What happened
On September 5, 2003, a single-occupant Aerostar (Raven) RX-7 hot air balloon, registration N3574M, was participating in the Spanish National Championship of Aerostation near Renedo de Esgueva, Valladolid. The flight was part of a competition stage where pilots aimed for specific coordinates.
Approximately 10 minutes into the flight, the pilot noticed an irregularity with the pilot light. A flame appeared around the burner area because a propane hose had become loose. In an attempt to manage the situation, the pilot shut off both fuel lines; however, the heat and fuel pressure caused one of the hoses to detach completely from the burner. The pilot attempted to grab the loose hose and move it outside the basket while using an onboard fire extinguisher to combat the flames. During this process, the pilot sustained serious burns to her face, neck, and arms. Unable to maintain altitude or steer to a clear landing zone, the balloon descended into a tree and a cottage, causing damage to the aircraft and third-party property.
The investigation
Investigators examined the wreckage and the burner assembly. They found that the fitting for the main fuel line could be easily loosened by hand, indicating it had not been properly secured with a wrench during preflight assembly. While the pilot carried a wrench in her pocket, the investigation concluded that the fittings were not adequately tightened.
The investigation also reviewed the aircraft's maintenance history and the pilot's equipment. It was noted that the pilot was not wearing protective gloves during the flight, which contributed to the severity of her injuries. Additionally, the investigation identified that the aircraft was carrying aluminum propane bottles that had been subject to a manufacturer service bulletin due to explosion risks in high-heat scenarios.