Did you know commercial jets usually have a "secret" engine hidden in the tail? 🤫 It is called the Auxiliary Power Unit (APU). This small turbine engine plays a massive role when the aircraft is parked on the ground. Since the main engines are usually turned off at the gate, the APU kicks in to generate electricity for the aircraft's systems. Most importantly, it powers the Air Conditioning (AC) to keep the cabin cool before departure. It is the unsung hero of ground operations! ❄️ 👉 Follow us