muc_maintenance on Instagram: "An Air Start Unit (ASU) is ground support equipment used to supply an aircraft with external pneumatic power for engine starting and maintenance purposes. It provides compressed air to the aircraft’s pneumatic start system when the APU or onboard bleed air sources are unavailable or not used. An ASU essentially operates like a small jet engine that generate the required air pressure and mass flow. When connected to the aircraft, the ASU delivers compressed air to t