What happened
On January 29, 2021, a private pilot operating an Avio Design Adler ultralight motor vehicle (ULM) departed from Punta de Piedates, Quintero, with one passenger on board. While flying southbound along the coastline at an altitude of approximately 150 meters, the aircraft experienced a sudden loss of engine power near Los Lilenes Beach in the commune of Concón.
In an attempt to manage the power loss, the pilot repeatedly applied the throttle, but the engine failed to recover. The pilot initiated an emergency landing on a paved area near the shore, during which the aircraft struck a two-meter-high perimeter fence. Following the impact, the aircraft plunged into the sea, coming to rest approximately 35 meters from the shoreline. The pilot escaped without injury, while the passenger sustained minor injuries.
The investigation
DGAC Chile investigators examined the wreckage and the aircraft's operational history. The investigation focused on the engine's performance and the maintenance records of the aircraft. Physical inspection of the engine's ignition system revealed that the spark plugs were fouled with fuel residue.
Furthermore, the investigation looked into the aircraft's regulatory status and maintenance logs. It was discovered that the aircraft was not registered in the DGAC's specific control registry for ultralight motor vehicles. Additionally, the operator lacked any documented maintenance history or chronological logs of work performed on the aircraft, making it impossible to verify its airworthiness prior to the flight.
Findings
- The primary cause of the accident was a partial loss of engine power at a low altitude, which led to the collision with the fence and subsequent impact with the sea.
- The spark plugs were found to be fouled, which disrupted the ignition system and caused irregular engine operation.
- The pilot's repeated attempts to accelerate the engine during the power loss contributed to an excess of fuel in the combustion chambers, further exacerbating the fouled condition of the plugs.
- The aircraft was not officially incorporated into the DGAC's ULM registry.
- There was a lack of maintenance documentation to ensure the aircraft was in optimal condition for flight.
- The fuel tank was found to be contaminated with seawater.