Abstract: An InfraRed Suppression System (IRSS) includes an exhaust manifold and a high aspect ratio exhaust duct along a longitudinal length thereof. The IRSS minimizes impingement of engine exhaust onto adjacent aircraft structure by discharging the flow upwardly and/or outwardly, away from the fuselage at relatively high velocity to reduce fuselage heating due to plume impingement in both hover and forward flight thus minimizing fuselage IR signature contributions. Furthermore, by directing the exhaust stream upward, a direct line of sight to the exhausted IR energy is masked from ground threats. The high aspect ratio exhaust duct and exhaust manifold are also preferably shrouded by an aerodynamic fairing which provides an aerodynamic contour to minimize aerodynamic impact to the aircraft and defines an air-cooled ejector gap to augment airflow to further insulate and obscure the high temperature exhaust gas exhausted through the exhaust duct.