Question

How many ILS systems does an airport require?

(a) 0

(b) 1

(c) Depends upon aircraft size

(d) Depends upon density of traffic on the airspace

I have been asked this question during an interview.

Origin of the question is Instrument Landing Systems in portion Landing Systems & Air-Traffic Management of Avionics

Answer 1

The correct option is (d) Depends upon density of traffic on the airspace

For explanation: High density airports where a lots of planes land and take off typically have more than one runways with multiple ILS systems. Chicago’s O’Hare airport had an ILS installed on 12 runways in 1996.