VNAV
Encyclopedia
In aviation
, Vertical NAVigation is an autopilot
function which directs the vertical movement of an aircraft (i.e. gains or losses in its altitude
) while cruising
and/or on approach to landing.
If used while cruising, VNAV causes an aircraft to climb or descend according to a pre-programmed FMS (flight management system)
flight plan
. The first aircraft to feature this use were Boeing 757
and 767
airliners in 1982.
When used on approach to landing, VNAV follows an ILS (instrument landing system)
glideslope toward the runway. This process is known as "autoland
" and has been available since the mid-twentieth century.
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, Vertical NAVigation is an autopilot
Autopilot
An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. An autopilot can refer specifically to aircraft, self-steering gear for boats, or auto guidance of space craft and missiles...
function which directs the vertical movement of an aircraft (i.e. gains or losses in its altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
) while cruising
Cruise (flight)
Cruise is the level portion of aircraft travel where flight is most fuel efficient. It occurs between ascent and descent phases and is usually the majority of a journey. Technically, cruising consists of heading changes only at a constant airspeed and altitude...
and/or on approach to landing.
If used while cruising, VNAV causes an aircraft to climb or descend according to a pre-programmed FMS (flight management system)
Flight management system
A flight management system is a fundamental part of a modern airliner's avionics. An FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew to the point that modern aircraft no longer carry flight engineers or navigators. A...
flight plan
Flight plan
Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority prior to departure...
. The first aircraft to feature this use were Boeing 757
Boeing 757
The Boeing 757 is a mid-size, narrow-body twin-engine jet airliner manufactured by Boeing Commercial Airplanes. Passenger versions of the twinjet have a capacity of 186 to 289 persons and a maximum range of , depending on variant and cabin configuration...
and 767
Boeing 767
The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...
airliners in 1982.
When used on approach to landing, VNAV follows an ILS (instrument landing system)
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...
glideslope toward the runway. This process is known as "autoland
Autoland
In aviation, autoland describes a system that fully automates the landing phase of an aircraft's flight, with the human crew merely supervising the process.-Description:...
" and has been available since the mid-twentieth century.