Dassault has selected the Thales TopStart electric starter-generator system for the Falcon 5X. The equipment manufacturer claims the unit reduces weight and improves engine durability. The system marks the first time the Paris-based company has combined electric starting and power generation functions in a single unit for a business jet.

The new system is particularly well suited to the Falcon 5X’s new-generation engine, the Snecma Silvercrest, according to Guy Lefebvre, president of Thales Avionics Electric Systems. “The control laws provide for a harmonious start-up sequence,” he told AIN. The system exchanges data with the engine’s control unit and selects one start-up control law. It factors in outside air temperature and blade tip clearances, among other parameters, to ensure rotation speed and torque increase progressively.

Lefebvre pointed out that new-generation engines have tighter internal clearances and avoiding brutal starts will extend the engine’s service life.

The auxiliary power unit (APU) supplies electric power to both engine starters. The APU itself is fitted with a similar starter, powered by the battery. After the start-up sequence, the starters quickly become generators, thus providing power to the aircraft’s electrical network. Lefebvre predicts that the only difference the crew will notice will be a smoother human-machine interface in Dassault’s installation of its system.

The complete TopStart package will comprise three starter-generators for the main engines and APU, three electronic control units, three transformer rectifier units and one electronic starter converter. The system, which combines two units into one, is more compact and lighter than a conventional pneumatic starter, Lefebvre emphasized. In addition, it increases energy efficiency from 70 to a promised 90 percent.

Lefebvre added that the Thales system will also be more reliable and will require only one maintenance check every five years.