An incorrectly installed weather radar contributed to a King Air charter flight entering a thunderstorm west of Toowoomba, Queensland, an ATSB investigation report details.
The aircraft, operated by Austrek Aviation, had departed Toowoomba for an air transport flight to Normanton, Queensland, with a pilot and five passengers on board, on 9 October 2024.
After encountering the storm 30 minutes into the flight, the pilot diverted to Roma, where the aircraft landed safely.
The ATSB investigation found the aircraft's airborne weather radar had been incorrectly installed, reducing its effectiveness at detecting cloud, and resulting in it providing misleading information.
"Although the pilot had identified the weather conditions prior to flight, delayed the initial departure, and consulted with more experienced colleagues, the ineffective radar degraded the pilot's in-flight assessing and planning, and the aircraft entered a thunderstorm," ATSB Director Transport Safety Stuart Macleod said.
The incorrect installation most likely resulted in the radar beam scanning the tops of the clouds rather than the most reflective areas within the storm. In addition, the outside air temperature of -23°C resulted in less reflective precipitation within the clouds.
"It was likely that the weather radar was over-scanning and the returns presented to the pilot would not have indicated where the most active storms were," explained Mr Macleod.
"This likely resulted in the severity of the storms in the area not being visible to the pilot."
While at approximately 26,000 ft, the aircraft entered cloud and began to accumulate ice. The pilot then elected to descend the aircraft. In the increasing turbulence the autopilot disconnected, and the pilot flew the aircraft manually.
"The pilot later reported that between entering cloud at about 1648 and becoming visual at approximately 1705 at 4,000 ft, they encountered turbulence, updrafts, downdrafts and icing, and observed lightning flashes," noted Mr Macleod.
"The pilot's recollection of lightning, turbulence and icing, plus the ADS-B flight data overlaid on ground-based radar imagery are both consistent with the aircraft flying into a thunderstorm."
After landing at Roma, a post flight engineering inspection of the aircraft did not identify any lightning strike damage, however, there was minor damage observed to the leading edges of the wings and the radome.
"This incident highlights how quickly weather conditions can change and that, where possible, remaining visual can provide better identification of the weather," Mr Macleod said.
"Equipment such as a weather radar can provide better situation awareness, but it must be installed correctly, and the pilot must become knowledgeable in its operation before needing to use it."
In response to this incident, Austrek Aviation has rectified the incorrect installation of the weather radar, and improved pilot training in its use.
The operator's flight planning software has also been reviewed to ensure correct parameters, after the ATSB's investigation identified the software used by the pilot before the flight included a final reserve fuel that was less than that defined in the operator's exposition.
Finally, the ATSB report credits the pilot contributing to the safety of the passengers by informing them of possible turbulence prior to the flight, and keeping the seatbelt sign on throughout.
