This system is used in Switzerland, within the approach sectors from Zurich and Geneva for IFR flights. It is not used in the Enroute Control. The system detects only the proximity of an aircraft with the ground, but not a "closing rate" like a normal GPWS does ! <img border="0" title="" alt="[Confused]" src="confused.gif" /> . .. .The system is divided in several aeras. Each of this area has a defined altitude, which is usely lower than the MSA and the minimum radar vectoring altitude. The remaining terrain clearance will be between 700 and 1000 ft. It works also on an ILS until about 2 miles final. If an aircraft goes below those defined altitudes, an oral warning "ALTITUDE" will be triggered and the altitude part of the radar-blip of the aircraft will change to RED. <img border="0" title="" alt="[Mad]" src="mad.gif" /> . .The controller has to acknoledge this alarm. The altitude will remain RED until the aircraft is above the minima's. <img border="0" title="" alt="[Smile]" src="smile.gif" /> . .. .It is, of course, possible to disactivate the system in case someone is doing a visual approach. <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" />