Air traffic's rapid expansion necessitates aircraft reconfiguring to mitigate greenhouse gas emissions. Hydrogen propulsion presents a promising alternative to reduce aviation's environmental impact, yet it introduces numerous new challenges, particularly in the design of novel system architectures. One promising solution is the hydrogen fuel cell (FC), which can generate electricity without CO2 emissions, with water as its unique byproduct. A versatile mathematical model is essential to analyze the behaviour and performance of these innovative devices during the early stages of aircraft design. This model must interact seamlessly with all Balance of Plant (BoP) components - devices facilitating the fuel cell's operation.