A system comprising: an engine for an aircraft, and an engine compressor bleed system of the engine, the engine compressor bleed system comprising: a plurality of compressor pressure ports (204, 206, 208) configured to supply bleed air to satisfy a cooling load for at least a first stage of a flight profile of an aircraft, wherein a first compressor pressure port of the plurality of compressor pressure ports is positioned in the compressor of the engine to provide a first bleed air flow having a first pressure at least equal to a cabin pressure of an aircraft during a climb or a cruise flight condition of the aircraft and a first temperature that does not exceed a predetermined threshold, wherein the first stage of the flight profile is the climb or cruise flight condition; a precooler, wherein the first compressor pressure port is configured to direct an entirety of the first bleed air flow along a bypass pathway bypassing the precooler, wherein a second compressor pressure port of the plurality of compressor pressure ports is configured to direct a second bleed air flow through the precooler, the second bleed air flow having a second pressure greater than the first pressure, and wherein a third compressor pressure port of the plurality of compressor pressure ports is configured to direct a third bleed air flow from the third compressor pressure port through the precooler; a precooler outlet conduit downstream of the precooler configured to mix the entirety of the first bleed air flow and the second bleed air flow upstream of an air to air heat exchanger of an environmental control system; wherein the first compressor pressure port is fluidly coupled to the precooler outlet conduit such that air from the low pressure port bypasses the precooler and is supplied directly to the environmental control system via the bypass pathway; and the second and third compressor pressure ports (206, 204) are fluidly coupled to the precooler such that bleed air drawn through either port (206, 204) first passes through the precooler before being provided to the environmental control system; wherein the engine includes at least two selected from the following: a high pressure spool, an intermediate pressure spool, and a low pressure spool; and wherein the first compressor pressure port is configured to bleed air from the high pressure spool; and wherein the first pressure port is a low pressure port relative to the remainder of the plurality of compressor pressure ports. a plurality of compressor pressure ports (204, 206, 208) configured to supply bleed air to satisfy a cooling load for at least a first stage of a flight profile of an aircraft, wherein a first compressor pressure port of the plurality of compressor pressure ports is positioned in the compressor of the engine to provide a first bleed air flow having a first pressure at least equal to a cabin pressure of an aircraft during a climb or a cruise flight condition of the aircraft and a first temperature that does not exceed a predetermined threshold, wherein the first stage of the flight profile is the climb or cruise flight condition; a precooler, wherein the first compressor pressure port is configured to direct an entirety of the first bleed air flow along a bypass pathway bypassing the precooler, wherein a second compressor pressure port of the plurality of compressor pressure ports is configured to direct a second bleed air flow through the precooler, the second bleed air flow having a second pressure greater than the first pressure, and wherein a third compressor pressure port of the plurality of compressor pressure ports is configured to direct a third bleed air flow from the third compressor pressure port through the precooler; a precooler outlet conduit downstream of the precooler configured to mix the entirety of the first bleed air flow and the second bleed air flow upstream of an air to air heat exchanger of an environmental control system; wherein the first compressor pressure port is fluidly coupled to the precooler outlet conduit such that air from the low pressure port bypasses the precooler and is supplied directly to the environmental control system via the bypass pathway; and the second and third compressor pressure ports (206, 204) are fluidly coupled to the precooler such that bleed air drawn through either port (206, 204) first passes through the precooler before being provided to the environmental control system; wherein the engine includes at least two selected from the following: a high pressure spool, an intermediate pressure spool, and a low pressure spool; and wherein the first compressor pressure port is configured to bleed air from the high pressure spool; and wherein the first pressure port is a low pressure port relative to the remainder of the plurality of compressor pressure ports.