Enhanced vision system

An Enhanced flight vision system (EFVS, sometimes EVS) is an airborne system which provides an image of the scene and displays it to the pilot, in order to provide an image in which the scene and objects in it can be better detected. In other words, an EFVS is a system which provides the pilot with an image which is better than unaided human vision. An EFVS includes imaging sensors (one or many) such as a color camera, infrared camera or radar, and typically a display for the pilot, which can be a head-mounted display or head-up display. An EFVS may be combined with a synthetic vision system to create a combined vision system.

An EFVS can be mounted on military or civilian aircraft, fixed wing (airplane) or rotary wing (helicopter). The image must be displayed to the pilot conformal to the scene, i.e. the pilot must see the artificially displayed elements in exact positions relative to the real world. Usually along with the enhanced image, the systrem will display visual cues such as a horizon bar and runway location.

Night vision devices for military personnel have been operational since the time of World War II. Their use has been adopted also by military pilots, mainly in rotary-wing aircraft (helicopters). The use of such devices has been suggested for use by commercial pilots since the 1970s, but it was not until 1999 that the first commercial, FAA certified system, was airborne. Still, the pilot could not use the system to lower an aircraft below the required natural vision limit.

Gulfstream in 2001 became the first civilian aircraft manufacturer to develop and earn certification on its aircraft for EVS produced by Elbit's Kollsman. The FAA permitted the use of the EVS to descend down to 100 feet above Touch-down zone, if no other restrictions apply. It was not clear at the time whether an EFVS could be used for descending below that height. The situation was amended in 2004 with corrections to FAA FAR 91.175. This marks the first time an EFVS gave a concrete commercial advantage over unaided vision.

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