Airbus Helicopters, in partnership with the French Civil Aviation Authority DGAC, has started flight testing an engine backup system (EBS) onboard its Flightlab. The project opens the way to a hybrid propulsion system for light helicopters while delivering flight safety improvements. The campaign's main target is to enhance flight safety of single engine operations by providing emergency electrical power in case of a turbine failure.

During testing the Flightlab was equipped with a 100kW electric motor connected to the main gearbox, which should provide electrical power for 30 seconds in the event of engine failure, giving the pilot extra time to react and maintain rotor speed. The engine back-up system contributes to a safer and smoother autorotation manoeuvre to the ground. The flight tests include the simulation of engine failure in different flight conditions, including takeoff and landing procedures and the corresponding limitations.

The flight testing aims to demonstrate a performance increase, in addition to evaluating the safety margins, due to the electrical power input. The potential performance increase of maximum takeoff weight is to compensate for the mass of the EBS system itself and also providing the helicopter with an additional payload.

“The engine back-up system is a good example of the incremental approach in our innovation strategy,” states Tomasz Krysinski, Head of Research and Innovation at Airbus Helicopters. “The current EBS flights are a very important first step towards a future hybrid propulsion system and we already foresee a second phase of the project with more energy and power on board. We are looking at developing a fully parallel hybrid propulsion system mixing thermal and electrical energy together with the aim of optimising fuel consumption and enabling hybrid single engine flights over urban areas.”