Si Fly Flight 3275 were found in good condition. Analysis from the crash site concluded that the plane struck tree tops first before impacting terrain. The first impact occurred 15 metres from the top of a ridge, in a rocky mid-mountain area. During the impact, the fuselage and wing disintegrated, the fuel ignited, and an explosion occurred. The French BEA then collected weather data prior to the crash. From Slovenia to Greece and from Italy to Bulgaria, the winds at altitude were very weak from the north. They were sufficient to create a foehn effect under the mountain winds that left the whole coast
Weather window than 72 hours can be defined as weather-limited operations. These operations can be planned independently of statistical data and based only on weather forecasts. For weather-limited operations, critical factors such as forces, movements and acceleration shall be calculated in a rather worse weather condition (design criterion) than the weather in which it is planned to perform the operation (operational criterion). This is due to the unreliability of weather forecasts. The longer the planned operation lasts, the greater the difference between the operational criterion and the design criterion. The relationship between the operational criterion and the design criterion is defined as