Investigation number
AO-2023-036
Occurrence date
Location
Caboolture ALA
State
Queensland
Report release date
Report status
Preliminary
Investigation level
Defined
Investigation type
Occurrence Investigation
Investigation phase
Evidence collection
Investigation status
Active
Aviation occurrence type
Collision
Occurrence category
Accident
Highest injury level
Fatal
Anticipated completion

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 the morning of 28 July 2023, the pilot of a Piper PA-25, registered VH-SPA and operated by Caboolture Gliding Club, took off from runway 06[1] at Caboolture Airfield, Queensland, with a glider in tow. It was a clear day with light winds. This was the pilot’s second flight of the day, having previously completed one prior glider aerotow in VH-SPA. After the glider was released, the pilot of VH-SPA entered the circuit for runway 06, with the intention of landing so that the aircraft could be used to tow a third glider into the air.

Caboolture Airfield was located within class G (non-controlled) airspace, and had a designated common traffic advisory frequency (CTAF) on which pilots made positional broadcasts when operating within the vicinity of the airport. To date no recordings of radio transmissions from any aircraft on the ground at Caboolture around the time of the accident have been identified (see Recorded data). Witness recollections of radio transmissions are being collated and analysed by the ATSB.

Some transmissions from aircraft in flight were recorded. While in the circuit, the pilot of VH-SPA made several radio calls on the CTAF, the last of which was at about 1030:19 and was partially recorded. According to several witnesses who heard the transmission, the pilot announced that VH-SPA was commencing a final approach to runway 06 and stated that the aircraft would be ‘holding short’, indicating that it would not be crossing the intersection with runway 11/29.

At about 1030:44, while VH-SPA was on final approach, the pilot of a Jabiru J430, registered VH‑EDJ, began take-off on runway 11. The pilot and passenger were conducting a private flight to Dirranbandi Airport, Queensland.

Also at that time, a Cessna 172, registered VH-EVR, was being taxied at the airfield by a solo student pilot. The pilot of VH‑EVR later reported having turned the radio volume down to conduct engine run-ups near the intersection of the two runways and had not restored normal volume upon completion. As a result, the pilot of VH-EVR did not hear any transmissions from the pilot of VH‑SPA, and was not aware of the aircraft approaching runway 06.

At 1030:49, just prior to VH-SPA touching down on runway 06, VH-EVR crossed runway 06 ahead of VH-SPA in a north-west direction. The pilot of VH-SPA initiated a go-around, and made an associated radio call (according to several witnesses) which was not recorded.

At 1030:55, VH-SPA began climbing while maintaining a runway 06 heading as VH-EDJ lifted off runway 11 before the runway intersection. About 5–10 seconds later, while the aircraft were climbing on crossing tracks, the pilot of VH-EDJ commenced a left turn, likely in an attempt to avoid a collision.

At 1031:11, the two aircraft collided on similar tracks above runway 06, just north-east of the 06/11 intersection, at a height of about 200–300 feet (Figure 1).

Figure 1: Approximate tracks of VH-EDJ and VH-SPA based on video footage

Figure 1: Approximate tracks of VH-EDJ and VH-SPA based on video footage

Source: Google Earth, annotated by the ATSB

The leading edge of the inboard left wing of VH-SPA struck VH-EDJ’s right wing at the outboard trailing edge, resulting in separation of the right wing tip and part of the right aileron. VH-EDJ rolled to the right while rapidly losing altitude. VH-EDJ collided with terrain in a nose-down, right‑wing-down attitude near the end of runway 06. The pilot and passenger were fatally injured.

VH-SPA sustained damage to its left wing in the collision but remained flyable and the pilot was uninjured. The pilot circled the airfield to direct people towards the accident site. The aircraft landed on runway 11 without further incident.

Context

Pilot information

Both pilots involved in the collision were experienced fixed-wing pilots. They were both qualified for their respective roles, and both held valid class 2 aviation medical certificates.

The pilot of VH-EDJ held an Air Transport Pilot Licence (aeroplane) and was a grade 2 flight instructor with various instrument ratings.

The pilot of VH-SPA held a Private Pilot Licence (aeroplane) and held endorsements for glider operations and glider towing operations. The pilot was also an accredited flight instructor/examiner for both gliders and tow aircraft.

The pilot of VH-EVR was a student pilot conducting flying training at Caboolture. The pilot had completed 2 solo navigation flights and was preparing to conduct a third flight at the time of the occurrence.

Aircraft information

VH-EDJ

The Jabiru J430 is an amateur-built high-wing light aircraft. It has a single Jabiru 3300 reciprocating engine and a ground-adjustable fiberglass propeller. VH-EDJ was constructed primarily by the pilot in Australia in 2019, and first registered on 19 February 2019, with 283.7 hours total time in service.

VH-SPA

The Piper PA-25-235 Pawnee B is a low-wing single-engine aircraft. It is powered by a Textron Lycoming O-540 reciprocating engine, with a fixed-pitch aluminium propeller. VH-SPA was manufactured in 1969, and first registered in Australia on 23 August, 1974. It had 10,181 hours total time in service, and had been operating as a tow aircraft at Caboolture airfield since January 1997.

