1.4 USE OF FLIGHT MANAGEMENT SYSTEM (FMS)/
AREA NAVIGATION (RNAV) EQUIPMENT
1.4.1 Where FMS/RNAV equipment is available, it may be used to fly conventional procedures provided:
a) the procedure is monitored using the basic display normally associated with that procedure; and
b) the tolerances for flight using raw data on the basic display are complied with.
from here
http://dcaa.trafikstyrelsen.dk:8000/...05th%20ed..pdf
PANS-OPS, you'll have to check for the latest version as I don't have time.