Abstract: Combined bleed air and hot section component cooling air systems for gas turbine engines and methods of operating combined bleed air and hot section component cooling air systems are disclosed. An example system may include a high-pressure bleed air line receiving high-pressure bleed air; a precooler receiving at least some of the high-pressure bleed air and discharging cooled high-pressure bleed air; a pressure regulator receiving at least some of the cooled high-pressure bleed air and discharging pressure-regulated cooled bleed air to a pneumatic systems supply line; and/or a hot section component cooling air line connected upstream of the first pressure regulator and configured to convey at least some of the cooled high-pressure bleed air to a hot section component for use as hot section component cooling air.

Abstract: Combined bleed air and hot section component cooling air systems for gas turbine engines and methods of operating combined bleed air and hot section component cooling air systems are disclosed. An example system may include a high-pressure bleed air line receiving high-pressure bleed air; a precooler receiving at least some of the high-pressure bleed air and discharging cooled high-pressure bleed air; a pressure regulator receiving at least some of the cooled high-pressure bleed air and discharging pressure-regulated cooled bleed air to a pneumatic systems supply line; and/or a hot section component cooling air line connected upstream of the first pressure regulator and configured to convey at least some of the cooled high-pressure bleed air to a hot section component for use as hot section component cooling air.

Abstract: A precooler for cooling compressor bleed air for an environmental control system includes a heat exchanger in fluid communication with a source of cooling air and operable for cooling the bleed air. A variable bypass valve between a bleed air source and environmental control system is operable for bypassing at least a portion of the compressor bleed air around the heat exchanger. The cooling air may be a portion of fan air modulated by a variable fan air valve. The bleed air source may be selectable between the low pressure bleed air source and a high pressure bleed air source. One method includes flowing the compressor bleed air from a single low pressure source only and increasing thrust sufficiently to meet a minimum level of pressure of the bleed air during one engine out aircraft operating condition during approach or loitering.

Abstract: A precooler for cooling compressor bleed air for an environmental control system includes a heat exchanger in fluid communication with a source of cooling air and operable for cooling the bleed air. A variable bypass valve between a bleed air source and environmental control system is operable for bypassing at least a portion of the compressor bleed air around the heat exchanger. The cooling air may be a portion of fan air modulated by a variable fan air valve. The bleed air source may be selectable between the low pressure bleed air source and a high pressure bleed air source. One method includes flowing the compressor bleed air from a single low pressure source only and increasing thrust sufficiently to meet a minimum level of pressure of the bleed air during one engine out aircraft operating condition during approach or loitering.