What is the difference between an ILS X rwy 35L and ILS Y rwy 35L

[Antonio30 0]

In my hometown Milan,Italy I see rwy designations for the Malpensa airport such asILS X rwy 35LILS Y rwy 35LILS Z rwy 35LWhat does the X,Y,Z indicate ?GraciaAntonio Vernas

[downscc 1,327]

Not sure about your country, but the US uses the different XYZ tags for similar approaches that have differences due to equipment or certification. The bottom line is that there are differences in the minimums. It is more common to see RNAV (GPS) X and Y designations where one includes vertical navigation capability, but I have seen these lables used for ILS in a few locations here. Gotta look closely at the required equipment and minimums parts of the chart to see the difference.

[Check_Airman 3]

Dan mentioned what those designations mean in the US. Perhaps if you could post the plates online, we could help you figure it out.paul

[oe_tsa 1]

Hello,I can second what Dan said and it's the same here in austria. The different designators mean different minima, sometimes different procedures, etc...I have an example from my home airport LOWW - ILS Approach Rwy 11:ILS X: http://charts.vacc-a...11_06062011.pdfILS Y: http://charts.vacc-a...11_06062011.pdfIf you look at the charts, you will notice that ILS X has a lot lower minima than ILS Y AND also quite a different missed approach procedure:

• with ILS X you would climb and fly straight ahead to VOR BRK crossing Rwy 16/34,
• with ILS Y and the much higher mimima and the different missed approach procedure (right turn to VOR SNU) you avoid coming near the airport and Rwy 16/34 and don't have to cross it at all.

In this example ILS Y will apparently be used when approaches to Rwy 11 AND approaches/departures from Rwy 16 are simultaneously used. As the missed approach procedures for Rwy 16 command a straight ahead climb, even two missed approaches can take place at the same time.I hope this example helps understanding the different designators.Greetings,Thomas