The Australian Transport Safety Bureau (ATSB) suspects the pilot of a TB20 Trinidad became disoriented in cloud before colliding with terrain near Mackay in 2023.
In the investigation report released today, the ATSB found the pilot of VH-JTY descended into cloud 35 nm west of Mackay, QLD, in October 2023 on a private flight from Montpelier to Palmyra. Tracking information showed the aircraft turned steeply to the left and descended before pitching up, then entering a second descending steep turn to the right.
The aircraft then collided with Bull Mountain at a steep downward pitch with high forward speed. Two people on board the aircraft died in the crash.
“The instability of the flight path with excessive rates of descent and climb are markers of spatial disorientation where pilots are aware of a departure from controlled flight and attempt to correct the unusual attitude,” ATSB Director Transport Safety Dr Stuart Godley said.
“It is very likely the pilot had entered weather conditions not suitable for visual navigation, leading to spatial disorientation and the descent into mountainous terrain.”
Investigators found the pilot was not instrument rated and had a history of using the autopilot to fly through cloud if necessary.
Due to the limited evidence available to the ATSB, investigators weren't able to determine why the autopilot–a King KAP 150–disconnected, either due to pilot action or technical failure, prior to the aircraft descending rapidly.
“For a non-instrument rated pilot, even with basic attitude instrument flying proficiency, maintaining control of an aircraft in IMC by reference to the primary flight instruments alone entails a very high workload that can result in narrowing of attention and loss of situational awareness,” Godley said.
“While autopilot can be used to reduce workload, it is not infallible and should not be relied upon or used by VFR pilots as a risk mitigator to decide to fly into unsuitable conditions.”
The full report is on the ATSB website.