That's not necessarily true, and not true on this approach. Here the GS intercept is outside the FAF. Sometimes they are co-located and sometimes they aren't.
Sorry, I meant to say pilots generally
aren't cleared to intercept the GS
inside the FAF. In this case, the FAF was GS interception at 2300', which, as you point out, is not collocated with the OM (presuming an ILS approach, which really isn't in evidence here, unless I'm mistaken). At the OM, the altitude would have been 2279', and this should have been used by the pilot as a check on his altimeter setting, had he gotten that far. Note that for an ILS approach the FAF
is the GS intercept. The OM is the FAF only for the LOC approach.
So my original contention stands. The pilot would not have been cleared below 2300' until intercepting the GS, which is done
south of the VOR, which Scott was
north of by as much as a mile. The OM was further south yet, though only a little bit. (I'll leave it as an exercise to the reader to calculate the horizontal distance traveled on a glideslope for a 21' vertical loss. It ain't much.)
Rough calculations indicate th me that, at the VOR, approximately 1nm north of the FAF, the glideslope would have been approximately 370' higher, so around 2770. So the pilot of the jet at the VOR should have had an altitude between 2300' and 2770'. Scott, an unspecified distance north of the VOR, was at 2200'.
But remember, it's SEE AND AVOID, even for IFR pilots!
I'll admit, and I suspect Scott may too, that we don't
like getting that close to the jets.
Unfortunately, airspace and C90 controllers in the Chicago area have rather tied our hands if we want to avoid
long detours. They don't know VFR Advisories or VFR Corridors from French Toast. I'm not saying they wouldn't
like to help us (though you'll find plenty here who'll make that claim), but they
do have some
very busy airspace, and VFR advisories are on the
bottom of their priority list! And they, not we, designed the airspace and neglected to put any transitions into it. With much of the airspace to the east of Chicago off-limits to many single-engine drivers because of safety concerns, it really hampers transitions through the area. Note that I'm speaking generally here, not about Scott's flight in particular.