The objective of this book is to bring each reader to the systems of an A320 to study their normal operation and to understand what is happening in the airplane while it is operated by the pilots from the cockpit. We will begin with the generalities of the airplane, then we will continue to advance through their systems, starting from the simplest to finishing in the most complex. It should be noted that in this manual we will cover all the contents of the normal operation of each system, omitting the resolution of faults or the abnormal operation of each one of them. Divided into four chapters, we will cover all the systems that make up the most sold and flown commercial aircraft in recent years.