This paper presents a comprehensive analysis of the reliability of a tethered high-altitude telecommunication platform through the application of risk tree analysis. It explores the potential risks involved in utilizing this platform to provide telecommunication coverage in a specific area. The study employs a well-known methodology to construct a risk tree, allowing for the calculation of key characteristics, including the distribution of occurrence times for significant risk events, along with their mean and variance, and the potential damages associated with them. Additionally, this technique identifies the most critical risk pathways and assesses the sensitivity of risk characteristics to the shape of initial data, thereby offering valuable insights for effective risk management and mitigation.