I've seen the false glideslopes but never actually captured one. As you are no doubt aware, they can exist in multiples of the glideslope angle, depending on how many false lobes are 'powerful' enough to be detected by your ILS receiver. So, with a 3 deg G/S you may see a false G/S at 6 deg, 9 deg etc, although I've only ever experienced the 6 deg variety.
If, as in your Turkish scenario, you will be approaching the G/S from above the only thing you can do is to ensure it's the correct path by doing the 3 times table. If you're on the G/S at 20nm and 12000' you know you're on the false G/S. I add this only by way of additional information, rather than trying to 'teach' you something you undoubtedly already know.
False G/S and an early capture of the altitude when in FLCH (Open Des or whatever it's called
) and then having to quickly reduce the MCP altitude so you can keep the descent going to capture the G/S from above certainly make for 'interesting' approaches. Sometimes these things can't be helped, especially with hills around. Now add in a 'foreign' accent or two and up goes the workload.
You would think those chaps and chapesses, with big brains, who design these things could put in an aircraft filter of some kind to stop the receiver 'seeing' the false G/S. They will, of course, always exist at the transmitter but I'm quite sure a simple 3 times table machine could be added to the aircraft. Yes, I know it would have to adjust to allow for other G/S angles but certainly not beyond the wit of man, especially as the G/S angle is written on the Legs page (I assume Jambes page on the 'Bus) .
Edited to add: DOH! Note to self: don't post at the same time as other people are adding proper stuff
