Why are we still using ILS?

[frogone]

Quite simply, the old adage:

'If it ain't broke, don't fix it'



IR

[Kliperoo]

Other technology aside, I would have thought the simple answer would have been that ILS is protected by ICAO until 2010 as the primary Precision Approach system (ref. TC AIM COM 3.13)

[beamer]

Don't tell the CAA - they still swear by NDB/ADF !

[twistedenginestarter]

Will GPS continue to be free of charge once the US military have no more use of it ?

It looks like they will be using for approaches themselves although I'm not sure whether it's ordinary GPS or one of their special military channels:
The Joint Precision Approach and Landing System (JPALS) is a key component enabling U.S. military forces to be highly mobile and capable of "rapid response" on a global basis to a wide range of military scenarios. Similar in concept to the civilian Local Area Augmentation System (LAAS), JPALS will be based on differential Global Positioning System (GPS) technology, and will consist of modular avionics and ground/shipboard components to provide a range of landing minima and system configurations. Aircraft will receive ranging and navigation data from the satellite constellation and differential ranging data or corrections from a ground/shipboard station via a data link

[411A]

411A , I seem to remember that the principles of ILS were German, by Lorenz if my memory is good, and was used during WWII by them.

You could well be right, ATC Watcher, however Sperry/Pigman held the US patents for ILS.
Reed Pigman especially was involved with many navigation systems and was also (later on) the CEO of American Flyers Airline.
He met a rather unfortunate end however when the Lockheed L188 he was commanding crashed just adjacent to Ardmore Oklahoma, many years ago.
Circling with a ceiling of 200 feet doesn't work all that well...

[PBL]

According to some official U.S. history, namely
http://www.centennialofflight.gov/es..._nav/POL14.htm
http://naco.faa.gov/index.asp?xml=fioo/fihistory
work began on an ILS in 1928, and the first successful landing using an ILS was conducted by a certain Lt. James Doolittle on Sep. 23rd, 1929. That makes the idea contemporary with the Radio Range.

It took a little while to refine. The first "modern VHF ILS" installation was demonstrated to the U.S. military and airline industry in 1940 (second ref above).

My copy of Kayton and Fried is at the Uni, so I don't know what they say.

PBL