An A320 ECAM alerted WHEEL N/W STRG FAULT on approach so a go around was executed to comply with the QRH; an emergency was declared; and a normal landing completed on a snowy runway after which the aircraft was towed to the gate.

Narrative

Weather: snow 3/4; visibility 300 overcast. ILS 35; Captain pilot flying. Aircraft configured on speed just out side the outer marker. Right before marker and glide slope intercept; ECAM alerted WHEEL N/W STRG FAULT. [We] briefly discussed options and meaning of ECAM while continuing approach. Told Tower we needed to break off approach and work issue. [We] climbed to 7;000 FT then soon after turned east and climbed to 9;000 FT. Ran WHEEL N/W STRG FAULT check list. No actions available in flight. Discussed issue 'no nose wheel steering.' [We] discussed techniques; outcomes; and reaction to outcomes due to no nose wheel steering on ground in snow and low visibility conditions upon landing. Briefed flight attendants and deadheading crewmembers. [We] attempted to contact Dispatch and Maintenance via ACARS. No reply in time we had decided to get on ground due to deteriorating weather conditions and the possibility of lower CAT approach weather than the aircraft potentially had capability of. [We] briefed new approach [and] ran normal checklist. DECLARED AN EMERGENCY and had the trucks roll with Approach Controller. No nose wheel steering on FAIR braking conditions on runway. [We] informed ATC of potential needs; TOWING. ILS 35 approach normal. Touch down and rollout normal with normal procedure; differential braking until 25 KTS. At approximately 25 KTS tested to steer aircraft with nose wheel steering. NO nose wheel steering available. [We] came to a full stop on centerline using differential braking. Contacted Tower and emergency vehicles; all was fine on and with the aircraft except we could not steer aircraft and needed tow. Shut down engines; coordinated with Ground Operations for tow in; briefed flight attendants and passengers. [We were] towed to gate; discussed event with Maintenance. Maintenance confirmed fault.