AIRCRAFT HYBRID COOLING SYSTEM

An environmental control system, ECS, (20) for use with a gas turbine engine has an air cycle system, ACS, (22) and a vapor cycle system, VCS, (24). The VCS (24) has along a vapor compression flowpath (630): a VCS compressor (30); a heat donor leg (33) of a VCS condenser (32); an expansion device (36); and a heat receiving leg (39) of a VCS evaporator (38). The ACS (22) has along a bleed flowpath (600): a bleed air inlet (100); a primary heat exchanger (102); an ACS compressor (106); a secondary heat exchanger (108); a turbine (112) coupled to the ACS compressor (106) to drive the ACS compressor (106); a heat donor leg (40) of the VCS evaporator (38); a water collector (118); and a heat receiving leg (121) of the VCS condenser (32).