I agree with most previous posts. The advantage in terms of noise abatement of a 4 degree glideslope would be minimal - and might lead to an increase in go-arounds.
Berlin/Tempelhof (THF/EDDI) has non-standard slopes too;
ILS 27L: 3.50 degrees / 6.1%, DH (Cat B a/c) 265', RVR 650m
NDB 27L: 3.50 degrees / 6.1%, MDH (Cat B a/c) 757', RVR 1,400m
VOR 27R: 3.70 degrees / 6.5%, MDH (Cat B a/c) 677', RVR 3,000m
The high DH/MDH/RVR values reflect the higher RoD. Runway 27L is 1,840m, 27R is 2,094m.
No big deal on an ATR72, although medium/heavy jets (737-300/700, A320 etc.) have been known to land there sometimes
http://www.airliners.net/photo/LTU--...ext_id=1263834
Cheers
