  We present preliminary results of the non-perturbative computation of the
RI-MOM renormalisation constants in a mass-independent scheme for the action
with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our
project requires dedicated gauge ensembles with four degenerate sea quark
flavours at three lattice spacings and at several values of the standard and
twisted quark mass parameters. The RI-MOM renormalisation constants are
obtained from appropriate O(a) improved estimators extrapolated to the chiral
limit.
