The Pratt & Whitney APS2300 APU was designed for the rigorous utilization of 60- to 110-passenger regional jet aircraft, namely the Embraer 170/195-series aircraft. The APS2300 APU is now installed in Embraer's fleet of E170/175/190/195 regional jets as well as Embraer's Lineage 1000 business jets. The APS2300 APU is an integral bleed, constant speed, continuous cycle gas turbine engine that incorporates a single-stage centrifugal compressor, a reverse flow annular combustor, and a two-stage axial turbine.
The APS2600 APU is the latest generation regional aircraft APU system available today. Derived from the APS2300, it has been designed to match today's regional market requirements. The APS2600 has been selected to be installed on Comac's ARJ21, Mitsubishi Aircraft Corporation's MRJ and Embraer's E-Jet E2.