What happened
On April 22, 2018, at approximately 20:35 UTC, a Piper PA-28-151, registration LV-FKO, was conducting a recreational local flight over Península Valdés, Argentina. The aircraft had departed from El Tehuelche Airport in Puerto Madryn roughly 15 minutes prior to the incident. While cruising at 4,000 feet under visual flight conditions, an uncontrollable fire erupted inside the cabin.
In response to the spreading flames, the pilot performed an emergency descent and executed a controlled landing on unprepared terrain consisting of pebbles and shrubs at Estancia La Adela, near Puerto Pirámides. Although the aircraft landed without a major impact, the fire intensified, leading to the total destruction of the airframe and engine. Tragically, the fire resulted in 3 fatalities among the passengers, while the pilot survived with injuries.
The investigation
The Argentine investigation established that the fire originated in the battery compartment located beneath the rear passenger seat. Technical analysis of the battery terminals revealed evidence of melting and solidification, indicating that an electrical arc occurred. Investigators determined that the battery installed in the aircraft was not an aviation-grade component and did not match the maintenance records, which specified a Gill G-35 battery.
Evidence suggests that the electrical discharge was caused by contact between the battery terminals and the seat springs. This contact was likely facilitated because the installed battery was taller than the authorized model, reducing the clearance between the battery and the seat. Furthermore, the investigation found that the cabin's interior upholstery had been recently refurbished using materials that lacked flame-retardant properties, which allowed the fire to spread rapidly through the cabin.
Findings
- The aircraft was not configured in accordance with current safety standards, as it contained a non-aviation grade battery.
- The use of non-flame-retardant materials for the cabin upholstery contributed to the rapid spread of the fire.
- An electrical arc occurred at the battery terminals due to physical contact with seat components.
- The lack of a protective thermoplastic cover for the battery prevented the containment of the initial electrical event.
Safety action
Following the investigation, recommendations were directed to the National Civil Aviation Administration (ANAC) to improve the oversight of cabin interior modifications and to ensure the traceability of flame-retardant treatments. Additionally, the authorities emphasized the need to promote the importance of using only certified aviation-grade materials during maintenance and modification tasks among aircraft owners and workshops.