Wildfires are an increasingly severe and global threat. Vegetation loss has a long-term effect on ecosystems, with losses causing increased risks of disease and pest infestations, while also contributing to carbon emissions. Aerial firefighting is an essential tool for suppressing and containing wildfires. However, with wildfires becoming more likely and impactful, current firefighting aircraft are unsuitable due to their limited operational capabilities. Rotorcraft do not possess the water capacity or range to effectively combat these fires. On the other hand, fixed-wing aircraft such as the Canadair CL-415 have greater speed, range and capacity, but their firefighting capabilities are limited by their inability to hover. Rotorcraft, however, are capable of Vertical Take-Off and Landing (VTOL), allowing far greater operational flexibility to combat fires. As such, there exists a need for a new aircraft with the water capacity, range, and speed of fixed-wing aircraft, and the VTOL capabilities, adaptability, and precision of rotorcraft.

The FireEagle aims to bridge the gap between modern firefighting rotorcraft and fixed-wing aircraft by combining both of their operational capabilities and performances. This is achieved by carrying 12 000 litres of water while reaching speeds greater than 500 km/h in cruise, with an on-station endurance of 2.5 hours. The FireEagle will have VTOL capabilities and a deployable water snorkel, so it can be refilled from diverse water sources. A modular payload system allows for mission flexibility: by mounting different attachments, operations such as firefighting, cargo transport, law enforcement, passenger transport and military operations can be conducted. Moreover, the integration of a Prognostics and Health Management (PHM) framework quantifies the probability of success of a given mission, allowing operators to reliably estimate the aircraft’s ability to operate in the given mission conditions, while also transitioning towards predictive maintenance.

Reconciling the high payload and cruise speed requirements with the VTOL capability was the greatest challenge faced. Guided by a trade-off between several concepts and inspired by the CH-47, a compound helicopter design approach was chosen, with tandem rotors allowing it to achieve VTOL capabilities while carrying 12 000 litres of water. To ensure the speed requirement is met, forward thrust is provided by two dedicated propellers mounted on the wing tips. In cruise, the wing is optimized to provide 75% of the total lift to exploit its efficiency compared to the rotors at high speed, while the vertical stabilisers are split to allow access to the modular payload attachment system. ensure reliable operations from take-off to landing, a new framework for PHM is proposed. From discussions with industry experts and extensive literature review, a multitude of sensors have been positioned within critical systems such as the engines and rotors. For each type of sensor, a data analytics model is used to predict the remaining useful life of the individual systems, which leads to a mission success rate of the aircraft.