''Visual flight'' is the control and navigation of an aircraft by using the view from the aircraft as the primary reference point. A pilot observes the outside world and uses the flight controls to take the aircraft safely to the place they want to go. The alternative is to fly the aircraft primarily using feedback from onboard instruments such as an artificial horizon and navigation devices.
Except in the simplest aircraft, such as ultralight aircraft, hang gliders or balloons, a pilot almost always makes some reference to instruments to determine their exact speed or altitude. Complex aircraft, such as a military jets or an airliners require more reliance on the instruments.
As well as flying the aircraft, a pilot is expected to avoid other aerial traffic. Looking outside as much as possible and developing a scan pattern that minimizes the amount of time spent "with the head down" is important. In weather considitions with reduced visibility (such as flying inside a cloud), the pilot flies by reference to instruments alone. Air traffic separation is ensured by radar contact with ATC and by appropriate use of air routes and flight plans.
The primary visual reference used is the natural horizon or the ratio of visible sky to ground, when the pilot is looking straight ahead. It is usually easy and intuitive to adapt to variations such as terrain or clouds that mask the appearance of a straight horizon. (en.wikipedia.org)
'''Navegación aérea observada''', o '''vuelo visual''', es la técnica por la cual el piloto, durante el vuelo, estima la posición de la aeronave a partir del reconocimiento visual del terreno, ya sea de instalaciones como de accidentes geográficos. (wikipedia.org)
'''Sichtnavigation''' ist eine Methode sich im Luftraum zu orientieren, welche überwiegend von Piloten kleiner Flugzeuge, die unter Sichtflugbedingungen fliegen, angewendet wird. (wikipedia.org)