the proposed Aero L-X supersonic fighter development proved to be financially demanding (up to US$2 billion), the less costly L-159 subsonic attack aircraft, derived from the L-39 Albatros, was approved for procurement instead. Conducted between 1994 and 1997, the technical development of the L-159 ALCA in Aero Vodochody consisted primarily of building a single L-159 two-seat prototype, based on the L-59 airframe, and utilizing western engine, avionics and weapon systems, with Rockwell Collins (eventually Boeing) as the avionics integrator. During 1995, the Czech government placed a large order for 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 collaborate with Aero Vodochody in the venture during May 1998. The maiden flight of the first L-159 prototype (5831, "376 white") occurred on 2 August 1997 with a two-seat version. On 18 August 1998, the single-seat L-159A prototype (5832, "356 white") first flew; it was completed to Czech customer specifications. On 10 April 2000, the first delivery of the L-159A took place to the Czech Air Force. Prototype (6073) of the two-seat L-159B variant first flew on 1 June 2002. During October 2004, the Czech government announced that Aero Vodochody was to be privatised, and Boeing decided to withdraw from involvement in both the L-159 and the overall company. During October 2006, Aero Vodochody was sold to Penta Investments. In 2009, Aero Vodochody selected V-Dot Systems (split off from Boeing) as the L-159 avionics integrator. V-Dot will replace the Honeywell multi-function displays (MFD) and upgrade the mission processors to support new functions. On 31 March 2017, following a 13 year stoppage in L-159 production after the delivery of the final Czech Air Force example, Aero Vodochody held a ceremony to mark the resumption of manufacturing; a new-build L-159 destined for the Iraqi Air Force was present. This batch of production aircraft featured several improvements, such as the use of a wet wing and increased endurance; further enhancements were also being worked on at that time. The company reportedly negotiated with Argentina on the topic of