john (verygom) First Officer

Is it normal in Fs (or for real) for two runways at an airport to have the same ILS/NAV frequency 😕

Jonathan (99jolegg) Chief Captain

I've never noticed in FS that two runways at one airport have the same ILS frequency, and I'm sure it would be a bug if there were. I believe all the ILS frequencies at a real world airport are different. 😉

Steve (megafoot) First Officer

The FAA uses a standard for nav radios that sets a minimum distance between transmitters on the same frequency and that distance is vast. several times the radius that the beacon can be dectected at. You are looking at a glitch. Which airport is it you are referring to?

Guest

Having taken a second look maybe I'm confused 😕 Am I correct in now thinking that if a runway is used in both directions it has the same ILS for each direction [e.g Manchester 6L heading 057 and 24R heading 237 both @ 109.50] and that ATC will indicate the direction? My problem arose with using EFIS which conflicted with ATC

Bindolaf Captain

Runways may have the same ILS frequency for opposite directions. For example LGAV (Athens, Greece) has two runways: 03L/21R and 03R/21L. The ILS for both 03R and 21L (same runway, opposite directions) is 111.100. Course 034 for 03R (identifier is IATR) and 214 for 21L (identifier IEVL). Someone more knowledgeable can correct/fill in the gaps, but that's the only case I can think of for same frequency being used for "two" different ILS (basically same runway, one being a backcourse)

john (verygom) First Officer

- sorry - me above - forgot to log on

Don Wood Guest

The previous posters are correct. A unique ILS freqency would never be used for two different runways in the same proximity. However, the same frequency is often used for landings on either end of the same physical runway. When you make the approach on the ILS end of that runway, it is a precision approach and you use the ILS minimums.

When you make the approach to the other end of that runway, it is a non-precision approach called a back-course approach. It is non-precision because the back-course does not provide reliable indications of your position on the glide slope. Also, on a back-course approach, when the course-line needle moves from the center line, you turn toward the needle instead of away from it to regain the center-line. You also use non-ILS minimums.