Before taking off, even if passengers have already boarded the airplane that will take them to their destination, there are a number of operations required for a successful flight.
It often happens that the plane just arrived from another destination. At that point, pilots are the ones who immediately receive instructions from the ground controllers – to which embarkation gate go ahead to a specific terminal.
Also, pilots must park in a perfect mood the airplane, the wheel on the right has a grounded position so that passengers can climb in optimal conditions. Subsequently, the engines stop and activate the Auxiliary Power Unit (APU) with which the ground air conditioning system can be activated.
Now some of the passengers are waiting for the landing, while others are still in the airport for boarding. Stairs will be attached to the airplane door to lower passengers, over time, on the other hand, the luggage is unloaded. They will be placed in a trolley that will carry them on a conveyor belt inside the plane.
New luggage will be picked up and loaded. Meanwhile, the passengers who landed take the bus that leads them to the airport entrance where they can pick up their luggage. On the other hand, the bus with the new passengers is on the bus from the airport to the plane.
At the same time, part of the crew deals with cleaning the cabin and loading with food and drink. Check on board and all controls to work. The toilet tanks are emptied and refilled all the time, and the aircraft is fueled if necessary. In principle, over 20 people handle all of these operations, especially as everything is counter-timed.
Once all these tasks have been accomplished, the new group of passengers can board aboard and the plane can take off to the proposed destination.