KJ-200 (Y-8 'Balance Beam') Airborne Early Warning Aircraft
Last updated: 7 September 2007
Shaanxi Aircraft Industry Corporation based at Hanzhong, Shaanxi Province has been developing an airborne early warning (AEW) aircraft under the codename “Project No.5” since the late 1990s. The aircraft was fitted with a linear-shape active electronically steered array (AESA) radar similar to the Swedish Ericsson PS-890 Erieye. An early prototype using the older Y-8F200 airframe made its maiden flight in November 2001. The finalised design known as KJ-200 based on a Y-8F600 airframe first flew in January 2005. However, the only prototype was lost in an air accident on 4 June 2006, putting the whole development project on hold.
In October 2004, a Y-8F200 turboprop transport aircraft was spotted undergoing modification to be fitted with a linear-shape ESA-type airborne early warning radar at Shaanxi. Later it was revealed that the AEW development programme had been in development since the late 1990s, in parallel with the KJ-2000/A-50I AWACS development project at Xi’an Aircraft Corporation (XAC). With the larger, more sophisticated KJ-2000 performing long-range, comprehensive aerial patrolling and control roles, the smaller KJ-200/Y-8 AEW can provide a less expensive platform for tactical AEW and electronic intelligence roles.
‘Balance Beam’ Radar
The AESA radar, nicknamed “Balance Beam” by military observers, appears to be similar in shape and size to the ERIEYE electronically steered phased-array radar introduced by Ericsson Microwave Systems in the late 1990s. Rather than conventional rotodome antenna system, “Balance Beam” has a fixed, dual-sided and electronically scanned antenna mounted on top of the fuselage. This design is particularly suitable for smaller aircraft with limited space and payload. The radar is capable of 360 degree detection and tracking of air (and possibly surface) targets over the horizon.
It is not clear whether the “Balance beam” radar has any connection to the ERIEYE, but much of the ESA radar technology is available in the ‘off-the-shelf’ commercial market nowadays. Should it have similar performance to the Swedish radar, it would provide a maximum search range of 300~450km. As a phased array radar, the system should be capable of ‘spot’ modes as well as wide search modes, enabling it to be used for ground mapping and targeting acquisition.
The finalised variant of the Y-8 ‘Balance Beam’ AEW system is based on the so-called “Category-III Platform” developed by Shaanxi. The Category-I and -II platform refer to the non-pressurised basic variant Y-8 and pressurised Y-8C respectively. The Category-III platform, also known as Y-8F600 in its commercial name, was incorporated with Western avionic technologies and has been in development since the late 1990s with assistance of Ukrainian Antonov Design Bureau.
Improvements on Y-8F600 include:
- Replacing the original three-man cockpit with a more advanced two-man cockpit fitted with modernised avionics including U.S. Honeywell navigation system
- Replacing the original ‘glass-in’ nose with a solid nose to accommodate mission equipment
- Four Pratt and Whitney Canada PW150B turboprop engines with British Dodi R-408 6-blade propellers
- Increased take-off weight and range
- Mission equipment pods on wingtips, vertical fin tip and nose
3 June 2006 Air Crash
Chinese state-run Xinhua News Agency reported on Sunday 4 June that a military plane carrying 40 people was lost in the eastern province of Anhui and no survivor was found. Chinese president Hu Jintao has expressed deep condolences over the loss of lives and ordered a full investigation into the cause of the accident.
Although the report did not reveal the detailed model of the plane or the identities of the people onboard, some Chinese websites later revealed that the plane was in fact the only prototype of KJ-200, which was under system testing when the accident happened. It was understood that most of the 40 people onboard the plane were believed to be PLA personnel and engineers from 14th Institute in Nanjing, which was responsible for the development of the onboard electronic equipment including the “Balance beam” ESA radar.
The accident happened at about 16:00 Beijing Time (08:00 GMT) on Saturday near the village of Yaocun, in Guangde county. The plane's body hit bamboo forest and its tail fell in fields.
The crash is the PLA’s worst accident since 2003. Immediately after the crash, an investigation team headed by the Vice-Chairman of the Central Military Commission (CMC) General Guo Boxiong was sent to the crash site for investigation. A Hong Kong newspaper reported that the crash scene was under heavy security due to its sensitivity.
The accident also caused a major setback in the KJ-200 development project due to the lost of test data and more importantly, the key persons involved in the development project.
KJ-200 Prototypes: The early model of the KJ-200 prototype based on a Y-8F-200 (left); and the later model based on the Y-8F-600 (Source: Chinese Internet)