What happened
On October 13, 2024, at approximately 10:30 local time, a privately owned BRISTELL RG, registration EC-XPO, was performing a short coastal flight departing from the Prat de la Plana airfield in Moià, Barcelona. Shortly after takeoff from runway 19, the pilot heard an unusual noise from the engine and the cockpit's carbon monoxide alarm activated at 3,000 feet.
In response to the alarm, the pilot performed a 180-degree turn to return to the airfield for an emergency landing on runway 01. During the approach, the pilot reduced power to manage the descent. However, as the aircraft approached a group of trees near the runway threshold, the pilot attempted to increase power to clear the obstacles, but found the throttle lever was loose and unresponsive. The aircraft's speed dropped to approximately 48 knots, and the pilot was unable to maintain altitude. The nose gear struck the trees, causing the aircraft to pitch forward and impact the ground heavily. The pilot sustained serious injuries and required surgical intervention.
The investigation
The CIAIAC investigation focused on the mechanical state of the engine and the throttle control system. Investigators examined the engine control unit (ECU) data, which showed that engine parameters remained constant and the engine did not stall until the impact.
Physical inspection of the aircraft revealed significant damage to the fuselage, engine mount, and engine block. Crucially, investigators examined the throttle control cable and its housing. The inspection found that the outer sheath of the throttle cable showed clear signs of heat damage. The nylon sleeve inside the assembly was deformed and blackened due to excessive heat exposure within the engine compartment.
Findings
- The primary cause of the accident was the loss of control of the aircraft during an emergency landing due to a failure of the throttle control.
- High temperatures in the engine compartment, likely caused by exhaust leaks, damaged the throttle cable's outer sheath.
- This heat-induced damage caused the steel cable to become stuck within its nylon sleeve, preventing the pilot from increasing engine power to clear trees during the approach.
- The pilot's decision to return directly to the airfield without performing a standard traffic pattern may have contributed to the inability to clear the obstacles.
- The aircraft's engine mount and engine block were destroyed upon impact with the terrain.