take them to Bowen.

One of the IFR-rated pilots recalled the weather as initially good at 7,000 ft, with little cloud. However, as the flight progressed, the weather deteriorated into instrument meteorological conditions (IMC)[7] with cloud and rain for the last 30–40 minutes of their flight to Bowen. They recalled becoming visual on the approach to Bowen below 2,000 ft with significant wind.

In-flight radio contact with the pilot VH-XWI was made intermittently during the flight. The pilot of VH-XWI indicated that they would descend from 7,500 ft to 3,500 ft during the flight due to cloud. The pilot of VH-XWI then advised the group that they were unable to get through and would try to descend below the cloud. Sometime later the pilot of VH-XWI advised that they were going to turn back.

On landing at Bowen, the other pilots checked on the progress of VH-XWI on web-based aircraft tracking software and raised the alarm with search and rescue authorities.

Further investigation

To date, the ATSB has collected evidence from the accident site, interviewed a number of parties and examined retrieved data from aircraft components, radar and portable electronic devices.

The investigation is continuing and will include further review and examination of:

  • the aircraft builder’s log for VH-XWI
  • pilot training records and recent flights
  • available electronic data
  • meteorological conditions around the time of the accident flight
  • the in-flight break-up sequence.

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.

 

__________

  1. Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft to operate in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules (VFR). Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
  2. 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.
  3. 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.
  4. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
  5. G load: the nominal value for acceleration. In flight, g load represents the combined effects of flight manoeuvring loads and turbulence and can have a positive or negative value.
  6. Informed participation relies on the premise that before you take part or pay for an activity that you are fully aware of the potential risks and consequences.
  7. Instrument meteorological conditions (IMC): weather conditions that require pilots to fly primarily by reference to instruments, and therefore under IFR, rather than by outside visual reference. Typically, this means flying in cloud or limited visibility.

Summary

The Australian Transport Safety Bureau (ATSB) is investigating an in-flight break-up involving a Van’s Aircraft RV-7A, VH-XWI, about 90 km south of Charters Towers, Queensland, on 23 April 2021.

The pilot, who was the sole occupant, was conducting a private flight from Winton to Bowen, Queensland. During the cruise, the aircraft experienced an in-flight break-up. The pilot was fatally injured, and the aircraft was destroyed.

Two transport safety investigators with experience in aircraft operations and aircraft maintenance travelled to the accident site to examine the wreckage, and map the site using a drone and other site survey equipment. An electronic primary flight display and an iPad were recovered from the accident site and taken to the ATSB’s technical facilities in Canberra for further examination.

The ATSB will also analyse available recorded data and weather information, and will interview witnesses and other involved parties.

A preliminary report is expected to be released in a number of weeks, while a final report will be published at the conclusion of the investigation.

However, should any critical safety issues be identified at any stage during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate safety action can be taken.

General details
Date: 23 April 2021   Investigation status: Active  
Time: 9:52 EST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): Charters Towers Aerodrome, 172° M 90 km   Investigation phase: Evidence collection  
State: Queensland   Occurrence type: Collision with terrain  
Release date: 27 July 2021   Occurrence category: Accident  
Report status: Pending   Highest injury level: Fatal  
Anticipated completion: 4th Quarter 2021    

Aircraft details

Aircraft details
Aircraft manufacturer Amateur Built Aircraft  
Aircraft model VANS RV7A  
Aircraft registration VH-XWI  
Serial number 73427  
Type of operation Private  
Sector Piston  
Damage to aircraft Destroyed  
Departure point Winton, Queensland  
Destination Bowen, Queensland  
Last update 27 July 2021