Aviation safety investigations & reports

Collision with terrain involving Cessna A150M, VH-CYO 5 km west-south-west of Peachester, Queensland, on 23 June 2021

Investigation number:
AO-2021-025
Status: Active
Investigation in progress

Prelim

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

Two private pilots contracted an aerobatics instructor to provide aerobatic flight training. On the morning of 23 June 2021, the three pilots gathered at the Sunshine Coast Airport, Queensland, for a pre-flight briefing. The briefing contained theoretical information about spin[1] training and recovery techniques, which were intended for the practical component of the aerobatic flights that day. The pilots had hired a Cessna A150M Aerobat, registered VH-CYO, from the Sunshine Coast Aero Club for the practical flight training.

At 1103 Eastern Standard Time,[2] VH-CYO took off from the Sunshine Coast Airport, with the instructor and one of the student aerobatic pilots on board. The flight was being conducted under visual flight rules (VFR), and visual meteorological conditions existed during the flight.

The aircraft departed to the south-west and climbed to about 6,000 ft above mean sea level (AMSL) (Figure 1). It arrived at the area intended to conduct aerobatics about 20 minutes after departure.

Figure 1: VH-CYO flight track radar data showing take-off point and accident site

VH-CYO flight track radar data showing take-off point and accident site

Source: Google Earth, annotated by the ATSB

Figure 2 shows recorded radar data for the last 3 minutes of the flight. It indicates that, within the last 90 seconds, the aircraft turned left, decelerated while maintaining altitude, and then descended rapidly. Shortly after, at about 1122, the aircraft impacted terrain. The aircraft was destroyed and the two occupants were fatally injured.

Figure 2: VH-CYO last 3 minutes of recorded flight data viewed from the left and above

VH-CYO last 3 minutes of recorded flight data viewed from the left and above

Radar positions (depicted by green pins) were recorded every 5 seconds. The last two points depicted without pins were predictive in nature and were not considered to be accurate. Source: Google Earth, annotated by the ATSB

The aircraft was reported missing by a member of the aero club at about 1515 EST. A subsequent search found the wreckage in bushland near Peachester several hours later.

Context

Aircraft information

The Cessna 150 is a high wing, two-seat, single piston engine aeroplane designed for flight training. The Cessna A150M Aerobat model was designed to conduct aerobatic training.

VH-CYO was manufactured in 1976 and first registered in Australia in 1995. It had been owned by the Sunshine Coast Aero Club since March 2021.  

Recorded information

The aircraft flight path was derived from primary[3] and secondary[4] surveillance radar data recorded by Airservices Australia. The data included the aircraft’s position with a time stamp and altitude at 5-second intervals. A groundspeed can be derived by calculating the distance travelled over a known time period.

Each of the green pins in Figure 2 depicts a recorded radar position. The recording stopped at about 1,200 ft AMSL, most likely due to the aircraft descending below radar coverage.

Site and wreckage examination

The accident site was located in a dense stand of trees, about 400 ft AMSL. The trees stood about 15–20 m high and straddled a creek line in a band about 50 m wide, with open areas of farmland on either side (Figure 3).

Figure 3: Area of accident site

Area of accident site

Source: Google Earth, annotated by the ATSB

The wreckage trail extended about 50 m from the initial tree impact point, until the final piece of wreckage, oriented in an east-west direction. There were several notable tree impact points, including trees that had been broken in half or completely felled by the impact forces.

Calculations of the tree impact damage heights indicated the final flight path angle was a descent of about 13°. The main wreckage came to rest at the base of a tree that was struck at a height of about 10 m.  

The aircraft structure was significantly disrupted as a result of impacting several trees (Figure 4).

Figure 4: Aircraft main wreckage at the base of a large tree that was struck

Aircraft main wreckage at the base of a large tree that was struck

Source: ATSB

The ATSB conducted an examination of the aircraft wreckage. This examination identified that:

  • the disruption to the aircraft and foliage, coupled with the length of the wreckage trail, indicated that the aircraft had significant forward speed at impact
  • the flaps were in the retracted position
  • the aircraft had no evident pre-impact defects with the flight controls or aircraft structure
  • the aircraft was intact prior to impact with terrain
  • the engine had no obvious defects upon external examination
  • the throttle setting was captured at an idle position during the accident sequence
  • the propeller rotational damage signatures were minimal, indicating a low power setting.

Ongoing investigation

The investigation is continuing and will include:

  • interviews with parties involved with the operation of the aircraft
  • further analysis of the radar data
  • examination of the pilots’ qualifications, experience, and medical/recent history
  • assessment of the aircraft’s flight performance characteristics
  • assessment of spin training requirements and practices
  • examination of aircraft maintenance and operational records
  • processes surrounding the use of flight notes or a nominated SARTIME to highlight expected arrival/return times so that aircraft are identified as overdue in a timely manner.

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. A spin is a sustained spiral descent of a fixed-wing aircraft, with the wing’s angle of attack beyond the stall angle.
  2. Eastern Standard Time (EST) was Coordinated Universal Time (UTC) + 10 hours.
  3. Primary radar returns are produced by radar transmissions that are passively reflected from an aircraft and received by the radar antenna. The received signal is relatively weak and provides only position information, not the aircraft’s altitude.
  4. Secondary radar returns are dependent on a transponder in the aircraft replying to an interrogation from a ground station. An aircraft with its transponder operating is more easily and reliably detected by radar and, depending on the mode selected by the pilot, the aircraft’s pressure altitude is also displayed to the air traffic controller.

Summary

The ATSB has commenced a transport safety investigation into the collision with terrain of a Cessna A150 Aerobat two-seat light aircraft near Cedarton, approximately 38 km south-west of Sunshine Coast Airport, Queensland, on 23 June 2021.

The aircraft was hired for a private flight to conduct aerobatics with an instructor pilot and another pilot on board. The aircraft departed Sunshine Coast Airport at 1103 and collided with terrain at about 1122. It was reported missing after failing to return to Sunshine Coast Airport during the afternoon. A subsequent search confirmed the aircraft had collided with terrain in bushland near Cedarton. The two pilots on board were fatally injured and the aircraft was destroyed.

The evidence collection phase of the investigation will include examination of the accident site and wreckage by ATSB investigators, and the collection of other relevant evidence, including recorded data and communications, air traffic control surveillance data, weather information, witness reports and pilot and maintenance records.

A report will be published at the conclusion of the investigation. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken. 

General details
Date: 23 June 2021   Investigation status: Active  
Time: 1122 EST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): 5 km WSW of Peachester, Queensland   Investigation phase: Evidence collection  
State: Queensland   Occurrence type: Collision with terrain  
Release date: 02 September 2021   Occurrence category: Accident  
Report status: Pending   Highest injury level: Fatal  
Anticipated completion: 2nd Quarter 2022    

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model A150M  
Aircraft registration VH-CYO  
Serial number A1500655  
Operator Sunshine Coast Aero Club Pty. Ltd.  
Sector Piston  
Damage to aircraft Destroyed  
Departure point Sunshine Coast, Queensland  
Destination Sunshine Coast, Queensland  
Last update 02 September 2021