Development was kept under stricter secrecy than the Chengdu J-10 fighter. Nearly ¥ 4 billion was initially invested and the WZ-1- became one of the most important programs begun in the 9th 5-yr plan. Publicly the 602nd Research Institute was assigned as the chief designer to promote the illusion of it being a domestically developed attack helicopter, while Harbin Aircraft Manufacturing Corporation (HAMC) of China Aviation Industry Corporation II (AVIC II) was assigned as the primary manufacturer. Nearly four dozen other establishments participated in the program. In the summer of 1999, AVIC II began to use a CAMC Z-8 to test newly developed Z-10 sub-systems. In autumn of the same year, a Harbin Z-9 was added to the test aircraft inventory. These tests concentrated on sub-systems such as the fire-control systems, HOTAS controls and navigation systems. South Africa provided limited help in the area of flight stability based on experience from designing the Denel Rooivalk. South African assistance ceased in 2001. In 2000, the Chinese again attempted to obtain a Russian attack helicopter, but the deal for the Kamov Ka-50 fell apart just as the Mil Mi-28 deal several years earlier. The repeated failures in obtaining foreign attack helicopters reinforced feelings that China had no choice but to ignore foreign options and develop its own such aircraft and work on the Z-10 accelerated. In the same year, HAMC transferred most of its production responsibilities to CAIC of AVIC II. The official reason given was excessive workload; HAMC was busy producing the HC120 and Harbin Z-9, as well as other fixed-wing aircraft such as the Harbin Y-12, and thus was stretched to the limit. However, many speculated that HAMC was not performing well enough due to rigid and ineffective Soviet-style management practices, believed to have caused the company to go into debt. Although HAMC was in the process of reform, which finally succeeded, the government and military were weary and impatient. The SH-5 factory had become very profitable after its successful restructuring and reform, but it had to get out of the aircraft manufacturing business for good, manufacturing pressurized tanks and other specialized containers. It was decided that the Z-10 program was too important to be run by HAMC, so a more stable contractor was sought and CAIC was selected. HAMC still retained responsibility for production of certain sub-systems and components, for which it could utilize experience gained from manufacturing parts for foreign helicopters and fixed-wing aircraft such as the Embraer ERJ 145 family.