A four-blade version of the A160 flew in November 2002 using a Subaru four-cylinder engine, and later a six-cylinder piston engine. Frontier Systems was awarded a contract for four more A160s in October 2003. A total of three vehicles were produced by Frontier Systems. Vehicles 1 and 3 were lost in crashes. Frontier began a planned KW600 Diesel engine for the vehicle, but never completed it. A Diesel engine would have nearly doubled the vehicle endurance due to lower fuel consumption.