Conducted between the years 1994 and 1997, the technical development of L-159 ALCA in Aero Vodochody consisted primarily of building one L-159 two-seat prototype based on the L-59 airframe utilizing western engine, avionics and weapon systems, with Rockwell Collins (eventually Boeing) as the avionics integrator. In 1995, the Czech government ordered a fleet of 72 L-159A single-seat aircraft at a cost around 50 billion CZK. The contract was signed on 4 July 1997. The number of aircraft to be delivered was based upon the size of the Czech Air Force at that time, taking into account the necessity to replace MiG-23BN and Su-22 fighter-bombers and Su-25 attack aircraft. Due to the cost of the project, the Czech government decided that a strategic partner, the Boeing Company, would be invited to join with the Aero Vodochody in the venture in May 1998. However, in October 2004, Boeing withdrew from the company and the government announced that the Aero Vodochody was to be privatised. In October 2006, it was sold to Penta Investments.