Accident Overview
On 24 January 2024, a Cessna 172S, registered VH-CPQ, was being used for pilot training by AltoCap Flight School at Camden Airport, New South Wales. The student had completed several circuits with an instructor on board and was deemed competent for a first solo flight. At 1504:39 local time, the student was cleared for take-off. Towards the end of the downwind leg, the aircraft rapidly descended and collided with terrain, resulting in fatal injuries to the pilot and destruction of the aircraft.
Investigation Findings
The Australian Transport Safety Bureau (ATSB) found that the aircraft departed level flight before turning onto base and collided steeply with terrain. There was no evidence of any in-flight failure of the airframe structure or flight control system. The engine appeared to have been producing significant power at impact.
Weather conditions were clear with low winds. No pre-accident defects were identified on the airframe or engine, and there was no evidence of a bird or drone strike. The aircraft's weight and balance were within limits. The stall speed was estimated at about 48 knots, and the airspeed at the start of the descent was estimated at 78 knots, inconsistent with a low-speed stall.
The aircraft was not fitted with an electric elevator trim system. The Honeywell KAP 140 autopilot only provided heading hold and had no control over elevators, elevator trim, or rudder. Inadvertent activation would have rolled wings level without pitch effect.
The ATSB considered the possibility of a stall above stall speed (accelerated stall), but the flight path data showed no significant altitude or direction change consistent with such a maneuver.
Discussion of Possible Causes
The ATSB examined potential reasons for the sustained nose-down control input. An inadvertent forward seat slide was considered, but impact damage indicated the seat was not in its forwardmost position at impact, and no longitudinal deceleration preceded the descent to cause such a slide. A rearward slide was deemed unlikely and would not produce a nose-down input.
A control jam was also considered. Most forms of flight control failure would not result in a rapid, steep, smooth descent. The exceptions would be elevator trim failure in a nose-down position or a stuck elevator, but no evidence of such failure was found.
In the absence of an identified mechanical problem, and in combination with the aircraft manufacturer's assessment, the ATSB determined that continual nose-down control input was almost certainly applied throughout the increasingly steep, accelerating descent. The reason for the continued control input could not be determined.