An instrument landing system (ILS) 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 meteorological conditions (IMC), such as low ceilings or reduced visibility due to fog, rain, or blowing snow.
Instrument approach procedure charts (or approach plates) are published for each ILS approach, providing pilots with the needed information to fly an ILS approach during instrument flight rules (IFR) operations, including the radio frequencies used by the ILS components or navaids and the minimum visibility requirements prescribed for the specific approach.
Radio-navigation aids must keep a certain degree of accuracy (set by international standards of CAST/ICAO); to assure this is the case, flight inspection organizations periodically check critical parameters with properly equipped aircraft to calibrate and certify ILS precision.
Read more about Instrument Landing System: Principle of Operation, Use, ILS Categories, Limitations and Alternatives, History, Future, Frequency List
Famous quotes containing the words instrument, landing and/or system:
“Whilst Marx turned the Hegelian dialectic outwards, making it an instrument with which he could interpret the facts of history and so arrive at an objective science which insists on the translation of theory into action, Kierkegaard, on the other hand, turned the same instruments inwards, for the examination of his own soul or psychology, arriving at a subjective philosophy which involved him in the deepest pessimism and despair of action.”
—Sir Herbert Read (1893–1968)
“I foresee the time when the painter will paint that scene, no longer going to Rome for a subject; the poet will sing it; the historian record it; and, with the Landing of the Pilgrims and the Declaration of Independence, it will be the ornament of some future national gallery, when at least the present form of slavery shall be no more here. We shall then be at liberty to weep for Captain Brown. Then, and not till then, we will take our revenge.”
—Henry David Thoreau (1817–1862)
“The individual protests against the world, but he doesn’t get beyond protest, he is just a single protester. When he wants to be more than that, he has to counter power with power, he has to oppose the system with another system.”
—Friedrich Dürrenmatt (1921–1990)