How is the ADI Loc and G/s display different from HSI other than having a big long CDI instead of a diamond? The ADI ILS info is raw data isn't it?
The only reason for for HSI ILS or expanded ILS would be for when you need the ILS DME and you can't get it on the normal DME readouts (which I dont think the 737 has an issue with) - but other Boeings do (ie 767 can only get ILS DME readout when expanded ILS is used)
Also whilst maps can be quite a long way off in the terminal area, the most accurate map updates come of ILS DME dont they - so by the time you commence an ILS they should be pretty good.
I am still surprised that Boeing/FAA or the relevant authorities haven't mandated that all large commercial jets have Map updating via GPS yet.
Last edited by blueloo; 5th Feb 2009 at 03:59.