The Japan Air Self-Defence Force (JASDF) wants to purchase a helmet-mounted sight to go with the development of its next generation XAAM-5 short-range air-to-air missile (AAM).

Japan has no indigenous programme under way to develop a helmet-mounted display. It is understood that the Japan Defence Agency (JDA) has instead approached several foreign suppliers, including Elbit, GEC-Marconi and Sextant Avionique.

A helmet-cueing system forms an essential part of the JDA's planned development of a high off-boresight missile to replace the JASDF's home-grown Mitsubishi AAM-3. Initial funding for the XAAM-5 programme is included in the JDA Technical Research and Development Institute's fiscal year 1998 budget.

Mitsubishi Electric is leading the development effort, which is scheduled for completion by 2004. XAAM-5 will have an NEC imaging infrared seeker and is likely to be capable of target acquisition at off-boresight angles of greater than 60°.

Compared with the existing AIM-9L-class AAM-3, the new missile will have much higher kinematics and the airframe will also lack the forward cruciform control surfaces.

The AAM-3 is notable for the large dogtooth leading edge on its forward fins. These are thought to be intended to produce turbulent airflow over the fin surface, improving manoeuvrability.

The XAAM-5 design is also understood to include narrow, near frame-length fuselage fins, which are intended to generate lift at high angles of attack. The design, which was recently validated by windtunnel testing, also includes thrust vectoring controls for improved manoeuvrability.

The JASDF is asking for a performance at least broadly comparable with that of the Matra BAe Advanced Short Range Air-to-Air Missile and Rafael Python-4, which it has already looked at.

As with other indigenous aerospace developments, the JDA will probably face political and industrial lobbying from the USA to buy the Raytheon AIM-9X instead.

Washington is already putting pressure on Tokyo to order large numbers of active-guided Raytheon AIM-120 advanced medium-range AAMs in preference to Mitsubishi's own radar-guided XAAM-4 missile.

Source: Flight International