The PBS APU SPARK40 is PBS's new generation auxiliary power unit, capable of supplying twice as much AC power to the aircraft onboard systems as its predecessor, and simultaneously compressed air in order to start the main engine or feed the environmental control system.
PBS APU SPARK40 represents the new generation of the successful APU SAFIR 5K/G MI, of which more than 1,200 units already operate worldwide.
Significant changes have been made to individual subsystems and parts to improve overall reliability and operating envelope. Specifically, completely new combustion chamber was designed to improve fuel burning and optimize starting in higher altitudes, and a new control unit was developed to allow non-operating altitude up to 8,000 m AMSL.
The fuel system was remade to decrease the risk of spontaneous ignition, the return fuel line to the airframe fuel system was cancelled. Also, fire resistant shielding of attachment points and fireproof insulation of cables were added. The combustion chamber housing and other connecting surfaces are now made of stainless-steel.