Rockwell Collins has announced the completion of the initial design phase of its Pro Line 21 Communication Navigation Surveillance (CNS) sensors. The first production prototype models of the NAV-4000, RIU-4000 and VHF-4000 have been assembled. Current system testing will produce flight-worthy hardware for aircraft testing this autumn, Rockwell Collins says. The DME-4000 prototypes are also scheduled for completion this autumn. TSO approval for the NAV, RIU and VHF is slated for late 2001.