 Other major improvements include a five-blade Spheriflex composite main rotor combined with the familiar shrouded Fenestron tail rotor to reduce vibration levels significantly.The EC155 B is powered by two 635 kW (851 shp) Turbomeca Arriel 2C1 turboshaft engines mounted over the luggage hold, which feature a dual-channel Full Authority Digital Engine Control (FADEC) system.The EC155 B1 features uprated 697 kW (935 shp) Arriel 2C2s.