Piloted Evaluation of a Fault Recovery System for an Aircraft with Distributed Electric Propulsion

Electrified aircraft powertrains contain multiple tightly coupled subsystems, making them much more
complex than traditional aircraft propulsion systems, both in terms of integration and control.
Electrification enables aircraft to have multiple distributed thrust-producing fans that the flight control
system can utilize for enhanced maneuverability, further increasing the control complexity. The SUbsonic
Single Aft eNgine (SUSAN) Electrofan is a NASA concept aircraft that leverages this technology.
SUSAN is a series/parallel partial hybrid electric single-aisle transport aircraft that takes advantage of its
electrified powertrain to provide fuel burn and emissions benefits when compared to the state-of-the-art.
Achieving these benefits requires an appropriately designed control architecture that coordinates the
various powertrain and flight control subsystems. As such, the SUSAN aircraft is designed with a high
level of automation, allowing it to properly manage coupled subsystems and react rapidly to failures and
anomalies. To do this effectively, algorithms that perform component health management, fault detection,
isolation, and accommodation, and continuous optimization, must be developed, tested, validated, and
implemented. This paper describes a piloted evaluation of such an algorithm in scenarios with multiple
fan failures, performed in a flight simulator, demonstrating failure recovery and continued safe operation
up to the limits of the powertrain. These scenarios are subsequently related to certification requirements.