Wreckage and impact information

The ATSB conducted an on-site examination of the aircraft wreckage. The right wing of VH-EDJ collided with the ground forward of the threshold marking for runway 24. The nose then struck the ground, and the aircraft tumbled to a stop 45 metres from the initial impact point (Figure 2).

Figure 2: Wreckage and impact point of VH-EDJ

Figure 2: Wreckage and impact point of VH-EDJ

Source: ATSB

VH-EDJ came to rest right-side down, and was later disturbed by first responders attempting to reach the pilot and passenger. First responders reported both the pilot and passenger were wearing seatbelts. The right wing tip and a section of the right aileron was recovered near the intersection of runway 11/06, near the point at which the two aircraft collided.

VH-SPA sustained impact damage to the leading edge of its left wing as a result of the collision (Figure 3).

Figure 3: Damage to VH-SPA following the collision with VH-EDJ

Figure 3: Damage to VH-SPA following the collision with VH-EDJ

Source: ATSB

Airfield information and procedures

Caboolture Airfield was an aircraft landing area,[2] located about 3.5 km east of Caboolture, Queensland. It had an elevation of 40 ft above mean sea level, and two intersecting runways with magnetic orientations of 114°/294° (runway 11/29), and 065°/245° (runway 06/24). Their lengths were 1,129 m and 820 m respectively. Both runways were unsealed grass, except for a sealed portion at the beginning of runway 11. Trees about 10–14 m high between the intersecting runways obscured parts of adjacent runways (Figure 4).

Figure 4: Obscured parts of the adjacent runway from the thresholds of runways 11 (orange) and 06 (yellow)

Figure 4: Obscured parts of the adjacent runway from the thresholds of runways 11 (orange) and 06 (yellow)

Source: Google Earth, annotated by the ATSB

The carriage and use of a radio was required by the aerodrome operator for all aircraft operating at Caboolture Airfield. As a non-controlled aerodrome, separation was maintained by ‘alerted see‑and-avoid’ principles guided by Civil Aviation Safety Authority (CASA) advisory circulars AC 91-10 Operations in the vicinity of non-controlled aerodromes and AC 91-14 Pilots’ responsibility for collision avoidance. These stated that pilots should broadcast position and intention so that nearby traffic would have an awareness of the aircraft and be able to plan accordingly.

Recorded data

VH-SPA carried no flight data recording devices, and no automatic dependent surveillance broadcast (ADS-B) transponder. An ADS-B transmitter was fitted to VH-EDJ but no data on the accident flight was available. Two data recording devices were recovered from VH-EDJ for later examination.

Video footage of the accident was recovered from a closed-circuit television system installed at Caboolture Airfield.

Common traffic advisory frequency (CTAF) broadcasts were not recorded at the airfield. Caloundra Airport, 32 km north-north-east of Caboolture, operated on the same CTAF frequency and recorded all transmissions received there. Due to distance and line-of-sight limitations, radio calls on or near the ground at Caboolture were generally not received, but some calls from within the Caboolture Airfield circuit were received and recorded. Recordings of radio calls made by the pilot of VH-SPA indicated that the aircraft’s radio was functional for transmitting and receiving.

Further investigation

To date, the ATSB has:

  • examined both aircraft and the accident site
  • recovered aircraft components, including the radio from VH-EDJ (which was damaged in the accident), and other items for further examination
  • interviewed relevant parties, including eyewitnesses and witnesses with access to common traffic advisory frequency (CTAF) transmissions
  • collected aircraft, pilot, aerodrome and operator documentation
  • analysed video recordings and CTAF transmissions.

The investigation is continuing and will include:

  • examination of aircraft components and other items recovered from the accident site
  • further review of aircraft, pilot, aerodrome and operator documentation
  • further analysis of video recordings and CTAF transmissions
  • analysis of aircraft flight paths, with particular attention given to potential visibility restrictions
  • a review of similar occurrences
  • analysis of procedures at non-controlled aerodromes with intersecting runways
  • interviews with other pilots familiar with Caboolture Airfield.

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]     Runway numbers represent the magnetic heading closest to the runway orientation (e.g. runway 11 is oriented 114º magnetic).

[2]     An aircraft landing area is an aerodrome that has not been certified by CASA. These aerodromes are non-controlled, unregulated facilities. It is the responsibility of pilots and operators to determine whether these aerodromes are suitable for use.

Aircraft Details
Departure point
Caboolture ALA
Destination
Dirranbandi Airport
Model
Jabiru J430
Serial number
827
Sector
Piston
Registration
VH-EDJ
Operation type
General Aviation
Damage
Destroyed
Manufacturer
Amateur built aircraft
Aircraft Details
Departure point
Caboolture ALA
Destination
Caboolture ALA
Model
PA-25-235
Serial number
25-5008
Sector
Piston
Registration
VH-SPA
Operation type
Part 91 General operating and flight rules
Damage
Substantial
Manufacturer
Piper Aircraft Corp
Aircraft Operator
Caboolture Gliding Club
Aircraft Details
Departure point
Caboolture ALA
Destination
Caboolture ALA
Model
172R
Serial number
17280252
Sector
Piston
Registration
VH-EVR
Operation type
Flying Training
Manufacturer
Cessna Aircraft Company
Aircraft Operator
Airwork Aviation