Ducted-fan tail-sitter unmanned aerial vehicles (UAVs) provide versatility and unique benefits. attracting significant attention in various applications. This study focuses on developing a safe reinforcement learning method for back-transition control between level flight mode and hover mode for ducted-fan tail-sitter UAVs. Our method enables transition control with a minimal altitude... https://www.petitmorpho.com/product-category/bucket-wringers-combos/